Adaptive decision-making under conditions of uncertainty: the case of farming in the Volta delta, Ghana
Sarku, Rebecca ; Dewulf, Art ; Slobbe, Erik van; Termeer, Katrien ; Kranjac-Berisavljevic, Gordana - \ 2020
Journal of integrative Environmental Sciences 17 (2020)1. - ISSN 1943-815X - p. 1 - 33.
Ada East District - Adaptive decision-making - deltas - farming - uncertainty - weather conditions
Farming in Ghana’s Volta delta is increasingly affected by variability in rainfall conditions and changes in land-use patterns. Under such socio-ecological conditions, little is known about farmers’ decision-making in response to uncertainties in uncertain rainfall conditions. To fill this gap and add to the literature on adaptive decision-making, we addressed the central question: what are the existing patterns of farming decision-making under uncertain rainfall conditions, and which decision-making strategies are adaptive? We developed an adaptive decision-making framework to investigate the behavior of farmers under variable rainfall conditions in Ghana’s Volta delta in the Ada East District. We conducted 5 interviews with agricultural extension agents, 44 in-depth interviews and 4 focus group discussion with farmers. Subsequently, we interviewed a sub-selection of 32 farmers. Findings of the study shows that farmers carry out different decision-making patterns in response to the variable rainfall conditions. We distinguished six strategies: three based on flexibility and three based on robustness. Flexible adaptive decision-making strategies are switching dates for sowing seeds through wait-and-see or delay strategy, muddling through the farming season with the application of various options and alternative irrigation strategies. Robust adaptive decision-making strategies are portfolio strategy of transplanting seedlings in batches, selection of robust (hardy) crops, and intercropping or diversification. Based on how farmers select strategies in response to uncertainty in rainfall conditions, we argue that some decision-making strategies are more adaptive than others. Findings of this study are relevant for the design and implementation of climate related agricultural projects.
Evaluation of Multicriteria Decision Analysis Algorithms in Food Safety: A Case Study on Emerging Zoonoses Prioritization
Garre, Alberto ; Boué, Geraldine ; Fernández, Pablo S. ; Membré, Jeanne Marie ; Egea, Jose A. - \ 2020
Risk Analysis 40 (2020)2. - ISSN 0272-4332 - p. 336 - 351.
Food safety management - MCDA - prioritization - risk ranking - uncertainty
Decision making in food safety is a complex process that involves several criteria of different nature like the expected reduction in the number of illnesses, the potential economic or health-related cost, or even the environmental impact of a given policy or intervention. Several multicriteria decision analysis (MCDA) algorithms are currently used, mostly individually, in food safety to rank different options in a multifactorial environment. However, the selection of the MCDA algorithm is a decision problem on its own because different methods calculate different rankings. The aim of this study was to compare the impact of different uncertainty sources on the rankings of MCDA problems in the context of food safety. For that purpose, a previously published data set on emerging zoonoses in the Netherlands was used to compare different MCDA algorithms: MMOORA, TOPSIS, VIKOR, WASPAS, and ELECTRE III. The rankings were calculated with and without considering uncertainty (using fuzzy sets), to assess the importance of this factor. The rankings obtained differed between algorithms, emphasizing that the selection of the MCDA method had a relevant impact in the rankings. Furthermore, considering uncertainty in the ranking had a high influence on the results. Both factors were more relevant than the weights associated with each criterion in this case study. A hierarchical clustering method was suggested to aggregate results obtained by the different algorithms. This complementary step seems to be a promising way to decrease extreme difference among algorithms and could provide a strong added value in the decision-making process.
Storage Policies: Stockpiling Versus Immediate Release
Wesseler, Justus - \ 2019
Journal of Agricultural and Food Industrial Organization (2019). - ISSN 2194-5896
food crisis - grain reserves - hoarding - stockpiling - storage - uncertainty
Storage policies are used in many countries to smooth price volatility and thereby support food security. When there is a global decrease in food supply caused by a number of extreme weather effects, food reserves are expected to reduce the potential negative implications for households with low purchasing power. In this paper, the properties of such a stockpiling policy are assessed and compared to a policy with storage but without stockpiling. The results show that a stockholding policy is an expensive strategy that generates economic benefits only in extreme cases.
Robotic-cell scheduling with pick-up constraints and uncertain processing times
Tonke, Daniel ; Grunow, Martin ; Akkerman, Renzo - \ 2019
IISE Transactions 51 (2019)11. - ISSN 2472-5854 - p. 1217 - 1235.
automated manufacturing equipment - cyclic scheduling - optimization - Robotic-cell scheduling - uncertainty
Technological developments have propelled the deployment of robots in many applications, which has led to the trend to integrate an increasing number of uncertain processes into robotic and automated equipment. We contribute to this domain by considering the scheduling of a dual-gripper robotic cell. For systems with one potential bottleneck, we determine conditions under which the widely used swap sequence does not guarantee optimality or even feasibility and prove that optimal schedules can be derived under certain conditions when building on two types of slack we introduce. With the addition of a third type of slack and the concept of fixed partial schedules, we develop an offline-online scheduling approach that, in contrast with previous work, is able to deal with uncertainty in all process steps and robot handling tasks, even under pick-up constraints. The approach can deal with single- or multiple-bottleneck systems, and is the first approach that is not restricted to a single predefined sequence such as the swap sequence. Our approach is well suited for real-world applications, since it generates cyclic schedules and allows integration into commonly-used frameworks for robotic-cell scheduling and control. We demonstrate the applicability of our approach to cluster tools in semiconductor manufacturing, showing that our approach generates feasible results for all tested levels of uncertainty and optimal or near-optimal results for low levels of uncertainty. With additional symmetry-breaking constraints, the model can be efficiently applied to industrial-scale test instances. We show that reducing uncertainty to below 10% of the processing time would yield significantly improved cycle lengths and throughput. We also demonstrate that the widely used swap sequence only finds solutions for less than 1% of the instances when strict pick-up constraints are enforced and processing times are heterogeneous. As our approach finds feasible solutions to all of these instances, it enables the application of robotic cells to a significantly broader application environment.
Dealing with uncertainty in collaborative planning: developing adaptive strategies for the IJsselmeer
Zandvoort, Mark ; Brugge, Rutger van der; Vlist, Maarten J. van der; Brink, Adri van den - \ 2019
Journal of Environmental Planning and Management 62 (2019)2. - ISSN 0964-0568 - p. 248 - 265.
adaptive planning - collaborative water management - flexibility - responsibility - uncertainty
Adaptive strategies to deal with uncertainty in water management are often collaboratively developed. So far, however, little attention has been paid to the influence of collaboration on handling uncertainty through adaptive planning. In this paper, we study how collaboration has influenced the handling of uncertainty through adaptive planning for water management strategies for the IJsselmeer area in the Netherlands. We show how a fixation on certainty, different perspectives among actors and unclear responsibilities between arenas affect the handling of uncertainty, and found that it is adversely affected by collaboration. The use of adaptive planning challenged current water uses and system functions, creating resistance from actors. We conclude that developing a shared problem perception, creating a common understanding of uncertainties and ensuring a clear demarcation between the water system, its societal functions and water usage, are necessary to make adaptive planning successful in handling uncertainty.
Automated body weight prediction of dairy cows using 3-dimensional vision
Song, X. ; Bokkers, E.A.M. ; Tol, P.P.J. van der; Groot Koerkamp, P.W.G. ; Mourik, S. van - \ 2018
Journal of Dairy Science 101 (2018)5. - ISSN 0022-0302 - p. 4448 - 4459.
automation - dairy cattle - morphological trait - three-dimensional vision - uncertainty
The objectives of this study were to quantify the error of body weight prediction using automatically measured morphological traits in a 3-dimensional (3-D) vision system and to assess the influence of various sources of uncertainty on body weight prediction. In this case study, an image acquisition setup was created in a cow selection box equipped with a top-view 3-D camera. Morphological traits of hip height, hip width, and rump length were automatically extracted from the raw 3-D images taken of the rump area of dairy cows (n = 30). These traits combined with days in milk, age, and parity were used in multiple linear regression models to predict body weight. To find the best prediction model, an exhaustive feature selection algorithm was used to build intermediate models (n = 63). Each model was validated by leave-one-out cross-validation, giving the root mean square error and mean absolute percentage error. The model consisting of hip width (measurement variability of 0.006 m), days in milk, and parity was the best model, with the lowest errors of 41.2 kg of root mean square error and 5.2% mean absolute percentage error. Our integrated system, including the image acquisition setup, image analysis, and the best prediction model, predicted the body weights with a performance similar to that achieved using semi-automated or manual methods. Moreover, the variability of our simplified morphological trait measurement showed a negligible contribution to the uncertainty of body weight prediction. We suggest that dairy cow body weight prediction can be improved by incorporating more predictive morphological traits and by improving the prediction model structure.
Navigating amid uncertainty in spatial planning
Zandvoort, Mark ; Vlist, Maarten J. Van der; Klijn, Frans ; Brink, Adri Van den - \ 2018
Planning Theory 17 (2018)1. - ISSN 1473-0952 - p. 96 - 116.
ambiguity - climate change - long-term consequences - moral responsibility - spatial planning - uncertainty
In view of the need to adapt to uncertain climate change through spatial interventions, this article explores how spatial planners might navigate amid uncertainty. To draw out insights for planning, we examine planning frameworks which explicitly recognise uncertainty and uncertainty descriptions from studies in environmental risk and climate uncertainty. We build our case by addressing the implications of different characteristics of uncertainty and describe how planners can handle uncertainty based on the nature, level and location of uncertainty. We argue that a plural–unequivocal characterisation of uncertainty helps planners in their search for adequate and warranted interventions amid uncertainty.
Handling uncertainty through adaptiveness in planning approaches : comparing adaptive delta management and the water diplomacy framework
Zandvoort, M. ; Vlist, M.J. van der; Brink, A. van den - \ 2018
Journal of Environmental Policy and Planning 20 (2018)2. - ISSN 1523-908X - p. 183 - 197.
Adaptiveness - environmental planning - planning approaches - uncertainty - water management
Planners and water managers seek to be adaptive to handle uncertainty through the use of planning approaches. In this paper, we study what type of adaptiveness is proposed and how this may be operationalized in planning approaches to adequately handle different uncertainties. We took a comparative case study approach to study two planning approaches: the water diplomacy framework (WDF) and adaptive delta management (ADM). We found that the approaches differ in their conceptualization of uncertainty and show that different types of adaptiveness are used in the approaches. While WDF builds on collaborative adaptive management as a set of ongoing adjustments and continuous learning to handle uncertainty, ADM deliberately attempts to anticipate future adaptations through a set of tools which allows for seizing opportunities and avoiding lock-in and lock-out mechanisms. We conclude that neither of the approaches is fully able to account for different uncertainties. Both approaches may benefit from specific insights in what uncertainty and adaptiveness entail for the development of water management plans.
Planning amid uncertainty : Adaptiveness for spatial interventions in delta areas
Zandvoort, Mark - \ 2017
Wageningen University. Promotor(en): A. van den Brink, co-promotor(en): M.J. Vlist; F. Klijn. - Wageningen : Wageningen University - ISBN 9789463437158 - 242
physical planning - deltas - climatic change - risk management - uncertainty - ruimtelijke ordening - delta's - klimaatverandering - risicobeheersing - onzekerheid
Planning for delta areas happens amid uncertainty, which may influence the location, type and form of interventions such as infrastructure, spatial strategies and design standards. Interventions, however, may fix the spatial configuration for decades, for which insight in the appropriate use of adaptiveness to account for uncertainty is essential. This thesis explores uncertainty and adaptiveness in spatial planning and studies their expression and empirical manifestation in planning approaches, planning tools and planning processes. Uncertainty’s characteristics are used to distill information about the (in)adequacy of specific interventions and are related to three domains of adaptiveness: adaptive management, adaptive capacity and adaptive planning. The thesis shows that while some uncertainties demand interventions aimed at ensuring the effectiveness of planning while anticipating future change, others require a focus on the planning process by the co-construction of knowledge, deliberating about values and increasing the adaptive capacity of actors and institutions.
Statistical modelling of variability and uncertainty in risk assessment of nanoparticles
Jacobs, R. - \ 2016
Wageningen University. Promotor(en): Cajo ter Braak, co-promotor(en): Hilko van der Voet. - Wageningen : Wageningen University - ISBN 9789462578197 - 205
modeling - statistics - particles - risk assessment - uncertainty - uncertainty analysis - nanotechnology - probabilistic models - modelleren - statistiek - deeltjes - risicoschatting - onzekerheid - onzekerheidsanalyse - nanotechnologie - waarschijnlijkheidsmodellen
Engineered nanoparticles (ENPs) are used everywhere and have large technological and economic potential. Like all novel materials, however, ENPs have no history of safe use. Insight into risks of nanotechnology and the use of nanoparticles is an essential condition for the societal acceptance and safe use of nanotechnology.
Risk assessment of ENPs has been hampered by lack of knowledge about ENPs, their environmental fate, toxicity, testing considerations, characterisation of nanoparticles and human and environmental exposures and routes. This lack of knowledge results in uncertainty in the risk assessment. Moreover, due to the novelty of nanotechnology, risk assessors are often confronted with small samples of data on which to perform a risk assessment. Dealing with this uncertainty and the small sample sizes are main challenges when it comes to risk assessment of ENPs. The objectives of this thesis are (i) to perform a transparent risk assessment of nanoparticles in the face of large uncertainty in such a way that it can guide future research to reduce the uncertainty and (ii) to evaluate empirical and parametric methods to estimate the risk probability in the case of small sample sizes.
To address the first objective, I adapted an existing Integrated Probabilistic Risk Assessment (IPRA) method for use in nanoparticle risk assessment. In IPRA, statistical distributions and bootstrap methods are used to quantify uncertainty and variability in the risk assessment in a two-dimensional Monte Carlo algorithm. This method was applied in a human health (nanosilica in food) and an environmental (nanoTiO2 in water) risk context. I showed that IPRA leads to a more transparent risk assessment and can direct further environmental and toxicological research to the areas in which it is most needed.
For the second objective, I addressed the problem of small sample size of the critical effect concentration (CEC) in the estimation of R = P(ExpC > CEC), where ExpC is the exposure concentration. First I assumed normality and investigated various parametric and non-parametric estimators. I found that, compared to the non-parametric estimators, the parametric estimators enable us to better estimate and bound the risk when sample sizes and/or small risks are small. Moreover, the Bayesian estimator outperformed the maximum likelihood estimators in terms of coverage and interval lengths. Second, I relaxed the normality assumption for the tails of the exposure and effect distributions. I developed a mixture model to estimate the risk, R = P(ExpC > CEC), with the assumption of a normal distribution for the bulk data and generalised Pareto distributions for the tails. A sensitivity analysis showed significant influence of the tail heaviness on the risk probability, R, especially for low risks.
In conclusion, to really be able to focus the research into the risks of ENPs to the most needed areas, probabilistic methods as used and developed in this thesis need to be implemented on a larger scale. With these methods, it is possible to identify the greatest sources of uncertainty. Based on such identification, research can be focused on those areas that need it most, thereby making large leaps in reducing the uncertainty that is currently hampering risk assessment of ENPs.
Effect of spatial sampling from European flux towers for estimating carbon and water fluxes with artificial neural networks
Papale, Dario ; Black, T.A. ; Carvalhais, Nuno ; Cescatti, Alessandro ; Chen, Jiquan ; Jung, Martin ; Kiely, Gerard ; Lasslop, Gitta ; Mahecha, Miguel D. ; Margolis, Hank ; Merbold, Lutz ; Montagnani, Leonardo ; Moors, Eddy ; Olesen, J.E. ; Reichstein, Markus ; Tramontana, Gianluca ; Gorsel, Eva Van; Wohlfahrt, Georg ; Ráduly, Botond - \ 2015
Journal of Geophysical Research: Biogeosciences 120 (2015)10. - ISSN 2169-8953 - p. 1941 - 1957.
artificial neural networks - gross primary production - latent heat - representativeness - uncertainty - upscaling
Empirical modeling approaches are frequently used to upscale local eddy covariance observations of carbon, water, and energy fluxes to regional and global scales. The predictive capacity of such models largely depends on the data used for parameterization and identification of input-output relationships, while prediction for conditions outside the training domain is generally uncertain. In this work, artificial neural networks (ANNs) were used for the prediction of gross primary production (GPP) and latent heat flux (LE) on local and European scales with the aim to assess the portion of uncertainties in extrapolation due to sample selection. ANNs were found to be a useful tool for GPP and LE prediction, in particular for extrapolation in time (mean absolute error MAE for GPP between 0.53 and 1.56 gC m-2 d-1). Extrapolation in space in similar climatic and vegetation conditions also gave good results (GPP MAE 0.7-1.41 gC m-2 d-1), while extrapolation in areas with different seasonal cycles and controlling factors (e.g., the tropical regions) showed noticeably higher errors (GPP MAE 0.8-2.09 gC m-2 d-1). The distribution and the number of sites used for ANN training had a remarkable effect on prediction uncertainty in both, regional GPP and LE budgets and their interannual variability. Results obtained show that for ANN upscaling for continents with relatively small networks of sites, the error due to the sampling can be large and needs to be considered and quantified. The analysis of the spatial variability of the uncertainty helped to identify the meteorological drivers driving the uncertainty. Key Points Uncertainty due to spatial sampling is evaluated using ANNs and FLUXNET data GPP and LE budgets and IAV are analyzed with different site networks The uncertainty in upscaling due to spatial sampling is highly heterogeneous
Propagation of positional error in 3D GIS : estimation of the solar irradiation of building roofs
Biljecki, Filip ; Heuvelink, Gerard B.M. ; Ledoux, Hugo ; Stoter, Jantien - \ 2015
International Journal of Geographical Information Science 29 (2015)12. - ISSN 1365-8816 - p. 2269 - 2294.
3D GIS - CityGML - error propagation - photovoltaic potential - uncertainty
While error propagation in GIS is a topic that has received a lot of attention, it has not been researched with 3D GIS data. We extend error propagation to 3D city models using a Monte Carlo simulation on a use case of annual solar irradiation estimation of building rooftops for assessing the efficiency of installing solar panels. Besides investigating the extension of the theory of error propagation in GIS from 2D to 3D, this paper presents the following contributions. We (1) introduce varying XY/Z accuracy levels of the geometry to reflect actual acquisition outcomes; (2) run experiments on multiple accuracy classes (121 in total); (3) implement an uncertainty engine for simulating acquisition positional errors to procedurally modelled (synthetic) buildings; (4) perform the uncertainty propagation analysis on multiple levels of detail (LODs); and (5) implement Solar3Dcity – a CityGML-compliant software for estimating the solar irradiation of roofs, which we use in our experiments. The results show that in the case of the city of Delft in the Netherlands, a 0.3/0.6 m positional uncertainty yields an error of 68 kWh/m2/year (10%) in solar irradiation estimation. Furthermore, the results indicate that the planar and vertical uncertainties have a different influence on the estimations, and that the results are comparable between LODs. In the experiments we use procedural models, implying that analyses are carried out in a controlled environment where results can be validated. Our uncertainty propagation method and the framework are applicable to other 3D GIS operations and/or use cases. We released Solar3Dcity as open-source software to support related research efforts in the future.
Robustness of life cycle assessment results : influence of data variation and modelling choices on results for beverage packaging materials
Harst-Wintraecken, E.J.M. van der - \ 2015
Wageningen University. Promotor(en): Carolien Kroeze, co-promotor(en): Jose Potting. - Wageningen : Wageningen University - ISBN 9789462575097 - 217
levenscyclusanalyse - onzekerheid - modelleren - gegevensanalyse - gegevens verzamelen - afvalverwerking - recycling - milieueffect - life cycle assessment - uncertainty - modeling - data analysis - data collection - waste treatment - recycling - environmental impact
Life cycle assessment (LCA) is a well-established method to evaluate the potential environmental impacts of product and service systems throughout their life cycles. However, it can happen that LCAs for the same product have different and even conflicting outcomes. LCA results need to be robust and trustworthy if they are used in decision making. The aim of this thesis is to evaluate whether the use of multiple data sets and multiple modelling options can increase the robustness of LCA results.
The research starts with identifying reasons for differences in LCA results for the same product. The results of ten existing LCAs for disposable beverage cups are compared to each other as to examine the consistency and robustness of these results. The comparison of the LCAs shows no consistent best or worst cup material. And, the quantitative results for cups made from the same material vary across the LCAs. The evaluation of the methodological choices and the used data sources in each LCA made it possible to identify possible sources for discrepancies in the LCA results. Reasons for differences in results include the variation in the properties of the cups, production processes, waste treatment options, allocation options, choices in system boundaries, impact indicators, and potentially also the data sets that are used.
The thesis next describes a novel method to evaluate and include the influence of data sets and modelling choices on the LCA results. The method is applied in a case study of a disposable polystyrene (PS) beverage cup. The study purposely uses different data sets from various sources for processes with an influential contribution to the LCA results. The study includes two waste treatment options (incineration and recycling). The multiple data sets represent the variability among processes, and the waste treatments represent choices in the modelling of the life cycle of the PS cup.
This variability among the data sets for a similar process is presented as a spread in the results. This spread in the results for the PS cup is caused by differences in the amount and type of the used resources and energy, reported emissions, the origin of the production location, the time period of data collection, or choices in the value of recycled PS. The overlapping spread in the quantitative results for incineration and recycling prevents a decisive conclusion on the preferred waste treatment option for the PS cups.
Next, the method for the use of multiple data sets and modelling choices is applied in a comparative LCA of disposable beverage cups. Three cups are compared: a PS cup, a polylactic acid cup (PLA, a biobased plastic), and a cup made from biopaper (paper with a lining of biobased-plastic). The waste treatment options consist of incineration and recycling for all three cups, and additionally composting and anaerobic digestion for the PLA and biopaper cup.
The use of multiple data sets and modelling choices leads to a considerable spread in the LCA results of the cups. The results do not point to the most environmentally friendly cup material, and neither to a preferred waste treatment option. The results clearly identify composting, however, as the least preferred waste treatment option for the PLA and biopaper cups. The spread in the results makes the comparison of the results for the cups more complex, but the results provides more robust information for decision makers. The combined inclusion of the variability among data sets and the waste treatment options makes the results more trustworthy.
The thesis then dives deeper into the methodological modelling of recycling in LCA and describes and evaluates six widely used recycling modelling methods: three substitution methods, an allocation method, the recycled-content method, and the equal-share method. The main difference among the six methods lies in the assumption on where and how to apply credits for recycled material in the life cycle of the product.
These six methods are applied in two case studies: a disposable PS beverage cup and an aluminium beverage can. The results for the aluminium can clearly depend on the applied recycling modelling method, the recycling rate of the disposed cans, and the amount of recycled material used in the cans. The results for the PS cup additionally depend on the consideration of a drop in the quality of the recycled PS compared to the original PS, and the other waste treatments (landfilling and incineration) for the cups. Including several recycling modelling methods in the LCA incorporates the various underlying modelling philosophies of the methods, and thus makes the results more robust.
This thesis demonstrates the added value of including multiple data sets and multiple modelling choices in LCA. The use of multiple data sets is especially useful if general processes instead of specific processes are used in the representation of the product system. The use of multiple data sets increases the accuracy of the results, and is a supplemental tool next to statistical methods which increase the precision of the results. The simultaneous handling of variability among data sets and modelling choices is hardly performed in LCA. The method presented in this thesis fills this gap and provides a transparent tool to capture these uncertainties. The trade-off between an increase in the robustness of the results and the additional demand for resources (time, money, effort) should be assessed, and depends on the goal of the study and on the intended use of the results. This thesis shows that inclusion of the uncertainty in the LCA results provides the decision maker with valuable information. This thesis thus provides a useful method to increase the robustness of LCA results.
Loss of animal seed dispersal increases extinction risk in a tropical tree species due to pervasive negative density dependence across life stages
Caughlin, T.T. ; Ferguson, J.M. ; Lichstein, J.W. ; Zuidema, P.A. ; Bunyavejchewin, S. ; Levey, D.J. - \ 2015
Proceedings of the Royal Society. B: Biological Sciences 282 (2015)1798. - ISSN 0962-8452 - 9 p.
spatial-patterns - rain-forest - recruitment - consequences - neighborhood - defaunation - habitat - uncertainty - diversity - abundance
Overhunting in tropical forests reduces populations of vertebrate seed dispersers. If reduced seed dispersal has a negative impact on tree population viability, overhunting could lead to altered forest structure and dynamics, including decreased biodiversity. However, empirical data showing decreased animal-dispersed tree abundance in overhunted forests contradict demographic models which predict minimal sensitivity of tree population growth rate to early life stages. One resolution to this discrepancy is that seed dispersal determines spatial aggregation, which could have demographic consequences for all life stages. We tested the impact of dispersal loss on population viability of a tropical tree species, Miliusa horsfieldii, currently dispersed by an intact community of large mammals in a Thai forest. We evaluated the effect of spatial aggregation for all tree life stages, from seeds to adult trees, and constructed simulation models to compare population viability with and without animal-mediated seed dispersal. In simulated populations, disperser loss increased spatial aggregation by fourfold, leading to increased negative density dependence across the life cycle and a 10-fold increase in the probability of extinction. Given that the majority of tree species in tropical forests are animal-dispersed, overhunting will potentially result in forests that are fundamentally different from those existing now.
Exploring climate change impacts and adaptation options for maize production in the Central Rift Valley of Ethiopia using different climate change scenarios and crop models
Kassie, B.T. ; Asseng, S. ; Rotter, R.P. ; Hengsdijk, H. ; Ruane, A.C. ; Ittersum, M.K. van - \ 2015
Climatic Change 129 (2015)1-2. - ISSN 0165-0009 - p. 145 - 158.
africa - yield - agriculture - risks - opportunities - vulnerability - temperatures - uncertainty - variability - projections
Exploring adaptation strategies for different climate change scenarios to support agricultural production and food security is a major concern to vulnerable regions, including Ethiopia. This study assesses the potential impacts of climate change on maize yield and explores specific adaptation options under climate change scenarios for the Central Rift Valley of Ethiopia by mid-century. Impacts and adaptation options were evaluated using three General Circulation Models (GCMs) in combination with two Representative Concentration Pathways (RCPs) and two crop models. Results indicate that maize yield decreases on average by 20 % in 2050s relative to the baseline (1980–2009) due to climate change. A negative impact on yield is very likely, while the extent of impact is more uncertain. The share in uncertainties of impact projections was higher for the three GCMs than it was for the two RCPs and two crop models used in this study. Increasing nitrogen fertilization and use of irrigation were assessed as potentially effective adaptation options, which would offset negative impacts. However, the response of yields to increased fertilizer and irrigation will be less for climate change scenarios than under the baseline. Changes in planting dates also reduced negative impacts, while changing the maturity type of maize cultivars was not effective in most scenarios. The multi-model based analysis allowed estimating climate change impact and adaptation uncertainties, which can provide valuable insights and guidance for adaptation planning.
Effects of technical interventions on flexibility of farming systems in Burkina Faso: Lessons for the design of innovations in West Africa
Andrieu, N. ; Descheemaeker, K.K.E. ; Sanou, T. ; Chia, E. - \ 2015
Agricultural Systems 136 (2015). - ISSN 0308-521X - p. 125 - 137.
crop-livestock systems - sub-saharan africa - climate-change - smallholder farmers - coping strategies - modeling approach - decision-making - constraints - uncertainty - variability
African farmers have always been exposed to climatic and economic variability and have developed a range of coping strategies. Such strategies form part of flexible farm management, an ability that may prove very valuable in the face of future climate change and market dynamics. The generally low productivity of African smallholder farming systems is usually addressed by research and development institutions by a variety of solutions for improving farm performance. However, changes to the system may affect the flexibility of farms and thus their ability to cope with variability. We quantified the added value of being flexible and how this flexibility is affected by technical changes, such as composting and cattle fattening recurrently proposed and promoted by research and development institutions and projects. The study was conducted in two villages of the agro-pastoral area of Burkina Faso, where livestock, cereals and cotton are the main farming activities. A whole-farm simulation model was developed based on information gathered during focus group meetings with farmers and detailed individual monitoring of farmers' practices. The model simulates farmers' decision rules governing the management of the cropping and livestock farm components, as well as crop and livestock production and farm gross margin. Using the existing decision rules, current farm performance was simulated by assessing the cereal balance, the fodder balance and the whole farm gross margin. Then, by comparing the mean and the coefficient of variation of these indicators resulting from (a) the existing decision rules (baseline scenario) and (b) a set of less flexible rules (rigid scenario), the added value of flexible management was revealed. The adoption of composting practices allowed a slight increase in gross margin associated with a decrease in its between-year variability in comparison with conventional practices. Cattle fattening only led to a higher gross margin in the years with high rainfall and low input prices when no management practices were used to limit dependence on external input. This kind of technical change thus requires increased management agility by farmers to deal with climatic and economic variability. We conclude that assessing the impact of technical interventions not only in terms of productivity but also in terms of changes in flexibility is useful for a better understanding of potential adoption of technical changes
Modelling of adaptation to climate change and decision-makers behaviours for the Veluwe forest area in the Netherlands
Yousefpour, R. ; Didion, M.P. ; Jacobsen, J.B. ; Meilby, H. ; Hengeveld, G.M. ; Schelhaas, M. ; Thorsen, B.J. - \ 2015
Forest Policy and Economics 54 (2015). - ISSN 1389-9341 - p. 1 - 10.
management - uncertainty - future - dynamics - germany - belief - face
We apply Bayesian updating theory to model how decision-makers may gradually learn about climate change and make use of this information in making adaptive forest management decisions. We develop modelling steps to i) simulate observation of a multi-dimensional climate system, ii) apply updating rules for beliefs about climate trends, iii) evaluate the performance of adaptive strategies, and iv) apply (i)–(iii) at the local and forest landscape scale to find and compare individual versus joint adaptive decisions. We search for optimal forest management decisions maximizing total biomass production as a measure of management performance. The results illustrate the benefits of updating beliefs to eventually utilize the positive effects and limit negative impacts of climate change on forest biomass production. We find that adaptive decision-making results in switching decisions over time and mostly differ from deterministic decisions ignoring any change in climate. Moreover, we find that the adaptation strategies are indispensable not only because of climate change but also because of the development of the forest biological system over time and the need to revisit decisions.
The interaction triangle as a tool for understanding stakeholder interactions in marine ecosystem based management
Rockmann, C. ; Leeuwen, J. van; Goldsborough, D.G. ; Kraan, M.L. ; Piet, G.J. - \ 2015
Marine Policy 52 (2015). - ISSN 0308-597X - p. 155 - 162.
traditional ecological knowledge - fisheries management - environmental assessment - citizen participation - resource-management - risk communication - uncertainty - governance - framework - science
Expectations about ecosystem based management (EBM) differ due to diverging perspectives about what EBM should be and how it should work. While EBM by its nature requires trade-offs to be made between ecological, economic and social sustainability criteria, the diversity of cross-sectoral perspectives, values, stakes, and the specificity of each individual situation determine the outcome of these trade-offs. The authors strive to raise awareness of the importance of interaction between three stakeholder groups (decision makers, scientists, and other actors) and argue that choosing appropriate degrees of interaction between them in a transparent way can make EBM more effective in terms of the three effectiveness criteria salience, legitimacy, and credibility. This article therefore presents an interaction triangle in which three crucial dimensions of stakeholder interactions are discussed: (A) between decision makers and scientists, who engage in framing to foster salience of scientific input to decision making, (B) between decision makers and other actors, to shape participation processes to foster legitimacy of EBM processes, and (C) between scientists and other actors, who collaborate to foster credibility of knowledge production. Due to the complexity of EBM, there is not one optimal interaction approach; rather, finding the optimal degrees of interaction for each dimension depends on the context in which EBM is implemented, i.e. the EBM objectives, the EBM initiator’s willingness for transparency and interaction, and other context-specific factors, such as resources, trust, and state of knowledge.
Preparing suitable climate scenario data to assess impacts on local food safety
Liu, C. ; Hofstra, N. ; Leemans, R. - \ 2015
Food Research International 68 (2015). - ISSN 0963-9969 - p. 31 - 40.
stochastic weather generator - multimodel ensemble - change projections - model - precipitation - cmip5 - uncertainty - temperature - calibration - growth
Quantification of climate change impacts on food safety requires food safety assessment with different past and future climate scenario data to compare current and future conditions. This study presents a tool to prepare climate and climate change data for local food safety scenario analysis and illustrates how this tool can be used with impact models, such as bacterial and mycotoxin growth and pesticide models. As an example, coarse gridded data from two global climate models (GCMs), HadGEM2-ES and CCSM4, are selected and downscaled using the “Delta method” with quantile-quantile correction for Ukkel, Belgium. Observational daily temperature and precipitation data from 1981 to 2000 are used as a reference for this downscaling. Data are provided for four future representative concentration pathways (RCPs) for the periods 2031–2050 and 2081–2100. These RCPs are radiative forcing scenarios for which future climate conditions are projected. The climate projections for these RCPs show that both temperature and precipitation will increase towards the end of the century in Ukkel. The climate change data are then used with Ratkowsky's bacterial growth model to illustrate how projected climate data can be used for projecting bacterial growth in the future. In this example, the growth rate of Lactobacillus plantarum in Ukkel is projected to increase in the future and the number of days that the bacteria are able to grow is also projected to increase. This example shows that this downscaling method can be applied to assess future food safety. However, we only used two GCMs. To obtain a more realistic uncertainty range, using many different GCM output datasets and working directly with climate modellers is recommended. Our approach helps food safety researchers to perform their own climate change scenario analysis. The actual algorithm of the downscaling method and its detailed manual is available in the supplementary material.
Rescue and renewal of legacy soil resource inventories: A case study of the Limpopo National Park, Mozambique.
Cambule, A. ; Rossiter, D.G. ; Stoorvogel, J.J. ; Smaling, E.M.A. - \ 2015
Catena 125 (2015). - ISSN 0341-8162 - p. 169 - 182.
acid sulfate soils - carbon sequestration - resurrection - uncertainty - gambia - maps
Many areas of developing countries are covered by legacy soil surveys, which, however are hardly used, as they are not available in digital form, used outdated standards, and have unknown quality. There have been very few attempts to rescue and renew these surveys, nor are there established criteria for the evaluation of their quality. We therefore decided to test the applicability of the Cornell Adequacy Criteria (CAC) to assess the quality of several renewed soil surveys in or near the Limpopo National Park, Mozambique (centroid: 23° 18' 55.57¿ S, 31° 55' 16.24¿ E), using the concepts of digital soilmapping. The qualitywas assessed formapping andmonitoring soil organic carbon (SOC), in terms of geodetic control, positional accuracy, map scale, and texture and adequacy of map legend. Metadata was attached to the renewed maps. SOC stocks were estimated qualitatively based on the description of themap units and quantitatively by themeasure-and-multiply approach fromlegacy laboratory measurements. The positional accuracy of georegistrationwas 13 to 45% of the square root of aMinimumLegible Area (MLA). Point and area-class layers could be created with high positional accuracy. However the index of maximumreductionwas high, indicating that the original publication scale could be reduced.Map unit definitions and overall information content of the surveyswere adequate. Integration of remotely sensed optical imagery and digital elevation models could be used to derive accurate contours, against which the positional accuracy of contour-basedmap borderswas assessed. Less than 30% of their lengths were within a distance equal to the square root of MLA. These sources could not be used to evaluate internal map borders, due to the subdued topography and major land-use changes since the original survey. Qualitative estimates of SOC are between lowand medium, consistent with other studies in this area. The CAC proved to be a useful framework for determining the fitness for use of legacy surveys.
Using ex ante output elicitation to model state-contingent technologies
Chambers, R.G. ; Serra, T. ; Stefanou, S.E. - \ 2015
Journal of Productivity Analysis 43 (2015)1. - ISSN 0895-562X - p. 75 - 83.
technical efficiency - cheap talk - cost - distributions - uncertainty - economics
Survey-elicited ex ante outputs are used to develop an empirical representation of an Arrow–Debreu–Savage state-contingent technology in an activity-analysis framework. An empirical test of output-cubicality is developed for that framework. We apply those tools to assess production characteristics of a sample of Catalan farmers specialized in arable crops. Results suggest that imposing nonsubstitutability between ex ante outputs results in no significant loss of information. Even though the technology appears to be output cubical, efficiency measurements based on ex post output observations do not appear to adequately represent the stochastic production environment and apparently yield downward biased technical efficiency measures.
Simulation testing the robustness of stock assessement models to error: some results from the ICES strategic initiative on stock assessment methods
Deroba, J.J. ; Butterworth, D.S. ; Methot, R.D. ; Dickey-Collas, M. ; Miller, D.C.M. ; Hintzen, N.T. - \ 2015
ICES Journal of Marine Science 72 (2015)1. - ISSN 1054-3139 - p. 19 - 30.
at-age analysis - management procedures - natural mortality - performance - uncertainty - fishery
The World Conference on Stock Assessment Methods (July 2013) included a workshop on testing assessment methods through simulations. The exercise was made up of two steps applied to datasets from 14 representative fish stocks from around the world. Step 1 involved applying stock assessments to datasets with varying degrees of effort dedicated to optimizing fit. Step 2 was applied to a subset of the stocks and involved characteristics of given model fits being used to generate pseudo-data with error. These pseudo-data were then provided to assessment modellers and fits to the pseudo-data provided consistency checks within (self-tests) and among (cross-tests) assessment models. Although trends in biomass were often similar across models, the scaling of absolute biomass was not consistent across models. Similar types of models tended to perform similarly (e.g. age based or production models). Self-testing and cross-testing of models are a useful diagnostic approach, and suggested that estimates in the most recent years of time-series were the least robust. Results from the simulation exercise provide a basis for guidance on future large-scale simulation experiments and demonstrate the need for strategic investments in the evaluation and development of stock assessment methods.
Understanding wicked problems and organized irresponsibility: challenges for governing the sustainable intensification of chicken meat production
Bueren, E.M. ; Lammerts Van Bueren, E. ; Zijpp, A.J. van der - \ 2014
Current Opinion in Environmental Sustainability 8 (2014). - ISSN 1877-3435 - p. 1 - 14.
supply chain management - antibiotic-resistance - escherichia-coli - risk - agriculture - uncertainty - future - issues - green
Framing sustainable intensification as a wicked problem reveals how inherent trade-offs and resulting uncertainty and ambiguity block integrated problem solving as promoted by sustainable chain management approaches to production and consumption. The fragmented institutional set-up of the chains avoids that individual actors take responsibility for risks they helped to produce, resulting in ‘organized irresponsibility’. Governance arrangements for sustainable chain management focus especially on reducing risk and uncertainty and ignore trade-offs instead of acknowledging them. For the Dutch chicken meat chain, this article explores how wicked problems and organized irresponsibility influence governance opportunities for sustainable intensification.
Catchments as simple dynamical systems: A case study on methods and data requirements for parameter indentification.
Melsen, L.A. ; Teuling, A.J. ; Berkum, S.W. van; Torfs, P.J.J.F. ; Uijlenhoet, R. - \ 2014
Water Resources Research 50 (2014)7. - ISSN 0043-1397 - p. 5577 - 5596.
rainfall-runoff models - hydrological model - calibration data - ungauged basins - uncertainty
In many rainfall-runoff models, at least some calibration of model parameters has to take place. Especially for ungauged or poorly gauged basins this can be problematic, because there is little or no data available for calibration. A possible solution to overcome the problems caused by data scarcity is to set up a measurement campaign for a limited time period. In this study, we determine the minimum amount of data required to determine robust parameter values for a simple model with two parameters. The model is constructed such that the parameters can be determined not only with automatic calibration, but also by recession analysis and a priori from Boussinesq theory. The model has been applied to a research catchment in Switzerland. For automatic calibration and recession analysis, one season (5 months) is found to be sufficient to give robust parameters for simulation of high flows over the full observation period. For automatic calibration, this should be the season with the highest precipitation, for recession analysis the season with least evapotranspiration. The Boussinesq equation is able to give good parameter estimates for modeling high flows, but detailed in situ knowledge of the catchment is required. Automatic calibration outperforms recession analysis and Boussinesq theory by far when it comes to parameter estimation with a focus on prediction of low flows. It was shown that a single set of parameters cannot simultaneously describe high and low flows with a reasonable accuracy, suggesting that more than two parameters are needed to characterize subsurface properties.
Editorial : Ensemble prediction and data assimilation for operational hydrology : Editorial
Seo, D.J. ; Liu, Y. ; Moradkhani, H. ; Weerts, A.H. - \ 2014
Journal of Hydrology 519 (2014)part D. - ISSN 0022-1694 - p. 2661 - 2662.
Effects of climate and nutrient load on the water quality of shallow lakes assessed through ensemble runs by PCLake
Nielsen, A. ; Trolle, D. ; Bjerring, R. - \ 2014
Ecological Applications 24 (2014)8. - ISSN 1051-0761 - p. 1926 - 1944.
ecosystem model pclake - danish lakes - phosphorus - state - eutrophication - restoration - equifinality - uncertainty - sensitivity - management
Complex ecological models are used to predict the consequences of anticipated future changes in climate and nutrient loading for lake water quality. These models may, however, suffer from nonuniqueness in that various sets of model parameter values may yield equally satisfactory representations of the system being modeled, but when applied in future scenarios these sets of values may divert considerably in their simulated outcomes. Compilation of an ensemble of model runs allows us to account for simulation variability arising from model parameter estimates. Thus, we propose a new approach for aquatic ecological models creating a more robust prediction of future water quality. We used our ensemble approach in an application of the widely used PCLake model for Danish shallow Lake Arreskov, which during the past two decades has demonstrated frequent shifts between turbid and clear water states. Despite marked variability, the span of our ensemble runs encapsulated 70–90% of the observed variation in lake water quality. The model exercise demonstrates that future warming and increased nutrient loading lead to lower probability of a clear water, vegetation-rich state and greater likelihood of cyanobacteria dominance. In a 6.0°C warming scenario, for instance, the current nutrient loading of nitrogen and phosphorus must be reduced by about 75% to maintain the present ecological state of Lake Arreskov, but even in a near-future 2.0°C warming scenario, a higher probability of a turbid, cyanobacteria-dominated state is predicted. As managers may wish to determine the probability of achieving a certain ecological state, our proposed ensemble approach facilitates new ways of communicating future stressor impacts.
On noice in data assimilation schemes for improved flood forecasting using distributed hydrological models
Noh, S.J. ; Rakovec, O. ; Weerts, A.H. ; Tachikawa, Y. - \ 2014
Journal of Hydrology 519 (2014)part D. - ISSN 0022-1694 - p. 2707 - 2721.
sequential data assimilation - ensemble kalman filter - surface soil-moisture - probabilistic forecasts - river-basin - streamflow - water - uncertainty - states - implementation
We investigate the effects of noise specification on the quality of hydrological forecasts via an advanced data assimilation (DA) procedure using a distributed hydrological model driven by numerical weather predictions. The sequential DA procedure is based on (1) a multivariate rainfall ensemble generator, which provides spatial and temporal correlation error structures of input forcing, and (2) lagged particle filtering to update past and current state variables simultaneously in a lag-time window to consider the response times of internal hydrologic processes. The procedure is evaluated for streamflow forecasting of three flood events in two fast-responding catchments in Japan (Maruyama and Katsura). The rainfall ensembles are derived from ground-based rain gauge observations for the analysis step and numerical weather predictions for the forecast step. The ensemble simulation performs multi-site updating using information from the streamflow gauging network and considers the artificial effects of reservoir release. Sensitivity analysis is performed to assess the impacts of noise specification in DA, comparing a different setup of random state noise and input forcing with/without multivariate conditional simulation (MCS) of rainfall ensembles. The results show that lagged particle filtering (LPF) forced with MCS provides good performance with small and consistent random state noise, whereas LPF forced with Thiessen rainfall interpolation requires larger random state noise to yield performance comparable to that of LPF + MCS for short lead times.
Challenges to scenario-guided adaptive action on food security under climate change
Vervoort, J.M. ; Thornton, P.K. ; Kristjansson, P. ; Foerch, W. ; Ericksen, P.J. ; Kok, K. ; Ingram, J.S. ; Herrero, M. ; Palazzo, A. ; Helfgott, A.E.S. ; Wilkinson, A. ; Havlik, P. ; Mason-D’Croz, D. ; Jost, C. - \ 2014
Global environmental change : human and policy dimensions 28 (2014). - ISSN 0959-3780 - p. 383 - 394.
sustainable development - uncertainty - agriculture - systems - adaptation - knowledge - science - scales
This paper examines the development and use of scenarios as an approach to guide action in multi-level, multi-actor adaptation contexts such as food security under climate change. Three challenges arehighlighted: (1) ensuring the appropriate scope for action; (2) moving beyond intervention-based decision guidance; and (3) developing long-term shared capacity for strategic planning. To overcome these challenges we have applied explorative scenarios and normative back-casting with stakeholders from different sectors at the regional level in East Africa. We then applied lessons about appropriate scope, enabling adaptation pathways, and developing strategic planning capacity to scenarios processes in multiple global regions. Scenarios were created to have a broad enough scope to be relevant to diverse actors, and then adapted by different actor groups to ensure their salience in specific decision contexts. The initial strategy for using the scenarios by bringing a range of actors together to explore new collaborative proposals had limitations as well as strengths versus the application of scenarios for specific actor groups and existing decision pathways. Scenarios development and use transitioned from an intervention-based process to an embedded process characterized by continuous engagement. Feasibility and long-term sustainability could be ensured by having decision makers own the process and focusing on developing strategic planning capacity within their home organizations.
Managing climate change in conservation practice: an exploration of the science–management interface in beech forest management.
Koning, J. de; Turnhout, E. ; Winkel, G. ; Blondet, M. ; Borras, L. ; Ferranti, F. ; Geitzenauer, M. ; Sotirov, M. ; Jump, A. - \ 2014
Biodiversity and Conservation 23 (2014)14. - ISSN 0960-3115 - p. 3657 - 3671.
fagus-sylvatica l. - ecological restoration - policy - future - range - biodiversity - shifts - uncertainty - responses - politics
Scientific studies reveal significant consequences of climate change for nature, from ecosystems to individual species. Such studies are important factors in policy decisions on forest conservation and management in Europe. However, while research has shown that climate change research start to impact on European conservation policies like Natura 2000, climate change information has yet to translate into management practices. This article contributes to the on-going debates about science–society relations and knowledge utilization by exploring and analysing the interface between scientific knowledge and forest management practice. We focus specifically on climate change debates in conservation policy and on how managers of forest areas in Europe perceive and use climate change ecology. Our findings show that forest managers do not necessarily deny the potential importance of climate change for their management practices, at least in the future, but have reservations about the current usefulness of available knowledge for their own areas and circumstances. This suggests that the science–management interface is not as politicized as current policy debates about climate change and that the use of climate change ecology is situated in practice. We conclude the article by discussing what forms of knowledge may enable responsible and future oriented management in practice focusing specifically on the role of reflexive experimentation and monitoring.
Measuring the impacts of production risk on technical efficiency: A state-contingent conditional order-m approach
Serra, T. ; Oude Lansink, A.G.J.M. - \ 2014
European Journal of Operational Research 239 (2014)1. - ISSN 0377-2217 - p. 237 - 242.
nonparametric frontier models - cheap talk - technologies - uncertainty - inference - corn
This article studies the influence of risk on farms' technical efficiency levels. The analysis extends the order-m efficiency scores approach proposed by Daraio and Simar (2005) to the state-contingent framework. The empirical application focuses on cross section data of Catalan specialized crop farms from the year 2011. Results suggest that accounting for production risks increases the technical performance. A 10% increase in output risk will result in a 2.5% increase in average firm technical performance. © 2014 Elsevier B.V. All rights reserved.
Innovation capabilities in food and beverages and technology-based innovation projects
Tepic, M. ; Fortuin, F.T.J.M. ; Kemp, R.G.M. ; Omta, S.W.F. - \ 2014
British Food Journal 116 (2014)2. - ISSN 0007-070X - p. 228 - 250.
product development - success factors - dynamic environments - chinese firms - performance - industry - uncertainty - system - perspectives - acceptance
Purpose - The aim of this paper is to establish the differences between the food and beverages (F&B) and technology-based industries with regards to the relation between previously identified success factors and innovation project performance. Design/methodology/approach - These differences are established on the basis of logistic regression analysis, using 38 innovation projects (18 F&B and 20 technology-based). Findings - Newness of the innovation project to the company, communication capabilities and market potential have a more negative impact on innovation project performance in the F&B than the tech-based industry. Especially functional upstream capabilities increase the likelihood of success in F&B, when compared to tech-based innovation projects. Practical implications - While functional upstream capabilities are important for success of F&B innovation projects, there is still room for improvement in order to deal effectively with newness of the innovation project to the company. Internalization of resources from the network and a balanced radical/incremental innovation project portfolio contribute to additional enhancement of functional capabilities of the F&B companies, improving their capacity to deal with newness. Through a larger focus on co-innovation with retail, F&B companies can improve their intra- and inter-firm communication capabilities to attain more consumer-oriented integration of R&D and marketing activities, improving the market potential of their innovations. Originality/value - This paper demonstrates that the previously identified critical success factors for innovation projects differ in impact and importance for F&B innovation project performance when compared to innovation projects in the technology-based industry.
The economic power of the Golden Rice opposition
Wesseler, J.H.H. ; Zilberman, D. - \ 2014
Environment and Development Economics 19 (2014)6. - ISSN 1355-770X - p. 724 - 742.
birth-weight - vitamin-a - health - uncertainty - benefits - growth - impact - costs - gm
Vitamin A enriched rice (Golden Rice) is a cost-efficient solution that can substantially reduce health costs. Despite Golden Rice being available since early 2000, this rice has not been introduced in any country. Governments must perceive additional costs that overcompensate the benefits of the technology to explain the delay in approval. We develop a real option model including irreversibility and uncertainty about perceived costs and arrival of new information to explain a delay in approval. The model has been applied to the case of India. Results show the annual perceived costs have to be at least US$199 million per year approximately for the last decade to explain the delay in approval of the technology. This is an indicator of the economic power of the opposition towards Golden Rice resulting in about 1.4 million life years lost over the past decade in India.
Stagnating Jatropha Biofuel Development in Southwest China: An Institutional Approach
Li, Jia ; Bluemling, B. ; Mol, A.P.J. ; Herzfeld, Th. - \ 2014
Sustainability 6 (2014)6. - ISSN 2071-1050 - p. 3192 - 3212.
future orientation - forestry - sustainability - perspectives - plantations - uncertainty - investment - management - prospects - biodiesel
Biodiesel from jatropha has been considered as a promising alternative to fossil fuels for some time. Consequently, China started promoting jatropha as one of the options to meet its ever-increasing energy consumption, and the Chinese biodiesel industry also gained interest. However, the excitement of the biofuel industry in jatropha faded after it did not bring about the expected results. This article investigates the stagnation in jatropha development and production for biodiesel in China, using two detailed case studies of jatropha biofuel production in southeast China. It is found that the underdeveloped biodiesel policy and regulation, such as a rather late formulation of standards for biodiesel (especially the B5) and the absence of mandatory targets, is an important reason for hampering jatropha development. Besides that, lack of financial support undermined sustained jatropha planting at the farm level and lack of sustained commitment from state-owned enterprises or private companies over a long time span further contributed to jatropha project’s failure. Better implementation of the rule of law, mandatory blending requirements, hazard insurance, as well as continuous financial support, might improve the continuation of jatropha plantation schemes.
Smallholder participation in large forestry programs: The camellia program in China
Li, J. ; Bluemling, B. ; Dries, L.K.E. ; Feng, S. - \ 2014
Outlook on Agriculture 43 (2014)1. - ISSN 0030-7270 - p. 45 - 51.
influencing peoples participation - land-tenure arrangements - climate-change - investment incentives - burkina-faso - costa-rica - uncertainty - adoption - risk - management
In recent years, many forestry projects have been implemented in developing countries. In China, a variety of large-scale afforestation and reforestation programmes have been carried out with multiple objectives, such as livelihood improvement and carbon sequestration. As in many developing countries, these projects have been implemented in a smallholder context. This paper investigates the determinants of smallholder participation in large forestry projects. Using the case of camellia, it explores the determinants of smallholder participation using a probit regression model. To distinguish between participation in international and government-run projects, a bivariate probit regression model is used. The findings show that only 37% of households in the sample had participated in the Camellia project; a major reason for the low participation rate is perceived tenure insecurity. The results of the bivariate probit model show that the education level of the household head and household size have a positive impact on the likelihood of household participation. The more 'off-farm' activities are taken up in a household, the less likely a household is to participate in an international project. For a government project, household size also has a positive impact on the likelihood of participation. Chinese forestry is diversifying since the devolution of forestland use rights, with a majority of households hesitating to invest, while some risk investment and others depend on government subsidies. The main policy implication is that, if the Chinese government wishes to achieve its goal of 1.68 million hectares of camellia, then improving tenure security is crucial.
Costs and benefits of adapting spatial planning to climate change: lessons learned from a large-scale urban development project in the Netherlands
Bruin, K. de; Goosen, H. ; Ierland, E.C. van; Groeneveld, R.A. - \ 2014
Regional Environmental Change 14 (2014)3. - ISSN 1436-3798 - p. 1009 - 1020.
policy - adaptation - economics - uncertainty - options - risks
Climate change increases the vulnerability of low-lying coastal areas. Careful spatial planning can reduce this vulnerability, provided that decision-makers have insight into the costs and benefits of adaptation options. This paper addresses the question which adaptation options are suitable, from an economic perspective, to adapt spatial planning to climate change at a regional scale. We apply social cost–benefit analysis to assess the net benefits of adaptation options that deal with the impacts of climate change-induced extreme events. From the methods applied and results obtained, we also aim at learning lessons for assessing climate adaptation options. The case study area, the Zuidplaspolder, is a large-scale urban development project in the Netherlands. The costs as well as the primary and secondary benefits of adaptation options relating to spatial planning (e.g. flood-proof housing and adjusted infrastructure) are identified and where possible quantified. Our results show that three adaptation options are not efficient investments, as the investment costs exceed the benefits of avoided damages. When we focus on ‘climate proofing’ the total area of the Zuidplaspolder, when the costs and benefits of all the presented adaptation options are considered together, the total package has a positive net present value. The study shows that it is possible to anticipate climate change impacts and assess the costs and benefits of adjusting spatial planning. We have learned that scenario studies provide a useful tool but that decision-making under climate change uncertainty also requires insight into the probabilities of occurrence of weather extremes in the future.
Merging validation and evaluation of ecological models to evaluation': a review of terminology and a practical approach
Augusiak, J.A. ; Brink, P.J. van den; Grimm, V. - \ 2014
Ecological Modelling 280 (2014). - ISSN 0304-3800 - p. 117 - 128.
individual-based models - risk-assessment - environmental-models - quality-assurance - simulation-model - complex-systems - beech forests - assessments - verification - uncertainty
Confusion about model validation is one of the main challenges in using ecological models for decision support, such as the regulation of pesticides. Decision makers need to know whether a model is a sufficiently good representation of its real counterpart and what criteria can be used to answer this question. Unclear terminology is one of the main obstacles to a good understanding of what model validation is, how it works, and what it can deliver. Therefore, we performed a literature review and derived a standard set of terms. ‘Validation’ was identified as a catch-all term, which is thus useless for any practical purpose. We introduce the term ‘evaludation’, a fusion of ‘evaluation’ and ‘validation’, to describe the entire process of assessing a model's quality and reliability. Considering the iterative nature of model development, the modelling cycle, we identified six essential elements of evaludation: (i) ‘data evaluation’ for scrutinising the quality of numerical and qualitative data used for model development and testing; (ii) ‘conceptual model evaluation’ for examining the simplifying assumptions underlying a model's design; (iii) ‘implementation verification’ for testing the model's implementation in equations and as a computer programme; (iv) ‘model output verification’ for comparing model output to data and patterns that guided model design and were possibly used for calibration; (v) ‘model analysis’ for exploring the model's sensitivity to changes in parameters and process formulations to make sure that the mechanistic basis of main behaviours of the model has been well understood; and (vi) ‘model output corroboration’ for comparing model output to new data and patterns that were not used for model development and parameterisation. Currently, most decision makers require ‘validating’ a model by testing its predictions with new experiments or data. Despite being desirable, this is neither sufficient nor necessary for a model to be useful for decision support. We believe that the proposed set of terms and its relation to the modelling cycle can help to make quality assessments and reality checks of ecological models more comprehensive and transparent. Keywords Model validation; Terminology; Decision support; Documentation; Ecological models; Risk assessment
Why the complex nature of integrated ecosystem assessments requires a flexible and adaptive approach
Dickey-Collas, M. - \ 2014
ICES Journal of Marine Science 71 (2014)5. - ISSN 1054-3139 - p. 1174 - 1182.
fisheries management - ecological indicators - mixed-fisheries - framework - implementation - policy - uncertainty - thresholds - scientists - support
This article considers the approach taken by the ICES to integrated ecosystem assessments (IEAs) in the context of the wider evolution of IEAs and the science/policy landscape within the ICES region. It looks forward and considers the challenges facing the development of IEAs, specifically those of scoping for objectives, participatory engagement, developing indicators and targets, risk analysis, and creating tools to evaluate management measures for marine anthropogenic activities. It concludes that expectations that the implementation of IEAs will take an ordered, stepwise approach will lead to disappointment and frustration. This is a consequence of the need to operate in an adaptive manner in a complex system. The ecosystem, the science support infrastructure, and the governance systems are all complex. Plus when engaged in a debate about societal objectives, we expect to encounter a complex and changing landscape. As a community, the challenge is to find leverage mechanisms to encourage IEA efforts to provide insights and tools within resources. We will need to innovate and be responsive to the complexity of the ecosystem and governance structures encountered when performing IEA.
Climate variability and change in Ethiopia : exploring impacts and adaptation options for cereal production
Kassie, B.T. - \ 2014
Wageningen University. Promotor(en): Martin van Ittersum, co-promotor(en): R.P. Rötter; Huib Hengsdijk; S. Asseng. - Wageningen : Wageningen University - ISBN 9789461738370 - 183
zea mays - maïs - klimaatverandering - klimaatadaptatie - simulatiemodellen - onzekerheid - ethiopië - zea mays - maize - climatic change - climate adaptation - simulation models - uncertainty - ethiopia
Key words: Climate change, Adaptation, Crop modelling, Uncertainty, Maize (Zea mays), Central Rift Valley.
Smallholder farmers in Ethiopia have been facing severe climate related hazards, in particular highly variable rainfall and severe droughts that negativelyaffect their livelihoods.Anticipated climate change is expected to aggravate some of the existing challenges and impose new risks beyond the range of current experiences. This study aimed at understanding current climate variability and future climate change and associated impacts, and providing insights on current climate risk management strategies and future adaptation options for adapting agriculture, in particular maize production.The study was conducted in the Central Rift Valley, which represents major cereal-based farming systems of the semi-arid environments of Ethiopia. A second case study area, Kobo Valley was also used for additional analysis in part of the study. Empirical statistical analyses, field survey methods, and a systems analytical approach, using field experimental data in combination with crop-climate simulation modelling were used to achieve the objectives of the study.Crop growth simulation modelling was carried out using two well-accepted crop models, which is an innovative feature of the methodology used in this thesis.
The analysis revealed that rainfall exhibited high inter-annual variability (coefficient of variation 15-40%) during the period 1977-2007 in the CRV. The mean annual temperature significantly increased with 0.12 to 0.54 oC per decade during 1977-2007. Projections for future climate suggested that annual rainfall will change by -40 to +10% and the annual temperature is expected to increase in the range of 1.4 to 4.1 oC by 2080s. Simulated water-limited yields are characterized by high inter-annual variability (coefficient of variation 36%) and about 60% of this variability is explained by the variation in growing season rainfall. Actual yields of maize in the CRV are only 28-30% of the simulated water-limited yield. Analysis of climate change scenarios showed that maize yield will decrease on average by 20% in the 2050s relative to a baseline climate due to an increase in temperature and a decrease in growing season rainfall. The negative impact of climate change is very likely, however, the extent of the negative impact has some uncertainties ranging from -2 to -29% depending on crop model and climate change scenario. From the selection of models used, it was concluded that General Circulation Models to assess future climate are the most important source of uncertainty in this study.
In response to perceived impacts, farm households are implementing various coping and adaptation strategies. The most important current adaptive strategies include crop selection, adjusting planting time, in situ moisture conservation and income diversification. Lack of affordable technologies, high costs for agricultural inputs, lack of reliable information on weather forecasts, and insecure land tenure systems were identified as limiting factors of farmers’ adaptive capacity. The crop model-based evaluation of future adaptation options indicates that increasing nitrogen fertilization, use of irrigation and changes in planting dates can compensate for some of the negative impacts of climate change on maize production. Developing more heat tolerant and high yielding new cultivars is critical to sustain crop production under future climate change. It was clear from the study that enabling strategies targeted at agricultural inputs, credit supply, market access and strengthening of local knowledge and information services need to become an integral part of government policies to assist farmers in adapting to the impacts of current climate variability and future climate change.
The socioeconomic vulnerability index: A pragmatic approach for assessing climate-change led risks-A case study in southwestern coastal Bangladesh
Ahsan Bapon, N. ; Warner, J.F. - \ 2014
International Journal of Disaster Risk Reduction 8 (2014). - ISSN 2212-4209 - p. 32 - 49.
adaptive capacity - social vulnerability - multiple stressors - natural hazards - cyclone sidr - adaptation - indicators - framework - level - uncertainty
We develop a Socioeconomic Vulnerability Index (SeVI) for climate change affected communities in seven unions1 of Koyra upazilla 2 in south-western coastal Bangladesh. We survey 60 households from each union to collect data on various vulnerability domains and socioeconomic indicators. The SeVI aggregate these collected data using a composite indicator index, where a relative weight is assigned to each indicator with a view to obtaining weighted average index scores for different vulnerability domains in different unions. Results suggest that southern and south-eastern unions are relatively more vulnerable, which are the most exposed to natural hazards and mostly surrounded by the mangrove forest Sundarbans. Furthermore- social, economic and disaster frequency are found as more influential indicators to adaptive capacity, sensitivity and exposure respectively in Koyra. This pragmatic approach is useful to figure out and monitor socioeconomic vulnerability and/or assess potential adaptation-policy effectiveness in data scarce regions by incorporating scenarios into the SeVI for baseline comparison.
Comparing two sensitivity analysis approaches for two scenarios with a spatially explicit rural agent-based model
Schouten, M.A.H. ; Verwaart, T. ; Heijman, W.J.M. - \ 2014
Environmental Modelling & Software 54 (2014)April. - ISSN 1364-8152 - p. 196 - 210.
land-use - environmental-models - agricultural policies - simulation - biodiversity - schemes - uncertainty - landscapes - management - protocol
In this paper two sensitivity analysis approaches are applied for scenario analysis in a spatially explicit rural agent-based simulation. The simulation aims to assess the socioeconomic and ecological impacts of agricultural policy interventions, market dynamics and environmental change on a regional scale. Two different methods of sensitivity analysis are investigated: i) a one-at-a-time approach where each parameter is varied one after the other, while all other parameters are kept at their nominal values; and ii) a procedure based on Monte Carlo sampling where random sets of input parameter values are related to outputs of the simulation. The complementarity of both approaches and their contribution to the overall interpretation of the model is shown in two scenarios simulating alternative European policy instruments for biodiversity conservation. Results show that a mixed approach of sensitivity analysis leads to a better understanding of the model’s behaviour, and further enhances the description of the simulation’s response to changes in inputs and parameter settings.
Process-based modelling of a headwater catchment in semi-arid conditions: the influence of macropore flow
Schaik, N.L.M.B. ; Bronstert, A. ; Jong, S.M. ; Jetten, V.G. ; Dam, J.C. van; Ritsema, C.J. ; Schnabel, S. - \ 2014
Hydrological Processes 28 (2014)24. - ISSN 0885-6087 - p. 5805 - 5816.
runoff generation - dehesas - uncertainty - management - hydrology - surface - spain
Subsurface stormflow is thought to occur mainly in humid environments with steep terrains. However, in semi-arid areas, preferential flow through macropores can also result in a significant contribution of subsurface stormflow to catchment runoff for varying catchment conditions. Most hydrological models neglect this important subsurface preferential flow. Here, we use the process-oriented hydrological model Hillflow-3D, which includes a macropore flow approach, to simulate rainfall-runoff in the semi-arid Parapuños catchment in Spain, where macropore flow was observed in previous research. The model was extended for this study to account for sorptivity under very dry soil conditions. The results of the model simulations with and without macropore flow are compared. Both model versions give reasonable results for average rainfall situations, although the approach with the macropore concept provides slightly better results. The model results for scenarios of extreme rainfall events (>13.3¿mm¿30¿min-1) however show large differences between the versions with and without macropores. These model results compared with measured rainfall-runoff data show that the model with the macropore concept is better. Our conclusion is that preferential flow is important in controlling surface runoff in case of specific, high intensity rainfall events. Therefore, preferential flow processes must be included in hydrological models where we know that preferential flow occurs. Hydrological process models with a less detailed process description may fit observed average events reasonably well but can result in erroneous predictions for more extreme events.
Assessing and communicating climate change uncertainties : case of the Rhine basin
Pelt, S.C. van - \ 2014
Wageningen University. Promotor(en): Pavel Kabat; Bas Arts; B.J.J.M. van den Hurk. - Wageningen : Wageningen University - ISBN 9789461738332 - 200
waterbeheer - klimaatverandering - onzekerheid - communicatie - risicobeheersing - simulatiemodellen - neerslag - hoogwaterbeheersing - risicoschatting - stroomgebieden - rijn - water management - climatic change - uncertainty - communication - risk management - simulation models - precipitation - flood control - risk assessment - watersheds - river rhine
The main aim of this thesis is to analyse the climate change uncertainties that are important to take into account for long term water management and to explore the communication of these uncertainties. The study design combines natural and social scientific theories and methods and consists of three different elements: 1) an assessment of the dominant uncertainty for changes in mean and extreme precipitation over the Rhine basin; 2) an assessment of the impact of the main uncertainties on changes in flood risk and associated damage in the Rhine basin and 3) an exploration of the use of simulation gaming to communicate about climate change uncertainties to water managers.
Exploring the efficiency of bias corrections of regional climate model output for the assessment of future crop yields in Europe
Bakker, A.M.R. ; Bessembinder, J.J.E. ; Wit, A.J.W. de; Hurk, B.J.J.M. van den; Hoek, S.B. - \ 2014
Regional Environmental Change 14 (2014)3. - ISSN 1436-3798 - p. 865 - 877.
weather generator - global radiation - change scenarios - era-interim - variability - precipitation - projections - simulation - uncertainty - circulation
Excessive summer drying and reduced growing season length are expected to reduce European crop yields in future. This may be partly compensated by adapted crop management, increased CO2 concentration and technological development. For food security, changes in regional to continental crop yield variability may be more important than changes in mean yields. The assessment of changes in regional and larger scale crop variability requires high resolution and spatially consistent future weather, matching a specific climate scenario. Such data could be derived from regional climate models (RCMs), which provide changes in weather patterns. In general, RCM output is heavily biased with respect to observations. Due to the strong nonlinear relation between meteorological input and crop yields, the application of this biased output may result in large biases in the simulated crop yield changes. The use of RCM output only makes sense after sufficient bias correction. This study explores how RCM output can be bias corrected for the assessment of changes in European and subregional scale crop yield variability due to climate change. For this, output of the RCM RACMO of the Royal Netherlands Meteorological Institute was bias corrected and applied within the crop simulation model WOrld FOod STudies to simulate potential and water limited yields of three divergent crops: winter wheat, maize and sugar beets. The bias correction appeared necessary to successfully reproduce the mean yields as simulated with observational data. It also substantially improved the year-to-year variability of seasonal precipitation and radiation within RACMO, but some bias in the interannual variability remained. This is caused by the fact that the applied correction focuses on mean and daily variability. The interannual variability of growing season length, and as a consequence the potential yields too, appeared even deteriorated. Projected decrease in mean crop yields is well in line with earlier studies. No significant change in crop yield variability was found. Yet, only one RCM is analysed in this study, and it is recommended to extend this study with more climate models and a slightly adjusted bias correction taking into account the variability of larger time scales as well
Multimodel assessment of water scarcity under climate change
Schellnhuber, H.J. ; Heinke, J. ; Gerten, D. ; Haddeland, I. ; Arnell, N.W. ; Clark, D.B. ; Dankers, R. ; Eisner, S. ; Kabat, P. - \ 2014
Proceedings of the National Academy of Sciences of the United States of America 111 (2014)9. - ISSN 0027-8424 - p. 3245 - 3250.
future food-production - model description - bias correction - river runoff - resources - availability - vulnerability - uncertainty - scenarios - trends
Water scarcity severely impairs food security and economic prosperity in many countries today. Expected future population changes will, in many countries as well as globally, increase the pressure on available water resources. On the supply side, renewable water resources will be affected by projected changes in precipitation patterns, temperature, and other climate variables. Here we use a large ensemble of global hydrological models (GHMs) forced by five global climate models and the latest greenhouse-gas concentration scenarios (Representative Concentration Pathways) to synthesize the current knowledge about climate change impacts on water resources. We show that climate change is likely to exacerbate regional and global water scarcity considerably. In particular, the ensemble average projects that a global warming of 2 °C above present (approximately 2.7 °C above preindustrial) will confront an additional approximate 15% of the global population with a severe decrease in water resources and will increase the number of people living under absolute water scarcity (
Variation in LCA results for disposable polystyrene beverage cups due to multiple data sets and modelling choices
Harst, E.J.M. van der; Potting, J. - \ 2014
Environmental Modelling & Software 51 (2014). - ISSN 1364-8152 - p. 123 - 135.
life-cycle assessment - environmental impacts - uncertainty - ensemble - system
Life Cycle Assessments (LCAs) of the same products often result in different, sometimes even contradictory outcomes. Reasons for these differences include using different data sets and deviating modelling choices. This paper purposely used different data sets and modelling choices to identify how these differences propagated in LCA results. Vehicle for this methodological exploration was an LCA case study of a typical polystyrene (PS) disposable cup. An initial LCA of PS cups was made using only one data set per process. Contribution and sensitivity analysis identified those processes with influential contribution to the overall environmental impact. Next additional data sets were acquired for all influential processes. The spread in impact results for each life cycle process was calculated after impact assessment for each individual inventory data set as to preserve the correlation between inventory data within each individual data set. The spread in impact results reflects uncertainty existing between different data sets for the same process and due to modelling choices. The influence on overall LCA results was quantified by systematically applying all combinations of data sets and modelling choices. Results from the different data sets and modelling choices systematically point to the same processes as main contributors to all impact categories (PS production, cup manufacturing, PS incineration and PS recycling). The spread in toxicity indicators exceeds the energy-related impact categories. Causes of spread are resources and energy used (type, amount, date and origin), reported emissions, and applied allocation procedures. Average LCA results show slight preference for recycling PS compared to incineration in most impact categories. Overlapping spread in results of the two waste treatments, however, does not support the preference for recycling. The approach in this paper showed how variation in data sets and modelling choices propagates in LCA outcomes. This is especially useful for generic LCAs as systematic use of multiple data sets and multiple modelling choices increases the insight in relative contributions of processes to, and uncertainty in the overall LCA. These results might be less easy to perceive, but they provide decision makers with more robust information.
On solving a bi-level stohastic dynamic programming model for analyzing fisheries policies: Fishermen behavior and optimal fish quota
Dijk, D. van; Hendrix, E.M.T. ; Haijema, R. ; Groeneveld, R.A. ; Ierland, E.C. van - \ 2014
Ecological Modelling 272 (2014). - ISSN 0304-3800 - p. 68 - 75.
bioeconomic model - game-theory - management - uncertainty - adjustment - resource - growth - sea
Stochastic dynamic programming (SDP) is a useful tool for analyzing policy questions in fisheries management. In order to understand and reproduce solution procedures such as value function iteration, an analytic elaboration of the problem and model characteristics is required. Because of the increased use of numerical techniques, our aim is to improve the understanding of mathematical properties of the solution procedure and to give more insight into their practical implementation by means of a specific case that uses value function iteration. We provide an analytic description of model characteristics and analyze the solution procedure of a bi-level SDP model to study fisheries policies. At the first level, a policy maker decides on the fish quota to be imposed, keeping in mind fish stock dynamics, capital stock dynamics, long-term resource rents and anticipating fishermen behavior. At the second level, fishermen reveal short-term behavior by reacting on this quota and on current states of fish stock and capital stock by deciding on their investments and fishing effort. An analysis of the behavior of the model is given and a method is elaborated to obtain optimum strategies based on value function iteration. Bi-level decision making enables us to present the model in an understandable manner, and serves as a basis for extension to more complex settings.
Including climate change projections in probabilistic flood risk assessment
Ward, P.J. ; Pelt, S.C. van; Keizer, O. de; Aerts, J.C.J.H. ; Beersma, J.J. ; Hurk, B.J.J.M. van den - \ 2014
Journal of Flood Risk Management 7 (2014)2. - ISSN 1753-318X - p. 141 - 151.
klimaatverandering - overstromingen - risicoschatting - modellen - climatic change - floods - risk assessment - models - rhine basin - model - precipitation - uncertainty - simulations - decisions
This paper demonstrates a framework for producing probabilistic flood risk estimates, focusing on two sections of the Rhine River. We used an ensemble of six (bias-corrected) regional climate model (RCM) future simulations to create a 3000-year time-series through resampling. This was complemented with 12 global climate model (GCM)-based future time-series, constructed by resampling observed time-series of daily precipitation and temperature and modifying these to represent future climate conditions using an advanced delta change approach. We used the resampled time-series as input in the hydrological model Hydrologiska Byråns Vattenbalansavdelning (HBV)-96 to simulate daily discharge and extreme discharge quantiles for return periods up to 3000 years. To convert extreme discharges to estimates of flood damage and risk, we coupled a simple inundation model with a damage model. We then fitted probability density functions (PDFs) for the RCM, GCM, and combined ensembles. The framework allows for the assessment of the probability distribution of flood risk under future climate scenario conditions. Because this paper represents a demonstration of a methodological framework, the absolute figures should not be used in decision making at this time.
Evaluating the effect of flood damage-reducing measures: a case study of the unembanked area of Rotterdam, the Netherlands
Moel, H. de; Vliet, M. van; Aerts, J.C.J.H. - \ 2014
Regional Environmental Change 14 (2014)3. - ISSN 1436-3798 - p. 895 - 908.
overstromingen - hoogwaterbeheersing - schade - risicovermindering - risicobeheersing - klimaatverandering - rotterdam - stedelijke gebieden - floods - flood control - damage - risk reduction - risk management - climatic change - rotterdam - urban areas - model - uncertainty - households - insurance - sector - meuse
Empirical evidence of increasing flood damages and the prospect of climatic change has initiated discussions in the flood management community on how to effectively manage flood risks. In the Netherlands, the framework of multi-layer safety (MLS) has been introduced to support this risk-based approach. The MLS framework consists of three layers: (i) prevention, (ii) spatial planning and (iii) evacuation. This paper presents a methodology to evaluate measures in the second layer, such as wet proofing, dry proofing or elevating buildings. The methodology uses detailed land-use data for the area around the city of Rotterdam (up to building level) that has recently become available. The vulnerability of these detailed land-use classes to flooding is assessed using the stage–damage curves from different international models. The methodology is demonstrated using a case study in the unembanked area of Rotterdam in the Netherlands, as measures from the second layer may be particularly effective there. The results show that the flood risk in the region is considerable: EUR 36 million p.a. A large part (almost 60 %) of this risk results from industrial land use, emphasising the need to give this category more attention in flood risk assessments. It was found that building level measures could substantially reduce flood risks in the region because of the relatively low inundation levels of buildings. Risk to residential buildings would be reduced by 40 % if all buildings would be wet-proofed, by 89 % if all buildings would be dry-proofed and elevating buildings over 100 cm would render the risk almost zero. While climate change could double the risk in 2100, such building level measures could easily nullify this effect. Despite the high potential of such measures, actual implementation is still limited. This is partly caused by the lack of knowledge regarding these measures by most Dutch companies and the legal impossibility for municipalities to enforce most of these measures as they would go beyond the building codes established at the national level.
Projected changes in soil organic carbon stocks upon adoption of recommended soil and water conservation practices in the upper Tana river catchment, Kenya
Batjes, N.H. - \ 2014
Land Degradation and Development 25 (2014)3. - ISSN 1085-3278 - p. 278 - 287.
climate-change - land-use - agricultural soils - data requirements - sequestration - management - uncertainty - impacts - world - dynamics
Large areas in the Upper Tana river catchment, Kenya, have been over-exploited, resulting in soil erosion, nutrient depletion and loss of soil organic matter (SOM). This study focuses on sections of the catchment earmarked as being most promising for implementing Green Water Credits, an incentive mechanism to help farmers invest in land and soil management activities that affect all fresh water resources at source. Such management practices can also help restore SOM levels towards their natural level. Opportunities to increase soil organic carbon (SOC) stocks, for two broadly defined land use types (croplands and plantation crops, with moderate input levels), are calculated using a simple empirical model, using three scenarios for the proportion of suitable land that may be treated with these practices (low¿=¿40¿per¿cent, medium¿=¿60¿per¿cent, high¿=¿80¿per¿cent). For the medium scenario, corresponding to implementation on ~348¿000¿ha in the basin, the eco-technologically possible SOC gains are estimated at 4·8 to 9·3¿×¿106¿tonnes (Mg) CO2 over the next 20¿years. Assuming a conservative price of US$10 per tonne CO2-equivalent on the carbon offset market, this would correspond to ~US$48–93 million over a 20-year period of sustained green water management. This would imply a projected (potential) payment of some US$7–13¿ha-1 to farmers annually; this sum would be in addition to incentives that are being put in place for implementing green water management practices and also in addition to the benefits that farmers would realize from the impact on production of these practices themselves
A Protocol for Better Design, Application, and Communication of Population Viability Analyses
Pe'er, G. ; Matsinos, Y.G. ; Johst, K. ; Franz, K.W. ; Turlure, C. ; Radchuk, V. ; Malinowska, A.H. ; Curtis, J.M.R. ; Naujokaitis-Lewis, I. ; Wintle, B.A. ; Henle, K. - \ 2013
Conservation Biology 27 (2013)4. - ISSN 0888-8892 - p. 644 - 656.
management options - biodiversity conservation - environmental-management - dynamic landscapes - density regulation - spotted owl - models - metapopulation - connectivity - uncertainty
Population viability analyses (PVAs) contribute to conservation theory, policy, and management. Most PVAs focus on single species within a given landscape and address a specific problem. This specificity often is reflected in the organization of published PVA descriptions. Many lack structure, making them difficult to understand, assess, repeat, or use for drawing generalizations across PVA studies. In an assessment comparing published PVAs and existing guidelines, we found that model selection was rarely justified; important parameters remained neglected or their implementation was described vaguely; limited details were given on parameter ranges, sensitivity analysis, and scenarios; and results were often reported too inconsistently to enable repeatability and comparability. Although many guidelines exist on how to design and implement reliable PVAs and standards exist for documenting and communicating ecological models in general, there is a lack of organized guidelines for designing, applying, and communicating PVAs that account for their diversity of structures and contents. To fill this gap, we integrated published guidelines and recommendations for PVA design and application, protocols for documenting ecological models in general and individual-based models in particular, and our collective experience in developing, applying, and reviewing PVAs. We devised a comprehensive protocol for the design, application, and communication of PVAs (DAC-PVA), which has 3 primary elements. The first defines what a useful PVA is; the second element provides a workflow for the design and application of a useful PVA and highlights important aspects that need to be considered during these processes; and the third element focuses on communication of PVAs to ensure clarity, comprehensiveness, repeatability, and comparability. Thereby, DAC-PVA should strengthen the credibility and relevance of PVAs for policy and management, and improve the capacity to generalize PVA findings across studies.
The Fatter the Tail, the Fatter the Climate Agreement. Simulating the Influence of Fat Tails in Climate Change Damages on the Success of International Climate Negotiations
Dellink, R.B. ; Dekker, T. ; Ketterer, J. - \ 2013
Environmental and Resource Economics 56 (2013)2. - ISSN 0924-6460 - p. 277 - 305.
international environmental agreements - stability likelihood - uncertainty - coalitions - strategies
International climate negotiations take place in a setting where uncertainties regarding the impacts of climate change are very large. In this paper, we examine the influence of increasing the probability and impact of large climate change damages, also known as the ‘fat tail’, on the formation of an international mitigation agreement. We systematically vary the shape and location of the distribution of climate change damages using the stochastic version of the applied game-theoretical STACO model. Our aim is to identify how changes to the distributional form affect the stability of coalitions and their performance. We find that fatter upper tails increase the likelihood that more ambitious coalitions are stable as well as the performance of these stable coalitions. Fatter tails thus imply more successful, or ‘fatter’, international climate agreements
Adoption of Improved Potato Varieties in Ethiopia: the role of Agricultural Knowledge and Innovation System and Farmers' Quality Assessment
Abebe, G.K. ; Bijman, J. ; Pascucci, S. ; Omta, S.W.F. - \ 2013
Agricultural Systems 122 (2013). - ISSN 0308-521X - p. 22 - 32.
technology adoption - irrigation technology - developing-countries - uncertainty - dynamics - africa - uganda - attributes - madagascar - networks
Although potato is considered to be one of the strategic crops for ensuring food security in Ethiopia, the adoption of high yielding and disease tolerant improved potato varieties is low. Common explanations include farmers’ attitudes to risk and socio-cultural factors. We develop a system perspective that explores farmers’ decisions about adopting improved varieties (IVs) in relation to (1) their engagement with the agricultural knowledge and innovation system (AKIS) and (2) their preferences for local varieties (LVs). On the basis of original data from 346 ware Ethiopian potato farmers we show that the frequency of use of technical assistance from NGOs and access to credit positively affect the adoption of IVs while the use of the main buyer as a source of advice negatively affects IV adoption. We found that farmers have a preference for LVs because of the perceived easier crop management and better stew quality attributes. Yield, disease resistance, and maturity period are less important attributes. Higher education of the household head and the presence of a radio and/or television also have a positive effect on adoption. As to the scale of adoption, we found that only the percentage of owned land, tuber size (of ware potatoes), access to credit, stew quality, and presence of a mobile phone have an impact on ware potato farmers’ decision on the amount of land to be used for growing IVs. These results imply that improved production-related quality attributes may not be enough to induce ware potato farmers to adopt new varieties. LVs with relatively low scores on production-related criteria continue to be appreciated by farmers due to demands from their customers. We recommend putting more emphasis on market-related quality attributes in new variety development.
The impact of climate and price risks on agricultural land use and crop management decisions
Lehmann, N. ; Finger, R. - \ 2013
Land Use Policy 35 (2013). - ISSN 0264-8377 - p. 119 - 130.
productivity - farmers - systems - policy - corn - profitability - uncertainty - algorithms - diversity - scenarios
This article aims to investigate the impacts of climate change and of lower and more volatile crop price levels as currently observed in the European Union (EU) on optimal management decisions, average income and income risks in crop production in Western Switzerland. To this end, a bioeconomic whole-farm model has been developed that non-parametrically combines the crop growth model CropSyst with an economic decision model using a genetic algorithm. The analysis focuses on the farm level, which enables us to integrate a wide set of potential adaptation responses, comprising changes in agricultural land use as well as crop-specific fertilization and irrigation strategies. Furthermore, the farmer's certainty equivalent is employed as objective function, which enables the consideration of not only impacts on average income but also impacts on income variability. The study shows that that the effects of EU crop prices on the optimal management decisions as well as on the farmer's certainty equivalent are much stronger than the effects of climate change. Furthermore, our results indicate that the impacts of income risks on the crop farm's optimal management schemes are of rather low importance. This is due to two major reasons: first, direct payments make up a large percentage of the agricultural income in Switzerland which makes Swiss farmers less vulnerable to market and climate volatility. Second, arable crop farms in Switzerland have by law to cultivate at least four different crops. Due to these diverse cropping systems and high government direct payments risk does neither under climate change, market liberalization nor combinations thereof, play a very decisive role in arable farming in Switzerland.
A critical comparison of ten disposable cup LCAs
Harst, E.J.M. van der; Potting, J. - \ 2013
Environmental Impact Assessment Review 43 (2013). - ISSN 0195-9255 - p. 86 - 96.
life-cycle assessment - environmental impacts - biodegradation - uncertainty - management - emissions - system
Disposable cups can be made from conventional petro-plastics, bioplastics, or paperboard (coated with petro-plastics or bioplastics). This study compared ten life cycle assessment (LCA) studies of disposable cups with the aim to evaluate the robustness of their results. The selected studies have only one impact category in common, namely climate change with global warming potential (GWP) as its category indicator. Quantitative GWP results of the studies were closer examined. GWPs within and across each study show none of the cup materials to be consistently better than the others. Comparison of the absolute GWPs (after correction for the cup volume) also shows no consistent better or worse cup material. An evaluation of the methodological choices and the data sets used in the studies revealed their influence on the GWP. The differences in GWP can be attributed to a multitude of factors, i.e., cup material and weight, production processes, waste processes, allocation options, and data used. These factors basically represent different types of uncertainty. Sensitivity and scenario analyses provided only the influence of one factor at once. A systematic and simultaneous use of sensitivity and scenario analyses could, in a next research, result in more robust outcomes.
Reconciling approaches to climate change adaptation for Colombian agriculture
Ramirez-Villegas, J. ; Khoury, C.K. - \ 2013
Climatic Change 119 (2013)3-4. - ISSN 0165-0009 - p. 575 - 583.
The projected impact of climate change on agro-ecological systems is considered widespread and significant, particularly across the global tropics. As in many other countries, adaptation to climate change is likely to be an important challenge for Colombian agricultural systems. In a recent study, a national-level assessment of the likely future impacts of climate change on agriculture was performed (Ramirez-Villegas et al. Clim Chang 115:611–628, 2012, RV2012). The study diagnosed key challenges directly affecting major crops and regions within the Colombian agricultural system and suggested a number of actions thought to facilitate adaptation, while refraining from proposing specific strategies at local scales. Further insights on the study were published by Feola (2013) (F2013), who stressed the need for transformative adaptation processes to reduce vulnerability particularly of resource-limited farmers, and the benefits of a predominantly stakeholder-led approach to adaptation. We clarify that the recommendations outlined in RV2012 were not intended as a recipe for multi-scale adaptation, but rather a set of actions that are required to diagnose and develop adaptation actions particularly at governmental levels in coordination with national and international adaptation initiatives. Such adaptation actions ought to be, ideally, a product of inclusive sub-sectorial assessments, which can take different forms. We argue that Colombian agriculture as a whole would benefit from a better outlining of adaptation needs across temporal scales in sub-sectorial assessments that take into account both RV2012 and F2013 orientations to adaptation. We conclude with two case studies of research on climate change impacts and adaptation developed in Colombia that serve as examples of realistic, productive sectorial and sub-national assessments.
Decision making under uncertainty in fisheries management: capital adjustment, fishermen behavior and stochasticity in fish stocks
Dijk, D. van - \ 2013
Wageningen University. Promotor(en): Ekko van Ierland, co-promotor(en): Rolf Groeneveld; Rene Haijema; Eligius Hendrix. - [S.l.] : s.n. - ISBN 9789461737304 - 103
visserijbeheer - visserij - visserijbeleid - bedrijfsinformatiesystemen - besluitvorming - investeringsbeslissingen - onzekerheid - economisch gedrag - vissers - visstand - quota - stochastische modellen - fishery management - fisheries - fishery policy - management information systems - decision making - investment decisions - uncertainty - economic behaviour - fishermen - fish stocks - quotas - stochastic models
The world’s marine fisheries are characterized by declining global catch, an increasing number of overexploited stocks and high natural variability in fish stocks. Policy makers are becoming more aware that effective management systems have to be implemented to rebuild overexploited fish stocks. The success of a management system is specified in terms of biological, economic, social and political objectives of policy makers and the fishing industry. However, the combination of these objectives makes the implementation of policies one of the main challenges in fisheries management. To prevent overfishing, different measures have been applied that limit catch and/or fleet capacity. Yet, the same management systems and economic behavior of fishermen may lead to an increase in investments in the fleet capacity, causing overcapacity. Decisions of policy makers and fishermen are made under uncertainty, such as uncertainty about fish stock dynamics and/or fish prices, and this can affect optimal management, investment decisions, healthy and productive fish stocks and resource rents. The objective of this thesis is to study the impact of different fisheries management systems on resource rents from the fishery, investment in the fleet capacity and fish stock under uncertainty about fish stock growth and the ex-vessel price of fish. Bi-level stochastic dynamic programming is used to model the interaction between the quota decision of a policy maker and fishermen behavior. The fisheries management systems of multiannual quota and a quota adjustment restriction are introduced and analyzed in terms of resource rents, overcapacity and fish stock. Real Options theory is used to determine for a fisheries management system of limited entry at what ex-vessel prices it is optimal for fishermen to make investment and disinvestment decisions.
A spatially explicit scenario-driven model of adaptive capacity to global change in Europe
Acosta, L. ; Klein, R.J.T. ; Reidsma, P. ; Metzger, M.J. ; Rounsevell, M.D.A. ; Leemans, R. - \ 2013
Global environmental change : human and policy dimensions 23 (2013)5. - ISSN 0959-3780 - p. 1211 - 1224.
klimaatverandering - scenario-analyse - modellen - klimaatadaptatie - europa - climatic change - scenario analysis - models - climate adaptation - europe - quantitative vulnerability assessment - fuzzy-set-theory - land-use change - climate-change - environmental-change - adaptation - indicators - growth - susceptibility - uncertainty
Traditional impact models combine exposure in the form of scenarios and sensitivity in the form of parameters, providing potential impacts of global change as model outputs. However, adaptive capacity is rarely addressed in these models. This paper presents the first spatially explicit scenario-driven model of adaptive capacity, which can be combined with impact models to support quantitative vulnerability assessment. The adaptive capacity model is based on twelve socio-economic indicators, each of which is projected into the future using four global environmental change scenarios, and then aggregated into an adaptive capacity index in a stepwise approach using fuzzy set theory
Fluctuating quota and management costs under multiannual adjustment of fish quota
Dijk, D. van; Haijema, R. ; Hendrix, E.M.T. ; Groeneveld, R.A. ; Ierland, E.C. van - \ 2013
Ecological Modelling 265 (2013). - ISSN 0304-3800 - p. 230 - 238.
north-sea plaice - pleuronectes-platessa l. - fisheries management - stock - uncertainty - sustainability - maturation - failure - trends - growth
North Sea fisheries are managed by the European Union (EU) through a system of annual quota. Due to uncertainty about future fish stocks, yearly revisions of these policies lead to fluctuation in quota, which in turn affects harvest and investment decisions of fishermen. Determination of quota requires high management costs in terms of obtaining information and negotiations between experts and policy makers. To reduce both quota fluctuation and management costs, the EU has proposed a system of multiannual quota. In this paper we study the effect of multiannual quota on quota volatility and resource rents, while accounting for management costs. We develop a bi-level stochastic dynamic programming model, where at level one, the EU determines the quota that maximizes resource rents. At level two, fishermen decide myopically on their harvest and investment levels, subject to the quota. Results show that policy makers can reduce quota volatility and improve resource rents from the fishery with multiannual quota. Important trade-offs are involved in the accomplishment of these objectives: fish stock and investments become more volatile, which leads to more overcapacity.
On data requirements for calibration of integrated models for urban water systems
Langeveld, J. ; Nopens, I. ; Schilperoort, R. ; Benedetti, L. ; Klein, J.J.M. de; Amerlinck, Y. ; Weijers, S. - \ 2013
Water Science and Technology 68 (2013)3. - ISSN 0273-1223 - p. 728 - 736.
afvalwaterbehandeling - afvalwaterbehandelingsinstallaties - riolering - watersystemen - stedelijke gebieden - monitoring - kalibratie - modellen - modelleren - oppervlaktewaterkwaliteit - noord-brabant - waste water treatment - waste water treatment plants - sewerage - water systems - urban areas - monitoring - calibration - models - modeling - surface water quality - noord-brabant - practical identifiability - simulation-models - optimization - uncertainty - quality
Modeling of integrated urban water systems (IUWS) has seen a rapid development in recent years. Models and software are available that describe the process dynamics in sewers, wastewater treatment plants (WWTPs), receiving water systems as well as at the interfaces between the submodels. Successful applications of integrated modeling are, however, relatively scarce. One of the reasons for this is the lack of high-quality monitoring data with the required spatial and temporal resolution and accuracy to calibrate and validate the integrated models, even though the state of the art of monitoring itself is no longer the limiting factor. This paper discusses the efforts to be able to meet the data requirements associated with integrated modeling and describes the methods applied to validate the monitoring data and to use submodels as software sensor to provide the necessary input for other submodels
Post-processing ECMWF precipitation and temperature ensemble reforecasts for operational hydrologic forecasting at various spatial scales
Verkade, J.S. ; Brown, J.D. ; Reggiani, P. ; Weerts, A.H. - \ 2013
Journal of Hydrology 501 (2013). - ISSN 0022-1694 - p. 73 - 91.
bias-correction - nonparametric postprocessor - probabilistic forecasts - logistic-regression - prediction system - united-states - model output - uncertainty - rhine - score
The ECMWF temperature and precipitation ensemble reforecasts are evaluated for biases in the mean, spread and forecast probabilities, and how these biases propagate to streamflow ensemble forecasts. The forcing ensembles are subsequently post-processed to reduce bias and increase skill, and to investigate whether this leads to improved streamflow ensemble forecasts. Multiple post-processing techniques are used: quantile-to-quantile transform, linear regression with an assumption of bivariate normality and logistic regression. Both the raw and post-processed ensembles are run through a hydrologic model of the river Rhine to create streamflow ensembles. The results are compared using multiple verification metrics and skill scores: relative mean error, Brier skill score and its decompositions, mean continuous ranked probability skill score and its decomposition, and the ROC score. Verification of the streamflow ensembles is performed at multiple spatial scales: relatively small headwater basins, large tributaries and the Rhine outlet at Lobith. The streamflow ensembles are verified against simulated streamflow, in order to isolate the effects of biases in the forcing ensembles and any improvements therein. The results indicate that the forcing ensembles contain significant biases, and that these cascade to the streamflow ensembles. Some of the bias in the forcing ensembles is unconditional in nature; this was resolved by a simple quantile-to-quantile transform. Improvements in conditional bias and skill of the forcing ensembles vary with forecast lead time, amount, and spatial scale, but are generally moderate. The translation to streamflow forecast skill is further muted, and several explanations are considered, including limitations in the modelling of the space–time covariability of the forcing ensembles and the presence of storages.
Thresholds, tipping and turning points for sustainability under climate change
Werners, S.E. ; Pfenninger, S. ; Slobbe, E.J.J. van; Haasnoot, M. ; kwakkel, J.H. ; Swart, R.J. - \ 2013
Current Opinion in Environmental Sustainability 5 (2013)3-4. - ISSN 1877-3435 - p. 334 - 340.
klimaatverandering - klimaatadaptatie - onzekerheidsanalyse - climatic change - climate adaptation - uncertainty analysis - social-ecological systems - decision-making - policy-makers - adaptation - science - uncertainty - information - world - transitions - 4-degrees-c
We review four bodies of literature that suggest that thresholds, tipping and turning points are important focal points for sustainability under climate change that can help bridge the science–policy interface. For decision-makers a critical threshold is reached, the moment that climate change renders policy untenable and alternative strategies must be considered.
We review four bodies of literature that suggest that thresholds, tipping and turning points are important focal points for sustainability under climate change that can help bridge the science-policy interface. For decision-makers a critical threshold is reached, the moment that climate change renders policy untenable and alternative strategies must be considered. A focus on thresholds and tipping points allows for a salient and credible dialogue between decision-makers and scientists about the amount of acceptable change, when unacceptable conditions could occur, how likely these conditions are and what adaptation pathways to consider. Uncertainty can be communicated as the time range in which a critical threshold is likely to be exceeded.
Rational versus adaptive forest management planning: exploratory research on the strategic planning practices of Dutch forest management organizations
Hoogstra-Klein, M.A. ; Burger, M. - \ 2013
European Journal of Forest Research 132 (2013)5-6. - ISSN 1612-4669 - p. 707 - 716.
future orientation - environment - uncertainty - impact
The long-running debate between the rational and the adaptive school of strategic forest management planning has received considerable attention. There is, however, little empirical evidence of whether and how forest management organizations actually plan strategically. The goal of this paper is to fill this empirical gap by describing the strategic planning practices of 22 Dutch forest management organizations faced with uncertain and unpredictable environments. Two characteristics on which the two planning approaches fundamentally differ form the basis of the description of the planning practices. The first characteristic relates to the way the external world is perceived; certainty is essential in the rational model, whereas uncertainty is central in the adaptive model. The second characteristic relates to the way the internal decision process is organized. Rational planning is much more static and stable, whereas adaptive planning processes are much more continuous, dynamic and natural. Interviews with the organizations studied point to a whole range of planning practices. Rational and adaptive planning are merely two ends of a continuum, and planning practices vary along this continuum. The rational–adaptive planning debate can therefore be considered oversimplified as it focuses only on the two extremes and does not incorporate the whole range of possible practices in between these extremes
Integraal waterbeheer : kritische zone en onzekerheden : integraal hoofdrapport
Schipper, P.N.M. ; Bogaart, P.W. ; Groot, A.T. ; Kroes, J.G. ; Mol-Dijkstra, J.P. ; Mulder, H.M. ; Supit, I. ; Verweij, P.J.F.M. ; Walsum, P.E.V. van; Wamelink, G.W.W. ; Baaren, E. van; Ek, R. van; Oude Essink, G. ; Faneca Sanchez, ; Bakker, A. ; Bessembinder, J. ; Janssen, P. ; Geer, M.F. van; Simmelink, E. ; Sluijs, J. van der - \ 2013
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2443) - 58
integraal waterbeheer - bodemwater - ecohydrologie - landbouw - natuur - klimaatverandering - onzekerheid - modelleren - achterhoek - zeeuwse eilanden - integrated water management - soil water - ecohydrology - agriculture - nature - climatic change - uncertainty - modeling - achterhoek - zeeuwse eilanden
In het kader van het Nationaal Modellen- en Datacentrum (NMDC) is in 2011 het NMDC innovatieproject 'Integraal waterbeheer - van kritische zone tot kritische onzekerheden' gestart (www.nmdc.eu). Dit project heeft tot doel om de modellen voor bodem, water, vegetatie en klimaat(verandering) door samenwerking beter op elkaar aan te laten sluiten, daarbij beter geschikt te maken om effecten van klimaatverandering te berekenen en om de verschillende typen onzekerheden bij dit soort studies in beeld te brengen. Het project is uitgevoerd door Alterra, Deltares, KNMI, PBL en TNO. In twee cases (Baakse Beek en Walcheren) hebben zij hun state-of-the-art modellen voor meteo, gewasgroei, vegetatie-ontwikkeling, hydrologie en geologie ingezet en aan elkaar gekoppeld. Dit rapport behandelt integraal de resultaten van het innovatieproject. De resultaten van de case voor de Baakse Beek zijn specifiek opgenomen in een NMDC deelrapport (Van Ek et al., 2012). Voor de case Walcheren wordt verwezen naar een artikel in voorbereiding (Kroes, J. et al., 2013). De resultaten bieden nieuwe inzichten in de vocht- en zouthuishouding van de bodem, potenties voor grondwaterafhankelijke natuur en groei van landbouwgewassen in het huidige klimaat en projecties voor klimaatverandering rond 2050. In het project zijn verschillende methoden toegepast om inzicht te krijgen in verschillende onzekerheden, hetgeen voor dergelijke integrale (model)studies praktische aanknopingspunten biedt voor de analyse van onzekerheden en effectieve samenwerking tussen de instituten.
De rol van onzekerheid in kennis in de MER procedure van het Volkerak-Zoommeer. Achtergrond document
Veraart, J.A. ; Klostermann, J.E.M. - \ 2013
Wageningen : Alterra (KvK96/2013 ) - 76
zoet water - watervoorziening - verzilting - klimaatverandering - waterbeheer - volkerak-zoommeer - onzekerheid - milieueffectrapportage - fresh water - water supply - salinization - climatic change - water management - volkerak-zoommeer - uncertainty - environmental impact reporting
In deze deskstudie is geïnventariseerd welke onzekerheden in kennis over het watersysteem, regionale watervoorziening en verzilting een rol gespeeld hebben in het onderhandelingsproces over de verschillende beheersvarianten voor het Volkerak-Zoommeer in de MER procedure. Er is gekeken welke netwerken en actoren kennis of onzekerheden over klimaatverandering, verzilting en regionale watervoorziening ter tafel gebracht hebben en welke definities en indicatoren daarbij gebruikt zijn
Expanding risk consideration in integrated models - the role of downside risk aversion in irrigation decisions
Finger, R. - \ 2013
Environmental Modelling & Software 43 (2013). - ISSN 1364-8152 - p. 169 - 172.
systems - management - climate - sustainability - productivity - agriculture - uncertainty - variability - switzerland - technology
We present a bio-economic model that accounts for the effects of water and nitrogen use on the first three moments of profit margin distributions in Swiss maize production. We thus also account for downside risks in farmers’ decision making processes, which extents currently used bio-economic modeling approaches that address agricultural water use. We find that because irrigation reduces the negative skewness of profit margin distributions, i.e. downside risk, farmers have an additional incentive to use irrigation more intensively. Not considering downside risks may thus imply an underestimation of agricultural water use.
A comprehensive dairy valorization model
Banaszewska, A. ; Cruijssen, F.C.A.M. ; Vorst, J.G.A.J. van der; Claassen, G.D.H. ; Kampman, J.L. - \ 2013
Journal of Dairy Science 96 (2013). - ISSN 0022-0302 - p. 761 - 779.
of-the-art - planning-models - supply chain - programming models - cheese manufacture - optimization model - industry - uncertainty - allocation - resources
Dairy processors face numerous challenges resulting from both unsteady dairy markets and some specific characteristics of dairy supply chains. To maintain a competitive position on the market, companies must look beyond standard solutions currently used in practice. This paper presents a comprehensive dairy valorization model that serves as a decision support tool for mid-term allocation of raw milk to end products and production planning. The developed model was used to identify the optimal product portfolio composition. The model allocates raw milk to the most profitable dairy products while accounting for important constraints (i.e., recipes, composition variations, dairy production interdependencies, seasonality, demand, supply, capacities, and transportation flows). The inclusion of all relevant constraints and the ease of understanding dairy production dynamics make the model comprehensive. The developed model was tested at the international dairy processor FrieslandCampina (Amersfoort, the Netherlands). The structure of the model and its output were discussed in multiple sessions with and approved by relevant FrieslandCampina employees. The elements included in the model were considered necessary to optimally valorize raw milk. To illustrate the comprehensiveness and functionality of the model, we analyzed the effect of seasonality on milk valorization. A large difference in profit and a shift in the allocation of milk showed that seasonality has a considerable impact on the valorization of raw milk
Regional projections of North Indian climate for adaptation studies
Mathison, C. ; Wiltshire, A. ; Dimri, A.P. ; Moors, E.J. ; Siderius, C. ; Ridley, J. - \ 2013
Science of the Total Environment 468-469 (2013)S1. - ISSN 0048-9697 - p. S4 - S17.
interannual variability - global precipitation - monsoon - model - heat - representation - uncertainty - irrigation - simulation - prediction
Adaptation is increasingly important for regions around the world where large changes in climate could have an impact on populations and industry. The Brahmaputra–Ganges catchments have a large population, a main industry of agriculture and a growing hydro-power industry, making the region susceptible to changes in the Indian Summer Monsoon, annually the main water source. The HighNoon project has completed four regional climate model simulations for India and the Himalaya at high resolution (25 km) from 1960 to 2100 to provide an ensemble of simulations for the region. In this paper we have assessed the ensemble for these catchments, comparing the simulations with observations, to give credence that the simulations provide a realistic representation of atmospheric processes and therefore future climate. We have illustrated how these simulations could be used to provide information on potential future climate impacts and therefore aid decision-making using climatology and threshold analysis. The ensemble analysis shows an increase in temperature between the baseline (1970–2000) and the 2050s (2040–2070) of between 2 and 4 °C and an increase in the number of days with maximum temperatures above 28 °C and 35 °C. There is less certainty for precipitation and runoff which show considerable variability, even in this relatively small ensemble, spanning zero. The HighNoon ensemble is the most complete data for the region providing useful information on a wide range of variables for the regional climate of the Brahmaputra–Ganges region, however there are processes not yet included in the models that could have an impact on the simulations of future climate. We have discussed these processes and show that the range from the HighNoon ensemble is similar in magnitude to potential changes in projections where these processes are included. Therefore strategies for adaptation must be robust and flexible allowing for advances in the science and natural environmental changes.
Monitoring and evaluation of spatially managed areas: A generic framework for implementation of ecoystem based marine management and its application
Stelzenmueller, V. ; Breen, P. ; Stamford, T. ; Dankers, N.M.J.A. ; Jak, R.G. ; Hofstede, R. ter - \ 2013
Marine Policy 37 (2013). - ISSN 0308-597X - p. 149 - 164.
sea use management - fisheries management - methodological approach - offshore waters - indicators - conservation - uncertainty - habitats - objectives - strategies
This study introduces a framework for the monitoring and evaluation of spatially managed areas (SMAs), which is currently being tested by nine European case studies. The framework provides guidance on the selection, mapping, and assessment of ecosystem components and human pressures, the evaluation of management effectiveness and potential adaptations to management. Moreover, it provides a structured approach with advice on spatially explicit tools for practical tasks like the assessment of cumulative impacts of human pressures or pressure-state relationships. The case studies revealed emerging challenges, such as the lack of operational objectives within SMAs, particularly for transnational cases, data access, and stakeholder involvement. Furthermore, the emerging challenges of integrating the framework assessment using scientific information with a structured governance research analysis based mainly on qualitative information are addressed. The lessons learned will provide a better insight into the full range of methods and approaches required to support the implementation of the ecosystem approach to marine spatial management in Europe and elsewhere.
Wicked problems and clumsy solutions: Planning as expectation management
Hartmann, Thomas - \ 2012
Planning Theory 11 (2012)3. - ISSN 1473-0952 - p. 242 - 256.
complexity - expectation management - participation - polyrationality - uncertainty
In 1973, Horst W Rittel and Malvin A Webber introduced the term 'wicked problem' in planning theory. They describe spatial planning as dealing with inherent uncertainty, complexity and inevitable normativity. This contribution picks up the concept of wicked problems, reflects on it from a planning-theoretical perspective, and proposes the use of Cultural Theory's concept of clumsy solutions as a response to wicked planning problems. In discussing public participation processes in spatial planning, it is then shown what clumsy solutions mean for spatial planning. The four rationalities of Cultural Theory are then used to explain why public participation in planning can become wicked, and how these rationalities provide a response that copes with this wickedness.
Efficiency comparison of conventional and digital soil mapping for updating soil maps
Kempen, B. ; Brus, D.J. ; Stoorvogel, J.J. ; Heuvelink, G.B.M. ; Vries, F. de - \ 2012
Soil Science Society of America Journal 76 (2012)6. - ISSN 0361-5995 - p. 2097 - 2115.
model-based geostatistics - spatial interpolation - peat soils - information - prediction - uncertainty - variables - knowledge - regression - science
This study compared the efficiency of geostatistical digital soil mapping (DSM) with conventional soil mapping (CSM) for updating soil class and property maps of a cultivated peatland in the Netherlands. For digital soil class mapping, the generalized linear geostatistical model was used. Digital mapping of the soil organic matter (SOM) content and peat thickness was done by universal kriging. The conventional soil class map was created by free survey, while the property maps were created with the representative profile description (RPD) and map unit means (MUM) methods. For each method, we computed the effort invested in the mapping in terms of the sampling and cost densities. The accuracies of the created soil maps were estimated from independent probability sample data. The results showed that for DSM, the cost density could be reduced by a factor of three compared with CSM without compromising accuracy. The map purity of both maps was around 55%. For conventional soil property mapping, the MUM maps were more accurate than the RPD maps. For SOM, CSM-MUM (RMSE 7.5%) performed better than DSM (RMSE 12.1%), although accuracy differences were not significant. For peat thickness, DSM (RMSE 23.3 cm) performed slightly better than CSM-MUM (RMSE 24.9 cm). Despite the differences in accuracy being small, the digital soil property maps were produced more efficiently. The cost density was a factor of 3.5 smaller. We conclude that for updating conventional soil maps in the Dutch peatlands, geostatistical DSM can be more efficient, although not necessarily more accurate, than CSM.
Seasonal semivariance of Dutch rainfall at hourly to daily scales
Beek, C.Z. van de; Leijnse, H. ; Torfs, P.J.J.F. ; Uijlenhoet, R. - \ 2012
Advances in Water Resources 45 (2012). - ISSN 0309-1708 - p. 76 - 85.
gauge measurements - calibration - uncertainty - resolution - hydrology - errors
Using 30 years (1979–2009) of data from 33 automatic rain gauges in the Netherlands, a study of the space–time variability of rainfall is performed. This study uses 90-day averaged semi-variograms to find seasonal signals in the fitted spherical semi-variogram parameters of rainrates in the Netherlands, for accumulation intervals between 1 and 24 h. These signals can be well-described by simple cosine functions. The dependence of these cosine functions on the accumulation interval is modeled in two different ways: (1) power-law relations between the variogram parameters and the accumulation interval, and (2) power-law relations between the parameters of the cosine functions and the accumulation interval. For the first method the cosine function at the 24-h accumulation interval is also needed. The second of these methods has more parameters, but is shown to model the temporal scaling best. The space–time scaling relations found in this paper are compared to those found by others for similar and contrasting climates. Seasonality is shown to play an important role in determining rainfall spatial variability.
Soil type mapping using the generalised linear geostatistical model: A case study in a Dutch cultivated peatland
Kempen, B. ; Brus, D.J. ; Heuvelink, G.B.M. - \ 2012
Geoderma 189-190 (2012). - ISSN 0016-7061 - p. 540 - 553.
markov random-fields - spatial prediction - categorical variables - information - classification - regression - uncertainty - knowledge - trend - maps
We present the generalised linear geostatistical model (GLGM) for soil type mapping and investigate if spatial prediction with this model results in a soil map of greater accuracy than a map obtained using a non-spatial model, i.e. a model that ignores spatial dependence in the soil type variable. The GLGM is central to the framework of model-based geostatistics. We adopted a pragmatic approach in which the five soil types in a cultivated peatland were separately modelled with a binomial logit-linear GLGM. Prediction with soil type-specific GLGMs resulted in five binomial probabilities at each prediction location, which were standardised to multinomial probabilities by selecting the soil type with maximal probability. A soil map was created from the predicted probabilities. In addition, two non-spatial models were used to map soil type. These were the multinomial logit model and the generalised linear model for Bernoulli-distributed data. Validation with independent probability sample data showed that use of a spatial model for digital soil type mapping did not result in more accurate predictions than those with the non-spatial models.
An Empirical Study on Governance Structure Choices in China's Pork Supply Chain
Ji, C. ; Felipe, J. de; Briz, J. ; Trienekens, J.H. - \ 2012
International Food and Agribusiness Management Review 15 (2012)2. - ISSN 1096-7508 - p. 121 - 152.
transaction-cost economics - resource-based view - or-buy decisions - competitive advantage - vertical integration - firm - uncertainty - information - determinants - capabilities
China´s pork chain is changing in several ways. Specialized and commercial productions are gaining importance although small scale (backyard) pig production still dominates production. Similarly, small slaughterhouses continue transactions with pig producers in spot market relationships, while big pork slaughtering and processing companies are actively exploring and advancing different forms of integration. This study explains the governance structure choices in China´s pork chain from both transaction cost economics and transaction value analysis perspec-tives using Structural Equation Modeling (SEM). It is revealed that governance choices in China´s pork chain are the joint effect of transaction cost and collaborative advantages.
What eddy-covariance measurements tell us about prior land flux errors in co 2-flux inversion schemes
Chevallier, F. ; Wang, T. ; Ciais, P. ; Maignan, F. ; Bocquet, M. ; Moors, E.J. - \ 2012
Global Biogeochemical Cycles 26 (2012)1. - ISSN 0886-6236 - 9 p.
carbon-dioxide exchange - interannual variability - soil respiration - atmospheric co2 - pine forests - water-vapor - oak forest - assimilation - uncertainty - grassland
To guide the future development of CO2-atmospheric inversion modeling systems, we analyzed the errors arising from prior information about terrestrial ecosystem fluxes. We compared the surface fluxes calculated by a process-based terrestrial ecosystem model with daily averages of CO2flux measurements at 156 sites across the world in the FLUXNET network. At the daily scale, the standard deviation of the model-data fit was 2.5 gC·m-2·d-1; temporal autocorrelations were significant at the weekly scale (>0.3 for lags less than four weeks), while spatial correlations were confined to within the first few hundred kilometers (
Geospatial analysis of species, biodiversity and landscapes: Introduction to the second special issue on spatial ecology
Laffan, S.W. ; Skidmore, A.K. ; Franklin, J. - \ 2012
International Journal of Geographical Information Science 26 (2012)11. - ISSN 1365-8816 - p. 2003 - 2007.
habitat - models - scale - distributions - conservation - uncertainty - diversity - distance - overlap - disease
A Neuroevolutionary Approach to Stochastic Inventory Control in Multi-Echelon Systems
Prestwich, S. ; Tarim, S.A. ; Rossi, R. ; Hnich, B. - \ 2012
International Journal of Production Research 50 (2012)8. - ISSN 0020-7543 - p. 2150 - 2160.
noisy genetic algorithm - supply chains - environments - optimization - uncertainty - management - design - model
Stochastic inventory control in multi-echelon systems poses hard problems in optimisation under uncertainty. Stochastic programming can solve small instances optimally, and approximately solve larger instances via scenario reduction techniques, but it cannot handle arbitrary nonlinear constraints or other non-standard features. Simulation optimisation is an alternative approach that has recently been applied to such problems, using policies that require only a few decision variables to be determined. However, to find optimal or near-optimal solutions we must consider exponentially large scenario trees with a corresponding number of decision variables. We propose instead a neuroevolutionary approach: using an artificial neural network to compactly represent the scenario tree, and training the network by a simulation-based evolutionary algorithm. We show experimentally that this method can quickly find high-quality plans using networks of a very simple form.
Institutions in the Mexican coffee sector : changes and responses
Rodriguez Padron, B. - \ 2012
Wageningen University. Promotor(en): Erwin Bulte; Ruerd Ruben, co-promotor(en): Kees Burger. - [S.l.] : s.n. - ISBN 9789461734181 - 201
instellingen - institutionele economie - mexico - koffie - landbouwsector - verandering - samenwerking - contracten - diversificatie - onzekerheid - markten - markthandelaars - institutions - institutional economics - mexico - coffee - agricultural sector - change - cooperation - contracts - diversification - uncertainty - markets - market traders
Keywords: Cooperation, contract arrangements, traders´ performance, market uncertainty, diversification, coffee, Mexico.
The main aim of this thesis is to investigate the institutional environment prevailing in the Mexican coffee sector and its effect on the producers, traders and households. Specific topics we examine are the contract arrangements and trade performance, the factors influencing the growers´ willingness to join a cooperative, the effects of cooperation on price variability, the influence of cooperation on the growers’ welfare, and coffee producers’ response to the falling coffee price through their engagement in diversification activities. To accomplish the main objectives we have used primary and secondary data. We applied ordinarily least squares, logistic, probit and multivariate probit regressions in the analysis. The main findings indicate that farmers were better off under the quota system than they are under the free market. Results also indicate that being a roaster and selling cherry coffee negatively affects traders’ use of contracts, whereas being vertically integrated has a positive effect on contracting. On the other hand, selling cherry coffee, participating in a competitive environment and having contracts positively influence intermediaries’ performance. Other results show that some individual, family and farm factors, as well as variability of the coffee price at the municipal level favour cooperative affiliation; whereas housing conditions, the proportion of farmers in the municipality and the level of producers selling to intermediaries at the municipal level negatively affect prospects for cooperative membership. We discovered overall positive effects of cooperative participation on household welfare through an increase in the price and total coffee income; results also indicate that households responded to the low coffee price periods with an increase in diversification.
Building crop models within different crop modelling frameworks
Adam, M.Y.O. ; Corbeels, M. ; Leffelaar, P.A. ; Keulen, H. van; Wery, J. ; Ewert, F. - \ 2012
Agricultural Systems 113 (2012). - ISSN 0308-521X - p. 57 - 63.
environmental-models - systems simulation - uncertainty - responses - protocol - apsim
Modular frameworks for crop modelling have evolved through simultaneous progress in crop science and software development but differences among these frameworks exist which are not well understood, resulting in potential misuse for crop modelling. In this paper we review differences and similarities among different developed frameworks and identify some implications for crop modelling. We consider three modelling frameworks currently used for crop modelling: CROSPAL (CROp Simulator: Picking and Assembling Libraries), APES (Agricultural Production and Externalities Simulator) and APSIM (Agricultural Production Systems sIMulator). The frameworks are implemented differently and they provide more or less flexibility and guidance, to facilitate assembly of crop model from model components. We underline the importance of systematic approaches to facilitate the selection of appropriate model structure and derive suggestions to facilitate it. We particularly stress the need for better documentation of the underlying assumptions of the modules on simulated processes and on the criteria applied in the selection of these modules for a particular simulation objective. Such documentation should help to point out the sources of uncertainties associated with the development of crop models and to reinforce the role of the crop modeller as an intermediary between the software engineer, coding the modules, and the end users, agronomists or crop physiologists using the model for a specific objective. Finally, the key contributions of modelling frameworks in the crop modelling domain are discussed and we draw conclusions for the prospects of such frameworks in the crop modelling field which should continue to reside on the principles of systems analysis but combined with up-to-date advances in software engineering techniques
Modeling the sensitivity of agricultural water use to price variability and climate change - An application to Swiss maize production
Finger, R. - \ 2012
Agricultural Water Management 109 (2012)June. - ISSN 0378-3774 - p. 135 - 143.
simulation-model - irrigation - risk - markets - uncertainty - switzerland - strategies - experience - grassland - cropsyst
We analyze the sensitivity of crop management under current and future climate scenarios to changes in economic boundary conditions. In particular, we focus on the effects of changing price risks. We combine a bio-economic modeling approach and a crop growth model CropSyst with an economic model that represents the decision making process of a risk-averse farmer. We apply the models to irrigated maize production in Switzerland. To analyze the sensitivity of optimal water and nitrogen use to likely future states of several economic variables, we conduct sensitivity analyses with respect to changes in price variability, the price–yield correlation, water and maize prices as well as farmers’ risk preferences. Results show that climate change leads to a strong increase in optimal water use for irrigation, with consequent increases in maize yields. However, our analysis also reveals that the consideration of economic drivers for farmers’ irrigation decisions is indispensable. Strong effects on optimal water use are found for changes in crop (positive) and water (negative) prices. We also find strong implications of risk aversion and price variability on irrigation decisions. A doubling of price variability, which would represent a shift from the current Swiss situation to price variability levels in its neighboring countries, could reduce optimal water use by up to 40%. We conclude that investigations of water demand should consider, beyond expectations on output and input price levels, also the variability of prices.
The influence of direct payments on farmers’ hail insurance decisions
Finger, R. ; Lehmann, N. - \ 2012
Agricultural Economics 43 (2012)3. - ISSN 0169-5150 - p. 343 - 354.
common agricultural policy - risk - uncertainty - management - reforms
We analyze determinants of hail insurance use of Swiss farmers, using FADN panel data covering the period 1990–2009. Mixed effect logistic regression models are estimated to identify the most important farm and farmer characteristics that trigger insurance use. In addition, information on local hail risk is taken into account in these models. It shows that larger farms, with specialization in crop production, and with larger local hail risks are more likely to adopt the hail insurance. Moreover, insurance users are usually older and better educated. Since the early 1990s, Swiss agricultural policy has reduced price support and introduced general and ecological direct payments. This has led to a much higher importance of direct payments for farmers’ incomes. Our analysis shows that this development has contributed to decreasing hail insurance adoption rates in Switzerland over the period considered. Our results indicate that the larger the share of direct payments for total farm revenue, the less attractive is insurance as a risk management strategy for farmers. This interdependency should be explicitly considered by agricultural policy in the design of support mechanisms.
The added value of participatory modelling in fisheries management - what has been learnt?
Rockmann, C. ; Ulrich, C. ; Dreyer, M. ; Miller, D.C.M. ; Tserpes, G. ; Pastoors, M.A. - \ 2012
Marine Policy 36 (2012)5. - ISSN 0308-597X - p. 1072 - 1085.
environmental assessment - credibility crisis - nusap system - uncertainty - science
How can uncertain fisheries science be linked with good governance processes, thereby increasing fisheries management legitimacy and effectiveness? Reducing the uncertainties around scientific models has long been perceived as the cure of the fisheries management problem. There is however increasing recognition that uncertainty in the numbers will remain. A lack of transparency with respect to these uncertainties can damage the credibility of science. The EU Commission's proposal for a reformed Common Fisheries Policy calls for more self-management for the fishing industry by increasing fishers' involvement in the planning and execution of policies and boosting the role of fishers' organisations. One way of higher transparency and improved participation is to include stakeholders in the modelling process itself. The JAKFISH project (Judgment And Knowledge in Fisheries Involving StakeHolders) invited fisheries stakeholders to participate in the process of framing the management problem, and to give input and evaluate the scientific models that are used to provide fisheries management advice. JAKFISH investigated various tools to assess and communicate uncertainty around fish stock assessments and fisheries management. Here, a synthesis is presented of the participatory work carried out in four European fishery case studies (Western Baltic herring, North Sea Nephrops, Central Baltic Herring and Mediterranean swordfish), focussing on the uncertainty tools used, the stakeholders' responses to these, and the lessons learnt. It is concluded that participatory modelling has the potential to facilitate and structure discussions between scientists and stakeholders about uncertainties and the quality of the knowledge base. It can also contribute to collective learning, increase legitimacy, and advance scientific understanding. However, when approaching real-life situations, modelling should not be seen as the priority objective. Rather, the crucial step in a science–stakeholder collaboration is the joint problem framing in an open, transparent way.
Economic analysis of pesticide use and environmental spillovers under a dynamic production environment
Skevas, T. - \ 2012
Wageningen University. Promotor(en): Alfons Oude Lansink, co-promotor(en): Spiro Stefanou. - S.L. : s.n. - ISBN 9789461732194 - 175
akkerbouw - bedrijfseconomie - pesticiden - dynamica - milieu - pesticidenresiduen - aanwendingen - gewasbescherming - stimulansen - productie - onzekerheid - nederland - milieubeleid - arable farming - business economics - pesticides - dynamics - environment - pesticide residues - uses - plant protection - incentives - production - uncertainty - netherlands - environmental policy
Pesticides are used in agriculture to protect crops from pests and diseases, with indiscriminate pesticide use having several adverse effects on the environment. In an era of an increasing public awareness on pesticides’ environmental spillovers, the EU is trying to update its pesticide policy by using economic incentives, aiming at reducing pesticide use and environmental spillovers. This dissertation focuses on assessing how pesticide use and its related environmental spillovers are affecting farmers’ production environment under a dynamic production setting, thus assisting policy makers in designing optimal pesticide policy tools.
Web-based environmental simulation: bridging the gap between scientific modeling and decision-making
Buytaert, W. ; Baez, S. ; Bustamante, M. ; Dewulf, A. - \ 2012
Environmental Science and Technology 46 (2012)4. - ISSN 0013-936X - p. 1971 - 1976.
earth system - science - uncertainty - services - topmodel - future
Data availability in environmental sciences is growing rapidly. Conventional monitoring systems are collecting data at increasing spatial and temporal resolutions; satellites provide a constant stream of global observations, and citizen scientist generate local data with electronic gadgets and cheap devices. There is a need to process this stream of heterogeneous data into useful information, both for science and for decision-making. Advances in networking and computer technologies increasingly enable accessing, combining, processing, and visualizing these data. This Feature reflects upon the role of environmental models in this process. We consider models as the primary tool for data processing, pattern identification, and scenario analysis. As such, they are an essential element of science-based decision-making. The new technologies analyzed here have the potential to turn the typical top-down flow of information from scientists to users into a much more direct, interactive approach. This may accelerate the dissemination of environmental information to a larger community of users. It may also facilitate harvesting feedback, and evaluating simulations and predictions from different perspectives. However, the evolution poses challenges, not only to model development but also to the communication of model results and their assumptions, shortcomings, and errors
Application of the Central Limit Theorem in microbial risk assessment: High number of serving reduces the Coefficient of Variation of food-borne burden-of-illness
Pérez-Rodríguez, F. ; Zwietering, M.H. - \ 2012
International Journal of Food Microbiology 153 (2012)3. - ISSN 0168-1605 - p. 413 - 419.
listeria-monocytogenes - uncertainty
The Central Limit Theorem (CLT) is proposed as a means of understanding microbial risk in foods from a Public Health perspective. One variant of the CLT states that as the number of random variables, each with a finite mean and variance, increases (¿8), the distribution of the sum (or mean) of those variables approximates a normal distribution. On the basis of the CLT, the hypothesis introduced by this paper states that the Coefficient of Variation (CV) of the annual number of food-borne illness cases decreases as a result of a larger number of exposures (or servings) (n). Second-order Monte-Carlo analysis and classical statistics were used to support the hypothesis, based on existing risk models on Listeria monocytogenes in deli meat products focused on elderly people in the United States. Likewise, the hypothesis was tested on epidemiological data of annual incidence of salmonellosis and listeriosis in different countries (i.e. different n). Although different sources of error affected the accuracy of the results, both the Monte-Carlo analysis (in silico) and epidemiological data (in vivo), especially for salmonellosis, demonstrated that the CV of the annual number of cases decreased as n increased as stated by the CLT. Furthermore, results from this work showed that classical statistical methods can be helpful to provide reliable risk estimates based on simple and well-established statistical principles
Reliability of Carbon Stock Estimates in Imperata Grassland (East Kalimantan, Indonesia), Using Georeferenced Information
Yassir, I. ; Putten, B. van; Buurman, P. - \ 2012
Soil Science 177 (2012)1. - ISSN 0038-075X - p. 22 - 30.
soil organic-carbon - spatial variability - regional-scale - land-use - uncertainty - management - storage - design - belgium - field
Knowledge of the spatial distribution of total carbon is important for understanding the impact of regional land use change on the global carbon cycle. We studied spatial total carbon variability using transect sampling in an Imperata grassland area. Spatial variability was modeled following an isotropic stationary process with spherical and exponential variogram functions. Range and sill were estimated at 100 m and 82.29 ton2 ha-2, respectively. For nugget, sill ratio was estimated at 24%, implying a rather strong spatial dependence. In a subsequent total carbon stock inventory based on the sampling design mentioned above, we applied three types of estimators, namely, “naive average procedure,” “spatial average procedure,” and “spatial optimal procedure.” Estimation of total carbon stock (in ton ha-1) following naive average procedure (which erroneously ignores the spatial dependence) resulted in a considerably too narrow 95% confidence interval of 37.52 to 39.75, whereas the outcomes using spatial average procedure and spatial optimal procedure were 36.54 to 40.73 and 37.14 to 40.78), respectively, using the spherical model, and 36.63 to 40.64 and 37.07 to 40.64, respectively, using the exponential model. Our research indicated that, when total carbon stock estimation is the main goal, random sampling is optimal, whereas wide design sampling (i.e., shortest distance between sampling locations not less than the range) can be preferred in some cases
Uncertainty in future N2O emissions due to land use change and socio-economic developments
Nol, L. ; Verburg, P.H. ; Moors, E.J. - \ 2012
Journal of Environmental Management 94 (2012)1. - ISSN 0301-4797 - p. 78 - 90.
nitrous-oxide emissions - methane emissions - scenario development - water-table - soil - uncertainty - inventory - model - scale - agriculture
Better insight in the possible range of future N2O emissions can help to construct mitigation and adaptation strategies and to adapt land use planning and management to climate objectives. The Dutch fen meadow landscape is a hotspot of N2O emission due to high nitrogen inputs combined with moist peat soils due to land use change. Socio-economic developments in the area are expected to have major impacts on N2O emission. The goals of this study are to estimate changes in N2O emissions for the period 2006–2040 under three different scenarios for the Dutch fen meadow landscape (rural production, rural fragmentation, and rural multifunctionality) and to quantify the share of different emission sources. Three scenarios were constructed and quantified based on the Story-And-Simulation approach. The rural production and the rural fragmentation scenarios are characterized by globalization and a market-oriented economy; in the rural production scenario dairy farming has a strong competitive position in the study region, while under the rural fragmentation scenario agriculture is declining. Under the rural multifunctionality scenario, the global context is characterized by regionalization and stronger regulation toward environmental issues. The N2O emission decreased between 2006 and 2040 under all scenarios. Under the rural production scenario, the N2O emission decreased by 7%. Due to measures to limit peat mineralization and policies to reduce agricultural emissions, the rural multifunctionality scenario showed the largest decrease in N2O emissions (44%). Under the rural fragmentation scenario, in which the dairy farming sector is diminished, the emission decreased by 33%. Compared to other uncertainties involved in N2O emission estimates, the uncertainty due to possible future land use change is relatively large and assuming a constant emission with time is therefore not appropriate.
Effect of parameter change upon the extra-tropical atmospheric variability
Levine-Moolenaar, H.E. ; Selten, F.M. ; Grasman, J. - \ 2012
Climate Dynamics 38 (2012)7-8. - ISSN 0930-7575 - p. 1649 - 1659.
north-atlantic oscillation - climate-change - fluctuation-dissipation - models - uncertainty - ensemble - flow
Global climate models contain numerous parameters with uncertain values. In the context of climate simulation and prediction, it is relevant to obtain an estimate of the range of climate outcomes given the parameter uncertainty. Instead of randomly perturbing parameters, we determine parameter perturbations from short-term integrations that potentially have a high impact on the climate of the model. For this purpose we consider a dry, spectral quasi-geostrophic, three-level model on the sphere and its tangent linear and adjoint equations. With an empirical forcing, the model produces a fairly realistic simulation of the extra-tropical winter circulation. We allowed perturbations in a 1,449 dimensional parameter space. As a measure of impact on the climate we compute the change in the probability density function of the dominant patterns of variability. We find that the largest climate response in a set of 1,000 simulations with potentially high impact perturbations is much larger than the largest response in a similar set of simulations with randomly picked perturbations. We conclude that parameter sensitivity calculations based on short term integrations contain valuable information about the sensitivity of the model climate to parameter perturbations. The approach is feasible for state-of-the-art climate models provided that the tangent linear and adjoint equations are implemented
Investment in flood protection measures under climate change uncertainty
Bruin, Karianne De; Ansink, Erik - \ 2011
Climate Change Economics 2 (2011)4. - ISSN 2010-0078 - p. 321 - 339.
Adaptation - climate change - flood protection - river basins - timing of investment - uncertainty
Recent severe river flooding in Europe has triggered debates among scientists and policy-makers on future projections of flood frequency and the need for adaptive investments, such as flood protection measures. Because there exists uncertainty about the impact of climate change on flood risk, such investments require a careful analysis of expected benefits and costs. The objective of this paper is to show how climate change uncertainty affects the decision to invest in flood protection measures. We develop a model that incorporates flexible timing of investment decisions and scientific uncertainty on the extent of climate change impact. This model allows decision-makers to cope with the uncertain impact of climate change on the frequency and damage of river flood events and minimizes the risk of under-or over-investment. One of the innovative elements of our paper is that we explicitly distinguish between structural and non-structural flood protection measures. Our results show that the effects of uncertainty on the optimal initial investment depends on the cost structure of these measures which has several important implications for flood management policy.
Een beoordelingslijst voor de complexiteit van modellen en bestanden
Voorn, G.A.K. van; Walvoort, D.J.J. ; Knotters, M. ; Bogaart, P.W. ; Houweling, H. ; Janssen, P.H.M. - \ 2011
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-paper 11) - 6
biometrie - modellen - voorspelling - evaluatie - kwaliteit - onzekerheid - biometry - models - prediction - evaluation - quality - uncertainty
Het Planbureau voor de Leefomgeving (PBL) maakt bij beleidsevaluaties en verkenningen gebruik van numerieke rekenmodellen die - voor een deel – samen worden ontwikkeld met Wageningen UR. De complexiteit van deze rekenmodellen neemt in het algemeen steeds verder toe. Het idee daarbij is dat het toevoegen van meer processen en variabelen aan een model leidt tot een groter toepassingsgebied, nauwkeuriger uitkomsten en dus tot betere voorspellingen. WOT-paper 11 geeft een beschrijving van een methode om de balans tussen (de complexiteit van) een rekenmodel, de toepassing en de beschikbare data te verbeteren.
Implementing Building with Nature in Complex Governance Situations
Slobbe, E.J.J. van; Lulofs, K. - \ 2011
Terra et aqua 124 (2011). - ISSN 0376-6411 - p. 16 - 24.
kustgebieden - bescherming - onzekerheid - besluitvorming - natuurtechniek - coastal areas - protection - uncertainty - decision making - ecological engineering
Two governance aspects of modern coastal engineering which seem to be of importance to many coastal projects all over the world are considered here. Reflections on these two aspects are related to the context in which projects take place. The first is the fragmentation of decision-making and funding. The second aspect is the growing sense of uncertainty actors experience as a result of the longer time horizons of projects and as a consequence of the integration of a growing number of functions to be served by the projects (including ecological ones). The question is: how to deal with this uncertainty? The issue of uncertainties inherent to “building with nature” is of special interest to projects and of relevance to governance.
Global patterns of land-atmosphere fluxes of carbon dioxide, latent heat, and sensible heat derived from eddy covariance, satellite, and meteorological observations
Jung, M. ; Reichstein, M. ; Cescatti, A. ; Richardson, A.D. ; Arain, A. ; Arneth, A. ; Bernhofer, C. ; Bonal, D. ; Chen, J. ; Gianelle, D. ; Gobron, N. ; Lasslop, G. ; Moors, E.J. - \ 2011
Journal of Geophysical Research: Biogeosciences 116 (2011)G3. - ISSN 2169-8953 - 16 p.
net ecosystem exchange - energy-balance closure - co2 flux - primary productivity - vegetation model - climate - uncertainty - respiration - sensitivity - dynamics
We upscaled FLUXNET observations of carbon dioxide, water, and energy fluxes to the global scale using the machine learning technique, model tree ensembles (MTE). We trained MTE to predict site-level gross primary productivity (GPP), terrestrial ecosystem respiration (TER), net ecosystem exchange (NEE), latent energy (LE), and sensible heat (H) based on remote sensing indices, climate and meteorological data, and information on land use. We applied the trained MTEs to generate global flux fields at a 0.5° × 0.5° spatial resolution and a monthly temporal resolution from 1982 to 2008. Cross-validation analyses revealed good performance of MTE in predicting among-site flux variability with modeling efficiencies (MEf) between 0.64 and 0.84, except for NEE (MEf = 0.32). Performance was also good for predicting seasonal patterns (MEf between 0.84 and 0.89, except for NEE (0.64)). By comparison, predictions of monthly anomalies were not as strong (MEf between 0.29 and 0.52). Improved accounting of disturbance and lagged environmental effects, along with improved characterization of errors in the training data set, would contribute most to further reducing uncertainties. Our global estimates of LE (158 ± 7 J × 1018 yr-1), H (164 ± 15 J × 1018 yr-1), and GPP (119 ± 6 Pg C yr-1) were similar to independent estimates. Our global TER estimate (96 ± 6 Pg C yr-1) was likely underestimated by 5–10%. Hot spot regions of interannual variability in carbon fluxes occurred in semiarid to semihumid regions and were controlled by moisture supply. Overall, GPP was more important to interannual variability in NEE than TER. Our empirically derived fluxes may be used for calibration and evaluation of land surface process models and for exploratory and diagnostic assessments of the biosphere
DREAM(D): an adaptive Markov Chain Monte Carlo simulation algorithm to solve discrete, noncontinuous, and combinatorial posterior parameter estimation problems.
Vrugt, J.A. ; Braak, C.J.F. ter - \ 2011
Hydrology and Earth System Sciences 15 (2011)12. - ISSN 1027-5606 - p. 3701 - 3713.
rainfall-runoff models - metropolis algorithm - differential evolution - global optimization - uncertainty - spaces - mcmc
Formal and informal Bayesian approaches have found widespread implementation and use in environmental modeling to summarize parameter and predictive uncertainty. Successful implementation of these methods relies heavily on the availability of efficient sampling methods that approximate, as closely and consistently as possible the (evolving) posterior target distribution. Much of this work has focused on continuous variables that can take on any value within their prior defined ranges. Here, we introduce theory and concepts of a discrete sampling method that resolves the parameter space at fixed points. This new code, entitled DREAM(D) uses the recently developed DREAM algorithm (Vrugt et al., 2008, 2009a, b) as its main building block but implements two novel proposal distributions to help solve discrete and combinatorial optimization problems. This novel MCMC sampler maintains detailed balance and ergodicity, and is especially designed to resolve the emerging class of optimal experimental design problems. Three different case studies involving a Sudoku puzzle, soil water retention curve, and rainfall – runoff model calibration problem are used to benchmark the performance of DREAM(D). The theory and concepts developed herein can be easily integrated into other (adaptive) MCMC algorithms.
Framing futures: visualizing on social-ecological systems change
Vervoort, J.M. - \ 2011
Wageningen University. Promotor(en): Tom Veldkamp, co-promotor(en): Kasper Kok; Ron van Lammeren. - [s.l.] : S.n. - ISBN 9789461730916 - 192
communicatie - visualisatie - onzekerheid - milieubeheer - multi-stakeholder processen - samenleving - communication - visualization - uncertainty - environmental management - multi-stakeholder processes - society
An appreciation of the complexity and uncertainty that characterizes linked human and natural systems - or social-ecological systems - has proliferated throughout the sciences in recent decades. However, dominant societal images, mental models and discourses frame the complexity of social-ecological systems in biased and simplified ways. Interactive media show much potential to help move beyond the current limitations of societal communication about complex systems. The objective of the research in this PhD thesis is to harness the potential of interactive visualization for the elicitation and communication of societal perspectives on complexity in social-ecological systems.
The thesis takes on two fundamental challenges: 1. eliciting and sharing analytic perspectives (addressed in chapters 3 and 4); and 2. combining analytic understanding with experiential engagement (chapters 4 and 5). These challenges are discussed in chapter 1. We take on these challenges through designing and evaluating a series of new communication tools. Throughout the thesis, accessibility, flexibility and feasibility of communication tools and concepts are crucial preconditions.
To frame the research,chapter 2 uses the challenges from the introduction chapter as a guide and touchstone to identify and evaluate the tools and strategies currently being developed and employed in different fields of environmental science communication. Starting with scenarios communication, the chapter goes on to explore the fields of landscape visualization, serious gaming, and visual analytics/information visualization. An evaluation of these fields concludes that as currently used, the tools and strategies from each domain had different strengths and weaknesses in terms of the communication of social-ecological systems change. To move beyond these limitations, the chapter proposes a design framework that was based on several new elements. Firstly, the use of web 2.0 technology that allowed for the fluid integration of multiple platforms. Secondly, pervasive gaming design that focused on user-generated sources of analytic communication and engagement instead of on realistic environments.
Chapter 3 reports on our first strategy to take on the challenge of eliciting and sharing analytic perspectives on social-ecological systems. The System Perspectives Scope is a tool to explore how participatory models could be used to capture societal actors’ perspectives on the spatial and temporal dimensions of complex systems. The application of this tool in two case studies demonstrates that it is possible to focus explicitly on spatial and temporal system levels and cross-level interactions, different understandings of temporal change, and different basic perspectives on the nature of change in social-ecological systems - all through a relatively simple and accessible format in an on-line context. Results indicate significant relationships between different perspectives on spatial and temporal system levels and different myths of nature.
Chapter 4explores a different analytic strategy with which key societal actors’ mental models could be captured more extensively and fundamentally. We start from the premise that change agents in social-ecological systems, in this case the agricultural innovators in the TransForum project, would have to be experienced at linking many conceptual dimensions in their efforts to create accepted change, including the biophysical dimensions but also the dimensions of institutions, networks, knowledge, power and so on. We also propose that these dimensions and the scales that change agents used to frame them would allow them to capture cross-scale dynamics that they saw as crucial in their systems. We conducted a series of in-depth interviews using the Scale Repertoire, a method that helped create multi-dimensional perspectives on change agents’ storylines that showed cross-scale interactions between these different interpretations of the project. This research confirms that change agents were in fact able to produce a wide range of scales which they could use to capture the cross-scale dynamics they saw as crucial. Based on these results the chapter argues that key societal actors should be involved in interdisciplinary research on the role of scale in the governance of complex systems. Furthermore, consciousness of scale in societal debates should be stimulated.
In chapter 5 we take on the second challenge, evaluating the complementary benefits of communication tools focused on analytic understanding and on experiential engagement in an interactive live setting. In an Oxfordshire, UK case study, we conducted workshops with local sustainable development groups where we combined a live version of the System Perspectives Scope (chapter 3) with ScenarioCommunities, an interactive storytelling tool. ScenarioCommunities proved engaging and vivid to the participants and able to motivate them into creating their own vivid storylines. The System Perspectives Scope elicited individual mental models and facilitated analytic reflection. These benefits are complementary and were perceived as such by the participants. The highly participatory nature of both tools was an asset both to the participants’ experience of the process and the methods’ ability to generate results. The workshop that started with the engagement-oriented tool produced more and better results and was seen as more successful by the participants than the workshop that started with the analytic tool. Though the case study was small, these results are consistent enough to suggest that the transition from experiential engagement to analytic understanding is more natural than the reverse order.
An alternative take on the challenge of combining the facilitation of analytic understanding and experiential engagement was to consider how these modes of communication could be fused. To explore this question, in chapter 6 we sought collaboration with multi-media designers and artists outside of science communication through a series of workshops. The collaborations with designers and artists generated ideas for serious games, group interactions, metaphors and social media storytelling. The computer game concepts and group interactions produced in the workshops proved to capture the widest range of complex systems dynamics, were engaging and focused on strategic knowledge. While the group concepts used participants’ physical experience, the game concepts are potentially limitless in the scale of their application. The social media storytelling concepts were rated highly in terms of engagement and intuitiveness, but less complex systems characteristics. The exploratory nature of this research meant that we were not able to test the actual effects of most concepts. Instead, we relied on expert opinions of their potential. Still, this research project indicates that experiential engagement and analytic understanding can be fused and that games and group concepts can lead to the development of strategic knowledge. Finally, this case study makes a strong argument for collaborative efforts between science communicators and multi-media designers and artists.
In the synthesis (chapter 7) I conclude that interactive visualization can be developed to focus directly on the elicitation and communication of analytic perspectives on social-ecological systems change. Also, combining analytic understanding and experiential engagement can be achieved through separate methods or through full integration to aim for the development of strategic knowledge. The preconditions of flexibility, accessibility and feasibility were turned from limitations into guidelines that focused the design of communication tools clearly on complexity while avoiding complicatedness. Our design-based research provided specific insights and an in-depth learning experience. I believe that focus on the diversity of individual perspectives provides an essential basis for more consensus-oriented work.Through our collaboration with artists and designers, it became clear that modes of communication can themselves represent new spaces for perspectives. I recommend that science communicators focus directly on the characteristics of complex systems and translate and integrate analytic and experiential and conceptual and practical modes of communication. Demands for accessibility, flexibility and feasibility should be turned into benefits. Artists and scientists should be collaborating on complex systems communication; design and art communities have to be informed and inspired. I recommend a conscious recognition of the role and goals of the communicator in a given context. Finally, I suggest that opportunities must be sought to institutionalize complexity-conscious communication strategies to up-scale their impact.
Bio-economic modeling of water quality improvements using a dynamic applied general equilibrium approach
Dellink, R. ; Brouwer, R. ; Linderhof, V.G.M. ; Stone, K. - \ 2011
Ecological Economics 71 (2011). - ISSN 0921-8009 - p. 63 - 79.
nutrient abatement - river-basin - management - cost - netherlands - uncertainty - strategies - economy - impacts
An integrated bio-economic model is developed to assess the impacts of pollution reduction policies on water quality and the economy. Emission levels of economic activities to water are determined based on existing environmental accounts. These emission levels are built into a dynamic economic model for the Dutch economy and subsequently coupled to a national water quality model. The modular approach has the advantage that the impacts on the economy and water quality are evaluated simultaneously, but each within their own domain based on the appropriate scale and level of detail. The dynamic nature of the economic model allows us to also evaluate a derogated water policy as foreseen in the European Water Framework Directive. The indirect costs of different water quality improvement policy scenarios are at least as high as the direct costs related to investments in pollution abatement technology. The stricter the policy scenario, the more important the role of economic adjustment and restructuring mechanisms at the macro-economic level. Significant water quality improvements can be achieved through stringent domestic emission reductions. However, reaching water quality standards is highly dependent on water quality improvement policy in surrounding river basin countries and climate change.
Estimation of N2O fluxes at the regional scale: data, models, challenges
Leip, A. ; Busto, M. ; Corazzo, M. ; Bergamaschi, P. ; Koeble, R. ; Dechow, R. ; Monni, S. ; Vries, W. de - \ 2011
Current Opinion in Environmental Sustainability 3 (2011)5. - ISSN 1877-3435 - p. 328 - 338.
nitrous-oxide emissions - greenhouse-gas inventory - agricultural soils - land-use - european agriculture - mechanistic model - ipcc methodology - cropped soils - uncertainty - information
Empirical and process-based models simulating N2O fluxes from agricultural soils have the advantage that they can be applied at the scale at which mitigation measures can be designed and implemented. We compared bottom-up results from studies providing N2O fluxes at a regional/country or continental scale with estimates from the process-based model DNDC-EUROPE and from the TM5-4DVAR inverse modeling system. While the agreement between different bottom-up models is generally satisfying, only in a few cases a thorough validation of the result was done. Complex empirical or process-based models do not appear to have a better agreement with inverse model results in estimating N2O emissions from agricultural soils for countries or country-groups than simple ones. Both bottom-up and inverse models are limited by the density and quality of observations. Research needs to focus on developing tools that inherit the advantages of both methods.
Calibration and resolution effects on model performance for predicting shallow landslide locations in Taiwan
Keijsers, J.G.S. ; Schoorl, J.M. ; Chang, K.T. ; Chiang, S.H. ; Claessens, L.F.G. ; Veldkamp, A. - \ 2011
Geomorphology 133 (2011)3-4. - ISSN 0169-555X - p. 168 - 177.
rainfall-induced landslides - physically-based model - soil redistribution - hazard assessment - dem resolution - uncertainty - sediment - patterns - terrain - region
In this paper we optimise the spatially explicit prediction of landslide hazard, landslide triggering and subsequent movement downslope of materials for a mountainous catchment in Taiwan. The location prediction is optimised by subsequently adding three location parameters: rainfall distribution, land-use classes and DEM derived slopes. Then the three most important model parameters are calibrated to find the best prediction for both stable and unstable areas. The landslides predicted by the LAPSUS-LS model are compared with a landslide inventory to validate the output. The optimal model settings for the calibration area are then applied to a validation area. Results show that model performance can be improved by adding the spatial distribution of rainfall and by stratifying according to land-use classes. Landslide prediction is better with fine resolution DEMs, mainly because the local topography is smoothed in coarser resolutions. Although in general the amount of landslides is over-predicted, the overall performance indicates that the model is able to capture the important factors determining landslide location. Additional spatially distributed data such as regolith or soil depth and regeneration rates of the legacy effect can further enhance the model's prediction.
Soil organic carbon stocks under native vegetation - revised estimates for use with the simple assessment option of the Carbon Benefits Project system
Batjes, N.H. - \ 2011
Agriculture, Ecosystems and Environment 142 (2011)3-4. - ISSN 0167-8809 - p. 365 - 373.
land-use - climate-change - world - sequestration - uncertainty - database - storage - matter - brazil - model
The Carbon Benefits Project (CBP) is developing a standardized system for sustainable land management projects to measure, model and report changes in carbon stocks and greenhouse gas (GHG) emissions for use at varying scales. A global framework of soil organic carbon (SOC) stocks under native vegetation for application in data poor regions, using the simple assessment option of the CBP system, is presented. It considers default classes for climate and mineral soils as required for IPCC Tier 1 (empirical) level GHG inventories. Suitable soil profiles were extracted from an expanded version of the ISRIC-WISE database. Probable outliers within each climate–soil cluster were removed using a robust outlier-rejection procedure. Mean SOC stocks, to the IPCC reference depth of 30 cm (SOC30), vary greatly within each cluster. Overall, present estimates of SOC30 are lower than those listed in the 2006 IPCC Guidelines (though not necessarily in the statistical sense) that drew on a smaller selection of profiles from a more limited geographic area. They represent globally averaged values of SOC stocks under native vegetation that may differ from country/region specific values. Finer criteria for defining climate zones and soil classes, and replacement of default reference stocks and stock change factors with region-specific values, will be necessary to reduce uncertainty.
Economic risk analysis of agroparks : final report
Ge, L. ; Asseldonk, M.A.P.M. van; Galen, M.A. van; Hietbrink, O. ; Verstegen, J.A.A.M. ; Ruijs, M.N.A. ; Mansfeld, M.J.M. van; Smeets, P.J.A.M. ; Simons, A.E. - \ 2011
[Den Haag] : LEI Wageningen UR - 29
agro-industriële complexen - agro-industriële sector - clusters - economische analyse - risicofactoren - risicobeheersing - onzekerheid - modellen - duurzame ontwikkeling - agroindustrial complexes - agroindustrial sector - clusters - economic analysis - risk factors - risk management - uncertainty - models - sustainable development
The concept of agroparks is a type of sustainable intensification that is consistent with metropolitan agriculture: an agropark is a spatial cluster of different agricultural functions and related economic activities. The concept of agroparks has been the object of increasing interest in recent years. One of the difficulties facing the development of an agropark is the uncertainty concerning the feasibility and the return to be obtained. This reflects the fact that an agropark consists of various mutually dependent businesses. The result is a complex set of uncertainties in relation to technological, institutional and market development. This research is concerned with analysing the uncertainties and opportunities of agroparks. This has resulted in a risk model that identifies the qualitative and/or quantitative uncertainties of an agropark. Appropriate measures and management strategies can be pinpointed as a result, thereby converting potential risks into realistic opportunities. The risk model goes hand in hand with a four-stage plan for risk analysis and management. The results of this research allow entrepreneurs to make well-founded investment choices, thereby contributing towards the development of agroparks and more sustainable agriculture.
Efficient versus Sustainable Livestock Grazing in the Sahel
Weikard, H.P. ; Hein, L.G. - \ 2011
Journal of Agricultural Economics 62 (2011)1. - ISSN 0021-857X - p. 153 - 171.
species composition - dynamics - systems - management - rangelands - degradation - cattle - precipitation - productivity - uncertainty
To date, there is no consensus on optimal stocking rates in the semi-arid Sahel. We develop a model for livestock management based on a detailed analysis of ecosystem dynamics, and we apply it to calculate optimal and sustainable livestock stocking rates in a Sahelian rangeland. The general model accounts for stochastic rainfall and the long-term impact of grazing on rangeland productivity. For the case study area, the model shows that the optimal stocking rate is higher than the sustainable stocking rate. Hence, with current prices, it is optimal for the pastoralist society to deplete their resource base. In our case study, we also find that the current stocking rate exceeds the optimal stocking rate, which adds to soil depletion
Evenwichtsanalyse modelcomplexiteit : een verkennende studie
Bogaart, P.W. ; Voorn, G.A.K. van; Akkermans, L.M.W. - \ 2011
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-werkdocument 226) - 49
biometrie - modellen - voorspelling - evaluatie - kwaliteit - onzekerheid - biometry - models - prediction - evaluation - quality - uncertainty
Dit werkdocument omvat een verkennende studie om de mogelijkheden te evalueren van de verhouding tussen de complexiteit van een model of bestand, de ondersteunende data, en de toepassing. Dit verhoudingsconcept wordt als „evenwicht¿ aangeduid. Doel is een reductie in de onzekerheid in voorspellingen door modellen en bestanden. In dit document wordt een prototype van een evaluatielijst voorgesteld. Deze lijst is gebaseerd op de relevante punten die een rol spelen bij evenwicht. De lijst bestaat uit twee sublijsten, die elk uit onderdelen met vragen bestaan. De ene sublijst is gebaseerd op de bestaande evaluatielijst voor „status A¿, die gebruikt wordt in de kwaliteitsborging bij de WOT Natuur & Milieu onderdeel van Wageningen UR. De andere sublijst omvat relevante kernvragen voor „evenwicht¿ die nog niet operationeel zijn. Elk onderdeel is gekoppeld aan een fase in de modelleercyclus, behalve het overkoepelende onderdeel „schaal¿. De discussie beschrijft het projectvervolg, waarin wordt beoogd om de evaluatielijst te toetsen aan casussen en de kennis van experts.