Additionality in NCX Carbon Accounting
Dr. Nan Pond
Dr. Nan Pond
16 November, 2021 min read

A key feature of calculating the impact of a forest carbon project is a concept called “additionality.” For forest carbon projects to effect real change on the landscape, we need to know what would have happened if the project didn’t take place.

In order to understand the impact of a forest carbon project, it’s crucial to have a clear, objective, and quantitative process for understanding what would happen if the landowner had not enrolled, and had instead followed their “business as usual” (BAU) plan. We discuss this in more detail in our Additionality: Creating Real Climate Impact blog post.

NCX is working with Verra to develop a new methodology for Improved Forest Management projects. Over the last few months, our data scientists and forest biometricians have been focused on expanding our “business as usual” framework for carbon projects into something reproducible by other developers who might use that methodology.

Previously, our approach to setting baseline for projects heavily leveraged remote sensing data – something we were quite comfortable with from our years of developing our Basemap dataset, but which was less extensible for other developers. We’ve revamped that system to incorporate much more measurement data from robust national datasets such as the USDA Forest Service Forest Inventory and Analysis program, and the National Woodland Owner Survey. The FIA data offers a wealth of information about where and what kinds of forest harvesting takes place across the US, and the NWOS survey is an amazing look at the past behavior and future plans of family forest owners around the country. 

NCX determines changes in carbon using a predictive BAU model based on peer-reviewed research around “likelihood of harvest” that measures the statistical likelihood that any acre would be harvested the following year. Inputs into this model include forest structure and composition, the property size and ownership type, proximity to mills, markets and transportation networks, and local market conditions.

We evaluate these components on an acre-by-acre basis – the same way a forester might evaluate merchantability and harvestability of one or more forest stands on a property. We’re pleased with this approach, and we’re grateful to the group of experts who helped us to review it prior to incorporating it into our Verra methodology.

These changes are important because they improve — and make more transparent — what we know about what would have happened if landowners did not enroll in the program. While they change how we make assessments going forward, the changes we made this year in our methodology won’t have any impact on landowners who are already enrolled as Accepted Sellers in our Spring or Summer 2021 cycles; their performance will be assessed using the BAU model used to generate their assessments at the time they entered the program.

Going forward, landowners who have previously received Eligibility Reports from us but have not yet been accepted into the program might see shifts in the number of estimated credits available to them – this is a reflection of our commitment to continually improve the math behind forest carbon projects. 

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about the author

Dr. Nan Pond

Dr. Nan Pond

Director of Certification
Dr. Nan Pond serves as the Director of Certification at NCX. She is responsible for ensuring that our natural capital products reflect the highest quality science as we hone our existing methods and expand into new credit types and new geographies. She is the recipient of the 2020 SAF Young Forester Leadership Award and has held multiple leadership roles within the Society of American Foresters. Dr. Pond earned a PhD in forest biometrics from Michigan Technological University and a Bachelor of Science in forest ecosystem science from SUNY ESF.