Trump threatens Canada over wildfire smoke choking US cities

Scientists also say the extreme heat North America has experienced from coast to coast this summer has been worsened by climate change.

The blanket of haze has sparked comparisons to another extreme summer in 2023, when record-breaking blazes in Canada sent clouds of smoke billowing over the eastern U.S. That year saw the country’s most destructive wildfire season on record, and studies suggest that climate change significantly increased the likelihood of the weather fueling the flames.

Warming temperatures are also changing where and when blazes occur. Western Canada has historically experienced the country’s largest and most destructive blazes. But research suggests that eastern Canada may also be at greater risk as global temperatures continue to rise.

“We’re not saying that climate change started each individual fire, but that extreme heat, along with the drier conditions that they’re experiencing in Ontario, along with the weather conditions that are becoming more likely — we’re seeing an increase in fire weather days,” said Shel Winkley, chief meteorologist at Climate Central. “All of those things put together allow for that explosive wildfire growth, like we saw early this week.”

An analysis by Climate Central shows that on July 13 — the day the cluster of blazes in Ontario and Minnesota causing most of the haze began — temperatures in the Canadian province were 25.2 degrees Fahrenheit above average.

“These temperatures would be virtually impossible to occur on July 13 in Ontario without the influence of climate change,” he said.

While forest management can mitigate the risk, Winkley said, spiking temperatures virtually guarantee more devastating wildfires prevail in the future.

And Canada is not alone in seeing historically active recent fire seasons.

So far this year, more than 5,740 square miles (14,860 square kilometers) of the United States has burned from wildfires, which is 31 percent more than the average of the previous 10 years on this date, according to the National Interagency Fire Center.

Stay inside

Wildfire smoke presents serious risks to human health.

Particulate matter from wildfire smoke attacks nearly every system in the human body, killing tens of thousands of people a year, numerous medical studies show.

Soot from blazes is linked to spiking asthma cases, heart attacks and other cardiovascular and lung issues, as well as mental health issues. It harms pregnant women, increasing the risk of premature births and low-weight babies who could have breathing problems the rest of their lives. It can also contribute to long-term health impacts, including dementia.