Academics Argue That Carbon Offsets Don’t Work and Should Be Phased Out, Especially Low-Quality Ones

 

     A new paper from researchers at the University of Oxford and the University of Pennsylvania has concluded that current practices of carbon offsetting are ineffective and riddled with problems. The first carbon offset was generated in 1989. The practice has long been criticized as emissions reductions can be hard to verify for many types of projects.

"We must stop expecting carbon offsetting to work at scale. We have assessed 25 years of evidence and almost everything up until this point has failed," says co-author Dr. Stephen Lezak, researcher at the Smith School of Enterprise and the Environment. "The present market failures are not due to a few bad apples but rather to systematic, deep-seated problems, which will not be resolved by incremental changes."

"We hope our findings provide a moment of clarity ahead of COP30: These junk offsets—the ones not backed by permanent carbon removal and storage—are a dangerous distraction from the real solution to climate change, which is rapid and sustained emission reductions," says lead author Dr. Joseph Romm, Senior Research Fellow at the Penn Center for Science, Sustainability and the Media.

     I should perhaps point out that Romm is a climate activist and a prominent Democratic political operative. In this case, he is likely correct that many carbon offset projects are problematic. I would disagree that carbon offsets are a false solution, “…a dangerous distraction from the real solution…” It is a common climate activist trope to say that things that have serious issues or are not perfect are false solutions.

     The researchers noted several issues with carbon offsets, including nonadditionality (generating credits without reducing emissions), impermanence, leakage, double counting, "perverse incentives," and the "gameability" of crediting systems. Bad actors are often involved, unfortunately.

"Despite efforts to implement safeguards, carbon offset projects continue to face documented cases of weak accountability, risking the perpetuation of neocolonial patterns of appropriation. While nature-based projects can deliver local benefits, these should be financed through mechanisms other than carbon credits, such as contribution claims where projects are financed while still ensuring that purchasing entities are responsible for reducing their own emissions," says co-author Amna Alshamsi, a doctoral researcher at the University of Sussex's School of Global Studies.      

     I think her statement is a bit overkill on the accusations of the “perpetuation of neocolonial patterns of appropriation, although there could be some environmental justice issues with some offset projects. While there may be some bad actors here and there, it is not like some organized crime or corruption is happening, and certainly not on a wide scale. I would be more concerned about the uncertainties of quantifying, measuring, and verifying emissions reductions, which is what is being exploited if there is deliberate deception. Aside from deliberate deception, there is probably something more like sloppy assumptions being made that may support questionable emissions reduction estimates.

     The authors cite previous research that most carbon offset projects overestimate emissions reduction, some by factors of 10 or more.

“Going forward, all offset markets should prioritize developing high-integrity, durable CDR and storage—with long-term measurement and verification—the authors conclude, while recognizing that effective and scalable CDR may not be possible, and will certainly require intensive research and investment.”

“This approach aligns with the Oxford Offsetting Principles, which encourage companies to reduce emissions first and foremost, and to transition to durable carbon removal offsetting for residual emissions.”

     The authors note that the problems with carbon offsetting accounting have led to the stalling of the voluntary carbon market. That does not have to be the case. I believe that better standards, better science, and more integrity among researchers and especially project developers, as well as better project oversight and third-party verification, can adjust carbon offsetting markets for the better, both compliance markets and voluntary markets. The authors also note that the durability of offsetting projects must be assured. We need to know if carbon is leaking out or if offsetting was overestimated. Durability timeframes also need to be agreed upon. 100 years and 1000 years are common estimates. Better estimates are needed for long-term storage retention. Better oversight is also needed. There needs to be a distinction between low-quality and high-quality credits. Some possible reasons why are explored in the quote below from the paper.

“What makes the offset market so unusual and prone to poor quality is that high quality is not a priority for many buyers (17, 43), because, to date, buyers have had little to gain from purchasing high-quality credits and little to lose from purchasing low-quality ones. Moreover, unlike almost every commodity, carbon credits do not correspond to a tangible object—they cannot be tested for purity or strength like steel, for instance. In fact, many companies have benefited from poor offset quality because it has reduced credit prices (43). Researchers have noted for a quarter-century that, even in compliance markets, “there are significant incentives for parties… to exaggerate a project's net emission reduction effects” (87, p. 16). A 2001 analysis warned that, in a competitive market, “projects whose accomplishments are easiest to exaggerate will be chosen by developers” (64, p. 51–52).”

     The authors also note that the quality problem of carbon offsets has persisted for decades and is not likely to go away. I think it can be bettered with more oversight and perhaps stricter monitoring and verification rules. They note that long-term monitoring needs to be enforced by national and international organizations. High-quality and low-quality offsets should be distinguishable and perhaps given different values. The goal is to identify and weed out low-quality projects or alter them to a higher quality.

     Land-based carbon removal is especially wrought with uncertainties about leaking and durability. A new report suggests that pledges at COP30 are favoring unrealistic carbon removal schemes, such as large-scale tree planting, over quality projects, and instead of protecting existing forests and phasing out fossil fuels. The research for the Land Gap Report was led by Dr. Kate Dooley of Melbourne University.

"Why are so many countries ignoring forest protection as a key pillar of climate targets? The answer is that they live in a world where heavy sovereign debt burdens and industry-friendly tax and trade policies force many of them to exploit forests to keep their economies from crashing," Dr. Dooley said.

"Yet the bitter irony is that over the long term, healthy forests are essential to healthy economies due to the climate benefits, job opportunities and ecosystem services they provide."

     The authors of the report are talking about a “land gap” where countries are pledging a certain amount of emissions reduction via land-based carbon removal, but the amounts pledged are unrealistic. It is similar for deforestation. Targets are not likely to be met, so they are considered unrealistic. The study focuses mainly on land-based CDR, such as large-scale tree planting, forest restoration, and bioenergy capture and storage projects. They also note that land-based methods may take decades to realize the emissions reductions pledged. More information from the Land Gap Report is given below.

“The Land Gap Report 2025 provides an updated assessment of land area required for carbon removal in climate pledges submitted to the UNFCCC up to November 2025. Pledged land for carbon removal now exceeds 1 billion ha - far beyond what is feasible or sustainable. This represents an increase from the Land Gap Report 2022 and the 2023 update which found that 990 million ha of land are required to meet climate pledges submitted by the end of 2023.”

“This report also assesses, for the first time, the scale of the 'forest gap' - the difference between commitments made over the past 15 years, to halt and reverse deforestation and forest degradation by 2030, and the actual plans that countries are putting forward in their NDCs and longer-term strategies. Current pledges result in a 'forest gap' of around 20 million ha projected to be lost or degraded each year by 2030.”

 

    

 

References:

 

Carbon offsets have failed for 25 years, and most should be phased out. Science X staff. Phys.org. October 14, 2025. Carbon offsets have failed for 25 years, and most should be phased out

Are Carbon Offsets Fixable? Joseph Romm, Stephen Lezak, and Amna Alshams. Annual Review of Environment and Resources. Volume 50. October 2025. Are Carbon Offsets Fixable? | Annual Reviews

 COP30 climate pledges favor unrealistic land-based carbon removal over emission cuts, says report. Science X staff. Phys.org. November 13, 2025. COP30 climate pledges favor unrealistic land-based carbon removal over emission cuts, says report

The 2025 Land Gap Report. The Land Gap report