Deadly Heatwaves Could Threaten Nearly Three-Quarters of World's Inhabitants

As a United Nations agency calls attention to the "unusually early" heatwaves gripping parts of Europe, the Middle East, North Africa, and the U.S., a new study brings an ominous warning about more killer heat near certain to come.

In a statement Tuesday, the World Meteorological Organization (WMO), citing the recent finding by National Oceanic and Atmospheric Administration (NOAA), said that the first five months of the year were the warmest on the books.

The agency pointed to several examples, such as the "[e]xtremely high temperatures of around 40degC (104degF) [that] contributed to the severity of the disastrous wildfire in Portugal which has claimed dozens of lives," and a heatwave that struck Morocco and and brought a record high 42.9degC (109degF) to one part of the country.

Agence France-Presseadds Wednesday that Italy's "current heatwave could turn out to be the most intense in 15 years," while "Britain was set to see its first five-day stretch of temperatures over 30degC (86degF) in June since 1995."

The U.S. Southwest has also been sizzling, as the WMO pointed out. So high were the temperatures in Phoenix on Tuesday--they reached 119degF (48degC)-- flights were being cancelled.

And according to a new global analysis, published Monday in the journal Nature Climate Change, deadly heatwaves could be faced by nearly three-quarters of humanity by 2100.

"We are running out of choices for the future," said lead author Camilo Mora, an associate professor of geography in the College of Social Sciences at the University of Hawai`i at Manoa.

As the Associated Press explains, Mora's "team of researchers examined 1,949 deadly heatwaves from around the world since 1980 to look for trends, define when heat is so severe it kills, and forecast the future." The data they looked at included the heatwave "in Chicago that killed 740 people in 1995, one in Paris that killed 4,870 people in 2003, and a 2010 heat wave in Moscow that killed 10,860," NBC Newswrites.

"We found this very unique threshold of temperature and humidity that allows us to identify why all these people die in all these cities around the world," Mora explained.

Right now, about one-third of the world's population is exposed to potentially killer heat for at least 20 days a year.

Even if drastic reductions to greenhouse gas are made, nearly half--48 percent--of the world's population will face such heat by 2100.

And if they grow unabated? About 74 percent of the population will face potentially deadly heatwaves.

"For heatwaves, our options are now between bad or terrible," Mora stated.

"An increasing threat to human life from excess heat now seems almost inevitable, but will be greatly aggravated if greenhouse gases are not considerably reduced," the researchers wrote.

Climate change, Mora adds, "has put humanity on a path that will become increasingly dangerous and difficult to reverse if greenhouse gas emissions are not taken much more seriously."

And decisions like President Donald Trump's to pull the United States out of the Paris climate agreement are the opposite of what's needed, he said.

"Actions like the withdrawal from the Paris agreement is a step in the wrong direction that will inevitably delay fixing a problem for which there is simply no time to waste," said Mora.