Opinion | Let’s Not Pretend Planting Trees Is a Permanent Climate Solution

2022-06-04

Excerpt from this New York Times essay authored by Zeke Hausfather, a contributing author to the IPCC Sixth Assessment Report, the climate research lead at Stripe and a research scientist with Berkeley Earth:

Trees are our original carbon removal technology: Through photosynthesis, they pull carbon dioxide out of the air and store it. They have lately been touted as a climate savior, a way to rapidly reduce the carbon dioxide that has accumulated in the atmosphere as we cut our emissions. A “trillion trees” initiative was launched with much fanfare at the World Economic Forum in Davos back in 2020, and it was one of the few climate solutions embraced by the Trump administration. Planting trees and protecting forests are a major part of many corporate efforts to offset emissions.

But there’s a catch. Carbon dioxide removed from the atmosphere is only temporarily stored in trees, vegetation and soil, while a sizable part of our emissions today, will remain in the atmosphere, much of it for centuries and some of it for millenniums to come.

Trees can quickly and cost-effectively remove carbon from the atmosphere today. But when companies rely on them to offset their emissions, they risk merely hitting the climate “snooze” button, kicking the can to future generations who will have to deal with those emissions.

We have a saying in the climate science world: “Carbon is forever.” Around 20 percent of the carbon dioxide we put into the atmosphere today will still be in the atmosphere many thousands of years from now. This means that to effectively undo emissions, the carbon we take out of the atmosphere needs to stay out. There is a real risk that, in a warming world with more wildfires, with pests preying on trees and with drying soil, carbon in tree plantations could end up back in the atmosphere sooner rather than later. For carbon to be permanently removed by planting trees, forests would have to remain in place for thousands of years. On top of that, the trees would have to be planted on land that would have been forest-free for those same thousands of years had the trees not been planted.