The Environmental Defense Fund says extreme heat, changing rainfall, and other climate change impacts will make it harder to grow U.S. staple crops as soon as 2030. The group says future food supplies and farmer livelihoods will be at stake without adaptation efforts getting underway immediately. The EDF report uses an ensemble of 20 computer models to analyze how climate change will alter the yields of staple crops in Iowa, Minnesota, and Kansas by 2030 and 2050. By 2030, nearly all counties in Iowa will see corn yields more than five percent lower than they would have been without climate change. More than half will see declines of 10 percent or more. Over half of Minnesota’s counties will see soybean yields drop by over five percent. Seventeen percent will see drops of more than 10 percent. Eight percent of Kansas counties will see winter wheat yields drop by over five percent by 2030.