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

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

Permafrost Thawing due to Rising Temperatures Predicted to Accelerate Climate Change

by Lindsay McCord

As a warming climate impacts Arctic and sub-Arctic regions, frozen soils, called permafrost hold the potential to release large amounts of greenhouse gases as they thaw, triggering a feedback cycle that can further accelerate climate change.

Permafrost is frozen soil that often contains large amounts of undecomposed organic matter. When permafrost thaws, microbes start to break it down, releasing carbon dioxide and methane gas, which accelerates atmospheric warming and furthers thawing of the permafrost in a positive feedback loop.

Much of the soil in the Arctic and sub-Arctic regions is permafrost, containing 1,330–1,580 billion tons of carbon. This estimate is probably low because it does not include subsea permafrost (frozen sediment at the bottom of shallow seas). It is also uncertain because current modeling does not accurately take into account variation in soil composition across the permafrost area. There also remain large, mostly remote areas where the amount of permafrost is entirely unknown. Continue reading

National Security Threatened Due to a Warming World

by Chloe Rodman

Jeff Goodell (2015) writes in Rolling Stone Magazine that 30 of the United States’ domestic military bases are in jeopardy due to climate change and rising sea levels. These stations either must be relocated in the near future or put out of commission because not only are they sinking into the ocean, but the compounds become flooded with each storm, making work almost impossible. Because of these recent trends, the Pentagon, as well as President Obama, believe that “…climate change poses immediate risks to our national security.” While many powerful and important members of the military and government believe action must be taken regarding climate change, some members of congress do not agree. These congress members, some of whom happen to be on various military committees, castigate those who believe in climate change or those who liken it to other global disasters such as terrorism or infectious disease. Continue reading

Modeling CO2 and CH4 Fluxes in the Arctic using Satellite data

by Rebecca Herrera

The peatlands and tundras of the Arctic perform vital ecosystem services to the earth through their ability to sequester carbon (CO2) and methane (CH4) and function as a carbon sink. The ability of the permafrost in the peatlands and tundra ecosystems of the Arctic to continue to function as a natural reservoir for carbon and methane may be disrupted by rising global temperatures that increase the rate of soil decomposition. Watts et al. (2014) integrate a terrestrial carbon flux (TCF) model to include a newly developed CH4 emissions algorithm. The new TCF model simultaneously assesses CO2 and CH4 fluctuations and the corresponding net ecosystem carbon balance (NECB), which is contingent upon gross primary productivity (GPP) subtracted from ecosystem respiration. The integrated TCF model uses data gathered through satellite remote sensors to assess fluxes in CO2 and CH4. Continue reading