Temperature increase reduces global yields of major crops in four independent estimates

TLDR

Wheat, rice, maize, and soybean supply two‑thirds of global calories, making their temperature sensitivity crucial for food security, yet studies disagree on the magnitude of the effect. The study aims to assess how global temperature rise affects yields of these four major crops. We compiled published results from four analytical approaches—grid‑based and point‑based models, statistical regressions, and field‑warming experiments—to evaluate temperature effects on crop yields. All methods consistently show negative temperature impacts on global yields, with each °C rise reducing wheat by 6.0 %, rice by 3.2 %, maize by 7.4 %, and soybean by 3.1 % in the absence of CO₂ fertilization, adaptation, or genetic improvement; results vary across crops and regions, but multimethod analysis strengthens confidence and points to crop‑ and region‑specific adaptation strategies.

Abstract

Wheat, rice, maize, and soybean provide two-thirds of human caloric intake. Assessing the impact of global temperature increase on production of these crops is therefore critical to maintaining global food supply, but different studies have yielded different results. Here, we investigated the impacts of temperature on yields of the four crops by compiling extensive published results from four analytical methods: global grid-based and local point-based models, statistical regressions, and field-warming experiments. Results from the different methods consistently showed negative temperature impacts on crop yield at the global scale, generally underpinned by similar impacts at country and site scales. Without CO2 fertilization, effective adaptation, and genetic improvement, each degree-Celsius increase in global mean temperature would, on average, reduce global yields of wheat by 6.0%, rice by 3.2%, maize by 7.4%, and soybean by 3.1%. Results are highly heterogeneous across crops and geographical areas, with some positive impact estimates. Multimethod analyses improved the confidence in assessments of future climate impacts on global major crops and suggest crop- and region-specific adaptation strategies to ensure food security for an increasing world population.