Contra Scientists Gong, Mathieu, and Hilmar

The "Doomsday Glacier" (CNN)

There are two hypotheses about how sea level changes when tidewater glaciers melt and enter the oceans around the globe. 

One is that most change is because of ice flowing as a sort of ice river towards the ocean:

"Numerical modeling of ice sheet dynamics is a critical tool for projecting future sea level rise. Among all the processes responsible for the loss of mass of the ice sheets, enhanced ice discharge triggered by the retreat of marine- terminating glaciers is one of the key drivers. Numerical models of ice sheet flow are therefore required to include ice front migration in order to reproduce today’s mass loss and to be able to predict their future. However, the discontinuous nature of calving poses a significant numerical challenge for accurately capturing the motion of the ice front."

(Numerical stabilization methods for level-set-based ice front migration, 2024). This is the traditional perspective .

The other is that the major quantity of tidewater glacier melt takes place where the glacier meets the tidewater at or near its grounding line:

"... in the Antarctic Peninsula we paid a lot of attention also in the Western Antarctic Ice Sheet sector in the Pine Island and Thwaites glacier. This glacier is a hundred and twenty kilometers wide. All of these glaciers feel the effect of more warm water. They are [speeding] up by 75%. They are retreating at one to two kilometers per year. There's not a single glacier on the face of the earth in Alaska alpine landscape or Himalaya ... that [melt more]. These are the fastest retreating glaciers on the face of the earth. But you wouldn't see it with a naked eye because it's happening a kilometer below the surface [but] you can see it with satellite techniques. Another glacier that ... got [my] attention is Totten glacier. This is a single glacier in East Antarctica which holds 3.5 meter[s of] sea level rise ..."

(Eric Rignot video below, beginning at about 20:16; cf. at about 8:45-9:25). A paper published by Eric, Enrico, and Bernd illustrates the point further (Widespread seawater intrusions beneath the grounded ice of Thwaites Glacier, 2024).

The answer to the question "How many glaciers each one kilometer wide would it take to match the width of the Thwaites glacier?" is "one hundred and twenty glaciers" (Totten Glacier adds another thirty, totaling 150 'normal sized' glaciers to match the volume of those two Antarctic glaciers).

Closing Comments

I think that improving the "models" that estimate the anticipated acceleration of the "grounding area" melt rates of tidewater glaciers in Antarctica is a better scientific endeavor than estimating how fast glaciers slide on the solid ground beneath them.

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