Carbon management startup Carbon Direct is buying another carbon credit startup, Pachama, the companies announced today.

Pachama laid off around 20 employees this summer as voluntary carbon markets softened. The company had attracted investments from a range of prominent names, including Amazon’s Climate Pledge, Breakthrough Energy Ventures, Lowercarbon Capital, and several celebrity angel investors, including Ellen DeGeneres, Laura Dern, and Serena Williams.

“The current uncertain and volatile financial, economic, and geopolitical climate, added to the anti-ESG agenda in the U.S., is indeed having an effect on corporate sustainability budgets,” Diego Saez Gil, CEO of Pachama, told Trellis when the layoffs happened. “The impact is especially acute in the voluntary carbon market, which was already in a moment of correction.”

Pachama had raised $88 million, while Carbon Direct had raised $60.8 million, according to PitchBook. Terms of the deal were not disclosed.

Pachama was focused on nature-based carbon credits, which typically result when forests are either restored or preserved. Carbon Direct, on the other hand, is more of a carbon market advisory and accounting firm, helping companies track and report their carbon footprints and then vet carbon credits to offset them.

The carbon markets have been roiled by uncertainty in the last few years, and not all of it has been the result of political whiplash in the U.S. and elsewhere. Voluntary carbon markets have come under fire for falling short of their promises.

For example, a major investigation by The Guardian found that more than 90% of one verifier’s credits did not actually result in any carbon reductions. One of the biggest challenges facing nature-based carbon credits is the question of whether forests protected by the purchases were threatened with destruction in the first place.

And while large companies have been dialing back their publicity around ESG measures, many are still interested in sticking to their net-zero promises. Carbon Direct customers include Microsoft, Shopify, American Express, JP Morgan, Alaska Airlines, and BlackRock.