The Arctic Carbon and Climate (ACCLIMATE) Observatory: Tundra Ecosystem Carbon Balance and Old Carbon Loss as a Consequence of Permafrost Degradation

Carbon release from the Arctic is a wildcard that could alter the future trajectory of climate change, a potential tipping point in the global carbon cycle that could accelerate sea-level rise, extreme weather, droughts, fires, and impacts on agriculture, at rates beyond those currently projected by models. The central hypothesis is that net transfer of carbon to the atmosphere will occur because of permafrost thaw and the microbial decomposition of organic carbon. Permafrost may act as an accelerating feedback to climate change if a significant amount of the old carbon that forms the bulk of the soil pool is respired to the atmosphere following permafrost thaw.  

Intellectual Merit: This project supported the development of The Arctic Carbon and Climate (ACCLIMATE) permafrost carbon observatory that used field observations to measure ecosystem carbon fluxes and pools in a tundra ecosystem that is undergoing rapid and irreversible change due to regional warming. Permafrost temperature at the Eight Mile Lake research watershed in Interior Alaska has been monitored for several decades starting before permafrost degradation began in the early 1990s. This upland tundra site is located in the southern permafrost region where permafrost temperature near zero is especially sensitive to ongoing changes in climate. The impact of permafrost degradation on plants, microbes, and ecosystem carbon balance began to be documented in the early 2000s. This is a unique site that has tracked tundra ecosystem function as the degradation of permafrost unfolded over decades, and provides an important southern counterpoint to other established northern tundra research sites. Work during this project phase has provided important insight into the decadal-scale evolution of ecosystem carbon fluxes linked to permafrost thaw, as well as critical information about the loss of old carbon that is especially important to the climate feedback. Data from this project has been published in peer-reviewed scientific journals, contributed to regional science synthesis activities and publications, and archived for public use as part of the Bonanza Creek Long Term Ecological Research database.

Broader Impacts: The ACCLIMATE observatory has integrated knowledge-transfer activities that link results to the broader scientific community, as well as to the wider public. Public outreach has occurred through established collaborations with staff of the highly visited Denali National Park, by co-hosting an annual site field trip for park seasonal staff, visitors, and local residents. This collaboration also featured a public presentation at the Murie Science and Learning Center. This project interfaced with the broader science community through ongoing synthesis work organized by the Permafrost Carbon Network. Observational datasets generated by this observatory were contributed to ongoing synthesis and modeling activities that need datasets from permafrost ecosystems for benchmarking purposes. In turn, these science synthesis activities have been linked to outreach publications aimed at broader audiences, such as NOAA’s Arctic Report Card, to communicate how a changing Arctic influences local and global society. In this way, the ACCLIMATE observatory has connected primary data collection with synthesis science and broader outreach in the service of increasing, distilling, and communicating our understanding of change in this remote region with its important consequences for global climate and society.