Before spring began, Canadian political leaders were already debating how to respond to the profound challenge of climate change. Now, they're doing it while neighbourhoods in Ontario, Quebec and New Brunswick are under water.

In theory, those rising waters ought to bring a new sense of urgency to the debate. But this spring's floods still seem unlikely to wash away the stark partisan differences that have emerged over climate policy in this country.

The flooding does at least put climate change front and centre. An abstract threat has been made tangible. A problem for the future is suddenly immediate and apparent.

And beyond the expressions of concern for the people directly affected, the conversation has quickly moved to necessary and important questions about adapting to climate change. Is this the new normal? And if it is, what should be done about the homes and infrastructure built in areas that could now be subjected to annual flooding?

It wouldn't be surprising if news coverage of the flooding leads to a spike in public concern about climate change. Last fall, researchers at the Yale Program on Climate Change Communication suggested that higher levels of concern about global warming in some parts of the U.S. were associated with direct experience: those living in states where the effects of climate change are more apparent (coastal storms, wildfires, flooding) tend to take it more seriously.

But other research has found a "weak and quickly dissipating relationship between Americans' experiences of extreme weather and their concern about climate change."

Experience may be a poor teacher

This is hardly the first time Canadians have been faced with the direct impacts of a changing climate. Recall the devastating Fort McMurray wildfire in 2016, or the flooding in Ontario and Quebec in 2017, or the record wildfires in British Columbia in 2018. None of those events produced an overwhelming or lasting consensus in Canada about the urgent need to reduce greenhouse gas emissions and mitigate the future impacts of climate change.

But those events might have been seen as rare, one-off calamities. A recurring series of increasingly devastating events eventually could push public opinion to a tipping point, both in terms of concern about climate change and public support for actions to meaningfully reduce carbon emissions.

Standing in the way of overwhelming agreement is a partisan divide — with Liberal, NDP and Green supporters on one side, Conservatives on the other.

Prime Minister Justin Trudeau shovels sand to fill sandbags with his son Xavier, as son Hadrien watches, in the Ottawa community of Constance Bay as flooding continues to affect the region on Saturday, April 27, 2019. (Justin Tang/Canadian Press)

Overall, 70 per cent of respondents to a recent Abacus Data survey said that climate change would be among their "top five" concerns when they vote in the federal election this fall.

But that national figure hides a significant split. Among those who support Justin Trudeau's Liberal government, 81 per cent consider it a top five issue. Eighty-six per cent of NDP supporters and 84 per cent of Green supporters agree. But only 46 per cent of Conservative voters consider climate change a top-five concern.

That roughly lines up with an earlier finding from Abacus on Canadians' belief in global warming. Seventy-four per cent of Liberal and NDP supporters said there is "conclusive" evidence that the planet is getting warmer. Just 49 per cent of Conservative supporters agreed.

A left/right split on climate change is not unique to Canada and it's less pronounced here than in the United States. But it's also higher here than in several other countries. In its own polling, Pew found a 22-point gap between "liberal" Canadians and "conservative" Canadians on the question of whether climate change was a major threat to their country (80 per cent versus 55 per cent). In France, that gap was just eight points (86 per cent to 78 per cent).

Conservative leader Andrew Scheer speaks to supporters before a door-knocking event for volunteers in the Kanata suburb of Ottawa on Thursday, April 25, 2019. (Justin Tang/Canadian Press)

All of which aligns with how climate change has been debated in the political arena over the past decade. Successive Liberal and NDP leaders have proposed pricing carbon to reduce emissions. Conservative leaders, many of whom once supported the idea of pricing carbon, have loudly condemned the Liberal and NDP proposals without quite explaining what they would do instead.

A brief glimmer of all-party agreement on the goal of reducing emissions emerged in 2017 when MPs voted 277 to 1 in support of the Paris accord on climate change. But the debate has since retrenched and is now more clearly than ever about different levels of commitment.

The debate over doing less

Andrew Scheer has refused to promise that a Conservative climate plan would align with Canada's international commitment to reduce emissions by 30 per cent below 2005 levels by 2030. His new provincial allies — Doug Ford in Ontario, Blaine Higgs in New Brunswick and Jason Kenney in Alberta — have all scaled back climate policies and goals in their respective provinces.

What could have been a debate about how to achieve Canada's climate targets seems instead to be turning into a debate about if the federal government should try.

As the Conservatives are now quick to point out, the Liberal government's current policies don't add up yet to the projected reductions necessary to meet Canada's target. That could undercut Liberal attacks on Scheer. It's also an opening for the NDP to criticize the Liberals for not going far enough.

But the basic question of concern still breaks along partisan lines.

If this month's flooding (and whatever else climate change has in store for us over the spring and summer) has a political impact, it might be to persuade the Conservatives to aim for something closer to Canada's Paris target. It might also motivate the Liberals to add to their agenda and fill in the gap between current projections and Canada's international target.

But the frame of this debate seems to be frozen in place. The planet might have to get even hotter before that changes.

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