What do the federal parties offer Quebecers in the fight against greenhouse gas emissions?

Even before Friday's mammoth climate march in Montreal, polls were suggesting the environment is a key priorityfor Quebec voters in this campaign.

Voters' awareness of the perils facing the planet haveonly been heightened, feeding their demand for public policies that have a real impact onglobal warming.

So what is an environmentally conscious voter to do come election day on Oct. 21?

There are manyways to evaluate the different party promises on the environment. You could, for example, look at where each partystands on carbon pricing or compare their respective conservation proposals.

But unlike some other provinces,the chief source of greenhouse gas emissions in Quebec istransportation. Indeed, it is the only sector of the economy that has seen a significant increase in emissions.

And no surprise: gas-guzzling vehiclesare the problem.In 2016, cars accounted for 34 per cent of all transportation emissions in the province;light trucks accounted for 30 per cent and heavy trucks, 36 per cent, according to the Quebec Ministry of the Environment and the Fight Against Climate Change.

So, any serious effort to reduce emissions will have to involve findinggreener ways for Quebecers to get around.

OK, so where do the partiesstand on electric vehicles?

In its last budget, the Liberal government introduced a $5,000 tax credit on zero-emission vehicles. The NDP has promised to maintain thatcredit if it iselected.

The Bloc Qubcois's platform includes several proposals to expand thattax credit, including boosting it by $1,500 for low-income earners.

"That could allow people who never thought of buying an electric vehicle to say: 'Oh, now it's affordable,'" said the Bloc'sleader, Yves-Franois Blanchet.

The Greens, meanwhile, are promising to ban outright the sale of internal combustion engine passenger vehicles by 2030, while also making electrical vehiclestax-free.

For their part, the Conservatives haven't committed to keepingthe electric vehicle tax credit. Their environment platform mentions working with the provincesand industry groupsto develop longer-lastingbatteries for electric vehicles.

What about public transit?

Another, perhaps simpler, way of reducing vehicle emissions is to getpeople to drive less. That means increasing mass transit.

"Public transit needs to be at the heart of the climate change debate," said Samuel Pag-Plouffe, a spokesperson for the Quebec lobby group Transit.

Pag-Plouffe said Liberal government's creation of a dedicated fund for public transit infrastructure projects helped get several projects in Quebec off the ground, including the extension of the Blue Line in Montreal and the tramway network in Quebec City.

"We're now at historical levels for dedicated funds for public transit at the federal level," Pag-Plouffe said, though he noted the federal program iscomplicatedfor municipalities to navigate.

The NDP has pledged to spend a further $6.5 billion on public transit projects across the country. It's not clear how much would be earmarked for Quebec.

When it comes to more specific proposals, the Greens saytheysupportthe Pink Line, a proposed addition to the Montreal Metro system that hasn't interested the provincial government.

The Conservatives have vowed to re-introduce a tax credit cut by the Liberals that would reduce the costof weekly and monthly transit passes by 15 per cent.

Pag-Plouffe said though thatmeasure wouldmake public transit more affordable, it doesn'taddress a more pressing problem theshortage of existing public transit options.

As for the Bloc, there is no mention at all of public transit funding in the party'scampaign platform.

What about new roads?

Another way of reducing transport emissions in Quebec entails rethinking what roads are built,and where.

For years, economists have been trying to draw the attention of elected officials tothe law of induced demand.

When applied to urban planning, this economic principle holds that building more roads or widening existing roadsactually increases congestion.

That's because road construction acts as an incentive for people to take their car, and all that extra pavement gets swamped with traffic just as soon as it is built. Somore cars, more congestion and more greenhouse gasemissions.

One way to counteract this effect is by imposing tolls. Another istosimply avoid building unnecessary roads and highways in the first place.

The proposed tunnel between Quebec City and Lvis, which the provincial government is pressing ahead with,has become a battleground for environmental groups trying to make that point.

They argue the link would not only be expensive (estimates range between $4 billion and $10 billion) andserveno discernibleneed (it connects an area responsible for only oneper cent of Quebec City's traffic), but that it wouldonly increaseemissions by encouraging more people to drive.

The NDP and the Greens have stated their firm opposition to the tunnel, dubbedthe "third link."

The Liberals haven't taken a position on the issue.

Bloc Qubcois Leader Yves-Franois Blanchet, for his part, said he's "not against" the third link.

Conservative Leader Andrew Scheer enthusiastically endorsesit. "As prime minister, the third link will be my priority," Scheersaid during a visit to Quebec City earlier this week.