On the day his party lost a B.C. seat to the Greens in a byelection this week, Jagmeet Singh took Justin Trudeau to task about climate change, an issue he raised again over the next two days.

It was a change of pace of sorts for the NDP leader.

There have been twenty-four House sittings since Singh claimed his seat on March 18, and he has led his party in question period on more than half of those occasions.

But until this week, he had yet to make climate change the main focus of his first round of questions to the government. That may become a more regular occurrence going forward.

Singh has been under pressure for months to raise his party’s game on climate change.

When he appointed Montreal MP Alexandre Boulerice to the role of deputy leader in March, both men stressed their intention to make the environment a central issue in the party’s upcoming platform.

Read more:

‘Intense sense of emergency’ drives Canadian version of Green New Deal

Opinion | Tony Burman: As climate change worsens, get ready for the political earthquake

What the Nanaimo-Ladysmith byelection can tell Canadians about the upcoming federal election

For many New Democrats, Monday’s defeat to the Greens in Nanaimo-Ladysmith has elevated that plan from priority to necessity.

But the result of the byelection also suggests that it is getting awfully late in the game for the New Democrats to try to upstage Green Party Leader Elizabeth May on the climate-change stage.

The more the NDP talks up the issue, the more it stands to play to the Green Party’s strengths.

Emboldened by the byelection victory, May is poised to spend the months between now and the election calling on voters who are concerned with global warming to send a strong enough Green contingent to Parliament to hold the next government’s feet to the fire. Her ideal scenario would be a minority government that finds the Greens holding the balance of power, as is currently the case in the B.C. legislature.

In so doing, May is borrowing a page from the NDP handbook — claiming for the Greens the role of environmental conscience in the Commons in an era when climate change has become as defining an issue for many voters as social justice once was.

NDP veteran Svend Robinson rightly sees that as a mortal threat to his party. This week he called the byelection result a wake-up call. He is urging Singh to adopt a more aggressive climate plan, even if that puts the federal party offside with some of the economic development projects endorsed by B.C.’s NDP Premier John Horgan.

Robinson says the urgency of global warming has drawn him back into the fray after a 15-year absence. But much has changed since he resigned his federal seat in 2004 and the NDP no longer has first call on environmental activists.

Loading... Loading... Loading... Loading... Loading... Loading...

It is convenient in New Democrat ranks these days to blame Singh’s uneven performance for all that ails the party, but the NDP relinquished the high ground on the environment to the Greens long before he became its leader.

In the 2008 election, Jack Layton campaigned against Stéphane Dion’s Green Shift, often using some of the same arguments as Stephen Harper’s Conservatives.

Layton claimed Dion’s proposed carbon tax would hurt consumers, and would be little more than a nuisance for energy producers. Like Harper’s party, his NDP was a promoter of a cap-and-trade system and a detractor of carbon taxes.

Layton’s successor was initially a fan of the Energy East pipeline.

“It's a win-win to bring (bitumen oil) from west to east. It’s better prices for the producers and therefore more royalties for the producing provinces. It’s better energy security for Canada and it's more jobs here,” Thomas Mulcair told Canadian Press about Trans Canada’s now defunct project in a 2014 interview.

Like Trudeau, the NDP spent the last election campaign not explicitly promising to nix Energy East, but committing instead to an overhaul of the regulatory process that leads to the approval of new pipelines.

For as long as the New Democrats had a credible shot at federal power, they did not need to spend too much time looking over their shoulders for the then-distant Green Party. As recently as four years ago, May was little more than a dot in Mulcair’s rearview mirror.

From the NDP’s perspective, it was good politics to campaign on being more committed to climate change than the other main parties without scaring off voters who favoured a middle course between energy and the environment.

But now May is breathing down the NDP’s tired neck and moves made by Singh’s immediate predecessors are coming back to haunt his party.

The NDP can only hope that its survival as a vital force in the next House of Commons does not depend on it beating the Greens to the climate-change punch next fall.

Chantal Hébert is a columnist based in Ottawa covering politics. Follow her on Twitter: @ChantalHbert

Read more about: