Climate change is having a major impact on major crop areas. When global crop yields fall, many people will have a problem with basic food shortages. This is a serious issue that needs to be addressed as soon as possible.

According to a study published in the Journal of Environmental Economics and Management, crop cultivation is very vulnerable to climate change. If rapid global warming continues, global crop yields would be 25% by century’s end.

A team of researchers from Boston University, Ca ‘Foscari University of Venice and the Euro-Mediterranean Center on Climate Change (CMCC) created a simulation of how crop yields could change in response to weather patterns.

“Farmers’ capacity to adapt, even over longer periods, might be limited,” explains Professor Ian Sue Wing from Boston University, lead author of the study. “Even in the United States, the world’s agricultural technology frontier, farmers have been able to only slightly compensate for the adverse impacts of extreme heat on yields of maize and soybeans over time frames of decades.”

Enrica De Cian, professor at Ca’ Foscari University and researcher at Cmcc, adds: “We asked ourselves: If difficulties to adapt are observed in the US, what can we then expect for food producers in the tropics, where 40% of the world’s population lives and high temperature extremes are projected to rise more than in the major calorie crop growing regions of the US?”

The authors focused on the 4 most vulnerable crops – corn, soybeans, rice and wheat. These crops make up 3/4 of the world’s calorie intake.

Crop cultivation must change

It is necessary to adapt crop production to the fact that the climate is constantly changing. It is possible to change crop varieties, types of fertilizers, irrigation and dates when crops are grown. It is possible to develop agricultural technologies that will be adapted to the changing climate.

“We used statistical models trained on large global gridded datasets of historical crop yields, temperature and rainfall, to separate changes in yield responses to heat and moisture exposure over their crop-specific growing seasons into two types of adaptation,” explains Malcolm Mistry, postdoc at Ca’ Foscari University of Venice. “On one hand, farmers’ short-run response to unanticipated weather shocks, and, on the other hand, long-run adjustments over decades.”

Have farmers been able to adapt so far?

“Surprisingly, at the global scale and in most world regions, the answer is no,” Professor Enrica De Cian states. “Our results showed that adverse impacts of extreme hot or dry days on the productivity of the crops from which we derive food calories persisted over decades, in line with the earlier findings for the US. Even worse, these negative long-run effects were sometimes larger than the impacts on yield that occurred due to transitory weather shocks.”

“The implication is that global calorie supplies are subject to continuing or even increasing vulnerability to climate change – Professor Ian Sue Wing concludes –. Now, we plan to build on these findings to investigate how irrigation investments and shifting cultivation over space can help offset the impacts of adverse climatic changes”.