The key role of forests in meeting climate targets requires science for credible mitigation.
When we think about fighting climate change, images of wind turbines and electric cars often come to mind. Yet, one of our most powerful climate allies has been with us all along: the world's forests. These vast natural systems absorb carbon dioxide from the atmosphere through photosynthesis, storing it in their wood and soils—effectively acting as a natural climate solution 6 .
However, a crucial question has long puzzled scientists and policymakers: how do we accurately measure and credit a country for the climate benefits of its forests, especially when some carbon changes would happen regardless of human intervention? This article explores the groundbreaking scientific approach that is bringing much-needed credibility to forest carbon accounting.
Country reduces harvesting to boost carbon storage, but the forest was already aging and would have stored more carbon anyway.
Country increases cutting, but the forest had recently been damaged by fires and some harvesting was necessary for regeneration.
This dilemma captures the core challenge of forest carbon accounting: disentangling human management from natural processes like age-related stand dynamics that result from past management and natural disturbances 1 .
Under the Kyoto Protocol (2013-2020), the solution was to use projected "forest reference levels"—essentially educated guesses about what would happen to forests in the future. These included assumptions about how future policies might increase harvest levels 1 .
This approach proved controversial. As one analysis noted, "unverifiable counterfactual scenarios with inflated future harvest could lead to credits where no change in management has actually occurred" 1 . In simple terms, countries could potentially receive credit for carbon savings that existed only on paper, based on harvest increases that never actually materialized.
In 2018, a team of researchers led by the European Commission's Joint Research Centre proposed a more rigorous, fact-based accounting system. Their revolutionary approach was strikingly simple: set reference levels based on documented historical forest management practices rather than speculative projections about future policy impacts 6 8 .
This science-based method still accounts for predictable, age-related forest dynamics but removes the influence of assumed future policies that may never be implemented 1 . It focuses on what has actually happened in forests rather than what might happen.
| Aspect | Kyoto Protocol Approach (Old) | Science-Based Approach (New) |
|---|---|---|
| Basis | Projected future scenarios including assumed policies | Documented historical management practices |
| Policy Impact | Included assumed future policy impacts | Considers only age-related dynamics |
| Verifiability | Based on unverifiable assumptions | Based on factual, historical evidence |
| Credibility | Controversial, potential for inflated credits | Enhanced transparency and credibility |
| Flexibility | Constrained by policy assumptions | Allows management flexibility while ensuring accountability |
To validate their new approach, the research team applied it across 26 European Union countries using the Carbon Budget Model developed by the Canadian Forest Service 6 8 .
The team first gathered documented forest management data from 2000-2009 across all EU member states, establishing what management actually looked like during this period 1 8 .
Using the Carbon Budget Model, they projected what would happen if these same management practices continued, accounting for natural age-related dynamics as forests matured 1 .
The researchers then compared their model's predictions with what actually happened in EU forests between 2013-2016 8 .
Finally, they contrasted these findings with the results generated under the Kyoto Protocol's accounting method 1 .
The findings were striking. Under the old Kyoto Protocol system, EU forests would have generated credits of 110-120 Mt CO₂ per year (capped at 70-80 Mt CO₂/year) for supposedly reducing emissions beyond what was expected 1 8 .
But the new analysis revealed these apparent "savings" were mostly illusory. The research showed these credits were "mostly due to the inclusion in the reference levels of policy-assumed harvest increases that never materialized" 1 .
| Accounting Approach | Expected Harvest Increase by 2030 | Primary Driver |
|---|---|---|
| Kyoto Protocol Method | Significant increase (exact percentage not specified) | Assumed future policy impacts |
| Science-Based Method | 12% increase relative to 2000-2009 | Age-related dynamics (maturing forests) |
With the new science-based approach, harvest levels are still expected to increase (by about 12% at EU level by 2030 relative to 2000-2009), but at a slower rate than forecast under the Kyoto Protocol method. This increase reflects real, age-related dynamics—specifically, increased growing stocks in maturing forests—rather than unverified policy assumptions 1 .
Modern forest carbon accounting relies on several sophisticated tools and methods that enable researchers to make accurate assessments:
An approach specifically designed for smallholder carbon projects that uses observed, real-world data to measure the true impact of project interventions. It has received recognition for high integrity in carbon accounting 3 .
Comprehensive national-level data on forest growth, species composition, age structure, and management interventions that form the factual basis for historical reference levels 1 .
Geospatial technology that provides independent verification of forest cover changes, growth patterns, and disturbance events across large landscapes 7 .
The science-based approach to forest carbon accounting represents more than just a technical adjustment—it's a fundamental shift toward greater transparency and credibility. By tethering accounting to historical evidence rather than speculative projections, it ensures that credited mitigation reflects genuine deviations from business-as-usual management 1 .
Science-based forest carbon accounting ensures that credited mitigation reflects genuine contributions to climate goals, not just paper savings.