title: The implication of irrigation in climate change impact assessment: a European-wide study.
abstract: This study evaluates the impacts of projected climate change on irrigation requirements and yields of six crops (winter wheat, winter barley, rapeseed, grain maize, potato, and sugar beet) in Europe. Furthermore, the uncertainty deriving from consideration of irrigation, CO2 effects on crop growth and transpiration, and different climate change scenarios in climate change impact assessments is quantified. Net irrigation requirement (NIR) and yields of the six crops were simulated for a baseline (1982-2006) and three SRES scenarios (B1, B2 and A1B, 2040-2064) under rainfed and irrigated conditions, using a process-based crop model, SIMPLACE <LINTUL5, DRUNIR, HEAT>. We found that projected climate change decreased NIR of the three winter crops in northern Europe (up to 81 mm), but increased NIR of all the six crops in the Mediterranean regions (up to 182 mm yr(-1) ). Climate change increased yields of the three winter crops and sugar beet in middle and northern regions (up to 36%), but decreased their yields in Mediterranean countries (up to 81%). Consideration of CO2 effects can alter the direction of change in NIR for irrigated crops in the south and of yields for C3 crops in central and northern Europe. Constraining the model to rainfed conditions for spring crops led to a negative bias in simulating climate change impacts on yields (up to 44%), which was proportional to the irrigation ratio of the simulation unit. Impacts on NIR and yields were generally consistent across the three SRES scenarios for the majority of regions in Europe. We conclude that due to the magnitude of irrigation and CO2 effects, they should both be considered in the simulation of climate change impacts on crop production and water availability, particularly for crops and regions with a high proportion of irrigated crop area.
authors.affiliation: Crop Science Group, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Katzenburgweg 5, D-53115, Bonn, Germany.
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Crop Science Group, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Katzenburgweg 5, D-53115, Bonn, Germany.
authors.forename: Heidi
authors.initials: H
authors.lastname: Webber
authors.affiliation: Crop Science Group, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Katzenburgweg 5, D-53115, Bonn, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Hoffmann
authors.affiliation: Plant Production Systems Group, Wageningen University, P.O. Box 430, 6700 AK, Wageningen, Netherlands.
authors.forename: Joost
authors.initials: J
authors.lastname: Wolf
authors.affiliation: Crop Science Group, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Katzenburgweg 5, D-53115, Bonn, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Siebert
authors.affiliation: Crop Science Group, Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Katzenburgweg 5, D-53115, Bonn, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Ewert
mesh_terms: D057914:Agricultural Irrigation; D002245:Carbon Dioxide / Q000378:metabolism*; D057231:Climate Change; D018556:Crops, Agricultural / Q000254:growth & development / Q000502:physiology*; D005060:Europe; D008954:Models, Biological; D018526:Plant Transpiration; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D002245:Carbon Dioxide
keywords: CO2 effects; LINTUL; SIMPLACE; climate change; crop model; irrigation; water availability; yield change