Five things to know about ‘short-lived pollutants’ and their climate impacts

OTTAWA – The White House says it will continue the work of the former Conservative government on “short-lived climate pollutants” as it takes over the two-year chair of the Arctic Council from Canada. Prime Minister Justin Trudeau is in Washington this week for a state visit, where he and President Barack Obama are expected to announce new measures to combat short-lived pollutants.

Here’s five things to know:

1. Short-lived pollutants include black carbon, methane, some hydrofluorocarbons (HFCs) and tropospheric ozone, which have lifespans in the atmosphere that last anywhere from days to 15 years. Carbon dioxide, by contrast, remains in the atmosphere far longer, with up to 60 per cent of emissions still in the atmosphere after 100 years and up to 25 per cent still in the atmosphere after 1,000 years.

2. Black carbon is a major component of soot and is caused by incomplete burning of fossil fuels. While it only lasts anywhere from a few days to a few weeks, black carbon’s climate warming impact is between 460 times and 1,500 times as strong as carbon dioxide. When black carbon falls on snow and ice it also increases the melt rate.

3. Methane is a naturally emitted greenhouse gas that is 20 times more potent than carbon dioxide as a climate warming agent. While it emanates from animals and from decomposing plants, 60 per cent of the methane in the world’s atmosphere comes from human sources, including natural gas and oil production, coal mines and landfills.

4. HFCs are used in air conditioning and refrigeration as well as foaming agents, aerosols and solvents. They remain in the atmosphere for less than 15 years and currently account for less than one per cent of total greenhouse gases. However, like other short-lived pollutants, hydrofluorocarbons have a much greater warming impact than carbon dioxide, and the use of HFCs is growing eight per cent per year as global demand for air conditioning increases.

5. In 2012, Canada joined Bangladesh, Ghana, Mexico, Sweden, the United States, and the United Nations Environment Programme in the Climate and Clean Air Coalition, a voluntary group aimed at reducing short-lived pollutants. At the time it was estimated that, if left unchecked, short-term climate pollutants would contribute about half of the climate warming effect from man-made emissions over the next two decades.

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