For the third time in the past four years, Americans are choking on smoke from Canada’s burning forests. Last week, roughly 900 wildfires turned the skies over Minneapolis, Chicago and New York into an apocalyptic haze. Air quality in parts of the Midwest ranked among the worst on the planet. More than 100 million people were under health alerts.

Why does this keep happening?

The smoke got President Trump’s attention. In a Friday post on Truth Social, Trump accused Canada of “Willful Negligence” and vowed to hold the country responsible for “not properly maintaining” its forests.

“The United States is being unnecessarily invaded by filthy, polluted, and unhealthy air, the quality of which is dangerous, and totally unacceptable!” he wrote, threatening to add the cost of the pollution to tariffs Canada already pays. 

Three days later, the White House announced 50% tariffs on nearly $20 billion of Canadian imports. The administration cited long-standing trade disputes, though the timing amplified tensions over the smoke.

Canada isn’t the only one with a wildfire problem. America’s forests are burning too. Fires are raging in northern Minnesota and across much of the western United States. Nearly 4 million acres have already burned nationwide this year, well above average for this point in the season. Over the weekend, smoke from fires in Washington and Oregon blanketed parts of British Columbia.

The response north of the border was predictable. Ontario Premier Doug Ford told the president to quit complaining and send help. Prime Minister Mark Carney fell back on a familiar defense: “Climate change is everyone’s responsibility,” he said, “including the United States.”

The climate argument is well-worn. Canada’s forests, the argument goes, are simply too vast and too remote to manage. Its dense stands of black spruce and jack pine evolved to burn in intense fires that destroy the main canopy and reset ecosystems. Once flames reach the treetops, a “crown fire” can race across the canopy too hot and fast for firefighters to attack directly.

There’s some truth to that. Fire seasons have lasted longer in recent years. But neither Canada nor the United States is condemned to a future of smoke-choked skies. Policy choices shape how large and destructive fires become. Both governments have underinvested in prevention while restricting the tools that reduce fire risk. Now Canadians and Americans alike are paying the price.

And it’s a steep price. Wildfire smoke carries fine particulate matter small enough to lodge deep in the lungs and enter the bloodstream. It aggravates asthma and raises the risk of heart attacks and strokes. A 2025 Nature study estimated that smoke from Canada’s record 2023 fires contributed to thousands of deaths in the United States.

Those fires also released roughly 640 million metric tons of carbon. That’s more than the annual emissions of all but three countries. If the fires were a country, they’d have ranked as the world’s fourth-largest carbon emitter. This year is on track for more of the same.

Fortunately, Canada and the United States have tools to reduce the danger. The media and politicians are quick to blame climate change, but the reality is that forest management works. Fuel treatments such as thinning, brush clearance and prescribed burning remove small trees, brush and dead material that allow flames to climb into the canopy and explode into a dangerous crown fire.

The evidence in western US forests is hard to dismiss. A 2024 Forest Service meta-analysis found that thinning followed by prescribed fire reduced the severity of later wildfires by 72% on average. Prescribed fire alone, or thinning followed by pile burning, reduced it by 62%.

Canada’s boreal forest poses a harder problem.

But even there, well-designed treatments can change a fire’s behavior. During Saskatchewan’s 2014 Lagoon Fire, a high-intensity crown fire dropped to the ground after reaching an area that had been thinned and pruned. Crews stopped the fire after it advanced about 400 feet into the treatment. In an Alaska experiment, another crown fire became a surface fire within about 100 feet of entering a treated zone.

Such treatments can save entire communities. The Westbank First Nation in British Columbia has long used thinning and controlled burning. The practices helped it escape major damage when flames approached during a 2021 fire.

Despite all this, Canada does strikingly little of this work. During Canada’s 2023 fire season, The New York Times reported that the country’s capacity to prevent wildfires had been “shrinking for decades,” turning some forests into “a tinderbox.” Canada conducts only “a handful of controlled burns” each year, the Times found.

“We don’t do anywhere near enough prescribed burning in [British Columbia],” Robert Gray, a Canadian wildland fire ecologist, told CNN that summer, noting that New Jersey does more controlled burns than the entire province. A new Canadian Senate report states that only about 17,000 acres nationwide were treated with prescribed burning in 2023 — an area barely larger than Manhattan, in a country with 10% of the world’s forests.

The problem is that Canada has regulated the cure nearly out of existence. “Essentially, you’ve handcuffed folks — foresters and silviculturists — from being able to get off successful prescribed burns because we made the rules so onerous and so restrictive,” Sarah Bros, an Ontario forester who has done controlled burning, told the Times.

Why has Canada let this tool wither? Its wildfire agencies were built to put fires out, not use them to manage forests. The result is a series of practical barriers: too few trained crews, steep liability risks and air-quality rules that restrict controlled burns due to smoke concerns — even though such burns produce far less total smoke than the megafires they help prevent.

This doesn’t mean Canada can manage its forests to prevent every large fire. But smarter targeting is needed: treating areas near towns, power lines and evacuation routes, plus adding strategic fuel breaks in remote areas.

American forest management is snarled by many of the same problems. Prescribed burning is common in the southeast but is badly underused across western states, where permitting, environmental review and litigation frequently stall the work. A recent study found it takes an average of five to seven years to implement major fuel treatment projects due to excessive litigation and federal red tape.

Both countries also struggle with firefighting coordination. The Canadian Senate report found that no single authority is responsible for national wildfire preparedness and response. Fire management is split among 10 provinces and three territories, with Ottawa providing money and emergency support. The report recommended creating a federal coordinating office for wildfires. Washington has begun moving in that direction by unifying the Interior Department’s fire programs under the new US Wildland Fire Service.

Faster detection could help, too. Lightning strikes account for more than 80% of the area burned in Canadian wildfires. Better lightning mapping and pre-positioned crews could catch more remote fires while they are still small. British Columbia is spending up to C$1 million to test a Vancouver startup’s claim that it can reduce cloud-to-ground lightning in high-risk storms. The technology is unproven, but a closely monitored field trial is a reasonable way to find out.

Washington has its own work to do. The bipartisan Fix Our Forests Act would speed fuel-reduction work in high-risk areas. It passed the House last year but still awaits a floor vote in the Senate.

Two related bills, the FIRE Act and the FENCES Act, would also help. The Clean Air Act can penalize states for the smoke from prescribed burns or from foreign sources, including Canadian blazes. The FIRE and FENCES acts would fix this. Both passed the House this spring but are stalled in the Senate.

Canada and the United States cannot stop every wildfire, but they can keep more fires from growing into disasters that choke cities hundreds of miles away. The fires will return. Both countries should give them less to burn.

Shawn Regan is a senior fellow at the Manhattan Institute.