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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State-of-the-art global models underestimate impacts from climate extremes
Schewe, Jacob ; Gosling, Simon N. ; Reyer, Christopher ; Zhao, Fang ; Ciais, Philippe ; Elliott, Joshua ; Francois, Louis ; Huber, Veronika ; Lotze, Heike K. ; Seneviratne, Sonia I. ; Vliet, Michelle T.H. Van; Vautard, Robert ; Wada, Yoshihide ; Breuer, Lutz ; Büchner, Matthias ; Carozza, David A. ; Chang, Jinfeng ; Coll, Marta ; Deryng, Delphine ; Wit, Allard De; Eddy, Tyler D. ; Folberth, Christian ; Frieler, Katja ; Friend, Andrew D. ; Gerten, Dieter ; Gudmundsson, Lukas ; Hanasaki, Naota ; Ito, Akihiko ; Khabarov, Nikolay ; Kim, Hyungjun ; Lawrence, Peter ; Morfopoulos, Catherine ; Müller, Christoph ; Müller Schmied, Hannes ; Orth, René ; Ostberg, Sebastian ; Pokhrel, Yadu ; Pugh, Thomas A.M. ; Sakurai, Gen ; Satoh, Yusuke ; Schmid, Erwin ; Stacke, Tobias ; Steenbeek, Jeroen ; Steinkamp, Jörg ; Tang, Qiuhong ; Tian, Hanqin ; Tittensor, Derek P. ; Volkholz, Jan ; Wang, Xuhui ; Warszawski, Lila - \ 2019
Nature Communications 10 (2019). - ISSN 2041-1723
Global impact models represent process-level understanding of how natural and human systems may be affected by climate change. Their projections are used in integrated assessments of climate change. Here we test, for the first time, systematically across many important systems, how well such impact models capture the impacts of extreme climate conditions. Using the 2003 European heat wave and drought as a historical analogue for comparable events in the future, we find that a majority of models underestimate the extremeness of impacts in important sectors such as agriculture, terrestrial ecosystems, and heat-related human mortality, while impacts on water resources and hydropower are overestimated in some river basins; and the spread across models is often large. This has important implications for economic assessments of climate change impacts that rely on these models. It also means that societal risks from future extreme events may be greater than previously thought.
LPJmL4 model output for the publications in GMD: LPJmL4 - a dynamic global vegetation model with managed land: Part I – Model description and Part II – Model evaluation
Schaphoff, Sibyll ; Bloh, Werner von; Rammig, Anja ; Thonicke, Kirsten ; Biemans, H. ; Forkel, Matthias ; Gerten, Dieter ; Heinke, Jens ; Jägermeyr, Jonas ; Knauer, Jürgen ; Langerwisch, Fanny ; Lucht, Wolfgang ; Müller, Christoph ; Rolinski, Susanne ; Waha, Katharina - \ 2018
soil carbon - vegetation carbon - global carbon balance - permafrost distribution - discharge - fractional burned area - crop yields - global dynamic vegetation model - vegetation dynamics
LPJmL4 is a process-based model that simulates climate and land-use change impacts on the terrestrial biosphere, the water and carbon cycle and on agricultural production. The LPJmL4 model combines plant physiological relations, generalized empirically established functions and plant trait parameters. The model incorporates dynamic land use at the global scale and is also able to simulate the production of woody and herbaceous short-rotation bio-energy plantations. Grid cells may contain one or several types of natural or agricultural vegetation. A comprehensive description of the model is given by Schaphoff et al. (2017a, http://doi.org/10.5194/gmd-2017-145). The data presented here represent some standard LPJmL4 model results for the land surface described in Schaphoff et al. (2017a,). Additionally, these results are evaluated in the companion paper of Schaphoff et al. (2017b, http://doi.org/10.5194/gmd-2017-146). The data collection includes some key output variables made with different model setups described by Schaphoff et al. (2017b). The data cover the entire globe with a spatial resolution of 0.5° and temporal coverage from 1901-2011 on an annual basis for soil, vegetation, aboveground and litter carbon as well as for vegetation distribution, crop yields, sowing dates, maximum thawing depth, and fire carbon emissions. Vegetation distribution is given for each plant functional type (PFT), crop yields, and sowing dates are given for each crop functional type (CFT), respectively. Monthly data are provided for the carbon fluxes (net primary production, gross primary production, soil respiration) and the water fluxes (transpiration, evaporation, interception, runoff, and discharge) and for absorbed photosynthetically active radiation (FAPAR) and albedo.
LPJmL4 Model Code
Schaphoff, Sibyll ; Bloh, Werner von; Thonicke, Kirsten ; Biemans, H. ; Forkel, Matthias ; Gerten, Dieter ; Heinke, Jens ; Jägermeyr, Jonas ; Müller, Christoph ; Rolinski, Susanne ; Waha, Katharina ; Stehfest, Elke ; Waal, Liesbeth de; Heyder, Ursula ; Gumpenberger, Marlies ; Beringer, Tim - \ 2018
Potsdam Institute for Climate Impact Research (PIK)
soil carbon - vegetation carbon - global carbon balance - permafrost distribution - discharge - fractional burned area - crop yields - global dynamic vegetation model - vegetation dynamics
LPJmL4 is a process-based model that simulates climate and land-use change impacts on the terrestrial biosphere, the water and carbon cycle and on agricultural production. The LPJmL4 model combines plant physiological relations, generalized empirically established functions and plant trait parameters. The model incorporates dynamic land use at the global scale and is also able to simulate the production of woody and herbaceous short-rotation bio-energy plantations. Grid cells may contain one or several types of natural or agricultural vegetation.
LPJmL4 - A dynamic global vegetation model with managed land - Part 1 : Model description
Schaphoff, Sibyll ; Bloh, Werner von; Rammig, Anja ; Thonicke, Kirsten ; Biemans, Hester ; Forkel, Matthias ; Gerten, Dieter ; Heinke, Jens ; Jägermeyr, Jonas ; Knauer, Jürgen ; Langerwisch, Fanny ; Lucht, Wolfgang ; Müller, Christoph ; Rolinski, Susanne ; Waha, Katharina - \ 2018
Geoscientific Model Development 11 (2018)4. - ISSN 1991-959X - p. 1343 - 1375.
This paper provides a comprehensive description of the newest version of the Dynamic Global Vegetation Model with managed Land, LPJmL4. This model simulates - internally consistently - the growth and productivity of both natural and agricultural vegetation as coherently linked through their water, carbon, and energy fluxes. These features render LPJmL4 suitable for assessing a broad range of feedbacks within and impacts upon the terrestrial biosphere as increasingly shaped by human activities such as climate change and land use change. Here we describe the core model structure, including recently developed modules now unified in LPJmL4. Thereby, we also review LPJmL model developments and evaluations in the field of permafrost, human and ecological water demand, and improved representation of crop types. We summarize and discuss LPJmL model applications dealing with the impacts of historical and future environmental change on the terrestrial biosphere at regional and global scale and provide a comprehensive overview of LPJmL publications since the first model description in 2007. To demonstrate the main features of the LPJmL4 model, we display reference simulation results for key processes such as the current global distribution of natural and managed ecosystems, their productivities, and associated water fluxes. A thorough evaluation of the model is provided in a companion paper. By making the model source code freely available at https://gitlab.pik-potsdam.de/lpjml/LPJmL we hope to stimulate the application and further development of LPJmL4 across scientific communities in support of major activities such as the IPCC and SDG process.
The critical role of the routing scheme in simulating peak river discharge in global hydrological models
Zhao, Fang ; Veldkamp, Ted I.E. ; Frieler, Katja ; Schewe, Jacob ; Ostberg, Sebastian ; Willner, Sven ; Schauberger, Bernhard ; Gosling, Simon N. ; Schmied, Hannes Müller ; Portmann, Felix T. ; Leng, Guoyong ; Huang, Maoyi ; Liu, Xingcai ; Tang, Qiuhong ; Hanasaki, Naota ; Biemans, Hester ; Gerten, Dieter ; Satoh, Yusuke ; Pokhrel, Yadu ; Stacke, Tobias ; Ciais, Philippe ; Chang, Jinfeng ; Ducharne, Agnes ; Guimberteau, Matthieu ; Wada, Yoshihide ; Kim, Hyungjun ; Yamazaki, Dai - \ 2017
Environmental Research Letters 12 (2017)7. - ISSN 1748-9318
daily runoff - flood - global hydrological models - GRDC - ISIMIP - peak river discharge - river routing
Global hydrological models (GHMs) have been applied to assess global flood hazards, but their capacity to capture the timing and amplitude of peak river discharge - which is crucial in flood simulations - has traditionally not been the focus of examination. Here we evaluate to what degree the choice of river routing scheme affects simulations of peak discharge and may help to provide better agreement with observations. To this end we use runoff and discharge simulations of nine GHMs forced by observational climate data (1971-2010) within the ISIMIP2a project. The runoff simulations were used as input for the global river routing model CaMa-Flood. The simulated daily discharge was compared to the discharge generated by each GHM using its native river routing scheme. For each GHM both versions of simulated discharge were compared to monthly and daily discharge observations from 1701 GRDC stations as a benchmark. CaMa-Flood routing shows a general reduction of peak river discharge and a delay of about two to three weeks in its occurrence, likely induced by the buffering capacity of floodplain reservoirs. For a majority of river basins, discharge produced by CaMa-Flood resulted in a better agreement with observations. In particular, maximum daily discharge was adjusted, with a multi-model averaged reduction in bias over about 2/3 of the analysed basin area. The increase in agreement was obtained in both managed and near-natural basins. Overall, this study demonstrates the importance of routing scheme choice in peak discharge simulation, where CaMa-Flood routing accounts for floodplain storage and backwater effects that are not represented in most GHMs. Our study provides important hints that an explicit parameterisation of these processes may be essential in future impact studies.
Reconciling irrigated food production with environmental flows for Sustainable Development Goals implementation
Jägermeyr, Jonas ; Pastor, Amandine ; Biemans, Hester ; Gerten, Dieter - \ 2017
Nature Communications 8 (2017). - ISSN 2041-1723
Safeguarding river ecosystems is a precondition for attaining the UN Sustainable Development Goals (SDGs) related to water and the environment, while rigid implementation of such policies may hamper achievement of food security. River ecosystems provide life-supporting functions that depend on maintaining environmental flow requirements (EFRs). Here we establish gridded process-based estimates of EFRs and their violation through human water withdrawals. Results indicate that 41% of current global irrigation water use (997 km 3 per year) occurs at the expense of EFRs. If these volumes were to be reallocated to the ecosystems, half of globally irrigated cropland would face production losses of ≥10%, with losses of ∼20-30% of total country production especially in Central and South Asia. However, we explicitly show that improvement of irrigation practices can widely compensate for such losses on a sustainable basis. Integration with rainwater management can even achieve a 10% global net gain. Such management interventions are highlighted to act as a pivotal target in supporting the implementation of the ambitious and seemingly conflicting SDG agenda.
Erratum to : Impacts of climate change on European hydrology at 1.5, 2 and 3 degrees mean global warming above preindustrial level
Donnelly, Chantal ; Greuell, Wouter ; Andersson, Jafet ; Gerten, Dieter ; Pisacane, Giovanna ; Roudier, Philippe ; Ludwig, Fulco - \ 2017
Climatic Change 143 (2017)3-4. - ISSN 0165-0009 - p. 535 - 535.
Impacts of climate change on European hydrology at 1.5, 2 and 3 degrees mean global warming above preindustrial level
Donnelly, Chantal ; Greuell, Wouter ; Andersson, Jafet ; Gerten, Dieter ; Pisacane, Giovanna ; Roudier, Philippe ; Ludwig, Fulco - \ 2017
Climatic Change 143 (2017)1-2. - ISSN 0165-0009 - p. 13 - 26.
Impacts of climate change at 1.5, 2 and 3 °C mean global warming above preindustrial level are investigated and compared for runoff, discharge and snowpack in Europe. Ensembles of climate projections representing each of the warming levels were assembled to describe the hydro-meteorological climate at 1.5, 2 and 3 °C. These ensembles were then used to force an ensemble of five hydrological models and changes to hydrological indicators were calculated. It is seen that there are clear changes in local impacts on evapotranspiration, mean, low and high runoff and snow water equivalent between a 1.5, 2 and 3 °C degree warmer world. In a warmer world, the hydrological impacts of climate change are more intense and spatially more extensive. Robust increases in runoff affect the Scandinavian mountains at 1.5 °C, but at 3 °C extend over most of Norway, Sweden and northern Poland. At 3 °C, Norway is affected by robust changes in all indicators. Decreases in mean annual runoff are seen only in Portugal at 1.5 °C warming, but at 3 °C warming, decreases to runoff are seen around the entire Iberian coast, the Balkan Coast and parts of the French coast. In affected parts of Europe, there is a distinct increase in the changes to mean, low and high runoff at 2 °C compared to 1.5 °C, strengthening the case for mitigation to lower levels of global warming. Between 2 and 3 °C, the changes in low and high runoff levels continue to increase, but the changes to mean runoff are less clear. Changes to discharge in Europe’s larger rivers are less distinct due to the lack of homogenous and robust changes across larger river catchments, with the exception of Scandinavia where discharges increase with warming level.
How might European Water Resources Change as a Result of a Two Degree Global Warming?
Donnelly, Chantal ; Gerten, Dieter ; Greuell, J.W. ; Pisacane, Giovanna ; Andersson, Jafet ; Roudier, Philippe ; Schaphoff, Sibyll ; Ludwig, F. - \ 2015
In: Abstract Book ECCA 2015. - - 1 p.
This study presents the potential changes to European water resources including mean river discharges, soil moisture stores and flood return levels, as a result of a +2 degree level of global warming. Changes were estimated using a multi-model ensemble made up of five pan-European hydrological models driven by eleven bias-corrected CORDEX climate change simulations representing three different RCPs (2.6, 4.5 and 8.5). This gave a total of 55 simulations, each centred on the time when the global temperature predicted by the GCM exceeds the preindustrial level by 2°C. Changes were compared to the 1971-2000 reference period. The five pan-European hydrological models are E-HYPE, Lisflood, LPJmL, VIC and WBM. River discharge is projected to increase in the majority of Europe in a +2 degree climate. The largest increases occur in the east and the far north while discharge decreases in parts of the Mediterranean. The spatial distribution of changes in discharge mainly followed the predicted changes in precipitation. Flood return periods were shown to ……Soil moisture is predicted to decrease for the southwestern Mediterranean regions, while other soil moisture changes were not consistent between models. Due to a large spread in model outcome the projected changes in discharge are only significant for about half of Europe’s area, where significant changes were defined as those where the absolute value of the median projected change across all ensemble members exceeds the standard deviation for any grid cell. It was found that uncertainty in discharge change was to a larger extent due to the climate models than to the hydrological models whereas uncertainty in soil moisture changes was mainly due to the hydrological models.
Seasonal forecasting of european river discharge: hindcast verification of VIC and LPJML models driven by ECMWF System4
Greuell, J.W. - \ 2015
In: Seasonal Hydrobiological Forecasting Workshop Book of Abstracts. - - p. 29 - 30.
hindcast verification, river discharge, VIC model, LPJmL model
The hydrological models VIC (Liang, Lettenmaier et al. 1994) and LPJmL (Gerten, Schaphoff et al. 2004) have been widely used for the assessment of climate change impacts on water resources and water dependent sectors, stand-alone (van Vliet, Franssen et al. 2013) and as part of multi-model ensemble studies (Haddeland, Clark et al. 2011, Prudhomme, Giuntoli et al. 2014). Here we implement the same models to assess their capabilities for seasonal forecasting purposes. We analyse whether any forecasting skill present in seasonal meteorological forecasts propagates into skill in hydrological forecasts.
The VIC and LPJmL models are implemented for the European domain, including routing schemes on a 0.5o grid. As research models, LPJmL model parameters are not calibrated for discharge and VIC only crudely. Baseline runs and model spin up are driven by WFD-EI data (Weedon, Gomes et al. 2011). Hindcast runs are driven by the full 15 member, 30 year, monthly initiated, 7 month forecasts of the ECMWF System4 (Molteni, Stockdale et al. 2011). Each model is driven by both raw forecast data and by the same data bias-corrected against the WFD-EI data. Skill is assessed by ROCSS and RPSS scores of the three terciles (above normal, near normal and below normal), primarily for discharge against both baseline simulations and against observations (mainly obtained from GRDC) from 46 stations covering the whole of the European domain and for other water balance terms against baseline simulations only.
Skills will be presented grouped by the major European climatic zones, as a function of lead time and season. Tentative results show considerable skill in northern Europe for positive and negative spring anomalies with up to 2 months lead time, but decreasing for summer. For central Europe the performance is similar, for western Europe we find very little skill, while for the Iberian peninsula we find some skill for negative anomalies in summer with considerable lead time. More robust results will be presented at the workshop.
Consensus building on the development of a stress-based indicator for LCA-based impact assessment of water consumption : outcome of the expert workshops
Boulay, Anne Marie ; Bare, Jane ; Camillis, Camillo De; Döll, Petra ; Gassert, Francis ; Gerten, Dieter ; Humbert, Sebastien ; Inaba, Atsushi ; Itsubo, Norihiro ; Lemoine, Yann ; Margni, Manuele ; Motoshita, Masaharu ; Núñez, Montse ; Pastor, A.V. ; Ridoutt, Brad ; Schencker, Urs ; Shirakawa, Naoki ; Vionnet, Samuel ; Worbe, Sebastien ; Yoshikawa, Sayaka ; Pfister, Stephan - \ 2015
The International Journal of Life Cycle Assessment 20 (2015)5. - ISSN 0948-3349 - p. 577 - 583.
Consensus-based - Water consumption - WULCA

Purpose: The WULCA group, active since 2007 on Water Use in LCA, commenced the development of consensus-based indicators in January 2014. This activity is planned to last 2 years and covers human health, ecosystem quality, and a stress-based indicator. This latter encompasses potential deprivation of both ecosystem and human, hence aiming to represent potential impacts more comprehensively than any other available LCA-oriented method assessing the “water scarcity footprint” (ISO 2014). Methods: A series of three expert workshops, including non-LCA experts from hydrology, eco-hydrology, and water supply science, was organized specifically on the topic of this generic midpoint indicator. They were held in Zurich on 10th September, in San Francisco on 5th October and in Tsukuba on 27th October 2014. In total 49 experts attended. The specific objectives of the workshops were twofold. First, it was to present the identified options of the stress-based indicator narrowed down by the active members of WULCA during the first 8 months of the project and to receive comments on the relevance, usefulness, acceptability, and focus of the selected indicator. Second, the workshop covered different challenges in the modeling of the indicator and presented the experts with background information and specific questions. This paper summarizes the discussions and outcome of these workshops. Where no agreement was reached, the working group of active members is considering all inputs received and continues the work. Results and discussion: The discussion covered first the question to be answered by such indicator, resulting on an agreement on the evaluation of the potential to deprive other users of water, independently of who the user is (i.e., human or ecosystems). Special attention was given to the special case of arid areas as well as the definition of environmental water requirements. Specific modeling challenges were then addressed: definition and quantification of human and ecosystem water demand, consideration of green water and terrestrial ecosystems, sources of data, distinction of groundwater and surface water, and temporal and geographical resolution. Conclusions: The input, decisions, and points of discussion were compiled and brought back within the group of active members. The group is using the recommendations and works further on the harmonization of the points of disagreement. It is expected that a selection of indicators representing different ways to address the most important issues will be produced and tested in spring 2015. The analysis of the result should lead to a provisional recommendation by summer 2015.

Validation of five hydrological models across Europe and their suitability for making projections of future changes
Greuell, J.W. ; Donnelly, C. ; Gerten, Dieter ; Ludwig, F. ; Pisacane, G. ; Rossberg, J. ; Roudier, P. ; Schaphoff, S. - \ 2015
Geophysical Research Abstracts 17 (2015). - ISSN 1029-7006 - 1 p.
One of the objectives of the EU-project IMPACT2C is to provide projections of water in Europe for the plus-two-degrees climate. For this purpose, a multi-model assessment was carried out using five hydrological models (E-HYPE, Lisflood, LPJmL, VIC and WBM) forced by the output from eleven selected CORDEX simulations, resulting in an ensemble of 55 simulations. We found significant changes in 30-year mean runoff in the north-eastern half of Europe, while significant drying is confined to some parts of the Mediterranean. In order to obtain insight in the suitability of the participating models to make climate projections, the models were extensively validated with river discharge measurements. Each model was run twice for the period 1979-2000 using two different climate forcing data sets, EOBS and WFDEI. Results show that model biases were very sensitive to the choice of the forcing data set, in particular to precipitation. However, we postulate that a model's ability to project climate change is better assessed by the skill of the model to simulate interannual variability than by the model bias. We then found that, despite large inter-model differences in structure and complexity, all models simulated interannual variability about equally well. Nevertheless, model rankings are shuffled considerably when EOBS forcing is replaced by WFDEI forcing. This was found both when models were ranked in terms of the magnitude of the bias and in terms of their ability to simulate interannual variability. We also validated the five hydrological models when forced by bias-corrected output from the CORDEX simulations for 1979-2000. We found that the computed discharges from the bias-corrected CORDEX simulations and the EOBS observational simulation differ insignificantly, in terms of all of the statistics that we considered and for all five models. This demonstrates the effectiveness of the bias corrections.
Evaluation of five hydrological models across Europe and their suitability for making projections under climate change
Greuell, J.W. ; Andersson, J. ; Donnelly, C. ; Feyen, L. ; Gerten, D. ; Ludwig, F. ; Pisacane, G. ; Roudier, P. ; Schaphoff, S. - \ 2015
Hydrology and Earth System Sciences Discussions 12 (2015). - ISSN 1812-2108 - p. 10289 - 10330.
The main aims of this paper are the evaluation of five large-scale hydrological models across Europe and the assessment of the suitability of the models for making projections under climate change. For the evaluation, 22 years of discharge measurements from 46 large catchments were exploited. In the reference simulations forcing was taken from the E-OBS dataset for precipitation and temperature, and from the WFDEI dataset for other variables. On average across all catchments, biases were small for four of the models, ranging between −29 and +23 mm yr−1 (−9 and +8 %), while one model produced a large negative bias (−117 mm yr−1; −38 %). Despite large differences in e.g. the evapotranspiration schemes, the skill to simulate interannual variability did not differ much between the models, which can be ascribed to the dominant effect of interannual variation in precipitation on interannual variation in discharge. Assuming that the skill of a model to simulate interannual variability provides a measure for the model's ability to make projections under climate change, the skill of future discharge projections will not differ much between models. The quality of the simulation of the mean annual cycles, and low and high discharge was found to be related to the degree of calibration of the models, with the more calibrated models outperforming the crudely and non-calibrated models. The sensitivity to forcing was investigated by carrying out alternative simulations with all forcing variables from WFDEI, which increased biases by between +66 and +85 mm yr−1 (21–28 %), significantly changed the inter-model ranking of the skill to simulate the mean and increased the magnitude of interannual variability by 28 %, on average.
Multi-model projections of water resources in Europe under two degree global warming
Ludwig, F. ; Donnelly, Chantal ; Gerten, Dieter ; Greuell, J.W. ; Pisacane, G. ; Rossberg, J. ; Roudier, Philippe ; Schaphoff, S. - \ 2015
Geophysical Research Abstracts 17 (2015). - ISSN 1029-7006 - 1 p.
One of the main objectives of the EU-FP7-project IMPACT2C is to develop projections of water fluxes and stores
in Europe under two degree global warming. For this purpose, a multi-model assessment was carried out using
eleven CORDEX climate change simulations, which were carried out with five different GCM/RCM combinations
driven by three different RCPs (2.6, 4.5 and 8.5). After making bias corrections, the output from the eleven climate
simulations was used to force five pan-European hydrological models (E-HYPE, Lisflood, LPJmL, VIC and
WBM), resulting in an ensemble of 55 simulations. The ensemble of climate changes (the plus-two-degrees climate
relative to 1971-2000) was evaluated in terms of the median, the standard deviation (measure for uncertainty)
and significant changes. The latter are defined as those changes for which the absolute value of the median exceeds
the standard deviation. We also performed a flood analysis for two return periods (10 and 100 years) fitting a GEV
distribution on the data. Changes in water resources and largely driven by changes in precipitation. Precipitation is
projected to increase in most parts of Europe with decreases confined to Southern Europe. Generally, the patterns
of changes in evapotranspiration and runoff mimic the precipitation change pattern. As a result river discharge is
projected to increase in the majority of Europe in the plus-two-degrees climate. The largest increases occur in the
east and the far north while discharge decreases in parts of the Mediterranean. Due to a large spread in model
outcome only in half of Europe the projected changes in discharge are significant. Changes (mostly decreases) in
soil moisture are significant only in parts of the Mediterranean. It was found that uncertainty in runoff change was
to a larger extent due to the climate models than to the hydrological models whereas uncertainty in soil moisture
changes was mainly due to the hydrological models.
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 (
Constraints and potentials of future irrigation water availability on agricultural production under climate change
Elliott, J. ; Deryng, D. ; Muller, C. ; Frieler, K. ; Konzmann, M. ; Gerten, D. ; Glotter, M. ; Florke, M.F. ; Wada, Y. ; Ludwig, F. - \ 2014
Proceedings of the National Academy of Sciences of the United States of America 111 (2014)9. - ISSN 0027-8424 - p. 3239 - 3244.
model description - requirements - food - scarcity - impacts - part
We compare ensembles of water supply and demand projections from 10 global hydrological models and six global gridded crop models. These are produced as part of the Inter-Sectoral Impacts Model Intercomparison Project, with coordination from the Agricultural Model Intercomparison and Improvement Project, and driven by outputs of general circulation models run under representative concentration pathway 8.5 as part of the Fifth Coupled Model Intercomparison Project. Models project that direct climate impacts to maize, soybean, wheat, and rice involve losses of 400–1,400 Pcal (8–24% of present-day total) when CO2 fertilization effects are accounted for or 1,400–2,600 Pcal (24–43%) otherwise. Freshwater limitations in some irrigated regions (western United States; China; and West, South, and Central Asia) could necessitate the reversion of 20–60 Mha of cropland from irrigated to rainfed management by end-of-century, and a further loss of 600–2,900 Pcal of food production. In other regions (northern/eastern United States, parts of South America, much of Europe, and South East Asia) surplus water supply could in principle support a net increase in irrigation, although substantial investments in irrigation infrastructure would be required.
Towards a revised planetary boundary for consumptive freshwater use: role of environmental flow requirements
Gerten, D. ; Hoff, H. ; Rockstrom, J. ; Jagermeyr, J. ; Kummu, M. ; Pastor, A.V. - \ 2013
Current Opinion in Environmental Sustainability 5 (2013)6. - ISSN 1877-3435 - p. 551 - 558.
safe operating space - future - humanity - impacts - food
We review the conceptual and quantitative foundation of the recently suggested ‘planetary boundary’ for freshwater (PB-Water; i.e. tolerable human ‘blue’ water consumption), and propose ways forward to refine and reassess it. As a key element of such a revision we suggest a bottom-up quantification of local water availabilities taking account of environmental flow requirements. An analysis that respects these requirements in a spatially explicit manner suggests a PB-Water of ~2800 km3 yr-1 (the average of an uncertainty range of 1100–4500 km3 yr-1). This is notably lower than the earlier suggestion based on a simpler top-down analysis (4000 km3 yr-1, the lower value of a range of 4000–6000 km3 yr-1). The new estimate remains provisional, pending further refinement by in-depth analyses of local water accessibility and constraints up-scaled to the global domain, including study of cascading impacts on Earth system properties. With a current blue water consumption of >1700 km3 yr-1, PB-Water is being approached rapidly. Thus, design opportunities to remain within PB-Water are imperative. We argue that their quantification requires analysis of tradeoffs with other planetary boundaries such as those for land use and climate change.
Future water resources for food production in five South Asian river basins and potential of adaptation options – a modelling study
Biemans, H. ; Speelman, F. ; Ludwig, F. ; Moors, E.J. ; Wiltshire, A.J. ; Kumar, P. ; Gerten, D. ; Kabat, P. - \ 2013
Science of the Total Environment 468-469 (2013)Suppl.. - ISSN 0048-9697 - p. S117 - S131.
global vegetation model - climate-change impacts - resolution - india - agriculture - sensitivity - simulation - requirements - availability - information
The Indian subcontinent faces a population increase from 1.6 billion in 2000 towards 2 billion around 2050. Therefore, expansion of agricultural area combined with increases in productivity will be necessary to produce the food needed in the future. However, with pressure on water resources already being high, and potential effects of climate change still uncertain, the question rises whether there will be enough water resources available to sustain this production. The objective of this study is to make a spatially explicit quantitative analysis of water requirements and availability for current and future food production in five South Asian basins (Indus, Ganges, Brahmaputra, Godavari and Krishna), in the absence or presence of two different adaptation strategies: an overall improvement in irrigation efficiency, and an increase of reservoir storage capacity. The analysis is performed by using the coupled hydrology and crop production model LPJmL. It is found that the Godavari and Krishna basins will benefit most from an increased storage capacity, whereas in the Ganges and the Indus water scarcity mainly takes place in areas where this additional storage would not provide additional utility. Increasing the irrigation efficiency will be beneficial in all basins, but most in the Indus and Ganges, as it decreases the pressure on groundwater resources and decreases the fraction of food production that would become at risk because of water shortage. A combination of both options seems to be the best strategy in all basins. The large-scale model used in this study is suitable to identify hotspot areas and support the first step in the policy process, but the final design and implementation of adaptation options requires supporting studies at finer scales.
Global Water Availability and Requirements for Future Food Production
Gerten, D. ; Heinke, J. ; Hoff, H. ; Biemans, H. ; Fader, M. ; Waha, K. - \ 2011
Journal of Hydrometeorology 12 (2011)5. - ISSN 1525-755X - p. 885 - 899.
high-resolution - climate-change - fresh-water - resources - agriculture - vegetation - scenarios - nations - balance - trade
This study compares, spatially explicitly and at global scale, per capita water availability and water requirements for food production presently (1971-2000) and in the future given climate and population change (2070-99). A vegetation and hydrology model Lund-Potsdam-Jena managed Land (LPJmL) was used to calculate green and blue water availability per capita, water requirements to produce a balanced diet representing a benchmark for hunger alleviation [3000 kilocalories per capita per day (1 kilocalorie = 4184 joules), here assumed to consist of 80% vegetal food and 20% animal products], and a new water scarcity indicator that relates the two at country scale. A country was considered water-scarce if its water availability fell below the water requirement for the specified diet, which is presently the case especially in North and East Africa and in southwestern Asia. Under climate (derived from 17 general circulation models) and population change (A2 and B1 emissions and population scenarios), water availability per person will most probably diminish in many regions. At the same time the calorie-specific water requirements tend to decrease, due mainly to the positive effect of rising atmospheric CO(2) concentration on crop water productivity which, however, is very uncertain to be fully realized in most regions. As a net effect of climate, CO(2), and population change, water scarcity will become aggravated in many countries, and a number of additional countries are at risk of losing their present capacity to produce a balanced diet for their inhabitants.
Multimodel estimate of the global terrestrial water balance: Setup and first results
Haddeland, I. ; Clark, D. ; Franssen, W.H.P. ; Ludwig, F. ; Voss, F. ; Arnell, N.W. ; Bertrand, N. ; Best, M. ; Folwell, S. ; Gerten, D. ; Gomes, S. ; Gosling, S. ; Hagemann, S. ; Hanasaki, N. ; Harding, R. ; Heinke, J. ; Kabat, P. ; Koirala, S. ; Oki, T. ; Polcher, J. ; Stacke, T. ; Viterbo, P. ; Weedon, G.P. ; Yeh, P. - \ 2011
Journal of Hydrometeorology 12 (2011)5. - ISSN 1525-755X - p. 869 - 884.
land-surface scheme - space-time climate - parameterization schemes - integrated model - project - simulation - resources - runoff - gcm - precipitation
Six land surface models and five global hydrological models participate in a model intercomparison project [Water Model Intercomparison Project (WaterMIP)], which for the first time compares simulation results of these different classes of models in a consistent way. In this paper, the simulation setup is described and aspects of the multimodel global terrestrial water balance are presented. All models were run at 0.5° spatial resolution for the global land areas for a 15-yr period (1985–99) using a newly developed global meteorological dataset. Simulated global terrestrial evapotranspiration, excluding Greenland and Antarctica, ranges from 415 to 586 mm yr-1 (from 60 000 to 85 000 km3 yr-1), and simulated runoff ranges from 290 to 457 mm yr-1 (from 42 000 to 66 000 km3 yr-1). Both the mean and median runoff fractions for the land surface models are lower than those of the global hydrological models, although the range is wider. Significant simulation differences between land surface and global hydrological models are found to be caused by the snow scheme employed. The physically based energy balance approach used by land surface models generally results in lower snow water equivalent values than the conceptual degree-day approach used by global hydrological models. Some differences in simulated runoff and evapotranspiration are explained by model parameterizations, although the processes included and parameterizations used are not distinct to either land surface models or global hydrological models. The results show that differences between models are a major source of uncertainty. Climate change impact studies thus need to use not only multiple climate models but also some other measure of uncertainty (e.g., multiple impact models).
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