Climate change may increase heat-related deaths by more than 5,000 in Boston, reports says

By David Abel, Globe Staff

An additional 150,000 or more Americans could die by the end of this century due to excessive heat caused by climate change, according to a report released Wednesday by the Natural Resources Defense Council.

The New York-based advocacy group, which based its findings on other studies, projects that Midwestern cities will bear the brunt of hotter summers, with 19,000 additional deaths by the end of the century in Louisville, 17,900 in Detroit, and 16,600 in Cleveland. The Midwestern cities are more vulnerable because of their greater temperature swings, lack of air conditioning and green space, and the types of buildings.

The report estimates an additional 5,715 people will die in Boston by the end of the century because of the increased heat.

The report says about 99 people in Boston now die during a typical summer on days with excessive heat -- when factors such as temperature, dew point, cloud cover, and wind speed combine to contribute to deaths.

As the number of such days increases from an average of 11 days now to 71 days a year by 2099, the council estimates the number of annual deaths due to the heat will increase to about 213 in Boston.

“This is a wake-up call,” said Dan Lashof, director of the council’s climate and clean air program, on a conference call with reporters. “Climate change has a number of real life-and-death consequences. One of which is that as carbon pollution continues to grow, climate change is only going to increase the number of dangerously hot days each summer, leading to a dramatic increase in the number of lives lost.”

The projected deaths are based on the assumption that carbon pollution will rise in the absence of new policies, increasing global temperatures between 4 and 11 degrees Fahrenheit by the end of the century. The estimates do not take into account how more people are likely to buy air conditioners or take other measures to avoid exposure to heat as temperatures rise.

Other cities’ estimated additional death tolls through the end of the century include: Baltimore, 2,900; Chicago, 6,400; Columbus, 6,000; Denver, 3,500; Los Angeles, 1,200; Minneapolis, 7,500; Philadelphia, 700; Pittsburgh, 1,200; Providence, R.I., 2,000; St. Louis, 5,600; Washington, D.C., 3,000.