Science·What on Earth?

How big a problem is idling?

In this week's issue of our environment newsletter, we look at the pollution cost of idling, historical carbon emissions and the connection between population and climate change.

Also: A look at historical carbon emissions

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(Sködt McNalty/CBC)

Hello, people! This is our weekly newsletter on all things environmental, where we highlight trends and solutions that are moving us to a more sustainable world. (Sign up here to get it in your inbox every Thursday.)

This week:

  • How big a problem is idling?
  • Carbon emissions: A historical look
  • Population and climate change

How big a problem is idling?

(Peter Macdiarmid/Getty Images)

Idling your car — at home, in a drive-thru line, at a red light — is environmentally harmful, and also largely unnecessary.

How bad is idling?

When a gasoline-powered vehicle is idling, it is in its least efficient mode. It's doing nothing but sitting there, burning fuel and sending emissions into the atmosphere.

Natural Resources Canada says if most Canadian drivers limited idling to three minutes a day, over the course of a year, 1.4 million fewer tonnes of CO2 emissions would go into the atmosphere.

It would save money, too. For every 10 minutes of idling, the average three-litre engine vehicle loses more than a cup (330 millilitres) of fuel, according to NRCan. 

It's even worse with diesel buses. Research done at the University of Waterloo in Ontario found a diesel bus loses four to eight litres of fuel every day to idling — or up to 2,000 litres per year. Amir Khajepour, the mechanical engineering professor behind the research, said that's the equivalent of 10,000 kilograms of greenhouse gases per bus per year. 

Doesn't my engine need to warm up in the winter?

It depends. Temperatures vary across Canada in winter, but Natural Resources Canada says even in cold weather, it's not necessary to warm up your car for more than two to three minutes.

What are cities doing about idling?

The first city to pass an idling control bylaw was Toronto, back in 1996. It was brought in to help reduce air pollution. Now, at least 67 cities and municipalities across Canada have anti-idling bylaws. But they vary. Most of these jurisdictions limit idling to three to five minutes, but some allow five, 10, even 15 minutes. Inuvik allows 30 minutes of idling.

All of these jurisdictions exempt emergency vehicles, as well as many service or refrigerated vehicles (which need to idle to keep the cooling process working). 

What else are cities doing?

Toronto also led the way in terms of banning the construction of new drive-thrus. Since its move in 2002, at least 26 Canadian municipalities have followed suit. 

How are the bylaws enforced? 

In many cities, anti-idling bylaws are enforced through a complaints-based process — i.e. someone makes a complaint to the city, which issues a warning or a fine.

In 2018, the City of Toronto issued warnings to about 2,000 people, but no fines. That same year, Edmonton issued three tickets, while Vancouver issued 118.

Does stop-start technology help?

A lot of idling can't be helped — like when you're waiting at a red light. You might think stopping and restarting your engine uses more fuel than leaving the car running, but it doesn't. Starting your engine uses less fuel than idling for 10 seconds.

NRCan estimates that a vehicle with stop-start technology — which automatically turns off a vehicle's engine when it idles, and restarts when the driver lifts their foot off the brake — saves anywhere from $260 to $1,540 in fuel costs and reduces carbon emissions by 610 kg to 3,540 kg over 10 years. That's the equivalent of taking one compact car off the road for a year. (NRCan breaks down the savings here.)

What's being done about buses and delivery trucks?

The University of Waterloo's Khajepour is working on a type of stop-start technology that would still allow a refrigerated truck to stay cool, or keep a city bus comfortable in all seasons. At a stop, the engine would turn off and the vehicle would draw on a battery.

"Instead of running the engine at its lowest efficiency [i.e. idling] in order to run the refrigeration system of a food delivery truck, you can charge your battery when the engine is at 40 per cent efficiency," Khajepour said. "So when the truck stops, and the engine is off ... we can use the energy that is already stored in that battery to run the refrigeration system."

Stephanie Hogan

Reader feedback

In response to Nicole Mortillaro's article last week on the history of plastic bottles, Suzanne Tilley wrote, "I feel strongly that companies like Coca-Cola should produce returnable bottles like glass ones used to be for a refund just like glass ones used to be. That will encourage people to [return them] and also prevent litter as well as damage to our waterways."

Susan Holtz had this to say: "I am not an advocate for plastic, but you should have mentioned that one of plastic's great advantages in packaging is it's much lighter weight than glass, thus reducing [usually fossil fuel] energy spent in shipping. In environmentally assessing commerce, as well as everything else, you always have to look at what you're competing with and displacing, in addition to looking closely at what you're doing yourself."

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Old issues of What on Earth? are right here.

The Big Picture: Historical carbon emissions

Most of the talk around carbon emissions focuses on which countries are currently releasing the most greenhouse gases. In that scenario, China is first by quite a margin, accounting for nearly 25 per cent of the global total — a fact that has given many politicians, in the U.S. and Canada especially, license to downplay their countries' own emissions. But if you take the longer view, the picture looks a little different. Between 1751 and 2017, the U.S. accounted for 25 per cent of global emissions, followed by countries that now make up the European Union.

Hot and bothered: Provocative ideas from around the web

  • In a major surprise to environmental activists, the U.K. has banned fracking, citing the risk of earthquakes while tacitly acknowledging that natural gas is responsible for a lot of carbon emissions. 

  • After many years of development and negotiation, the Tsilhqot'in First Nation in B.C. has opened the largest solar farm in the province. The 3,456-panel array will provide power to about 135 homes. Chief Russell Myers Ross told The Narwhal it's "the first project to generate our own source of revenue for our Tsilhqot'in organization and the community, which is significant for our overall goal of self-sufficiency."

Is population control the answer to fixing climate change?


Often, when discussion turns to modifying our behaviours in order to keep the planet from warming 1.5 C or 2 C above pre-industrial levels — the threshold that would result in widespread damage — one word creeps up more often than not: overpopulation.

The argument is that fewer people on Earth would mean fewer greenhouse gas emissions, thus helping avert the worst effects of climate change. But experts say population control isn't the answer.

"Population issues certainly are an important dimension of how society … will be able to cope with this crisis over the course of this century," said Kathleen Mogelgaard, a consultant on population dynamics and climate change and an adjunct professor at the University of Maryland.

"But it's not a silver bullet, and it's certainly not the main cause of climate change. And fully addressing population growth is not, on its own, going to be able to solve the climate crisis."

For one thing, a larger population doesn't necessarily produce more CO2 emissions, at least not on a per capita basis.

Michael Barnard, chief strategist with TFIE Strategy Inc., which specializes in energy and low-carbon solutions, points to China as an example: While the country of 1.4 billion people is the No. 1 emitter of CO2 in the world, on a per capita basis, it produces far fewer emissions than either the U.S. (the world's second-top emitter) or Canada (the 10th).

According to the Union of Concerned Scientists, the U.S.'s CO2 emissions from fuel combustion per capita is 15 tonnes, and Canada sits at 14.9 tonnes. China? It's at just 6.4 tonnes per capita — a trend that is starting to drop. That's also the case for India, Barnard said.

Between India and China, "one-third of the [world's] population already have lower per capita CO2 emissions than we do, and they're dropping faster," he said.

Not only that, but global birth rates are actually declining. The United Nations had previously projected that the global population would reach 11.2 billion by 2100, but recently updated that forecast to 10.9 billion.

Darrell Bricker, a fellow at the University of Toronto's Munk School of Global Affairs and Public Policy and co-author of Empty Planet: The Shock of Global Population Decline, said a big driver of the decline in population is urbanization.

In the 1960s, roughly 33 per cent of the population lived in a city; now it's 54 per cent. The UN projects that by 2050, that number will climb to 68 per cent. And when people move to the city, more women join the workforce and overall, people tend to have fewer children.

As a result, instead of the population continuously increasing, Bricker believes it will peak at around eight or nine billion people around mid-century and then begin to decline.

Rather than looking at population control as the biggest factor in the battle against climate change, experts say it's about looking at better education for women, adopting cleaner energy and changing our overall consumption patterns, especially in developed countries.

"Just because we slow population growth, if we continue to use coal-fired power plants to generate electricity, or if we continue to cut down forests at the rate that we're cutting down forests, those are going to be challenges regardless of what the population is," said Mogelgaard.

Nicole Mortillaro

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Editor: Andre Mayer | Logo design: Sködt McNalty


  • An earlier version of this story quoted NRCan as saying stop-start technology saves anywhere from $260 to $1,540 in fuel costs and reduces carbon emissions by 610 kg to 3,540 kg per year. In fact, that's over 10 years.
    Nov 08, 2019 8:20 AM ET
  • An earlier version of this story quoted NRCan as saying for every 10 minutes of idling, the average three-litre engine vehicle loses more than a litre of fuel. In fact, it loses more than a cup (330 millilitres) of fuel.
    Nov 18, 2019 7:37 AM ET