A pair of new studies find that not only will climate-fueled heatwaves cause far greater agricultural losses than previously thought, but global warming has already slashed agriculture productivity growth. Research published Thursday in Nature Climate Change found climate change has — despite significant gains in farming technology and fertilizers — already reduced global agricultural productivity growth by about 21% since 1961, with even more severe impacts in warmer regions such as Africa, and Latin America and the Caribbean.

Scientists at the universities of Colorado, Minnesota and Wisconsin-Milwaukee also published research in the Journal of the European Economic Association, finding future agricultural losses from heatwaves could be 10 times greater than previously thought. These changes have devastating consequences for inhabitants of impacted areas — acute hunger, along with the devastation wrought by climate-fueled storms, is contributing to the increased migration of so-called climate refugees from Guatemala, where the price of beans shot up nearly 20% last year, as well as other Central American countries. (Productivity growth: Bloomberg $, The Guardian; Heatwave losses: E&E $; Guatemala hunger crisis: Washington Post $; Climate Signals background: Heatwaves; Hurricanes)