Modelling permafrost carbon
Håvard Kristiansen, Geosciences
Permafrost contains twice as much carbon as the atmosphere. Climate change is causing permafrost to thaw, with the consequence that some of the carbon will decompose and be emitted to the atmosphere as CO2 or methane. Once in the atmosphere, these greenhouse gases will contribute to further climate change, which can cause more permafrost to thaw and so on. This self-reinforcing cycle is known as the permafrost carbon feedback.
But how vulnerable is the carbon to thawing? And how much of the carbon will be emitted as CO2 and how much as methane, which is a more effective greenhouse gas?
Another question is how a warmer climate and less frost will affect the plants and animals that contribute carbon to the soil. Satellite images have already shown that the Arctic has gotten greener as a result of more favourable growing conditions for plants. Because plants capture CO2 from the air, this would seem to counteract climate change. But how do changes in plant cover affect below-ground carbon?
In this project, we are developing a computer model that simulates the energy, water and carbon balance of soil to answer these questions. We start by modelling how carbon has accumulated in the soil, because we figure that if we want to predict the future, we should understand the past.
We will present preliminary results of carbon accumulation and greenhouse gas fluxes between the soil and the atmosphere, as well as illustrations of arctic greening and the geographic distribution of permafrost.