Heat Could Keep 79 Million Workers on Farms by 2100

A study published on Aug. 28, 2026, in Environmental Research Letters projects that heat stress on crops and farm workers leaves global economic output roughly 1% lower by 2100 under a business-as-usual emissions future, with the shortfall reaching up to 3% in tropical regions. Both figures are the model's output, not measurements.

The model was run by Di Sheng, Jae Edmonds and six colleagues at the Joint Global Change Research Institute of the Pacific Northwest National Laboratory, with co-authors at the International Institute for Applied Systems Analysis and the University of Maryland. It couples a global multisector economic model to emission-driven atmospheric projections, so that emissions, warming, the biophysical damage and the economy's response to it all move together in one framework. The authors state the results are "conditional on the selected biophysical response functions and model structure."

Most of the projected loss comes from workers rather than plants. Heat reduces both crop yields and labor productivity in the model, and the macroeconomic losses tied to labor heat stress are the larger of the two.

The mechanism runs through the labor market. To offset lost productivity, the model holds roughly 79 million workers in agriculture in 2100 who would otherwise have shifted into higher-paying non-agricultural sectors, slowing structural change and cutting output most in tropical regions. That number is the model's own accounting of where labor sits, not a projection of migration.

The same run also lowers agricultural output, raises food prices and moves farm production toward temperate regions. The study was funded by the U.S. Department of Energy's Office of Science and by Battelle Memorial Institute, and is open access under a CC BY 4.0 license.