Are carbon offsets bullshit? A renowned climate expert weighs in.

Onstage at TC Sessions: Climate 2022 this week, climate modeling expert Dr. William Collins shared why he’s deeply skeptical of carbon offsets, and tree-based offsets in particular.

According to Collins, they are, “as far as we can tell, a feel-good measure.” Likewise, tree-planting programs pedestalized by companies like United Airlines are “fool’s gold,” he said. “It’s essentially impossible to monitor whether or not the stuff is going to stay in the trees. The minute you have a forest fire — game over.”

You might be bummed to hear that from Collins, who directs Berkeley Lab’s Climate and Ecosystem Sciences Division and Carbon Negative Initiative. Collins also served as a lead author of several IPCC assessments, one of which won a Nobel Peace Prize in 2007.

Forest preservation is critical, and it’s most successful when it’s led by indigenous communities. Forest preservation credits and corporatized mass-planting initiatives are a different story. A 2019 ProPublica investigation found that “carbon credits for forest preservation” in particular “may be worse than nothing.”

Collins also pointed to forest-preservation pledges that were baked into the Paris Agreement: “A third of the countries in the Paris accord are essentially saying, ‘we won’t cut down our forests [and that] is our primary contribution to greening the planet.’” Collins argues it’s entirely unclear what material gains these pledges offer in terms of carbon sequestration.

“The estimates that they have given for how much [carbon] their forests hold vary by factors of four across country boundaries,” said Collins. “That tells you that they’re making the numbers up.”

On a related note, there probably isn’t enough space for all the trees that corporations alone aspire to plant.

Collins did not go into as much detail on other types of offset programs, such as those that turn biomass into oil for underground storage (more on that here) and atmospheric carbon removal credits.

Salesforce, Microsoft and Google recently pledged to put $500 million toward atmospheric carbon removal. So far, proponents of the tech have not proved that it’s worth the hype.