More than 150,000 Americans may die by the end of this century as a result of a growing number of excessive heat events caused by climate change, according to an analysis of peer-reviewed scientific literature conducted by experts at the Natural Resources Defense Council. With global warming projected to raise North America’s average temperatures another 4°F -11°F this century, according to the U.S. Global Change Research Program, excessive heat events are expected to increase in frequency.

The risks to public health are greatest when high temperatures and certain weather conditions combine to cause Excessive Heat Events. EHE days occur when a location’s temperature, dew point temperature cloud cover, wind speed and surface atmospheric pressure throughout the day combine to cause or contribute to heat-related deaths in that location.
Health impacts spike during these excessive heat events. For example, when deadly heat waves swept across most of the nation in 2006, California was hit the hardest. During a two-week period, 655 deaths, 1,620 excess hospitalizations, and more than 16,000 additional emergency room visits occurred, resulting in nearly $5.4 billion in costs.