The Science Based Targets initiative (SBTi) has been urged not to exclude nature-based solutions from its net-zero standard. The plea comes from more than 40 experts who fear the organization will overly favor engineered solutions, such as direct air capture.

At the heart of the group’s argument, made in an open letter published last week, is opposition to the idea that because fossil carbon emissions originate from long-term geological stores, they should only be counterbalanced by removals that can be sequestered for a thousand or more years. The SBTi’s Corporate Net Zero Standard is undergoing revisions and the current draft suggests using this “like-for-like” principle to help determine which carbon credits companies can use.

“It’s just a fundamentally flawed concept,” said Joe Fargione, North America science director for The Nature Conservancy, who signed the letter along with 12 colleagues from the organization. 

‘False binary’

The signatories’ objections to like-for-like include the “false binary” that defines permanent storage as “either 1,000 years or failure.” They argue instead for a focus on “durability,” which encompasses how long the carbon is likely to remain stored and the mechanisms used to deal with potential reversals. 

In this view, credits from storage mechanisms with relatively high risk of reversal — such as forests, which can release carbon back to the atmosphere in the event of fire — can be used in net-zero frameworks provided adequate insurance mechanisms are in place. These include holding back some credits from sale so that they can be used to compensate for potential future losses.

The letter also warns of the opportunity cost of excluding nature-based solutions. That’s partly an issue of scale: The authors peg the removals potential of these solutions as 11 gigatons of carbon dioxide a year over the next decade, around a fifth of current annual total global emissions. In addition, investing in nature helps safeguard existing forests, which, if lost, could release enormous amounts of carbon.

All about the claim

One expert often seen as an advocate of like-for-like is Robert Höglund, head of climate strategy and carbon dioxide removal at