Understanding the Melting Arctic

The Greenland Ice Sheet is melting nonlinearly, and will become the chief source of sea level rise. Madeline Drexler of Wood's Hole reports on research by glaciologist Sarah Das.

Between 2005 and 2014, loss of ice mass from the Greenland ice sheet alone accounted for a fifth of global mean sea level rise. Now the second-largest contributor to rising seas worldwide, Greenland is on track to become the top source of added water.

She found that, rather than increasing in a steady linear trend as climate warms, the melt rate trajectory of Greenland’s ice sheet is “nonlinear,” curving up faster and faster for every degree of warming. According to Das, compared to even the late 19th century, it now takes very little additional warming to trigger huge spikes in ice sheet melting and runoff.

(IPCC) projections  …  don’t account for all of the newly understood, ocean-driven dynamic changes in glacial behavior—especially the melting of ice from underneath by warm waters—that may prove to be far more consequential, especially in the continent-size ice sheet at the bottom of the globe.

“Antarctica is still the biggest wild card when it comes to ice loss,” said Das. [emphasis mine]

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I wouldn't make that leap if I were there, nor would I be willing to trust my ability to survive the speed of the water and the cold should I fall in!

Volcanic activity underneath the ice contributes to the fast melting of ice. The eruptions may not reach the surface of the glaciers, however, studies of ice water seeping out of the glaciers or into the water under the ice shelf contain chemicals that reveal when volcanic activity takes place. Does Greenland have volcanic activity? 

”Greenland is not known for having volcanic activity. Getting a handle on Greenland’s geology is hampered by the fact that the majority of the island is covered with hundreds or thousands of meters of ice. But geologists in the field who have studied the exposed rock along the coasts and on mountains above the ice found evidence of volcanoes in Greenland’s past.”

~ George Hale. (December 2, 2014). Rock, Ice and Fire: Volcanoes of Greenland's Past. 

https://blogs.nasa.gov/icebridge/author/ghale/

Drilling into polar ice sheets, t]he 1390-meter deep ice core provided evidence of three separate climatic oscillations.

~Icelandic Volcanoes and the Greenland Ice Sheet Connection.

https://chandra.harvard.edu/edu/formal/icecore/Icelandic_Volcanoes_...

1390-meter = 0.86370596 of a mile? Am I correct? 

I just learned, from Seven Worlds: One Planet, that Antarctic Melt is doubling every decade. That's nonlinear big time.

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