Washington released a draft forest offset rule, and there’s a lot to like
The Washington Department of Ecology has released a new draft of its forest offset protocol within it’s cap-and-invest program. The draft rule includes significant updates that could have a positive impact on the quality of carbon credits and ultimately, the program’s ability to deliver real climate benefits. Many of these changes reflect improvements outlined in our recent assessment of forest carbon protocols and there are a few areas that could be even further strengthened. Washington’s draft rule is a major step in the right direction, and we have submitted public comments in support of its adoption.
Clean Air Task Force (CATF), alongside a team of leading U.S. forest carbon scientists, published a deep dive into the rules that govern a wide range of forest carbon credit certifications relevant to North America in May 2025. We used the recommendations from this study to inform our comments on Washington state’s draft rule. The assessment examined rules of the road for quantifying carbon credits and identified what works well, where there are weaknesses, and outlined opportunities for improvements to ensure that forest carbon credits achieve their promised climate benefits.
A quick overview of Washington’s Cap-and-Invest Program
Washington State’s Cap-and-Invest Program, launched in January 2023 under the Climate Commitment Act, is one of the most ambitious climate policies in the United States. It caps greenhouse gas emissions for large polluters and allows the limited use of carbon credits as offsets to help meet compliance obligations.
Offsets play a limited but notable role. Early in the program, companies can use offsets for up to 8% of their emissions, dropping to 6% after 2027. All offset projects must show direct environmental benefits to Washington, and every credit issued counts “under the cap,” meaning that certified offsets replace allowances, rather than add to them.
Why forest offsets are tricky
Forests are a critical ally in fighting climate change because they soak up carbon dioxide and store it in away in trunks, roots, and soils. In theory, forest offset projects can deliver meaningful climate benefits by paying for the implementation of new management approaches that protect and enhance carbon sequestration in forests. But the details matter, especially for compliance markets where each offset stands in for a ton of fossil fuel emissions. Weak rules can lead to overcrediting, where projects get more credits than the real climate benefit they deliver. That risks undermining the program’s emission reduction goals.
What Washington State is proposing
The draft rule makes several changes to how forest carbon credits are calculated and verified.
CATF supports many of these revisions, especially where they align with recommendations from our research:
- More frequent baseline recalculations for improved forest management projects.
Currently, once a project’s baseline (the “business-as-usual” scenario) is set, it can remain fixed for decades. Ecology proposes recalculating it every 10 years, which will better reflect expected changes in forest and socioeconomic conditions. This adds rigor while maintaining decadal-scale certainty for project operators. CATF supports this change and suggests exploring empirical dynamic baselines in future updates, an approach gaining traction in voluntary markets.
- Smarter buffer pool contributions.
Projects contribute a portion of credits to a buffer pool to insure against carbon loss from fire, pests, or disease. Climate change increases the frequency and severity of these threats, raising the risk that stored carbon will be released back into the atmosphere. Ecology’s proposed revision would set these contributions using spatially explicit risk data that’s updated over time—a move CATF strongly supports. However, we urge Ecology to remove the default buffer pool contribution cap for fire and biotic risks and to ensure that buffer pool contribution reductions based on risk reduction treatments are scientifically justified for each risk category, so that these features do not undermine the improvements.
- Higher default market leakage rate.
When timber harvests shift from protected project areas to other forests, that “leakage” of market-driven harvest erodes climate benefits. In the proposed rule, the default leakage deduction would rise from 20% to 40%, making the program more conservative. CATF supports this, but urges the development a Washington-specific leakage rate in the future that would more accurately reflect leakage impacts in the state.
- New rules for initial carbon stocks.
Highly stocked forests, or those that store a lot of carbon compared to the regional average, are important to climate but can also be overcredited under current methods. The revision would limit credits issued to a project when initial carbon stocks are outside the 90% confidence interval for “common practice” regional averages. CATF supports the intent to discourage cherry-picking overstocked forests for enrollment, but urges Ecology to test how this would work in practice before finalizing the rule.
- Standardized additionality templates.
Additionality means the project’s carbon storage wouldn’t have happened without the offset program. Ecology has proposed templates to standardize how developers justify additionality, which should reduce subjective interpretations. CATF recommends making these templates prescriptive, especially around timber harvest economics, to promote objectivity and to make things more straightforward for project operators.
- Updated common practice baseline data.
Ecology proposed to use the U.S. Forest Service’s EVALIDator tool for Forest Inventory and Analysis (FIA) data, updated regularly without a full rulemaking, to set the common practice values for the program. This keeps numbers current and transparent. CATF suggests adding a contingency plan in case this tool or the underlying dataset ever become unavailable.
- Changes to real estate appraisals for avoided conversion projects.
Currently, these projects rely on real estate appraisals to justify additionality and prove the land would otherwise be developed based on economic factors. CATF’s research found this method weak. Ecology’s proposal to require two independent appraisals is an improvement, but CATF recommends exploring data-driven methods to assess conversion risk instead.
Why this matters beyond Washington
With Washington’s Cap-and-Invest Program soon linking with California and Quebec’s markets, its forest offset rules could carry even greater influence. Strong protocols here can set a precedent for other jurisdictions and help build confidence in forest carbon markets overall.
These revisions move the program in the right direction—toward more rigorous, transparent, and conservative crediting. But there’s still room for improvement, especially in adopting empirical baseline methods and reducing reliance on subjective appraisals.
The stakes are high: every offset credit must truly represent a ton of CO₂ kept out of the atmosphere, or Washington risks missing its legally mandated goal of a 95% reduction in greenhouse gas emissions by 2050. Strong forest protocols aren’t just good forestry—they’re climate policy that works.
