THIS POST IS A CRITICAL REVIEW OF A LIVESCIENCE ARTICLE THAT SAYS THAT THE THWAITES GLACIER IS THREATENED BY A HIDDEN RIVER OF WARM WATER WITH THE WARMTH OF THE WATER ATTRIBUTED TO CLIMATE CHANGE . LINK TO THE LIVESCIENCE ARTICLE: https://www.livescience.com/thwaites-glacier-hidden-rivers-mapped.html

PART-1: WHAT THE LIVESCIENCE ARTICLE SAYS

Hidden rivers of warm water threaten vast Antarctic glacier
By Rafi Letzter

Sea levels could rise more than two feet if just this one glacier collapses.

Instruments aboard the British Antarctic Survey ship RV Nathaniel B Palmer helped scientists map the channels under the glacier.
Instruments aboard the British Antarctic Survey ship RV Nathaniel B Palmer helped scientists map the channels under the glacier. One of the largest, most unstable glaciers in Antarctica is sliding into the ocean. That’s due, in large part, to hidden rivers of warm water that lubricate its underbelly, more so now than ever in the era of climate change. Now, researchers know what those unseen channels look like. By using equipment that can measure fluctuations in gravity, radar and seismic waves, scientists were able to map precisely where these glacier-melting channels cut through the deep seabed. “It was fantastic to be able to map the channels and cavity system hidden beneath the ice shelf; they are deeper than expected some are more than 800 meters deep. They form the critical link between the ocean and the glacier.

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Thwaites Glacier is a vast brick of ice flowing into Pine Island Bay in western Antarctica. If you took off in an airplane from El Paso, Texas and flew due south — across about 590 miles (950 kilometers) of western Mexico and 5,700 miles (9,200 km) of Pacific Ocean — you’d see it out your window as a white expanse with sheer cliffs where it meets open water. The Thwaites has moved toward the ocean its entire existence, but that rate of motion has increased fivefold over the last 30 years, to the point where snowfall at the rear of the glacier can no longer replenish ice lost in the front. That lost ice has contributed to about 4% of global sea level rise over those three decades. If the entire glacier were to collapse into the ocean, sea levels would increase by about a whopping 65 centimeters. This dramatic increase would devastate current coastlines, so scientists are trying to understand the dynamics driving Thwaites’ seaward motion and how fast these processes are accelerating the melt.

This new research, published Sept. 9 as a pair of papers in the journal Cryosphere, combined several under-glacier detection techniques to build detailed maps of those hidden channels. A key method: directly detecting gravity from the seafloor. The action happens where the seabed, water and ice at the bottom of the glacier meet. Ice is less dense, and therefore lighter, than water and this difference in mass causes gravity to fluctuate from one part of the glacier to the next. Sensitive instruments on boats or airplanes flying overhead can pick up those fluctuations — revealing details hidden deep below the ice surface. By combining that gravity data with radar and seismic measurements taken on the ice’s surface, scientists have created the most complete description yet of that hidden world, where warm water slicks the glacier bottom — its “bathymetry,” in scientific-speak.

The results confirm a major marine channel more than 800 meters deep that extends tens of kilometers to the front of Thwaites Glacier while the adjacent ice shelves are underlain by more complex bathymetry. {bathymetry=submarine topography = shape of the ocean floor}.What they found is that the bottoms of younger ice conform tightly to the jagged seafloor, while older ice shelves tend to have flatter bottoms. Details like that will help scientists refine models of how ice moves over ocean floors.

This research has filled a critical data gap. The new coastal sea floor maps and the cavity maps track the deep channels for over 100 km to where the glacier sits on the bed. For the first time, we have a clear view of the pathways along which warm water can reach the underside of the glacier, causing it to melt and contribute to global sea-level rise.

PART-2: CRITICAL COMMENTARY

It appears that costly and sophisticated research by these very dedicated climate scientists has made the amazing discovery that maps the deep channels on the seafloor bathymetry by which warm water reaches the underside of the Thwaites glacier and thus explains how this Doomsday glacier melts.

Yet another consideration, not given much attention in this research, is the issue not of identifying the channels by which the deep ocean waters flow to the bottom of the Doomsday Glacier, but of identifying the source of the heat that makes the water warm. Only if that source of heat is anthropogenic global warming caused by fossil fuel emissions that can be moderated by taking climate action, can the observed melt at the bottom of the Thwaites glacier be attributed to AGW climate change.

However, no such finding is made in this research project possibly because these researchers know, as do most researchers who study Antarctica, that this region of Antarctica is extremely geologically active. It is located directly above the West Antarctic Rift system with 150 active volcanoes on the sea floor and right in the middle of the Marie Byrd Mantle Plume with hot magma seeping up from the mantle. As described in a related post LINK: https://tambonthongchai.com/2020/02/09/antarctica-threatens-florida/ and in this related online article LINK https://www.labroots.com/trending/earth-and-the-environment/27/song-of-ice-and-fire-active-volcano-found-beneath-antarctic-snow ice melt at the bottom of the Thwaites glacier must be understood not in terms of man made fossil fuel emissions but in terms nature’s geological activity.

Details of these relevant geological features of Antarctica may be found in a related post on this site: LINK: https://tambonthongchai.com/2019/06/27/antarctica/