Our carbon method passed peer review
The way we measure carbon on our sites, using ground plots checked against satellite data, was published in a peer-reviewed journal after eighteen months of review.
We have always said we measure carbon on our sites rather than estimate it from a model. Saying that on a fundraising page and showing your working in a journal are different things, and the second is the one that counts. After eighteen months of review, the paper setting out our method has been published.
The method pairs ground plots, where a team physically measures every tree, with satellite data that lets us scale those measurements across the whole site. The paper lays out the entire approach in detail, including the places where it is uncertain, so anyone who wants to pull it apart has what they need to do so.
Dr Amara Okonkwo led the rewrite after she joined last July. Tightening this method was the first thing she did, and it shaped everything that followed. The restoration ecology lab at the University of Leeds was the partner on the work.
Review was not comfortable. The reviewers made us redo two years of plot data under a stricter error bound, which meant going back through measurements we had already reported. It was slow and it stung in places.
The redone numbers came out slightly lower than our earlier figures, and a great deal more defensible. We would rather publish a smaller number we can stand behind than a larger one we cannot. We have already updated our public carbon figures to match the reviewed method.
The point of all this is not the paper itself. It is that our carbon claims can now be checked by anyone with the patience to read the method, and that is the only basis on which those claims deserve to be believed.
