Does paper recycling benefit the climate? It depends

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For many people, the most familiar way to go green" or be eco-friendly" is probably paper recycling. (And perhaps its aging office cousin: Consider a tree before you print this email.") There are many ways to evaluate the environmental benefits of such actions, and one of those is greenhouse gas emissions. So how does paper recycling stack up in this regard?

That's a more interesting question than it may seem, namely because of the way paper products are made. Processing pulp to make paper is typically powered by black liquor"-a byproduct organic sludge with some useful properties. Burning it for heat and electricity to run the mill is approximately carbon neutral, since the carbon you emit into the air started out in the air (before a temporary stint as tree stuff). So if your recycling process generates CO₂ as it makes new paper, recycling could end up increasing emissions.

A new study led by Stijn van Ewijk at Yale University tries to do the math on this, using practical scenarios for the next few decades. Namely, they calculate whether increasing paper recycling would make it easier or harder to hit emissions targets that would halt global warming at 2C.

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