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YSE Research Scientist Sara Kuebbing was on a panel of leading forest scientists who evaluated forest carbon credit protocols — finding them to be flawed and at the root of problems facing the carbon offset market.
Forests and forest lands absorb approximately 29% of the carbon dioxide emitted every year — making them a powerful ally in global efforts to slow climate change. In recent decades, the sale of carbon credits has emerged as a key avenue in the protection, management, and restoration of forests as carbon sinks, with forest carbon credits accounting for nearly 40% of the voluntary carbon market. Yet, the market, which peaked at $2 billion in 2022, has been hampered by ongoing uncertainty over the quality and integrity of credits. Projections suggest the voluntary carbon market could either shrink further or grow to $1 trillion by 2050, depending, in part, on confidence in credit quality.
Sara Kuebbing, research director of the Yale Applied Science Synthesis Program (YASSP) at YSE, was part of a team of leading forest scientists that evaluated 20 forest carbon credit protocols across voluntary and compliance markets in North America. The panel, which was organized by the Clean Air Task Force, recently released a study on their findings and a report with recommendations for improving forest carbon credit protocols. YSE News spoke with Kuebbing about the project and possible next steps.
Measuring the climate impact of forest carbon crediting policies is extremely challenging. We have an existing landscape where there are a lot of different protocols generating credits, each using different methods for ensuring that credits achieve key quality elements, including additionality, robust carbon measurement, permanence, and leakage. Clean Air Task Force brought together a panel of scientists with a broad range of expertise to evaluate the protocols and asked the panel to score the strength of approaches used within protocols for achieving each quality element. The theory of change was that if all the standards meet a minimum bar, then all the credits coming out of the standard — if they've been verified — should, therefore, meet that minimum bar. I was one of the scientists invited to join the expert elicitation. They were very careful to invite people who didn't have any type of financial conflict of interest with carbon markets, who have not been paid through nor engaged on boards in the carbon markets.
Our approach was to look at each element individually and then score our confidence level in each approach to that element. For example, when considering how a protocol evaluated the risk of future fire with a forest carbon project, we scored the approach that assigns a static default value as “weak,” while we scored the approach that uses a regionally appropriate fire risk map as “satisfactory.” When we discussed a given approach, we didn't necessarily know which protocol or registry it was tied to. After scoring individual approaches, we then combined all the scores to create a final protocol score.
Our key finding is that nearly all the 20 protocols we reviewed are too weak to ensure that the forest carbon credits issued are high-quality. What that means is, we felt as scientists that the minimum bar for the protocols would not guarantee high-quality credits. A very important caveat here is that this does not mean that high-quality credits couldn't come out of a protocol. It means that the minimum bar within the protocols may or may not generate a high-quality credit, which puts the onus on credit buyers to do a lot of homework on individual projects and credits. We see this playing out in the market today. There are a lot of credit rating agencies [SK1] out there that are doing their own custom analytical evaluation of carbon credits to help buyers parse out the quality of credits.
Overall, the panel thought that there were some new scientific tools and data streams that could be incorporated into protocol methods today. First, protocols can strengthen how they assess the risk that forest carbon could be re-released (or ‘reversed’) in the future. For example, we recommended that protocols require re-evaluation of risk at least every five years — to account for rapidly changing climatic conditions — and that they derive risk-assessment probabilities from third-party risk assessment maps. Second, protocols should require periodic updates to forest carbon baselines — or the estimated forest carbon gains or losses that would have happened in the absence of the crediting project. This is important for ensuring that credits aren’t over-allocated in forested areas where deforestation threats dissipate or under-allocated in areas where deforestation threats increase through time. The panel also found that for some protocol elements, such as the assessment of leakage, we need more investment in research to develop better standardized data and methods. Leakage occurs when a crediting project increases forest carbon stocks in one forest (for example, by reducing timber harvests or forest development), but this shift in activity inadvertently leads to increased carbon emissions in another forested region to compensate for the activity reduction.
But what I think is very important to note here is that we found that more recent protocols are already adopting some of these newer approaches. This suggests that there is already change happening within protocol development, and that some of these approaches are feasible to incorporate today. That is a very positive development.
At YASSP, we’re continuing to develop “protocol intercomparison projects” to assess how different methodological choices across protocols affect crediting outcomes. We are also collaborating with scientists at the Yale Center for Natural Carbon Capture (YCNCC) to explore how MRV efforts can be integrated across carbon removal approaches, including forest management, reforestation, and enhanced weathering. Additionally, we are working with The Nature Conservancy to build a research network, the Science for High Integrity Frameworks to Transform Carbon Markets (SHIFT-CM), that focuses on addressing critical scientific gaps in ecosystem carbon accounting. A recent workshop, hosted with support from YCNCC, brought together scientists and carbon market experts to identify priority research needs. Many of these align with gaps highlighted in the Clean Air Task Force assessment, such as additionality, leakage, and permanence risks. Through all this work, YASSP aims to build independent, transparent tools and methods that improve confidence in the benefits of natural climate solutions.
