Glen Kenny usually knows when someone is about to succumb to heat. He’s seen it a thousand times.
Workers may become less responsive than usual. They might struggle to stay focused on the task at hand, or forget to follow safety protocols. They might be short-tempered or aggressive when someone interrupts them. They might tell someone to back off, to leave them alone.
“Their body is under stress,” says Kenny, a professor of physiology at the University of Ottawa who studies the human heat stress response. “And for them, any voices, any distraction, that takes away their focus on themselves becomes an irritation for them. So you’re going to see irritability, you’re going to see loss of awareness of their surroundings, an inability to communicate effectively, all these become critical signs.”
The scary thing is, by the time an individual starts to feel unwell, they are already in the danger zone. Unlike strenuous exercise, heat stress is gradual. It builds, often without the individual noticing it—until all of a sudden, he or she does.
Earlier this month, at least 10 cities in Arkansas, Colorado, Oklahoma, and Texas broke high-temperature records, some by as much as six degrees Fahrenheit. Last week, Texas officials asked residents and businesses to conserve electricity during the hottest times of the day to help avoid overwhelming the grid, as temperatures climbed above 100 degrees Fahrenheit, reaching 113 degrees in Somerville, a small town about an hour’s drive northwest of Houston.
Significant parts of England and Wales are under a heat warning until Tuesday, and temperatures in London today are forecast to climb above 90 degrees Fahrenheit—about 18 degrees hotter than usual this time of year. The United Kingdom will be one of the hottest places on earth today, reaching temperatures more commonly seen in the Western Sahara and the Caribbean. Temperatures in Portugal and Spain soared to triple digits last week as wildfires ripped through both countries. The heat wave that has engulfed Western Europe could last for weeks; meteorologists say it could be the worst Europe has seen since 1757.
China, too, issued alerts to residents of nearly 70 cities as temperatures rose to 104 degrees Fahrenheit last week. According to a state news agency, Shanghai has only experienced temperatures greater than 104 degrees Fahrenheit on 15 days since 1873. Last month was the warmest June on record in 60 years. Roofs have melted and roads have buckled in the heat.
And this is all happening nearly simultaneously—the new normal, brought on by global warming.