Collaborative Research: Interacting Effects of Increasing Wildfire Severity and Abrupt Permafrost Thaw on the Carbon Balance of High-latitude Ecosystems (WATCH)

University Of Alaska Fairbanks Campus, Fairbanks AK

Investigators

Abstract

Wildfires are increasing in severity and frequency as global temperatures rise. This trend is more pronounced in northern ecosystems, where temperatures have risen at twice the rate of the rest of the globe. These ecosystems store vast amounts of carbon (C) in soils and permafrost – more than double the amount of carbon currently in the atmosphere. Most of this permafrost is protected from climate-induced thaw by deep organic soils. Severe wildfires that burn deeply into the insulating layer of organic soil can destabilize permafrost soils and lead to the loss of carbon to the atmosphere that has been stored for 100s to 1000s of years. Our research seeks to assess how increasing wildfires affect permafrost carbon in boreal forests and Arctic tundra ecosystems. This information will improve our ability to identify where permafrost carbon is likely to be lost with wildfire. It will also help us understand how increasing wildfires will affect future climate. We will sponsor three Alaskan artists to help engage the public on the impacts of wildfire on boreal and tundra ecosystems via an art-science exhibit, and we will assess the impacts of science-art integration on artists, scientists, and audiences. Historically, boreal forest and tundra ecosystems have acted as a net carbon sink, accumulating carbon from the atmosphere over numerous fire cycles and centuries. Fire-triggered loss of permafrost carbon could shift boreal and tundra ecosystems from net carbon sink to net carbon source to the atmosphere. We will integrate long-term field observations with novel radiocarbon dating methods and earth system modeling to assess the impact of increasing wildfire severity on the loss of permafrost carbon and carbon source-sink dynamics in boreal forest and Arctic tundra ecosystems. This information is critical for predicting where and when high-latitude ecosystems are likely to cross tipping points and undergo state changes, and where current model representations are likely inadequate. Given that boreal and tundra ecosystems soils store approximately 30% of global terrestrial carbon, understanding where and when permafrost soil carbon is lost following wildfire and incorporating these results into models is critical for determining whether these ecosystems will accelerate or mitigate climate change through carbon cycling feedbacks to climate. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.