500 Vertical Meters Of Ice Gone In 7 Years From West Antarctica's Smith Glacier
EDIT
However, direct evidence of such a powerful melt dynamic had not yet been directly observed in Antarctica’s glaciers. Fresh water lenses were developing, rates of glacial loss were quickening. Basal melt rates looked bad. But the kind of tremendous losses necessary to produce rapid sea level rise were not yet fully in evidence.
That situation changed during recent weeks when two scientific papers broke the news that some of West Antarctica’s glaciers had lost upwards of a half a kilometer of ice thickness due to contact with warm ocean waters over the past decade.
The studies, entitled Rapid Submarine Ice Melting in the Grounding Zones of Ice Shelves in West Antarctica and Grounding Line Retreat of Pope, Smith and Kohler Glaciers took a comprehensive look at both surface and underside melt of three major west Antarctic glaciers near the Thwaites and Pine Island Glacier systems. These glaciers included Pope, Smith and Kohler — which have seen increasing instability and rates of seaward movement during recent years. Using multiple instruments, the scientists found evidence of massive ice losses and speeding ice flows.
?w=600&h=338
(Surface velocity of Kohler, Smith and Pope Glaciers provided by NASA. More rapid seaward movement of glaciers = faster rates of sea level rise.)
The losses occurred at a time when an influx of warmer water (warming circumpolar deep water) was heating the ice shelves and grounding lines buttressing these three partially submerged glaciers. This warming was found to have produced melt along the grounding zones of these glaciers in the range of 300 to 490 meters from 2002 to 2009. In other words, about 1/3 to 1/2 a kilometer of ice thickness at the grounding line was lost in just seven years. Melted away from below by warming deep ocean conditions at the rate of up to 70 meters or around 230 feet per annum.
EDIT
https://robertscribbler.com/2016/10/26/half-a-kilometer-of-ice-gone-in-just-7-years-west-antarctics-smith-glacier-points-to-nightmare-melt-scenario/