[URBAN NOTE] "Remember the greenhouse gases"

[rfmcdonald]

At Spacing Toronto, Shoshanne Saxe argues that the greenhouse gas emissions of various modalities of transit, in Toronto and elsewhere, should be

The type of infrastructure that gets built will strongly influence the types of travel choices people make and the emissions associated with each trip. For instance, where walking or cycling are options, trips can be made without any greenhouse gas emissions, but getting more people onto bikes will require more bike routes and a change in tone on cycling policy. For powered trips, public transit is generally much “greener” than private transit, like cars or motorcycles. A bus is greener than car travel as long as the bus route averages an occupancy of six; in other words, as long as there are at least six passengers on every bus, those passengers are contributing less carbon to the atmosphere than drivers in private vehicles. Streetcars, light rail, and the subway need to average only a few people per carriage to emit fewer greenhouse gases per passenger kilometer travelled than cars.

However, people can’t choose public transit unless we build it, especially in parts of the city that are underserved or over capacity. The trade off is that building anything results in greenhouse gas emissions through material use and the energy required in construction. To make real progress towards reducing greenhouse gas emissions the transit infrastructure built should facilitate transit usage in a way that rapidly pays back the initial greenhouse gas emissions invested.

In 2007, Toronto City Council unanimously adopted greenhouse gas reduction targets for the city. Council committed to reducing the city’s emissions by 80% from 1990 (PDF) levels by 2050. Interim targets of 6% by 2012, and 20% by 2020 were also set at the time.

For Toronto to meet these goals, we will have to cut our growing transportation emissions while also keeping in mind the greenhouse gas impact of building new infrastructure. From 1990 to 2011, the city’s total greenhouse gas emissions from power, transport and waste decreased by 15%, despite transportation emissions increasing by 15%. The impact of the construction industry is not reported in the Toronto inventory, but to give an idea of scale, global cement production alone accounts for 5% of all anthropogenic greenhouse gas emissions.

Transport emissions are increasing for a number of reasons: The city is growing, more people means more trips; these trips are also getting longer, annual average travel distance is Canada (PDF) is increasing, often in larger cars (there are more SUVs on the road). Transportation is making up a growing slice of the emissions pie, now accounting for 36% of total emissions, up from 27% in 1990. It could appear that this doesn’t matter given the overall improvement in greenhouse gas output, but a large part of the progress made so far comes from the closing of Ontario’s coal plants, which resulted in much cleaner electricity for Toronto. The electricity supply mix in Ontario is now relatively green (PDF) and will be hard to make much greener over the coming decades. Further emission reductions will need to come from other sectors.