Quantifying Climate Feedbacks from Abrupt Changes in High-Latitude Trace-Gas Emissions

• Main Authors: Schlosser, Courtney Adam, Walter-Anthony, Katey, Zhuang, Qianlai, Melillo, Jerry
• Other Authors: United States. Department of Energy., United States. Department of Energy. Office of Biological and Environmental Research.
• Format: Report
• Language: English
• Published: Massachusetts Institute of Technology 2013
• Subjects: 54 Environmental Sciences; Arctic; permafrost; Thermokarst
• Online Access: https://doi.org/10.2172/1076751; https://digital.library.unt.edu/ark:/67531/metadc830590/

Our overall goal was to quantify the potential for threshold changes in natural emission rates of trace gases, particularly methane and carbon dioxide, from pan-arctic terrestrial systems under the spectrum of anthropogenically forced climate warming, and the extent to which these emissions provide a strong feedback mechanism to global climate warming. This goal is motivated under the premise that polar amplification of global climate warming will induce widespread thaw and degradation of the permafrost, and would thus cause substantial changes in the extent of wetlands and lakes, especially thermokarst (thaw) lakes, over the Arctic. Through a coordinated effort of field measurements, model development, and numerical experimentation with an integrated assessment model framework, we have investigated the following hypothesis: There exists a climate-warming threshold beyond which permafrost degradation becomes widespread and thus instigates strong and/or sharp increases in methane emissions (via thermokarst lakes and wetland expansion). These would outweigh any increased uptake of carbon (e.g. from peatlands) and would result in a strong, positive feedback to global climate warming.