DOUG FORD says his first official act as leader of Canada’s most populous province, Ontario, will be to kill the cap-and-trade programme put in place by the Liberal government that his Progressive Conservatives defeated earlier this month. As of June 29th, the date of the handover, Mr Ford promises that what he describes as “the cap-and-trade carbon tax” will be gone. The climate-change programme is provincial policy, but it also forms part of Canada’s national plan, which crucially depends on each of the 10 provinces and three territories reducing greenhouse-gas emissions. In withdrawing Ontario, the second-largest emitter after energy-rich Alberta, will Mr Ford wreck the national climate-change plan?

Canada has long been seen as a laggard in addressing greenhouse-gas emissions. Justin Trudeau, the prime minister, sought to change that after his Liberals defeated climate-sceptic Conservatives in 2015. He signed the Paris agreement, committing Canada to a reduction in emissions of 30% below 2005 levels by 2030. In 2016 he knitted together a climate-change compromise to meet those Paris commitments, which was solid enough to please greener provincial leaders but had enough leeway to bring energy-producing provinces like Alberta and Newfoundland & Labrador on board. So pipeline projects like the Trans Mountain Expansion from Alberta to the west coast were allowed to proceed, but under tougher environmental standards.

A key part of the national plan is a national carbon price starting at C$10 a tonne and increasing to C$50 a tonne by 2022. Provinces can meet this in a number of ways. British Columbia has a carbon tax of $35 a tonne. Alberta has what it calls a carbon levy of C$30 a tonne. Ontario, Quebec and the American state of California had a shared cap-and-trade system where firms bought and traded pollution permits. The latest and seemingly last Ontario auction in May valued carbon at just over C$18 a tonne. Mr Ford, who says he wants to stop drivers from being “gouged at the pumps”, has the authority to cancel the provincial cap-and-trade plan and also has the majority to pass necessary legislation. But the aftermath will be messy. Firms holding an estimated C$2.8bn in now value-less permits (Quebec and California are no longer accepting Ontario trades) will want compensation. The partners had agreed to give each other 12 months’ notice of any intention to withdraw.

More importantly for Mr Ford, the Canadian government has passed legislation giving it the right to impose a carbon tax on any province that does not have a carbon-pricing plan in place by the end of this year. Saskatchewan is asking its Court of Appeal whether the federal government has that right. Mr Ford says Ontario will join that challenge. It is probably a lost cause. Manitoba asked for a legal opinion, which persuaded it to join the national climate-change plan. Manitoba and Saskatchewan are smaller provinces so the plan could proceed without them; Ontario’s opposition is harder for the federal government to deal with. Mr Ford’s decision will not wreck the plan in the first instance, but it may only be a matter of time. Polls indicate the United Conservative Party led by Jason Kenney will replace the climate-friendly New Democratic government in Alberta next year. Mr Kenney is promising to end Alberta’s climate-change plan. Imposing a carbon tax on Canada’s largest province will be tough. Taking on Alberta at the same time could well prove impossible.