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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Photo Friday: Vanishing Glaciers by Project Pressure

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PhotoFriday: When I am Laid in Earth

The Lewis Glacier on Mount Kenya is one of the most surveyed tropical glaciers on Earth, and has been monitored and mapped regularly since 1934. In 2010, scientists found that the Lewis had shrunk by 23 percent in just the previous six years.

The New York Times reports, “Our glaciers, we’re told, are disappearing freakishly fast, but fast for a glacier can still be too slow for the human imagination to seize on.” How do we document this change, and raise awareness of glacial retreat? Award-winning photographer Simon Norfolk answered this question through photography.  His series, When I am Laid in Earth was developed in collaboration with Project Pressure, a nonprofit organization that aims “to photograph and publish the world’s vanishing and receding glaciers, and to document first hand the environmental impact of climate change.” Norfolk’s photo series relied on historical maps and GPS data to mark the contours of the glacier’s retreat and, in the middle of the night, light those lines on fire.

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When I am Laid in Earth was recently featured at the French photography festival, Les Recontres d’Arles. To read more about the works featured in this series, please download the associated newsletter, which details both the series and the Project Pressure initiative.

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Roundup: Glacier beds; Laser Scanning; Kenya’s Glaciers

Glacier beds get slipperier as sliding speed increases

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“As a glacier’s sliding speed increases, the bed beneath the glacier can grow slipperier, according to laboratory experiments conducted by Iowa State University glaciologists.

They say including this effect in efforts to calculate future increases in glacier speeds could improve predictions of ice volume lost to the oceans and the rate of sea-level rise.”

Read more at EurekAlert.

 

Laser Scanner Techniques to Monitor Glaciers

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“The Ossoue glacier in the Vignemale massif (3,298 m) is currently the longest and second largest of the Pyrenees (1,400-m length, 50-ha area), and the only one presenting glacier tongue morphology. We describe 50 MHz ground penetrating radar (GPR) and laser scanner surveys from which we assess the current state and dynamics of the glacier. ”

Read more at Journal of Environmental and Engineering Geophysics.

 

Mount Kenya’s Vanishing Glaciers

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“It’s important to know two things about the adventure that followed, which Benuzzi chronicled in his book, “No Picnic on Mount Kenya.” First, Benuzzi did manage to escape the camp and climb to the summit of the mountain’s third-highest peak. Second, when Benuzzi came back down, after 18 days on the mountain, he apparently felt so rejuvenated — as if he had absorbed enough beauty to sustain him — that he decided to sneak back into the camp and picked up his life again as a prisoner. The mountain was that large and impressive, that sublime. ”

Read more at The New York Times.

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