Abstract: While crop models are widely used to assess the change in crop productivity with climate change, their skill in assessing irrigation water demand or the risk of crop failure in large area impact assessments is relatively unknown. The objective of this study is to investigate which aspects of modeling crop water use (reference crop evapotranspiration (ET0), soil water extraction, soil evaporation, soil water balance and root growth) contributes most to the variability in estimates of maize crop water use and the risk of crop failure, and demonstrate the resulting uncertainty in a climate change impact study for Europe. The SIMPLACE crop modeling framework was used to couple the LINTUL5 crop model in factorial combinations of 2-3 different approaches for simulating the 5 aspects of crop water use, resulting in 51 modeling approaches. Using experiments in France and New Zeland, analysis of total sensitivity revealed that ET0 explained the most variability in both irrigated maize water use and rainfed grain yield levels, with soil evaporation also imporatant in the French experiment. In the European impact study, net irrigation requirement differed by 36% between the Penman and Hargreaves ET0 methods in the baseline period. Average EU grain yields were similar between models, but differences approached 1-2 tonnes in parts of France and Southern Europe. EU wide esimates of crop failure in the historical period ranged between 5.4 years for Priestley-Taylor to every 7.9 years for the Penman ET0 methods. While the uncertainty in absolute values between models was significant, estimates of relative changes were similar between models, confirming the utility of crop models in assessing climate change impacts. If ET0 estimates in crop models can be improved, through the use of appropriate methods, uncertainty in irrigation water demand as well as in yield estimates under drought can be reduced.

Abstract: Impacts of climate change on European agricultural production, land use and the environment depend on its impact on crop yields. However, many impact studies assume that crop management remains unchanged in future scenarios, while farmers may adapt their sowing dates and cultivar thermal time requirements to minimize yield losses or realize yield gains. The main objective of this study was to investigate the sensitivity of climate change impacts on European crop yields, land use, production and environmental variables to adaptations in crops sowing dates and varieties’ thermal time requirements. A crop, economic and environmental model were coupled in an integrated assessment modelling approach for six important crops, for 27 countries of the European Union (EU27) to assess results of three SRES climate change scenarios to 2050. Crop yields under climate change were simulated considering three different management cases; (i) no change in crop management from baseline conditions (NoAd), (ii) adaptation of sowing date and thermal time requirements to give highest yields to 2050 (Opt) and (iii) a more conservative adaptation of sowing date and thermal time requirements (Act). Averaged across EU27, relative changes in water-limited crop yields due to climate change and increased CO2 varied between -6 and + 21% considering NoAd management, whereas impacts with Opt management varied between + 12 and + 53%, and those under Act management between 2 and + 27%. However, relative yield increases under climate change increased to + 17 and + 51% when technology progress was also considered. Importantly, the sensitivity to crop management assumptions of land use, production and environmental impacts were less pronounced than for crop yields due to the influence of corresponding market, farm resource and land allocation adjustments along the model chain acting via economic optimization of yields. We conclude that assumptions about crop sowing dates and thermal time requirements affect impact variables but to a different extent and generally decreasing for variables affected by economic drivers.

Abstract: The workshop was called to define an overarching question to be answered by all Regional  Pilot Studies and to select from the existing studies those that fit best to the aims of  MACSUR. The question that evolved from the discussions is “What would be the different  contributions of different European adaptation strategies to ensure global food security  until 2050 at different scales (farm to EU) while keeping the GHG targets?” Workshop  participants agreed to use the newest climate simulations related to Representative  Concentration Pathways that were also used by the AgMIP and ISI-MIP projects. There was  also agreement to use a subset of the AgMIP scenarios (S2-S6) for impact assessments, with  AgMIP scenario S1 as the reference scenario, for details see Table 3 below. The selection  of Regional Pilot Studies was discussed separately for European Grand Regions, but there  was no concluding decision taken. The Project Steering Committee will finally decide on  showcase studies at a meeting in the first week of July based on characterisations sent in  by interested members. Questionnaires for characterising the Regional Pilot Studies will be  sent by the Hub to the regional contact persons mentioned in Table 2 to fill in. The  characterization list can be extended. The questionnaires should be filled in by the end of  June. Stakeholder meetings are planned for October 2013 in each region where  preliminary/sample outputs of the regional pilot studies should be presented. Results will  be presented at the mid-term meeting in April 2014. The last year of MACSUR is then  available to improve the studies.The geographic extent of the Regional Pilot Studies is  approximately county level – representing the area of the studies they are based on. The  Regional Pilot Studies will be linked within the grand regions (northern, central, southern  Europe) by consistent regional and continental Representative Agricultural Pathways (RAP).  These regional RAPs will feed into the RAP process underway at AgMIP. Through the  common RAPs the Regional Pilot Studies will reflect the common challenges of the greater  region and by having several Regional Pilot Studies the diversity of the environment,  farming systems, and political systems is represented. The workshop was a first step into  further planning and performing the Regional Pilot Studies that will fine-tune the results of  the workshop. No Label