Introduction: Can we grow and burn our way out of climate change?

Abstract

To help fight climate change, the world needs to burn less coal, oil, and natural gas. The reasons are twofold: When burned, these fossil fuels emit large amounts of carbon dioxide. Also, the carbon they contain was originally formed by the decay of plants and animals that were alive before the age of the dinosaurs – hence the adjective “fossil.” During all the time that passed since they died, the carbon contained in those organisms was safely locked away deep underground – but now that it’s extracted and burned, that material becomes a fresh source of carbon in the atmosphere, one that had not been in play for millennia. Saying that the world has to stop using fossil fuels is simple, but implementing a new energy system built largely on renewable energy is difficult, as anyone knows who follows the news from Washington, D. C. One possible solution that has gained traction in the last decade involves replacing the burning of coal in electrical generating plants with the burning of wood – or any other kind of vegetation, including corn, sunflower stalks, grapevines, soybeans, and other forms of what is technically known as “biomass.” In the most financially successful version of this technology to date, huge swathes of forests in North America are clearcut and ground into little wood pellets that look like the dry feed available at the corner pet store. These pellets are then shipped thousands of miles across the Atlantic Ocean to generate electricity at power plants in Europe – the most well-known of which is probably the one located in the town of Drax in the United Kingdom. Formerly one of the largest coal-burning power plants in the world, the Drax facility has been retrofitted at a cost of an estimated $1 billion to burn wood pellets. The promoters of this technology have been heavily touting Drax as the prototype of a so-called “green” way to combat climate change, claiming that the power plant merely re-uses carbon that is already in the carbon cycle rather than consuming fossilized carbon; policy makers in the UK and EU agree with them and have given Drax massive subsidies and tax writeoffs. This facility is just one – albeit the biggest and most (in)famous – of several such power plants. Intuitively, cutting down trees to burn them seems nonsensical in a climate change context. Trees are, after all, elegant, living systems that extract carbon from thin air and sequester it in solid form: wood. But the question of whether biomass burning can truly be green generates strong reactions, both pro and con. To lead off this special issue, Oxford University physics professor and Bulletin Science and Security Board member Ray Pierrehumbert lays out some of the key issues involved in replacing fossil fuel with biomass and explains what biomass burning is and why it could work – at least in theory. In his article “Plant power: Burning biomass instead of coal can help fight climate change, but only if done right,” Pierrehumbert argues that the answer to the question of whether biomass is green or not comes down to how the growing, harvesting, processing, shipping, and burning is conducted in everyday practice; the crux of the matter, he says, is that even if biomass could arguably be a win for carbon emissions, it is not easy to produce biomass in a socalled “sustainable” way. In “Does wood bioenergy help or harm the climate?” MIT researcher John Sterman and his colleagues William Moomaw, Juliette N. Rooney-Varga, and Lori Siegel (of the Fletcher School at Tufts University, the University of Massachusetts at Lowell, and Climate Interactive, respectively) make the case that by declaring that wood biofuels are flat-out carbon neutral, the UK and EU make the faulty assumption that regrowth of the forests is predictably rapid and certain. They write: “To avoid the worst harms from climate change we must not only keep the vast majority of remaining fossil carbon in the ground, but must also keep the vast majority of the carbon in forests on the land.” In “Sustainable biomass: A paper tiger when it comes to reducing carbon emissions,” researcher Mary Booth of the Partnership for Policy Integrity observes that burning wood emits carbon dioxide and other air pollutants, and that while trees may be “renewable,” forest ecosystems are not. Recent events make Europe’s biomass policies even more concerning, she says: “The acute need to replace Russian fossil fuels, preferably