Peatlands, carbon, and climate: the role of drought, fire, and changing permafrost in northern feedbacks in climate change

摘要

Peatlands store -30% of the world's soil carbon and are located primarily at northern latitudes, where they are experiencing rapid climate warming. As climate change alters peatland hydrology and soil temperatures, changes in ecology and biogeochemistry may alter rates of carbon storage as peat. Moreover, warmer and drier conditions may enhance the decomposition of old carbon in peatlands, accelerating greenhouse gas emissions with positive feedbacks to climate change. Here, I present findings from experiments, regional surveys, and modeling studies that examine the consequences of warming, drought, and disturbance on the ecology and carbon cycling of boreal peatlands. While fast ecosystem responses to drought include reduced ecosystem carbon storage, a long-term experiment showed that drainage increased woody inputs to soils and soil carbon storage. However, increased forest cover made these drained ecosystems more susceptible to burning during wildfires, leading to large carbon losses through fuel combustion and ecosystem succession. In addition to changes in ecosystem carbon storage and exchange, additional research on other aspects of radiative forcing, such as surface albedo change, is required for a more complete understanding of the role ofpeatlands in climate warming.