The climate has become warmer in Montana and continues to do so. The glaciers in Glacier National Park have receded and are predicted to melt away completely in a few decades. Many Montana cities set heat records during July 2007, the hottest month ever recorded in Montana. Winters are warmer, too, and have fewer cold spells. Previously these cold spells had killed off bark beetles which are now attacking the forests of western Montana. The combination of warmer weather, attack by beetles, and mismanagement during past years has led to a substantial increase in the severity of forest fires in Montana. According to a study done for the U.S. Environmental Protection Agency by the Harvard School of Engineering and Applied Science, portions of Montana will experience a 200-percent increase in area burned by wildfires, and an 80-percent increase in related air pollution.