IPY: Understanding the impacts of permafrost degradation and thermokarst lake dynamics in the Arctic on carbon cycling, CO2 and CH4 emissions, and feedbacks to climate change

Project Summary

Research

This research integrates field studies in a range of disciplines (geomorphology, geophysics, paleoecology, hydrology, limnology) with process modeling of permafrost thaw, lake formation, carbon cycling, and greenhouse gas (GHG) emissions to understand how permafrost degradation in the Arctic, particularly thermokarst-lake evolution, affects long-term atmospheric trace gas dynamics by releasing ancient carbon (C) stored in permafrost as carbon dioxide (CO₂) and methane (CH₄).

Map adapted from Guido Grosse, 2008.

The overarching goals are to:

1. describe comprehensively the state of thermokarst (permafrost degradation) in Siberia and Alaska
2. quantify its impact on landscape configuration through the alteration of surface geomorphology and drainage patterns
3. estimate its impacts on the C cycle via enhanced GHG (CO₂, CH₄) emissions, and
4. examine its potential to influence global climate —potential C release from thawing permafrost in Siberia alone totals >50% of the current atmospheric C burden.

In the long term we will establish:

1. a legacy of geographic, stratigraphic and process data from permafrost regions and data on thermokarst dynamics (past, present and future)
2. a working model of thermokarst processes
3. scenarios of thermokarst-GHG emissions driven by climate change from the Last Glacial Maximum (LGM) to the year 2200, and
4. an enhancement of collaborations within the Arctic Observing Network at observatories in North Siberia (Cherskii) and Alaska (Toolik Lake)

This photo was taken from a helicopter in October 2003, flying over the forested tundra zone near Andrushkina, Russia. This is not far from the town of Cherskii in the Sakha Republic of Russia's Far East. It is a zone of continuous permafrost, and the landscape is covered by millions of thermokarst lakes releasing methane. This photo is a good example of how much of the land surface is covered by lakes in some regions of the Arctic. The majority of lakes emit large quantities of CH₄.
Photo by Katey Walter Anthony

Partner Institutions

Work will be an international collaborative effort with Bristol University (UK), the Alfred Wegener Institute for Polar and Marine Research and the Max Planck Institute for Microbiology (both Germany) and the Permafrost Institute, Yakutsk (Russia). The project is integrated with other IPY certified projects: "Permafrost Observatories: Thermal State of Permafrost", "Arctic Circum-Polar Coastal Observatory Network", and "Carbon Pools in Permafrost Regions".

Thermokarst Background

Thermokarst lakes dominate large areas of the Arctic land surface and may expand as permafrost continues to warm and thaw. We will explore a new frontier in polar science: the relation of thermokarst lakes to global climate change. The cross-disciplinary research will link process-based ecological and trace-gas flux measurements, geophysical field measurements, remote-sensing based observations, paleo-environmental analyses of permafrost and lake cores, and laboratory incubations of thawed permafrost soils and lake sediments in order to drive a quantitative model of CO₂ and CH₄ emissions from thermokarst lakes in Alaska and Siberia from the LGM to the present. Using permafrost characteristics, geomorphologic constraints and earth-system model-based projections of future climate change we will estimate CO₂ and CH₄ emissions from thermokarst lakes during the next 100-200 years — a positive feedback to climate change. Potential negative feedbacks (e.g. C-sequestration in lake bottoms) will also be taken into account. We will apply innovative geophysical methods along with paleo-techniques and carbon-cycling studies to understand the structure, function and evolution of thermokarst lakes. Geophysical and remote-sensing techniques will be used to explore possible CH₄ emission from disintegrating CH₄ hydrates and sub-permafrost free-phase CH₄ associated with thermokarst-lake development. Our approach will establish a legacy of methodologies and data and lead to an understanding of the role of thermokarst lakes in climate change over millennial time scales. Resulting data will be archived and broadly available through the Geographical Information Network Alaska (GINA) and the Arctic Long-term Ecological Research database (LTER).