The Senate Says Burning Trees Is Carbon Neutral. Oh Really Now?
Killing trees is bad for the environment, and so is burning stuff for energy. So why would combining the two be anything other a flaming middle finger pointed at our planet? Here’s the thinking: Unlike fossil fuels, trees are already part of Earth’s carbon cycle. So when you burn a tree, you’re only releasing the carbon that the tree had stored up, carbon that would have been released anyway when the tree died and decomposed. That’s why the new energy bill that just passed in the Senate—with bipartisan support, no less—includes an amendment saying that biomass should be classified as a carbon neutral energy source.
So does this mean that the Senate has actually made a positive environmental policy decision? No, you crazy optimist. The Senate is just buying into the carbon-accounting loophole that the European Union has been exploiting: Burning wood pellets doesn’t actually give you a carbon footprint of zero, it’s just a sneaky way to have your cake and eat it too.
Basically, this is just the latest update from the “ketchup is a vegetable” school of science that politicians seem to love. The interest here, though, is the way the science almost works out.
You, me, your dog, the trees in the forest, the rocks in the ground, the Pacific Ocean, are all part of the global carbon cycle: the way carbon gets passed around the planet by processes like respiration and photosynthesis. Forests are a particularly important part of that cycle because they convert the carbon in carbon dioxide into carbohydrates, a form of long-term storage called carbon sequestration. Once it becomes part of the wood, that carbon will stay trapped in a time out for the complete lifecycle of the tree. Which, in our carbon dioxide-saturated world, is pretty important. It’s also why your neighbor thinks planting some trees will offset the emissions belching out of their SUV’s tailpipe.
Thinking that biomass is carbon neutral takes this a step further. To convert biomass into usable energy, you have to burn wood pellets made of compressed sawdust to generate thermal energy, which power plant turbines convert to mechanical energy, which a generator then turns into electrical energy. Essentially, wood pellets are to biomass what coal is to fossil fuels. If you consider the wood alone, burning a tree as wood pellets can only release the carbon that was already in the tree. That amount goes up into the atmosphere. You plant another tree in its place, that tree sucks the carbon dioxide back down, sequesters it, and boom, you’re carbon neutral.
Net zero is theoretically possible. But in the real world? It requires some careful regulations and a long list of qualifiers, none of which this amendment, found in the Energy Policy Modernization Act, takes into account.
Biomass is carbon neutral when you consider the lifecycle of a whole forest, which could be as long as a century, according to Scott Johnstone, Executive Director of the Vermont Energy Investment Corporation, a non-profit dedicated to renewable energy sources. Too bad we need to stop climate change now. And trusting humanity to responsibly cut down trees—taking only mature trees, encouraging understory growth, and replanting—is like trusting kids to responsibly ration their Halloween candy. “It would be great to strengthen the laws around sustainable harvesting,” says Johnstone.
And a forest isn’t only trees. “A very large percentage of the carbon stored in the forest is actually stored in the soil itself,” says Sami Yassa, senior scientist at the Natural Resources Defense Council. “Say you go in and log a forest, take the lumber to a sawmill, and burn only the tops of the branches. That might be carbon neutral. But all of that soil that gets disturbed gets oxidized.” Oxidation releases carbon that would otherwise be stored, and a lot of it: According to the US Forest Service, soil can sequester up to twice as much carbon as the aboveground forest ecosystem.
In fact, even the scientists who signed a letter that the amendment’s primary sponsor, Senator Susan Collins—a Maine Republican—cites as scientific backing are hedging. “I haven’t signed something in support of the Collins Amendment,” said Professor James A. Allen, Executive Director of Northern Arizona University’s School of Forestry. “I signed a cover letter that outlined general, I think uncontroversial, principles regarding carbon biomass accounting.”
That cover letter, which was signed by many scientists, notably does not say that biomass is categorically carbon neutral. And it’s the a priori classification that has scientists so worried. Yassa says treating biomass as carbon neutral will erode the gains made by the Clean Power Plan—which puts heavy restrictions on coal use—by up to 11 percent. “You create emissions you’re not counting,” she says. “And that will contribute to and accelerate climate change and its damaging effects.”
And, like almost everything to do with climate change, this policy shift could disproportionately and adversely affect the poor. While its supports will tell you again and again that biomass is the way to go because it’s ‘carbon better’ or ‘greener‘ than fossil fuels, no one is going to claim that it’s less expensive. “Price becomes an issue,” said Gary Kronrad, Professor of Resource Economics at SFA’s Arthur Temple College of Forestry and Agriculture. “If the price of electricity goes up, you know who is going to suffer.” Economically speaking, the only winners are going to be the landowners, because, as Kronrad points out, “trees are a high value product just standing in the forest.”
Except trees don’t just stand around doing nothing. And even if it were possible to chop and regrow efficiently enough to make biomass carbon neutral, the forest would only be barely breaking even. In other words, not pulling out the excesses of carbon dioxide already in the atmosphere. So, killing trees, still bad for the environment.
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