Global wheat production with 1.5 and 2.0°C above pre‐industrial warming
Authors: Liu Bing , Martre Pierre , Ewert Frank , Porter John R. , Challinor Andy J. , Müller Christoph , Ruane Alex C. , Waha Katharina , Thorburn Peter J. , Aggarwal Pramod K. , Ahmed Mukhtar , Balkovič Juraj , Basso Bruno , Biernath Christian , Bindi Marco , Cammarano Davide , De Sanctis Giacomo , Dumont Benjamin , Espadafor Mónica , Eyshi Rezaei Ehsan , Ferrise Roberto , Garcia‐Vila Margarita , Gayler Sebastian , Gao Yujing , Horan Heidi , Hoogenboom Gerrit , Izaurralde Roberto C. , Jones Curtis D. , Kassie Belay T. , Kersebaum Kurt C. , Klein Christian , Koehler Ann‐Kristin , Maiorano Andrea , Minoli Sara , Montesino San Martin Manuel , Naresh Kumar Soora , Nendel Claas , O’Leary Garry J. , Palosuo Taru , Priesack Eckart , Ripoche Dominique , Rötter Reimund P. , Semenov Mikhail A. , Stöckle Claudio , Streck Thilo , Supit Iwan , Tao Fulu , Van der Velde Marijn , Wallach Daniel , Wang Enli , Webber Heidi , Wolf Joost , Xiao Liujun , Zhang Zhao , Zhao Zhigan , Zhu Yan , Asseng Senthold 
Published: December 2018

Efforts to limit global warming to below 2°C in relation to the pre‐industrial level are under way, in accordance with the 2015 Paris Agreement. However, most impact research on agriculture to date has focused on impacts of warming >2°C on mean crop yields, and many previous studies did not focus sufficiently on extreme events and yield interannual variability. Here, with the latest climate scenarios from the Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) project, we evaluated the impacts of the 2015 Paris Agreement range of global warming (1.5 and 2.0°C warming above the pre‐industrial period) on global wheat production and local yield variability. A multi‐crop and multi‐climate model ensemble over a global network of sites developed by the Agricultural Model Intercomparison and Improvement Project (AgMIP) for Wheat was used to represent major rainfed and irrigated wheat cropping systems. Results show that projected global wheat production will change by −2.3% to 7.0% under the 1.5°C scenario and −2.4% to 10.5% under the 2.0°C scenario, compared to a baseline of 1980–2010, when considering changes in local temperature, rainfall, and global atmospheric CO2 concentration, but no changes in management or wheat cultivars. The projected impact on wheat production varies spatially; a larger increase is projected for temperate high rainfall regions than for moderate hot low rainfall and irrigated regions. Grain yields in warmer regions are more likely to be reduced than in cooler regions. Despite mostly positive impacts on global average grain yields, the frequency of extremely low yields (bottom 5 percentile of baseline distribution) and yield inter‐annual variability will increase under both warming scenarios for some of the hot growing locations, including locations from the second largest global wheat producer—India, which supplies more than 14% of global wheat. The projected global impact of warming <2°C on wheat production is therefore not evenly distributed and will affect regional food security across the globe as well as food prices and trade.