US President Donald Trump has again threatened to impose new tariffs on Canada unless it halts the flow of wildfire smoke into American airspace, a demand he said he delivered directly to Prime Minister Mark Carney during the World Cup final in New Jersey on Sunday. Speaking to reporters at Joint Base Andrews later that evening, Trump stated that while he maintains a good relationship with Carney, “maybe they should pay us some damages or something, or we should do some tariffs.” The remarks follow a social media post last week in which Trump accused Canada of “wilful negligence” in forest management and declared the US was being “invaded by filthy, polluted, and unhealthy air.”

Viewed from Washington, the tariff threat is framed as a cost-recovery measure for what the administration describes as the “incalculable” economic burden of smoke blanketing major cities and forcing business closures, particularly in Michigan. Commerce Secretary Howard Lutnick amplified the pressure by publicly celebrating a separate revenue-sharing agreement on the Gordie Howe Bridge as a negotiating win. However, the reciprocal nature of the smoke hazard complicates the US position. Officials in British Columbia issued air quality warnings on Saturday, attributing smoky conditions to fires burning south of the border in Washington and Oregon, according to the provincial wildfire service. The White House has not addressed the cross-border impact of American fires.

Canadian officials have rejected the accusations, with Carney sidestepping the tariff threat by emphasising that “fighting climate change is the responsibility of all countries, including the United States.” Ontario Premier Doug Ford, whose province is battling nearly 200 active fires, called the US criticism “unacceptable” and reminded Washington of Canada’s past assistance during California wildfires and Hurricane Helene. “That’s what neighbours do,” Ford said. “You don’t get on and start threatening and criticizing because guess what? One day, it’s gonna be your turn.” The federal government in Ottawa notes that it has deployed more than 5,000 firefighters and nearly 300 aircraft, and has increased Ontario’s annual firefighting budget from C$70 million in 2018 to C$150 million today.

The fires have burned over 735,000 hectares in Ontario alone, forced the evacuation of more than 1,800 people from 13 communities, and triggered air quality alerts across the US Midwest and Northeast. While recent rain has slowed some blazes, officials warn that sustained precipitation is needed to bring the situation under control. The diplomatic row is set to intensify this week as Ford and other provincial premiers meet with Carney in Prince Edward Island to push for a national wildfire strategy. No formal tariff action has been announced, but the US president’s repeated linkage of trade penalties to environmental events marks a further deterioration in a bilateral relationship already strained by earlier tariff rounds and Trump’s references to Canada as the 51st state.