OTTAWA -- Monday's byelection win for the Green party in B.C. is a sign that Canadians are "preoccupied" with the issue of climate change going into this fall's federal election, says Prime Minister Justin Trudeau.

Green hopeful Paul Manly took a commanding 37.3 per cent of the vote in the Vancouver Island riding of Nanaimo-Ladysmith, besting Conservative challenger John Hirst, who earned 24.8 per cent of ballots cast. The NDP's Bob Chamberlin came in third at 23.1 per cent.

Trudeau's Liberals, represented by Michelle Corfield, managed just 11 per cent of the vote and were never a factor in the riding, vacated by former NDP MP Sheila Malcolmson, who now sits in the provincial legislature. But the prime minister seemed upbeat about the result nonetheless.

"I think as we see the rise of successful conservative politicians at the premier level right across the country who don't believe in taking climate action, it is going to be really, really important that Canadians pick a government this fall that is committed to climate action," he said before a cabinet meeting Tuesday.

"That's certainly the point we are going to be making throughout the fall."

An improvement in Green fortunes across the country -- they now comprise the official Opposition in P.E.I., and posted a respectable third-place finish in a Quebec byelection in February -- would presumably be bad news for the New Democrats, who share similar territory on the political spectrum. That, in turn, could lift sagging Liberal fortunes in a national contest with the Opposition Conservatives.

The prime minister has faced concerted pushback on his carbon tax plan from Andrew Scheer's federal Tories, as well as Saskatchewan Premier Scott Moe, Alberta Premier Jason Kenney and Ontario Premier Doug Ford.

On Friday, the Saskatchewan Court of Appeal ruled in a split decision that the tax imposed on provinces without a carbon price of their own is constitutional.

Once he's sworn in, Manly will become only the second Green party member in Parliament, joining leader Elizabeth May, who was first elected in 2011. Both say they are confident their ranks will be even larger come October.

"People really want to see action on climate change," Manly said Monday of his "historic" win. "It's time to step up and do what needs to be done and have a little bit of political courage to deal with climate change properly."

In a statement, May cheered what she called the courage of voters.

"It is brave to vote for real change," she said. "Paul and I will work tirelessly to continue to earn the trust of Canadians."