Dense evergreen plantations in Canada’s boreal forest absorb so much winter sunlight that the resulting surface warming can offset 6 to 20 percent of the climate benefit they are credited with.
Dense evergreen plantations in Canada’s boreal forest absorb so much winter sunlight that the resulting surface warming can offset 6 to 20 percent of the climate benefit they are credited with. Canada’s current carbon accounting frameworks measure the carbon stored but largely omit the heat absorbed by these forests, according to a new Policy Brief from the United Nations University Institute for Water, Environment and Health (UNU-INWEH). The result is inflated mitigation estimates and public investment in forests that may not deliver the cooling they promise.
The Policy Brief “From Carbon Accounting to Net Cooling: Securing the Albedo-Carbon Double Win in Canada’s Boreal Forest” argues that Canada should judge reforestation by its net effect on temperature rather than by tonnes of carbon stored. “Canada has an opportunity here that few countries have,” said Professor Kaveh Madani, Director of UNU-INWEH. “It can be the first to verify forests on what they actually do to the climate, not on what they store on paper. That protects public money, and it protects the credibility of every credit this country issues. Climate leadership isn’t about planting more trees anymore. It’s about being able to show, decades from now, that the forest we planted is still cooling the ground it stands on.”
In snow-covered landscapes, the color of the land surface matters as much as what grows on it. Open snow reflects most of the sunlight that reaches it, but a dark spruce canopy absorbs it. A dense evergreen stand across a snowy landscape makes the ground measurably darker for months of the year, warming the surface even as the trees pull carbon from the air. Scientists call this reflectivity albedo, and most carbon accounting frameworks in use today do not subtract it.
Read More: United Nations University
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