Killer heat is getting worse, a new study shows. Deadly heat waves like the one now broiling the American West are bigger killers than previously thought and they are going to grow more frequent, according to a new comprehensive study of fatal heat conditions. Still, those stretches may be less lethal in the future, as people become accustomed to them. A team of researchers examined 1,949 deadly heat waves from around the world since 1980 to look for trends, define when heat is so severe it kills and forecast the future. They found that nearly one in three people now experience 20 days a year when the heat reaches deadly levels. But the study predicts that up to three in four people worldwide will endure that kind of heat by the end of the century, if global warming continues unabated. “The United States is going to […]