Arctic Lakes and Methane Emission

Thermokarst depressions and thermokarst lakes (TKLs) dominate large areas of the arctic land surface and may expand as permafrost continues to warm and thaw, releasing large quantities of methane (CH4) and carbon dioxide (CO2) to the atmosphere. We propose to define the relationship of TKLs to global climate change by developing remote sensing methods to quantify thermokarst and greenhouse gas (GHG) emissions from TKLs in regions (>1 million km2) of organic-rich, icy permafrost and ice-poor permafrost. We will use fine and broad scale remote sensing and field validation to determine the role of thermokarst as both a source (GHG release) and sink (peat accumulation) for carbon (C), thereby improving understanding of the behavior of a major C pool (icy permafrost) previously poorly considered in global C cycle sciences. By integration of our remotely sensed spatial data, information derived from multi-temporal satellite data (50 years), radiocarbon dated TKL sediment records (up to ~15,000 years old), and available and predicted climatic data, we will inform the sophisticated 2-D and 3-D numerical permafrost models of our collaborators for prediction of spatial and temporal thermokarst dynamics and related GHG emissions in scenarios for up to 200 years into the future as permafrost warms and thaws under global warming.