Skip to main content
U.S. flag

An official website of the United States government

Quantifying Climate Feedbacks of the Terrestrial Biosphere Under Thawing Permafrost Conditions in the Arctic

Funding Program Area(s)
Project Type
University Grant
Project Term
to
Project Team

Principal Investigator

Collaborative Institutional Lead

Our overall goal is 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 conditions under which these emissions provide a strong feedback mechanism. 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 to the landscape of wetlands and lakes, especially thermokarst (thaw) lakes, across the Arctic. Through a suite of numerical experiments that encapsulate the fundamental processes governing methane emissions and carbon exchanges – as well as their coupling to the global climate system. We intend to test the following hypothesis in the proposed research: There exists a climate warming threshold beyond which permafrost degradation becomes widespread and stimulates large increases in methane emissions (via thermokarst lakes and poorly-drained wetland area upon thawing permafrost along with microbial metabolic responses to higher temperatures) and increases in carbon dioxide emissions from well-drained areas. Besides changes in biogeochemistry, this threshold will also influence global energy dynamics through effects on surface albedo, evapotranspiration and water vapor. These changes would outweigh any increased uptake of carbon (e.g., from peatlands and higher plant photosynthesis) and would result in a strong, positive feedback to global climate warming.

This proposed research will take another step towards our goal of having a fully coupled earth system based on a suite of models of surface and groundwater hydrology, permafrost, carbon and methane dynamics, atmospheric chemistry and climate, ocean chemistry and circulation and the global economy. With the coupled modeling system, we will:

  1. Quantify the biophysical (via changes of albedo, evapotranspiration, and permafrost freezing and thawing) and biogeochemical (via net CO2 and CH4 emissions) feedbacks of northern high latitudes to the global climate system using an ensemble simulation approach
  2. Investigate the thresholds of climate, permafrost dynamics, and hydrology that result in rapid large emissions of these gases and their feedbacks to climate.

While we will consider all terrestrial ecosystems in the region, our primary focus is on peatland/wetland and aquatic (lakes) ecosystems where large carbon pools may change from accumulating carbon due to slow decomposition in the past to losing carbon due to permafrost thawing in the future.

The success of this project will contribute to SciDAC research missions. The development of modeling thawing permafrost in wetland and lake systems and their effects on hydrological and carbon dynamics will contribute to having better Earth System Models so that the thresholds and nonlinearities of dynamics of permafrost, hydrology and carbon and their feedbacks to climate system will be examined.