“This study has been able to quantify the likely impacts of differing degrees of climate change on yields, by crop and by region,” said co-author Netra Chhetri, a faculty member with the Consortium for Science, Policy & Outcomes at Arizona State University.

“In general, Sub-Saharan Africa and South Asia showed significant yield reductions for the second half of the century.”

In the study, the researchers created a new data set by compiling the results from 1,700 published simulations to evaluate yield impacts of climate change with and without adaptations for rice, maize and wheat. Due to increased interest on the impacts of climate change in global food security, the study was able to create the largest dataset to date on crop responses, with more than double the number of studies that were available for researchers to analyse for the previous IPCC Assessment Report in 2007. “One of the most important findings of this study is that adaptation may not be as effective for rice and maize as it is for wheat,” said Chhetri.

The researchers conclude that, on aggregate, we will see an increasingly negative impact of climate change on crop yields from the 2030s onward. The impact will be greatest in the second half of the century, when decreases of over 25 percent will become increasingly common.

These statistics account for possible adaptation techniques by farmers to mitigate the effects of climate change, such as adjustments in the crop variety and planting date. Later in the century, greater agricultural transformations and innovations will be needed in order to safeguard crop yields for future generations.
“Climate change means a less predictable harvest, with different countries winning and losing in different years. The overall picture remains negative, and we are now starting to see how research can support adaptation by avoiding the worse impacts,” said Challinor.