OMG: Oceans Melting Greenland

One of the fascinating phenomena of the early twenty first, we are witnessing the rapid melting of the cryosphere, the glaciers and ice caps. My own view is that this process will be the geological marker for the Anthropocene, leaving an indelible mark on the planet in the form of many meters of sea level rise.

I’m pretty sure that the die is cast, there is no way to halt the process. But it is really cool to be able to watch it happen in our lifetime.

For one thing, it’s not clear exactly how all the variables work together, and feed back on each other. Warmer air melts ice, but may change precipitation patterns. Iceless water and rock warms quicker, melting more ice. Melted ice water flows into the ocean, possibly changing currents and cooling or warming sea ice. There is plenty of work for scientists.

One project is the not-at-all-subtly-named “OMG – Oceans Melting Greenland” from NASA JPL. Using remote and in situ sensing, the project examining the interactions of glaciers, the ocean, and the geometry of the continental shelf.

The Greenland ice sheet is about the area of Texas, and is a mile deep. If and when the ice melts completely, it is enough water to raise sea levels by 6 meters. (Odds are that you, my friend, are under water when it gets over 2 meters higher.)

That massive ice sheet touches the sea along more than 44,000 kilometers (27,000 miles) of jagged coastline. Hundreds of fjords, inlets, and bays bring ocean water right to the edge of the ice and, in some places, under it. This means the ice sheet is not just melting from warm air temperatures above; it is also likely being melted from water below.

NASA Earth Observatory map by Joshua Stevens, using Oceans Melting Greenland (OMG) data courtesy of Josh Willis/JPL. Photograph by Josh Willis. Caption compiled by Mike Carlowicz from reporting by Patrick Lynch and Carol Rasmussen, NASA Earth Science Communications.

The NASA mission is using aircraft to collect high precision maps of the extent and height of the ice over a number of years, ships to map the sea floor, and floating instruments to record temperature and salinity of the ocean at various depths. Together, this data will help model the complex interactions, and perhaps understand how fast the ice will melt.

 

Space Saturday

 

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