Climate change has likely already affected global food production

TLDR

Crop yields are projected to decline under future climate conditions, and recent evidence indicates that yields have already been affected, though the extent across diverse crops and regions remains uncertain. The study aims to evaluate how observed climate change has affected yields of the world's ten major crops. Using linear regression models that link weather variables to reported crop yields across about 20,000 political units, the authors estimated climate impacts on each crop. The analysis shows that climate change has already reduced global food production, with yield impacts ranging from –13.4 % for oil palm to +3.5 % for soybean, largely negative in Europe, Southern Africa, and Australia, positive in Latin America, mixed elsewhere, and causing an average 1 % drop in calories from these ten crops, reducing caloric availability in about half of food‑insecure countries.

Abstract

Crop yields are projected to decrease under future climate conditions, and recent research suggests that yields have already been impacted. However, current impacts on a diversity of crops subnationally and implications for food security remains unclear. Here, we constructed linear regression relationships using weather and reported crop data to assess the potential impact of observed climate change on the yields of the top ten global crops-barley, cassava, maize, oil palm, rapeseed, rice, sorghum, soybean, sugarcane and wheat at ~20,000 political units. We find that the impact of global climate change on yields of different crops from climate trends ranged from -13.4% (oil palm) to 3.5% (soybean). Our results show that impacts are mostly negative in Europe, Southern Africa and Australia but generally positive in Latin America. Impacts in Asia and Northern and Central America are mixed. This has likely led to ~1% average reduction (-3.5 X 1013 kcal/year) in consumable food calories in these ten crops. In nearly half of food insecure countries, estimated caloric availability decreased. Our results suggest that climate change has already affected global food production.