In a cavernous theater lit up with the inexperienced shapes of camels and palms at COP28 in Dubai, ecologist Thomas Crowther, former chief scientific adviser for the United Nations’ Trillion Bushes Marketing campaign, was doing one thing he by no means would have anticipated just a few years in the past: begging environmental ministers to cease planting so many timber.
Mass plantations are usually not the environmental answer they’re presupposed to be, Crowther argued when he took the ground on December 9 for one of many summit’s “Nature Day” occasions. The potential of newly created forests to attract down carbon is commonly overstated. They are often dangerous to biodiversity. Above all, they’re actually damaging when used, as they typically are, as avoidance offsets— “as an excuse to keep away from reducing emissions,” Crowther stated.
The recognition of planting new timber is an issue—at the least partly—of Crowther’s personal making. In 2019, his lab at ETH Zurich discovered that the Earth had room for an extra 1.2 trillion timber, which, the lab’s analysis prompt, might suck down as a lot as two-thirds of the carbon that people have traditionally emitted into the ambiance. “This highlights international tree restoration as our only local weather change answer up to now,” the research stated. Crowther subsequently gave dozens of interviews to that impact.
This seemingly simple local weather answer sparked a tree-planting craze by firms and leaders desirous to burnish their inexperienced credentials with out really reducing their emissions, from Shell to Donald Trump. It additionally provoked a squall of criticism from scientists, who argued that the Crowther research had vastly overestimated the land appropriate for forest restoration and the quantity of carbon it might draw down. (The research authors later corrected the paper to say tree restoration was solely “one of the crucial efficient” options, and will suck down at most one-third of the atmospheric carbon, with massive uncertainties.)
Crowther, who says his message was misinterpreted, put out a extra nuanced paper final month, which exhibits that preserving current forests can have a higher local weather affect than planting timber. He then introduced the outcomes to COP28 to “kill greenwashing” of the sort that his earlier research appeared to encourage—that’s, utilizing unreliable proof on the advantages of planting timber as an excuse to maintain on emitting carbon.
“Killing greenwashing doesn’t imply cease investing in nature,” he says. “It means doing it proper. It means distributing wealth to the Indigenous populations and farmers and communities who’re residing with biodiversity.”
