The Midwest and Northeast registered some of the worst air quality in the world last week as wildfire smoke shrouded cities from Minneapolis to New York in an apocalyptic haze. More than 100 million Americans were under air-quality alerts, with smoke even reaching Washington, D.C., by the weekend.
Most of the smoke came from Canada, where about 900 wildfires were burning by Friday. Over 100 were burning in northwestern Ontario alone. Fires are also raging in northern Minnesota and across the western United States, where another brutal fire season is underway. Nearly 80 large fires are uncontained nationwide, and more than 3.9 million acres have burned this year.
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When wildfire smoke blankets America’s largest cities, as it has several times in recent years, people look for scapegoats. Climate change is the reflexive answer. President Trump has a different culprit. In a Truth Social post on Friday, he blamed Canada’s “Willful Negligence” in failing to manage its forests and threatened to add the smoke’s “incalculable” costs to the tariffs Canada already pays.
Both diagnoses are incomplete. Fire needs fuel, and a century of aggressive suppression, combined with too-little thinning and prescribed burning, has allowed dead wood and dense undergrowth to pile up across North American forests. The charge of negligence broadly applies on both sides of the border. Governments in both countries have had to spend heavily fighting fires after they start, while neglecting the work that would make them less severe.
We have seen the consequences before. In 2023, Canada’s worst fire season on record, more than 45 million acres burned, about 5 percent of the country’s forests. The damage extends well beyond the trees. Wildfire smoke carries fine particulate matter hundreds or even thousands of miles, where it lodges in lungs and aggravates respiratory and heart disease. A study published last year in Nature estimated that smoke from Canada’s 2023 fires contributed to roughly 33,000 premature deaths in the United States. The fires also released more carbon than the annual fossil-fuel emissions of almost every country.
Climate change certainly plays a role by lengthening fire seasons and drying fuels, but the severity of fires ultimately depends on how landscapes are managed. Targeted fuels treatment—including forest thinning, brush clearance, and prescribed burning—removes the dense vegetation that causes wildfires to spread and intensify. These treatments don’t necessarily keep fires from starting, but they reduce their intensity, restore more natural forest conditions, and give firefighters a better chance to contain blazes once they break out.
Canada does far too little of this. The New York Times reported in 2023 that approvals for prescribed burns were so slow and burdensome to obtain that the provinces managed to do only “a handful of controlled burns each year.” Little has changed since. According to a recent Canadian Senate report, prescribed burns treated only about 7,000 hectares nationwide in 2023, an area barely larger than Manhattan. The United States, by contrast, treats millions of acres with prescribed fire each year. Florida alone burns more than 2 million acres annually.
Canada has begun to recognize the problem. Ottawa adopted a national prevention and mitigation strategy in 2024 and launched a five-year, $285 million Wildfire Resilient Futures Initiative. Yet responsibility remains fragmented: provinces and territories manage fires but Ottawa supplies funding, science, and emergency coordination. The Canadian Senate report found that no single authority is responsible for national wildfire preparedness—everyone owns a piece of the problem, so no one owns the outcome—and that the system tends to mobilize only after a disaster is underway.
Canada’s boreal forest differs from the dry western forests of the United States, where forest thinning and prescribed burning are more common. Many boreal ecosystems are adapted to large, stand-replacing fires—blazes intense enough to kill most or all of the trees in given section—and the landscape is too vast and remote to treat every acre.
But that makes it essential to target treatments where they will do the most good. Past thinning and burning practices helped protect First Nations communities in British Columbia from encroaching flames during previous extreme fire seasons. Canadian governments should approve and fund far more thinning and beneficial fire near communities and critical infrastructure.
The United States already shares firefighters and equipment with Canada. Given how much Canadian smoke harms Americans, it should also explore sharing the cost of carefully targeted prevention work. Americans experienced three times as many person-days of exposure to Canada’s 2023 smoke as Canadians did, according to the 2025 Nature study. Prevention, in other words, is a cross-border public good.
The work makes economic sense. A recent study of nearly 300 western wildfires found that each dollar spent on fuel treatments avoided $3.73 in smoke and property damage. A separate study found that every dollar spent on treatments in the Pacific Northwest saved five to six dollars in federal suppression costs. Investing in prevention, in other words, means paying far less once fires break out.
American forests need the same attention. The bipartisan Fix Our Forests Act, which the House passed last year, would accelerate fuel-reduction projects in high-risk areas and limit procedural and litigation delays. Two other House-passed bills would remove air-quality obstacles. Colorado Rep. Gabe Evans’s FIRE Act would make it easier for states to exclude smoke from prescribed burns from Clean Air Act calculations. The FENCES Act would provide similar relief for foreign emissions, including Canadian wildfire smoke. All three measures await Senate action.
Both countries know how to make fires smaller and less severe. The question is how many more suffocating summers it will take before their governments figure out that managing forests is better and cheaper than watching them burn.