We can reverse climate change if we redefine what carbon neutral looks like, said Gabrielle Walker, cofounder of carbon removal startup CUR8, at WIRED Impact in London in November 2023. Scientists define net zero not just as the reduction of carbon emissions, but the removal of carbon from the atmosphere too—a complete negation of the greenhouse gases emitted by humanity. Business is now catching up.
Carbon offsets are worthless, and companies have therefore been “stampeding away” from buying cheap offsets to avoid reputational damage, Walker says. She suggests carbon removal credits as a better solution for reaching net zero.
“Removal credits take carbon dioxide out of the sky and keep it out,” Walker explains. “In your own net-zero target, reduce your emissions and remove whatever’s left.”
Growing more trees is one potential way of removing carbon from the atmosphere. But trees might be burned, Walker points out, so a better way to lock in their carbon removal is to use carbonated timber to construct buildings. This method—where the wood is lightly charred before being used—seals it against water and mildew. Building with it displaces CO2-heavy cement, and locks a tree’s carbon in for as long as the building is there.
Walker recommends other removal methods too. Low-level technologies such as biochar—created by burning wood in very low oxygen—alongside basal rocks, which absorb CO2 over thousands of years, make good fertilizer that locks carbon in. And machines including Orca, a large plant in Iceland, will soon be sucking 4,000 metric tons of CO2 from the air every year, mineralizing it and turning it to stone.
Walker finished with a chilling picture of a plaque in Iceland on the site of the first glacier to disappear. “A letter to the future,” the inscription reads. “In the next 200 years, all other glaciers are expected to follow the same path. This monument is to acknowledge that we know what is happening and what needs to be done. Only you know if we did it.”
This article appears in the March/April 2024 issue of WIRED UK magazine.
