18 March 2014: A study published in Nature Climate Change finds that moderate warming will be more detrimental to crops in temperate and tropical regions than previously thought. In ‘A Meta-Analysis of Crop Yield under Climate Change and Adaptation,’ the authors find that, with warming of two degrees Celsius and without adaptation measures, the mean yields of wheat, rice and maize are reduced in these regions from the 2030s onwards.

The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) had largely projected yield increases in temperate regions for local mean temperature rises up to two degrees Celsius, but, according to the Nature article, there is a greater risk for yield decreases than previous data had shown. The authors’ data set builds on one created for the AR4, doubling the number of studies to include more than 1,700 published simulations. A large part of the data presented in the study is reproduced in the IPCC Fifth Assessment Report (AR5).

The findings suggest that the negative impacts on crop production can be at least partially mitigated by adaptation. The study also finds that yield variability on a year-to-year basis is likely to increase with time. However, the authors note that most studies have examined mean yield, making it difficult to draw conclusions on year-to-year variability.

The study was supported by the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) and the Natural Environment Research Council (NERC) EQUIP Programme, with the financial assistance of the EU, the Canadian International Development Agency, the World Bank, and the New Zealand Ministry of Foreign Affairs and Trade and Danida. [To access A Meta-Analysis of Crop Yield under Climate Change and Adaptation] [CCAFS Website] [NERC EQUIP Website] [CCAFS Blog Post]