That is fair enough, and we can probably write to the committee with an explanation—I say to Sara Grainger that there is no need for her to look so horrified. [Laughter.]
I can run through in broad terms the four main reasons for the revisions, and begin to set out what some of the issues are.
First, there are changes to international scientific guidelines. Those changes are made elsewhere and may take a while to filter through. Basically, we use methods to compile the UK inventory that are consistent with international guidance from the UN, and that guidance is periodically reviewed and updated. Therefore, we can get changes at that big, international level.
We can also get improvements to UK-level methodologies. The UK inventory is regularly peer reviewed by the UN, which then makes recommendations for improvement. Again, continuous improvement happens at that level.
There are also revisions to UK-wide data sources. Sometimes those are revisions to statistical publications—for example, fuel consumption statistics might change—which can lead to revisions to the UK inventory. Those can be minor, but they can happen.
Finally, there may be improvements to the methods used to disaggregate the UK inventory. Sometimes there are improvements in Scotland-specific data that can allow for improvements to be made to how the UK inventory is disaggregated. Again, those changes tend to be minor.
Most of the changes are really at the level of the international science, and they then filter through to us. That is not done by Scottish scientists, although Scottish scientists might be involved—we are talking about the internationally understood scientific measurement of carbon emissions from degraded peat, for example. That change in people’s understanding means that they get better at measuring and the science gets better, and that then has to come through to our science.
Perhaps we could outline some of the things have happened over the past couple of years. For example, last year, I think, we benefited from some changes in forestry science that were down to the ability to capture a wider range of smaller forestry units, adding them into the total amount. That gave us a better measurement—and a bit of an advantage. However, some things on the waste side had a negative impact. We can give examples of some of those science changes, but we do not necessarily have control over most of this. These are UK Government decisions, and we have to play with the hand that we are dealt.