British Columbia Opposition Leader John Rustad is proposing a "carbon tax" on U.S. thermal coal that is shipped out of B.C. ports to use as leverage against threats of American tariffs on Canadian softwood lumber.

Rustad says such a tax would be a "tool to fight back" on softwood tariffs and duties proposed by U.S. President Donald Trump, which Forests Minister Ravi Parmar said last week could increase to more than 50 per cent.

He says that until "unfair and unwarranted" U.S. duties on B.C. softwood are removed, the province needs "to be ready to hit the Americans where it hurts.”

The B.C. Conservatives had previously said that "rather than retaliate and exacerbate" the tariff threat, it should be considered an "opportunity to rapidly advance B.C.’s economy."

Rustad today distinguished between retaliating with tariffs and applying a "graduated carbon tax" that would be increased until B.C. got a softwood lumber deal.

He says 18 million tonnes of U.S. thermal coal is shipped through Vancouver, but the province doesn't use it.

Rustad also proposed a ban on American funding for B.C. environmental activists, who he called "troublemaking layabouts" who wasted police and courts' time and "dragged our resource industries through costly litigation."

The governing NDP is meanwhile calling for unanimous endorsement for a motion condemning Trump and backing a national plan for "strategically targeted retaliatory action."