Burning trees for energy really does heat the climate, scientists argue

A rising push to pull energy from the world’s forests is heating the planet — despite industry claims otherwise, a new report argues.

The report from Princeton researcher Timothy Searchinger and Yale economist Steve Berry cuts against the idea at the core of the growing wood pellet industry: that burning trees for fuel actually drives emissions down.

The U.S. Department of Agriculture is looking into the accuracy of that idea as it considers whether the wood-burning industry should get access to clean energy tax credits — which, if granted, would help fuel the industry’s expansion.

Such expansion, Searchinger and others argued in a Nature article last fall, would lead to the equivalent of about three times the emissions of the aviation industry.

But other scientists have challenged those claims, arguing that the numbers put forward in the Nature article are wrong because the bigger the market for forest products, the more forests themselves will be encouraged to grow. One paper argued that the increased profits from burning a lot more trees for energy would lead to an amount of land four times the area of India being converted to forest.

As a basis for this claim, the paper’s authors cited a 2002 study they argued had found that doubling U.S. wood energy use would lead to a 30 percent increase in forest extent.

But all the papers in that vein, Searchinger and Berry argued on Wednesday, were based on a core error: Researchers, they charged, had misread the 2002 paper. 

By corresponding with the author of that paper, Searchinger and Berry learned he had meant something very different: that doubling forest profits would lead to only a tiny increase (0.4 percent) in national forest cover — and that this might well be offset by increased conversion of forests to cropland elsewhere.

The two also pushed back on the idea that burning wood for energy is carbon neutral because forests are expanding —  logic, they argued, which is akin to saying that a business losing money could be argued to be profitable because businesses elsewhere in the country are making money.

They conceded that forests are expanding globally, but argued this expansion was despite increased wood harvests, rather than because of them. The expansion, they argued, was driven by the increased heat and carbon in the atmosphere – making their continued and uninterrutpted growth a vital method of slowing climate change.

That’s not an argument against wood use per se, they said. “The world has valuable uses for wood, just as it has valuable uses for food and many other products that also cause emissions.”

But for wood “as for other goods, the goals should be both to reduce the greenhouse gas emissions involved in wood production and to hold down overall consumption,” they argued.