As smoke pours over U.S., Canadian wildfires spark cross-border tensions

Hazardous smoke from Canadian wildfires billowed into the United States this week, prompting warnings for Long Islanders to limit outdoor activity — and drawing the ire of lawmakers in the Midwest who say their northern neighbors are to blame.

”Thanks to Canada’s failed leadership, Ohio’s skies are seeing the worst pollution on record and Ohioans across the state are being subjected to hazardous conditions — we will not tolerate this incompetence,” said Sen. Bernie Moreno (R-Ohio) in a news release Friday announcing a bill that would sanction some Canadian officials and call on the secretary of state to declare the Canadian ambassador persona non grata.

Earlier in the week, four Republican members of Congress from Michigan wrote a joint letter to Canadian Prime Minister Mark Carney complaining of “chronic under-investment in forest thinning, fuel reduction, and prescribed burns, along with inadequate enforcement against arson. … American lungs are paying the price for Canadian inaction, year after year.”

Representatives for the Canadian federal government did not comment, but Ontario Premier Doug Ford answered the Michigan lawmakers at a Friday news conference. “Maybe what you should do rather than complain is send support, send help. Because we have ‌done the ⁠exact same thing for our American friends, and that's what you're supposed to do," he said, according to Reuters.

In a Truth Social post Friday afternoon, President Donald Trump also criticized Canada for “not properly maintaining their Forests,” which he said leads to the United States “being unnecessarily invaded by filthy, polluted, and unhealthy air, the quality of which is dangerous, and totally unacceptable.”

Members of Long Island’s congressional delegation did not respond to requests for comment.

Across Canada on Friday there were 895 wildfires, including 126 burning out of control, covering nearly 6.7 million acres, according to the Canadian federal government’s department for natural resources management. A department website attributed half of the fires to human causes but said natural causes like lightning were to blame for 90% of the burned land.

Wildfires are a natural part of the life cycle of Canada’s 1.2-billion-acre boreal forest, the largest intact forest ecosystem in the world, releasing nutrients on the forest floor, stimulating new growth and allowing some tree species to reproduce.

Sometimes — like in 2023, when Long Island skies turned orange, and this week, when they turned merely hazy — the smoke gets blown our way. "There was a big ridge, or heat dome, in the middle of the country, and we were on the edge of that," said Jase Bernhardt, associate professor of geology, environment and sustainability at Hofstra University. "There was a giant push from northwest to southeast."

But recent fire seasons have also burned much more acreage than average, according to the Canadian government, throwing vast quantities of tiny particulates — often referred to by the shorthand PM 2.5, meaning each one measures 2.5 micrometers or less across — high into the atmosphere, where they blow hundreds of miles. 

John Gradek, faculty lecturer in operations and integrated aviation management at McGill University in Montreal, said Canada needed to respond more aggressively to wildfire seasons supercharged by the warming climate. 

“Your politicians are right — we haven’t done a good job to change our mitigation strategies,” he said.

For years, Gradek said, Canadian authorities monitored but did not attack remote fires deemed to pose no imminent threat to human life or infrastructure.

But the boreal forest is both growing — expanding north into areas previously unsuitable for forest growth — and drying. “We now have a more explosive situation,” he said. “It burns much more intensely, more severely than it has in millennia."

“We have a health issue that unfortunately is crossing the border,” he said.

Gradek favors using manned and autonomous aircraft “to actively monitor and attack forest fires in their nascent form” within minutes of detection. He said the strategy would cost billions of dollars up front and billions annually to maintain but was gaining traction with Canadian leaders.

Gradek said he disagreed with some of the remedies demanded by American lawmakers: "You cannot thin an area the size of Western Europe with no roads into it, and the fires producing this smoke are lightning-caused in country where nobody lives. Arson enforcement doesn't reach lightning. And sanctioning officials or revoking visas doesn't put water on a fire.”