(This article is longer than what you normally see on media websites.)
Last month, CBC's polling analyst Éric Grenier wrote an article showing the "path of least resistance" for the Trudeau Liberals to win a majority government in October.
It showed the party capturing 55 of the 75 seats in Quebec.
That's a big leap from the 40 seats won by the Liberals in Quebec in the 2015 election.
The path of least resistance for a Conservatives majority would involve taking 19 seats in Quebec.
That's a substantial increase over the 12 seats won by the Conservatives in 2015.
To win a majority, one party must win 170 seats.
But what if Quebec voters decide in large numbers that Trudeau is a phony when it comes to tackling climate change and that Scheer is a climate disaster?
Trudeau's talking a good game on greenhouse gas emissions, even using the hashtag #ActForTheAmazon.
But his government's actions, including buying the Trans Mountain pipeline system, have turned him into a pariah among many climate activists.
On September 20 as the election campaign will be fully underway, there will be a global climate strike followed by a week of climate actions.
The next month, a group called Extinction Rebellion is planning a series of peaceful direct actions around the world, including in Canada. It employs Gandhian tactics to draw attention to the climate emergency.
This will keep this issue in front of Canadian voters.
And that could shatter the dreams of the Liberals and Conservatives to make major gains in Quebec.
This, in turn, would elevate the likelihood of a minority government in Canada that could take stronger action to curb greenhouse gas emissions.
Nantel becomes Green voice in Quebec
All of this should heighten Canadians' interest in the recent defection of Longueuil–Saint-Hubert NDP MP Pierre Nantel to the Greens, a.k.a. Le Parti vert du Canada.
"In Quebec, the October election will be a climate referendum," Nantel said in a Green party news release. "There will be two sides: the Liberal and Conservative side that wants more oil exports, and the side that will protect our climate."
Nantel is a two-term MP with a strong record of advocacy for action on the climate crisis.
One of his passions has been the electrification of transportation, powered by renewable hydroelectricity produced in Quebec.
His seat is in a Montreal suburb on the south shore of the Saint Lawrence River. It was represented for many years by MPs with the Bloc Québécois.
Nantel has extensive experience in the arts and media industries of Quebec, so he'll likely emerge as a major Green spokesperson in that province during the election campaign.
He faces a difficult challenge getting reelected, given the Greens' traditional weakness in Quebec. But his party's position on climate change is in tune with many voters' views in that province.
A Nanos Research poll in late May and early June found that the climate was most likely to influence votes of those living in Quebec. On a scale of one to 10, they stated that it ranked at 7.8.
Greens want to end oil imports
The Greens are running on the message that the real divide of the 21st century is not left versus right, but insiders (the one percent) versus the rest of us.
They have set very ambitious goals in their climate plan, including:
* a 60 percent reduction in greenhouse gas emissions below 2005 levels by 2030 and zero emissions by 2050;
* ending all imports of foreign oil and only using Canadian fossil fuels while investing in upgraders to turn solid bitumen into gas, diesel, and other products;
* and modernizing the electricity grid to increase transmission of renewable energy between provinces.
Meanwhile, the federal New Democrats have promised a new "Canadian Climate Bank" to finance renewable energy, energy efficiency, and low-carbon technology.
They're pledging to help provinces enhance electricity grids to promote distribution of clean power across the country.
The NDP has also promised to legislate "ambitious, science-based greenhouse gas reductions targets".
But the party remains vulnerable to the Greens in B.C. That's because the provincial NDP government led by John Horgan continues to allow fracking of natural gas and has offered a sales-tax holiday to lure a giant LNG plant.
That played a role in Green candidate Paul Manly's decisive victory in the Nanaimo-Ladysmith by-election.
And Nantel is telling voters in Quebec that he wanted out of the NDP caucus because it wasn't pushing hard enough against climate change.
In 2016, the Quebec government banned the fracking of natural gas.
Quebec voters are fickle
The NDP has 14 MPs in Quebec, so it would seem to have the upper hand over the Greens going into the fall campaign.
But this province has seen wild swings in various elections.
In 1984, for example, the Conservatives fared exceptionally well, winning 59 seats with Brian Mulroney as leader.
In 1993, the Bloc Québécois captured 54 seats, thanks to Lucien Bouchard. And in 2011, the NDP came out of nowhere and won 59 seats when Jack Layton became the preferred federal leader in Quebec.
All three of these politicians had the advantage of being born in Quebec.
Perhaps Trudeau will take a large number of seats this time around because of his ease in the French language.
The Liberals have also recruited high-profile Quebec anti-pipeline activist Steven Guilbeault as a candidate.
His presence on the slate might help offset criticism of the Trudeau government's decision to buy a pipeline system.
Conversely, it could also increase cynicism about the Liberals in Quebec.
Trudeau and the fringe People's Party of Canada's Max Bernier are the only leaders of truly federalist parties who were born in Quebec.
The separatist Bloc Québécois has been hampered by internal dissension and its new leader, former Parti Québécois cabinet minister Yves-François Blanchet, has only had this position for seven months.
But it's conceivable that he could catch fire in the province with his arguments that Quebeckers received nothing in return after placing their trust in Layton in 2011 and Trudeau in 2015.
The Bloc's campaign is centred around "the fundamental values of the Quebec nation", including French as a common language and secularism of the state. It's also promoting equality of gender and sexual orientation, environmental restoration, and a nation-to-nation relationship Indigenous peoples.
"Under the current regime, Quebec is an obligatory accomplice of global warming by supporting the exploitation and export of oil and gas reserves in western Canada through its taxes," Blanchet says on his party's website.
To drive home his commitment on climate change, Blanchet is promising to run a carbon-neutral campaign.
The Greens, on the other hand, have sent mixed messages on the Quebec government's ban on public servants wearing religious symbols at work, according to a recent CBC News story.
Leader Elizabeth May has not called for any federal legal response whereas the deputy leader and Outremont candidate, Daniel Green, believes the feds should seek intervenor status in court challenges.
Nantel, on the other hand, previously suggested that NDP Leader Jagmeet Singh might have trouble appealing to Quebec residents because of his "ostentatious religious symbols".
May's appeal hurts Liberals
English Canada, particularly out west in British Columbia, doesn't usually pay a great deal of attention to what's happening in Quebec during federal elections.
But given that any path to a majority government will run through Quebec, this is one campaign in which the views of its voters could carry even more weight than usual.
The Liberals are hoping to vacuum up soft federalist voters who went with the NDP under Tom Mulcair but who are less willing to support a party led by Jagmeet Singh.
But the Liberals are also aware that the Greens have made breakthroughs in other provinces in recent years, first in B.C., then in Ontario, and more recently in Prince Edward Island and New Brunswick.
If the Green message catches on in Quebec, it will upset the Liberal apple cart.
That's because the Greens have considerable appeal to traditional Liberal voters, especially those who feel that the party establishment and leadership is in the back pocket of Big Oil.
And the Green leader, Elizabeth May, appeals to female voters, who are key to a Liberal victory.
The only way the Liberals can run the table in Quebec is by doing exceptionally well with female voters and attracting far more votes from those who went with the NDP in the last two elections.
That's why Nantel's defection to the Greens is so intriguing.
It could conceivably create more difficulties for Trudeau by boosting the Greens' appeal to Quebec voters who preferred Mulcair over Singh at the helm of the NDP.
That could lead to unusual vote splits, possibly playing a role in Canadians electing a minority government.
If that happens, it could lead to more dramatic action on climate change, given the positions of the Bloc, NDP, and Greens.