Carbon-offsetting schemes may not actually prevent deforestation

Most carbon-offsetting programmes that support forest conservation efforts as a way to counteract contributions to global warming don’t significantly reduce deforestation, an analysis has found.

Andreas Kontoleon at the University of Cambridge and his colleagues studied 18 large carbon-offset projects around the world promoted under the REDD+ scheme, an international framework set up through the United Nations climate negotiations.

The scheme is overseen by Verra, the world’s leading provider of carbon offsets. Verra certifies that carbon credits purchased by individuals or organisations equate to an amount of carbon dioxide reduced or removed from the atmosphere.

Carbon-offset schemes calculate their effectiveness based on predictions of how much forest would have been destroyed if the projects they support hadn’t been funded. Some researchers, including Kontoleon, suggest their methods are too simplistic and rely on outdated information.

The researchers looked at historical data showing how much deforestation was prevented in the 18 areas in Peru, Colombia, Cambodia, Tanzania and the Democratic Republic of the Congo. They then compared that with what happened in areas with similar features, including forest cover and soil fertility, that weren’t covered by the REDD+ scheme.

This showed that 16 of the 18 projects claimed that far more deforestation had been prevented than their comparator sites suggested would have happened. Only 6 per cent of the carbon credits produced by those 18 projects were actually linked to saving trees, the researchers found.

“These payments are not doing what they’re claiming to be doing, in terms of changing deforestation rates in a statistically significant way compared to a counterfactual,” says Kontoleon.

“Any of us who work on tropical forests and care about the future of tropical forests find the results deeply depressing,” says Julia Jones at Bangor University, UK. “It’s really critical those forests stay standing and sequestering and storing carbon – so the findings are rather concerning.”

Jones says that while the results show that those who have bought REDD+ credits haven’t slowed deforestation as much as has been claimed, it is a different question to ask whether carbon offsetting works. “This does not mean that we shouldn’t be investing in tropical forest conservation,” she says. “Those habitats are so important. There’s a bit of a ‘don’t throw the baby out with the bathwater story’ here. We must not give up on conserving those tropical forests.”

A Verra spokesperson told New Scientist that the study is similar to one the organisation provided a technical review about in January, which argued that the findings were flawed. “Our initial analysis of this version indicates that, despite some minor changes, the overall methodology, results and conclusions are the same – and, therefore, the significant concerns we flagged earlier this year still hold,” the spokesperson said.

“We recognise the areas for improvement in the current system and are committed to fostering that ongoing evolution,” they added. Verra has been developing a consolidated REDD methodology since 2020, which will be released later this year. It “directly addresses many of the concerns raised and builds upon our extensive, decades-long experience in forest-based climate solution”, the spokesperson said.