Biofuels are being touted as a green way to cut reliance on Russian oil. But new modeling bolsters the evidence that biofuels aren’t the climate solution we’d hoped for.
One of the big drivers of this shift has been bioethanol—transportation fuel usually made from fermented corn. Since 2005 the US government’s Renewable Fuel Standard has mandated that gasoline producers blend corn ethanol into their fuel. The amount the RFS requires to be mixed in has ratcheted up each year from the policy’s start, and since 2016 gasoline producers have been instructed to blendinto transportation fuel.
Lark’s study found that the RFS significantly pushed up the price of corn. This incentivized the expansion of total US cropland by 2.1 million hectares between 2008 and 2016—an increase of 2.4 percent. Often the areas newly converted to cropland were grasslands on the western edge of the Corn Belt. “Over millennia these grasslands have created really carbon-rich soils.
The supposed benefit of biofuel is that, although it still releases carbon dioxide when it burns, that carbon was drawn down from the atmosphere by the plants that make up the fuel rather than being released from oil that was once underground. But growing fuel creates emissions too.