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When the European Union set up its pioneering carbon emissions trading scheme in 2005, it defined wood as a zero-emissions fuel, Sarah Gibbens reports. At first, that seemed to make sense: If a new tree grows to replace the one that was burned, it will absorb carbon from the air to offset the emissions from the burning.
“The whole wood pellet industry is basically being driven by this,” Princeton researcher Tim Searchinger told Gibbens. Coal-fired power plants in the U.K. and elsewhere have been switching to wood pellets, thereby reducing their emissions fees—but not their actual emissions.
The problem, Searchinger and many other scientists say, is that while trees do indeed absorb carbon, they do so only in the long run—they take decades longer to grow than they do to burn. But in the long run the glaciers will have melted; we don’t have decades to wait to cut emissions. And right now, most evidence suggests, burning whole trees puts more carbon in the air than coal, because wood is less efficient. (Pictured at top, young pines in Virginia; below left, the pellets; below right, logs at a North Carolina pellet factory.)
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