The melting Arctic icecap. Record-smashing wildfires across several provinces. A country that, on average, is warming at twice the rate of the rest of the world.

And yet, as Canadians go to the polls Monday, climate change isn’t even among the top 10 issues for voters, according to recent polling.

“That’s just not what this election is about,” said Jessica Green, a political scientist at the University of Toronto who focuses on climate issues.

What the election is about, nearly everyone agrees, is choosing a leader who can stand up to Donald J. Trump. The American president has been threatening Canada with a trade war, if not total annexation as the “51st state.”

Leading in the polls is the Liberals’ Mark Carney, who has a decades-long pedigree in climate policy. For five years, he was United Nations Special Envoy on Climate Action and Finance, and he spearheaded a coalition of banks that promised to stop adding carbon dioxide to the environment through their lending and investments by 2050.

Despite that résumé, Mr. Carney has not made climate central to his campaign. When Prime Minister Justin Trudeau stepped down, one of Mr. Carney’s first moves was to scrap one of his predecessor’s least popular policies, a tax on fuel that included gasoline at the pump and was based on emissions intensity.