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The tree solution

24th May 2008

Planting trees would counteract global warming - but only if we plant the equivalent to all the trees cut down in the past century

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With carbon-dioxide emissions still rising and polluting the atmosphere, the idea of sucking it out of the air has driven much research.

So far, however, we haven’t a single technology that can do this effectively (or cheaply) – which has caused some to reconsider another idea that is already well understood: photosynthesis.

One suggestion that has been made many times is to fertilize the oceans to create vast blooms of green algae.

But this is “a stupid idea,” says Fritz Scholz of the University of Greifswald in Germany.

He says this would pollute the oceans and seriously disrupt the food chain, and much of the carbon would ultimately be returned to the atmosphere when the algae died.

Instead, he argues in the May issue of the journal ChemSusChem, we should plant fast-growing trees, which would absorb carbon as they grow. Once mature, the trees could be cut down and buried in old mines or underwater, where they would not decompose.

The entire process would also create “millions” of jobs, control erosion and increase rainfall, Prof. Scholz says.

Just one catch: To absorb the approximately 32 gigatonnes of CO2 emitted globally every year, we would have to plant about a billion hectares of forest – equivalent to all the trees we cut down in the past century worldwide.

“This is not going to be a panacea – nothing will,” says Malcolm Campbell at the University of Toronto, a botanist and expert on carbon sequestration. “But this could certainly be one piece in a tapestry of solutions.”

Published in The Green Report in The Globe and Mail

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• Tags:
• Climate Change
• CO2
• Geoengineering
• Research
• Science
• Trees

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