Roundup: Ice Streams, Carbon Sequestration and Glacier Recession

Instability of Northeast Greenland Ice Stream

From Nature: “The sensitivity of the Northeast Greenland Ice Stream (NEGIS) to prolonged warm periods is largely unknown and geological records documenting such long-term changes are needed to place current observations in perspective. Using cosmogenic surface exposure and radiocarbon ages, the magnitude of NEGIS margin fluctuations over the last 45  kyr (thousand years) was determined. The NEGIS experienced slow early Holocene ice-margin retreat of 30–40  meters per year, likely as a result of the buttressing effect of sea-ice or shelf-ice. This retreat was smaller than present for approximately half of the last ~45 kyr and is susceptible to subtle changes in climate, which has implications for future stability of this ice stream.”

Discover more about ice stream and melting in Greenland here.

Aerial Image of Greenland Ice Sheet showing ice streams (Source: NOAA).

 

Sea Ice, Blue Carbon and Antarctic Climate Feedbacks

From The Royal Society: “Sea ice, including icebergs, has a complex relationship with the carbon held within animals (blue carbon) in the polar regions. Sea-ice losses around West Antarctica’s continental shelf generate longer phytoplankton blooms (less sea ice increases phytoplankton blooms, benthic growth, seabed carbon and sequestration) but also make it a hotspot for coastal iceberg disturbance. Significant benthic communities establish where ice shelves have disintegrated (giant icebergs calving), and rapidly grow to accumulate blue carbon storage. When 5000 km2 giant icebergs calve, we estimate that they generate approximately 106 tonnes of immobilized zoobenthic carbon per year (t C yr−1).”

Read more about the physical, chemical and biological processes of carbon sequestration here.

Fauna growth in Antartica on places exposed due to melting
Fauna growth in Antarctica on places exposed due to melting (Source: Biomes of the World).

 

Analysis of Mt. Kenya’s Glacial Recession

From the American Journal of Environmental Science and Engineering: “In a bid to discover what has been causing the retreat of glaciers of Mount Kenya, Optical Landsat data for 1984 to 2017 and climatic data of the same years were used. Glaciers and forest coverage were extracted from Landsat images and its thermal band was used to extract temperature data. Correlation with the respective year’s climatic data and forest cover area were done to justify the assumption that the shrinkage in the glaciers coverage has been caused by changes in climate and/or deforestation… Mt Kenya glaciers are likely to have still completely disappeared by the year 2100.”

Explore more about the modelling of Mount Kenya’s glaciers here.

Mount Kenya's Lewis Glacier
Photo of Mount Kenya’s largest glacier – the Lewis Glacier (Source: Earth Day Network/ Pinterest).

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