Dr. Rogier Schulte:

The Deputy asked a pertinent question about the carbon cycle. He is right that agriculture does both things. Agriculture takes up carbon and sequesters it in soils, plants and trees. It also emits carbon.

There are a number of reasons that it is not a zero sum game. One of the dominant reasons is that our ruminants converge one form of carbon into another. They converge what was carbon dioxide taken out of the atmosphere into methane. The problem is that methane is a much more powerful greenhouse gas than carbon dioxide. We often hear about carbon dioxide as a greenhouse gas but methane is much more powerful. Nitrous oxide is more powerful again in terms of the amount of heat it traps. This is why it is not a zero sum game. In the framework that we and our EPA colleagues refer to for the post-2020 period, we are aiming to at least bring these emissions from agriculture which are currently counted together with the credits in terms of the carbon uptake so that at least the positives and negatives are accounted for in the same framework. It is unlikely to ever become a zero sum game.