Stable, charred, or disappeared: Peatland soil temperatures and permafrost sensitivity to interactions between temperature increases and changing disturbance regimes

Permafrost and peatlands are both common features throughout the northern latitudes, which are predicted to warm faster and more severely than temperate latitudes. This has major implications for ecosystem stability and function. Continuous and discontinuous permafrost now cover an estimated 11-12 million km2, but this area is predicted to decrease significantly within the next 100 years due to rising temperatures. Much of the discontinuous permafrost area occurs within peatlands; degradation of permafrost within peatlands affects the site C balance and may be crucial to understanding the impacts of climate change on northern regions due to the strong feedbacks of these large C pools. In addition to increasing temperatures, disturbance frequencies are also predicted to increase; however, the combined effects of both changing temperatures and changing disturbance regimes are unknown. We compare the relative effects of climate change and disturbance (such as wildfire) on permafrost in peatlands using a peatland-specific coupled hydrologic and thermodynamic model. The model simulates soil temperatures, active layer thickness, soil moisture and water table level. We estimate the sensitivity of permafrost within peatlands to current temperatures and future temperature projections. Additionally, we estimate the effects of increased temperatures coupled with wildfires on permafrost stability within peatlands, which has implications for both C storage and ecosystem stability