U.S. swelters in latest heat wave, with Texas and Oklahoma hitting 115°F

The latest extreme heat wave to hit the United States is showing no mercy, leaving more than 105 million Americans in 28 states under heat advisories and excessive heat warnings from the National Weather Service.

Temperatures of 115 degrees Fahrenheit have been recorded in Texas and Oklahoma this week, and more than 211 million people across the country will experience heat of 90 degrees or higher on Wednesday.

In a year when record-breaking heat waves have become commonplace, scientific research has shown that climate change is behind the uptick in their frequency and duration.

“While each heat wave itself is different, and has individual dynamics behind it, the probability of these events is a direct consequence of the warming planet,” Jason Smerdon, a climate scientist for the Columbia Climate School’s Lamont-Doherty Earth Observatory in New York, told ABC News.

Residents of Texas, a state that has been subjected to daily triple-digit temperatures and is in the midst of a mega-drought affecting much of the West, have for weeks been asked to conserve water and electricity.

As in much of Europe, where local officials have urged residents to avoid unnecessary travel as a heat wave there has buckled roadways, airport runways and rail lines, people in several U.S. states have retreated inside air-conditioned spaces.

“When it’s 110 outside, you’re a prisoner in your home,” Andrew Dessler, a professor of atmospheric sciences at Texas A&M University, told the Washington Post. “Is this the kind of life you want to live?”

Like Texas, Oklahoma has been particularly hard hit by the heat, with every one of the state's 120 weather monitoring stations recording temperatures of 102°F or higher on Tuesday.

Coupled with high humidity, the high temperatures pose a serious risk to human health. The human body sweats in order to cool off, but when humidity is high and there is too much moisture in the atmosphere, that sweat cannot evaporate and results in even higher internal temperatures.

Over the last several days in Spain and Portugal, where temperatures have reached near 110°F, more than 1,700 people have died due to heat-related causes.

Officials in Phoenix are worried that the city will once again break heat-death records this year, especially among the vulnerable homeless population.

“I wouldn’t be surprised if we are in worse shape from a heat-associated-death standpoint than we were last year because there are so many more unsheltered folks that are at 200 to 300 times the risk of heat-associated death,” David Hondula, director of the city’s Office of Heat Response and Mitigation, told Yahoo News.

While climate change skeptics often argue that excessive heat is simply a normal seasonal consequence, scientists have established that the burning of fossil fuels since the start of the Industrial Revolution is responsible for rising temperatures.

This year alone, there have been 92 new high-temperature records set in the U.S., compared with just five new records for low temperatures. That same pattern has played out across the planet, with 188 new high-temperature marks having been set through July 16 as compared with 18 new record lows, data from the National Oceanic and Atmospheric Administration shows.

Of course, that would be exactly what you would expect if, as has been proved, global temperatures are rising. In states sweltering in triple-digit heat, meanwhile, the reality of climate change is playing out in real time.

“It looks like we're going to stay in the range of highs of 100 to 105 degrees for the next week and a half,” Erin Maxwell, a meteorologist at the National Weather Service in Norman, told the Oklahoman. “But in terms of real relief from the heat, that doesn't look to be on the horizon any time soon.”