Among all the drama of calving icebergs and collapsing ice shelves on the Antarctic Peninsula and around the Weddell Sea, one crumb of comfort has been the relative stability of the ‘eastern’ side of the continent, facing the Indian Ocean.
Previously, the only substantial threat of melting in this region has been the large east Antarctic glacier known as ‘Totten’, which, after being studied for several years, appeared to be slowly responding to warmer conditions with a gradual retreat. Were it ever to melt entirely, Totten is voluminous enough to raise sea levels by 3.4 metres (11 feet) all by itself.
‘Totten is the biggest glacier in east Antarctica, so it attracts most of the research focus,’ explains Catherine Walker, a glaciologist at NASA’s Goddard Space Flight Center. ‘But it turns out that other nearby glaciers are responding in a similar way to Totten.’
This map shows the flow of the Antarctic ice sheet as measured by the tracking of subtle surface features across millions of Landsat satellite repeat image pairs. The ‘doughnut hole’ marks the maximum latitude visible by the Landsat satellites
For the first time, hints of melting in glaciers around Totten have emerged, with evidence that several have been losing mass over the past decade. With data collected from a range of sources – including floating sensors, sensor-tagged animals and ocean temperature simulations – NASA findings reveal that heat is increasingly moving into this region of Antarctica, especially around Wilkes Land and Vincennes Bay (respectively to the east and west of Totten).
‘Those two groups of glaciers drain the two largest subglacial basins in east Antarctica, and both basins are grounded below sea level,’ explains Walker. ‘If warm water can get far enough back, it can progressively reach deeper and deeper ice. This would likely speed up glacier melt and acceleration, but we don’t know yet how fast that would happen. That is why people are looking at these glaciers, because if you start to see them picking up speed, that suggests that things are destabilising.’
This was published in the February 2019 edition of Geographical magazine
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