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Faye Flam

Plant a Trillion Trees, But Don’t Stop There

The fight against climate change requires big ideas. Plural.

New forests are necessary but not sufficient.

New forests are necessary but not sufficient.

Photographer: Mauro Pimentel/AFP, via Getty Images

It’s easy to criticize just about any proposed climate change solution as not effective enough. The buildup of greenhouse gases is simply too big of a problem to be solved by one course of action alone, whether it’s increasing the use of solar energy or giving up beef or capturing carbon from the atmosphere. A recent estimate that planting lots of trees could soak up most of our excess carbon is, unfortunately, a little too good to be true.

The claim comes out of a paper published last week in the journal Science. Researchers from the Swiss Federal Institutes of Technology in Zurich estimated how many more trees our planet could hold, and how much carbon those would absorb. They reached the conclusion that new trees could soak up a whopping two-thirds of the excess carbon humanity has added to the atmosphere since the industrial revolution. (Others have chimed in to say the theoretical potential is just one-third, and that the practical potential is much less because some of the proposed land is currently grazing pastures or natural savannas with their own unique ecosystems.)