Tropical forests are biodiversity hot spots; preserving them is a crucial part of global efforts to mitigate the effects of climate change. When these verdant ecosystems are destroyed, they release millions of metric tons of carbon dioxide each year, emissions numbers second only to those driven by fossil fuel consumption.
A host of international efforts have emerged to help curb tropical forest loss. The Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD+) program, established in 2005, is a United Nations–supported initiative for countries to sustainably manage and conserve forested land to reduce greenhouse gas emissions. Countries receive financial incentives to preserve and maintain their forests—compensation intended to make forests more valuable intact than cut down.
There are more than 350 REDD+ projects worldwide, and in many project locations, habitats have been protected, and deforestation has slowed.
Many other projects, however, may not be delivering results as hoped, and their climate benefits may be overstated. A new study from an international team of researchers quantifies these concerns, suggesting that only 19% of REDD+ projects met their emissions targets and even fewer met their deforestation goals. But, the authors suggest, REDD+ shouldn’t be abandoned. Instead, it needs to be fixed.
REDD+ in Review
Most REDD+ projects are funded through the program’s sale of carbon credits, which are permits that represent 1 metric ton of carbon dioxide removed from the atmosphere. The companies, communities, or individuals that voluntarily buy carbon credits are doing so to offset their own emissions. By 2021, REDD+ projects accounted for two thirds of the 227.7 million land use carbon offsets traded (excluding agriculture) and represented $1.3 billion in market value. (Land use carbon credits include forest, wetland, and grassland conservation. Other carbon offsets include renewable energy projects and technology-based solutions such as carbon capture.)
In recent years, scientists and stakeholders have started to question the efficacy of REDD+ programs. Critics say some projects either fail to reduce deforestation or the results are smaller than claimed.
Many REDD+ projects lack additionality, explained Thales A. P. West, an environmental scientist at Vrije Universiteit Amsterdam. Additionality describes the concept of determining whether a project’s emissions reductions would happen without carbon credit revenue.
“Reductions are estimated based on a baseline scenario: What would have happened in the absence of the project. The more ‘catastrophic’ the baseline deforestation is, the more credits projects can claim. Thus, there is an incentive for project developers to exaggerate project baselines,” said West, who was not an author of the recent study.
Real REDD+ Results
To assess REDD+ efforts, researchers examined 66 REDD+ project units across tropical regions in 12 countries, focusing on avoiding unplanned deforestation (AUD) projects. AUD projects are a major component of REDD+ efforts to protect forests from small-scale farming, logging, and fuelwood use.
Researchers used a synthetic control method, a type of statistical analysis in which they compared areas with REDD+ projects in place with nearby locations that shared the REDD+ area’s environment and socioeconomic conditions. By comparing forest loss in the REDD+ area with its counterpart where no REDD+ interventions had occurred, the scientists could estimate the true impact of the REDD+ project. Finally, they compared these findings with the data reported as part of the REDD+ projects themselves to evaluate whether the carbon credits issued were backed by a real reduction in deforestation.
“We followed up on previous work that said, ‘Hey, you know, when you get the math right, this mechanism doesn’t seem very effective.’”
Twenty-one out of the 66 REDD+ sites studied (32%) showed significantly lowered deforestation—meaning successful climate mitigation. At one site in the Brazilian Amazon, deforestation rates were cut by up to 99%.
But other project sites painted a less positive picture. Seventeen percent of the REDD+ project areas showed increased deforestation compared with their controls. Thirty-five percent of the projects reported deforestation baselines that were 10 times higher than the researchers’ estimates, especially at sites in Colombia. When the researchers compared forest loss with reported carbon credits, only 13.2% could be verified by actual forest preservation, throwing the validity of the carbon credit system into question.
“We followed up on previous work that said, ‘Hey, you know, when you get the math right, this mechanism doesn’t seem very effective,’” said Jonathan Chase, an ecologist from the German Centre for Integrative Biodiversity Research and one of the study’s authors. “We show that these credits are not at the level that one would hope they could be.”
The Future of REDD+
This new study is important, West explained, because “it corroborates previous findings and contributes to the growing scientific evidence that many REDD projects do not deliver what they claim, consequently compromising the environmental integrity of their carbon offsets.”
“I think we can certainly do a better job with the statistics, but ultimately, it comes down to doing a better job with protecting these habitats.”
Despite the variable results from the REDD+ project areas covered in the new study, many sites still showed improvements, leading researchers to suggest that this program doesn’t need to be abandoned entirely, just reorganized or reformed. More attention could be paid to shifting political and economic trends, as those social factors can shape patterns of deforestation occurring in a particular country or region. Stricter baselines, increased transparency, and stronger oversight might also help build a more robust REDD+ program.
“I think we can certainly do a better job with the statistics, but ultimately, it comes down to doing a better job with protecting these habitats,” said Chase.
—Rebecca Owen (@beccapox, @beccapox.bsky.social), Science Writer
Citation: Owen, R. (2025), REDD+ results and realities,
Eos, 106, https://doi.org/10.1029/2025EO250408. Published on 31 October 2025.
Text © 2025. The authors.
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