New analysis of climate model projections suggest that in the US, the average number of days in August with temperatures over 95 degrees Fahrenheit could nearly triple by 2050, and the average number of days over 100 degrees could nearly double.
Beyond being uncomfortable, these projected increases in extreme heat will have important societal impacts, including: heat stress mortality in humans and livestock; increases in peak energy demand; crop damage; and increased demand for water.
The analysis was done by researchers at Climate Central, US, to illustrate expected increases in extreme summer heat in the country.
According to Climate Central's Associate Director for Strategic Initiatives, Dr. Ben Strauss, the numbers are not predictions.
"We're talking about best estimates and averages. No matter how close the projections turn out to be, some years will have more hot August days, and others will have fewer," he said.
Staff scientists drew on regional scenarios from a dozen highly sophisticated computer climate models to compare 1980 and 1990 averages with 2050 projections in three categories, namely, average number of days in August over 90, average number of days in August over 95, average number of days in August over 100.
All of these measures were projected to increase or stay level in every city analyzed.
The bottom line is that locations across the US are likely to experience significant jumps in the number of extreme hot days in August and other summer months, from New York to Los Angeles, and from Florida to the Midwest to Seattle, which just experienced an unusual heat wave earlier this summer.
Worldwide, since 1995, tens of thousands of people have died in heat waves.
Other important impacts include increases in demand for energy (particularly electricity for cooling), and increases in urban and agricultural water demand.
The severity of increases in extreme heat and their impacts will depend on the extent of future use of fossil fuels.
"We do have some choice here," said Dr. Berrien Moore III, Climate Central's Executive Director. "How hot it will get will depend on the choices we make about energy and transportation in the years to come," he added.