Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    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.
    uncertainty
    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.
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