SEATTLE -- Hundreds of Seattleites are projected to die in severe heat waves as the globe warms.
How much humans limit greenhouse gas emissions will have a significant impact on just how many people perish, according to a new study published earlier last week in the journal Science Advances.
Researchers used climate-warming scenarios and heat-mortality data to predict the severity of future heat waves for 15 U.S. cities, including Seattle.
Here, about 725 people are projected to die in each extreme heat event if global temperatures rise about 5.4 degrees Fahrenheit since pre-industrial times. In that scenario, Seattle could see daily mean temperatures (averaging day and night measures) of about 97 degrees Fahrenheit at their highest.
If countries meet the greenhouse gas reduction levels they pledged in the 2016 Paris Agreement, global temperatures could reach or approach that mark by about 2100, according to previous research cited in the study.
President Donald Trump vowed in 2017 to withdraw from that deal. Meanwhile, global carbon dioxide emissions hit record highs last year, according to scientists' projections. Washington state's most recent tally of its greenhouse gas emissions showed a rise.
Scientists have warned for years that climate change would cause killer heat waves, but the Science Advances paper estimates specific impacts for individual cities like Seattle and makes clear how many lives are at stake.
"These are the first estimates of what that increased burden from extreme heat waves would be if we don't cut emissions," said Kristie Ebi, a professor of global health at the University of Washington who was one of the study's authors.
That could help clarify the climate threat to the public, scientists said.
"This puts numbers on it to communicate that risk a little better to people," said Karin Bumbaco, Washington's assistant state climatologist, who was not involved in the paper.