The analysis, published on Thursday, found that 18 big forest offsetting projects had produced millions of carbon credits based on calculations that greatly inflated their conservation impact. The schemes, which generate credits by avoiding hypothetical deforestation, were found not to reduce forest loss or to reduce it by only small amounts, far less than the huge areas they were claiming to protect, rendering the credits largely hot air.

The findings follow a 2020 study of 12 projects in the Brazilian Amazon by the same group, which found they had a negligible impact on stopping deforestation despite generating credits on the basis they were preventing large areas from being destroyed. A 2022 study of 40 Verra-approved projects led by University of Cambridge researchers found that while some projects did stop deforestation, most stopped none or small amounts.