Researchers say that over a four-decade period ending in 2007, the world lost a tenth of its cereal grain crops, such as rice, wheat and corn, due to droughts, heat waves and other extreme weather, reports the New York Times. The study covered 16 crops and 2,800 weather disasters in 177 countries. “They found that droughts cut a country’s crop production by 10 percent, and heat waves by 9 percent, but that floods and cold spells had no effects on agricultural production levels,” said the Times. Rice, wheat and corn supply 50 percent of the world’s calories, said Navin Ramankutty, author of the report. “When these grain baskets are hit, it results in food price shocks, which leads to increasing hunger.” The researchers found that crop losses from drought were more severe in developed countries than in underdeveloped countries. They also said droughts have been more severe since 1985 than before, which could be an effect of climate change or of better reporting of disasters in recent years.