Americans want payback for smoky skies. Are they right?

People on both sides of the Canada - U.S. border have been choking on smoke in recent weeks, much of it coming from fires burning in Canada's forests. Now, U.S. President Donald Trump is threatening new, fire-related tariffs in retaliation. Climate scientists like Zeke Hausfather say wildfires in Canada’s vast boreal forest are linked to global warming and can't be blamed on just one country. And…