Montreal and its greenhouse gases

  • Magazine

Many efforts have already been made to reduce greenhouse gases in our metropolis. Here we look at the issue from an encouraging perspective.

A city can do a lot to reduce greenhouse gases (GHG), which accelerate global warming. Montreal encourages its citizens to travel by bike, take the bus and metro, sign up for a carsharing service and use electric vehicles. Known for its leafy neighbourhoods, the city maintains a wide network of green spaces and sidewalk planters full of greenery.

But do all these acts really help to reduce GHG? No doubt about it, according to Félix Gravel, Urbanist and Deputy Director at the Conseil régional de l’environnement de Montréal and specialist in land-use planning, climate change and transport. “The effect has been documented and demonstrated,” he explains. “For example, the STM has assessed the contribution that public transit use has made to reducing GHG, and Bixi provides each of its users with a personalized GHG reduction report. We also know that one tree can replace around 10 air conditioning units. We have more and more verifications that document just how efficient certain measures are at reducing GHG.”

In the Rapport de quantification des émissions de gaz à effet de serre évitées par le transport collectif dans la région métropolitaine de Montréal, published by the STM in 2016, it was demonstrated that by using public transit, Montrealers can make a major difference in reducing GHG.

More STM, less CO2

Currently, public transit reduces CO2 by 404,000 tonnes a year, and by 452,000 more tonnes by easing congestion, resulting in a total reduction of 856,000 tonnes. Per individual opting to take public transit, it’s the equivalent of a reduction in 1.4 kg of CO2 per day. If we take into account Montreal’s entire urban community, the annual reduction in CO2 comes to 3,911,000 tonnes.

Public transit also allows the population to be densified. Montreal’s population currently requires 2,336 km2 in surface area. Without public transit, that figure would be 8,535 km2. The report indicates that this is the type of reduction that has the biggest impact, lowering the annual volume of CO2 by 2,341,000 tonnes.

Densification currently reduces GHG by 22%, easing congestion reduces it by 17% and not using a car by 16%. This 55% overall contribution is very important, and developing public transit can only improve these figures. “If people relied more on car sharing it would make a major difference to the environment,” adds Gravel. “Ridesharing has enormous potential. There are 8 to 10 million available spaces in cars per day in the greater Montreal region.”

Along with oceans, trees are the leading carbon absorbers: the more there are in a city, the more effective their capacity is to capture CO2. Exhaust pipes release fine ozone and sulphur particles that remain suspended just above the asphalt for several days. To effectively biofilter these particles, grass, earth, porous asphalt or honeycomb paving are all needed as they allow water to filter through – the city is therefore in a position to make decisions that could make all the difference.

To get Montrealers walking, the city should be less concrete-heavy and vegetation needs to be increased, believes Gravel. In his eyes, sidewalk planters, trees and green spaces increase air quality and thus incite citizens to walk more. Gravel believes that Montreal is brimming with ideas.

For example, despite our harsh winters, biking as a mode of transport has become increasingly popular, and many citizens are building green alleyways and considering using geothermal alleyways to heat their homes. “All the initiatives carried out from start to finish are making a real difference,” says Gravel. “I’m getting positive feedback from all of this.”


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