An analysis of satellite images has revealed that extreme temperatures are cutting wheat yields in northern India, indicating that the adverse impacts of rising temperatures on wheat production in warmer climes may be more severe than previously believed. Using nine years of imagery of India’s fertile Ganges plain, Stanford University researcher David Lobell found that wheat turned from green to brown earlier when average temperatures were higher, an indication that the warmer conditions are causing the crops to age prematurely. The effects were particularly strong when temperatures exceeded 34 degrees C (93 degrees F), Lobell found. He calculated that an average temperature increase of 2 degrees C could trigger a 50 percent greater yield loss than existing models suggest. Earlier studies calculated that wheat-growing areas could see yield drops of 5 percent for every 1 degree C that the average temperature rises above 14 degrees C. Wheat is the world’s second-biggest crop and provides about one-fifth of the world’s protein.