Satellite Remote Sensing of Permafrost

by Lindsay McCord

Using a new approach to measure the extent of permafrost (permanently frozen soil), researchers have confirmed consistent widespread decline in stable permafrost that coincides with regional climate warming. This model provides greater resolution for looking at the condition of permafrost on a regional scale, and combined with other models, allows us to understand how permafrost is reacting to rising temperatures. Permafrost occupies roughly a quarter of land area in the Northern Hemisphere, over 40% of which is vulnerable to melting according to the new model. Twenty percent of permafrost land area is at a moderate risk, while 23% is facing severe degradation risk. In addition, the study found that permafrosts in boreal forests are more vulnerable than the more northern tundra permafrost. The model further confirms significant increasing regional trends of permafrost melting in the past 30 years in response to climate warming. Continue reading

New Model Predicts How Debris-Covered Glaciers Will React to Climate Change

by Lindsay McCord

Glaciers are vulnerable to melting due to climate change, however debris-covered glaciers respond differently to changes in temperature due to insulation from the debris. A new model factors in this variable for debris-covered glaciers in order to predict how these glaciers will react to a changing climate. Focusing on the Khumbu Glacier in the Himalayas of Nepal, the model predicts a loss of 8-10% of total glacial mass by 2100 followed by increased losses as the tongue (frontmost part of the glacier where debris accumulates) separates from the rest of the glacier. This separation process exposes more surface area of the glacier which causes accelerated loss of mass. Continue reading

Vegetation Disturbance Triggers Greenhouse-Gas Emitting Feedback Loop in Permafrost

by Lindsay McCord

Vegetation changes have the ability to rapidly destabilize permafrost soil, illustrating vulnerability of these ecosystems to disruptions. Study sites that removed shrub vegetation experienced both increased thaw depth of permafrost as well as soil subsidence, lowering the permafrost table by 31 cm in comparison to control sites. This created localized wetlands of water-saturated depressions, which become hotspots for additional thawing as well as increased methane emissions. Continue reading