Extreme weather threatens human health worldwide

Heat waves are synonymous with summer for most people. But this summer’s heat has broken records for temperatures and duration. As of late July, Texas had experienced highs over 100° Fahrenheit for more than 30 days straight. China posted its highest temperature ever recorded, and Europe’s heat may surpass last year’s onslaught, when more than 60,000 people may have died due to excessive heat.

The hot, dry weather helped fuel coast-to-coast wildfires in Canada, with smoke spilling south and blanketing the U.S. Midwest and East Coast. For many people, it was their first experience with dangerous air quality caused by wildfires, a plague that has become all too familiar to people in the western United States.

Scientists know that wildfire smoke can harm human health, staff writer Meghan Rosen reports. Tiny particles that can lodge deep in the lungs are a big concern, and smoke can contain chemicals like formaldehyde and benzene. But researchers don’t yet know the long-term effects of being exposed to wildfire smoke intermittently over many years and are now focused on answering that question.

The Northern Hemisphere heat waves are being driven by warmer oceans amped up by climate change plus the return of a natural climate cycle called El Niño, staff writer Nikk Ogasa reports. Another factor is meandering jet streams, which have pinned hot air in place.

I asked Rosen, Ogasa and earth and climate writer Carolyn Gramling the question we at Science News have been asking for a few years now: Is this the year that climate change smacks even the least vulnerable?

When it comes to human capacity to withstand extreme heat and high humidity, “there’s this grim feeling like we’re pushing the limit, except we don’t know what the limit is,” Gramling said. She reported last summer that human heat tolerance may be lower than thought (SN: 8/27/22, p. 6). People are definitely talking and thinking more about it, Ogasa said. And he’s adapting himself, going for runs when it’s least humid. Gramling also noted that there’s been a decrease in the number of people saying that climate change doesn’t exist. “People are considering things now that maybe they were less open to before.”

I asked these reporters what questions on climate change and health they’d like to dig into next.

Rosen: “I’d like to know more about how heat and wildfire smoke may affect a developing fetus. Are there particular windows of pregnancy where it’s especially dangerous for someone to be inhaling smoke, or living through a heat wave?”

Ogasa: “I’m curious about how we’re going to reckon with the growing need for cooling. So many places are starting to face unlivable conditions. How do we deal with that growing energy demand, what alternatives are there for people who can’t get traditional AC and in which climates do those alternatives work?”

Gramling: “I’m definitely interested in the limit of human heat tolerance. What even is adaptation?” As we all travel into what feels like uncharted territory, we’ll keep reporting on big questions about climate change, like how much people can adapt and the technological advances that may make a difference.

Nancy Shute is editor in chief of Science News Media Group. Previously, she was an editor at NPR and US News & World Report, and a contributor to National Geographic and Scientific American. She is a past president of the National Association of Science Writers.