A major East Antarctic glacier has retreated 3.3 miles and we didn’t notice it before!

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The global warming phenomenon has not taken a break, even amidst the COVID-19 crisis. Satellite observations say that a big glacier in East Antarctica has retreated around 3.3 miles or 5.4 kilometers in the past 22 years.

The majority of the planet’s glaciers are retreating. According to reports, more than half the planet’s ice is locked up in the East Antarctica region. This is enough for the sea level to rise by 5 feet. This region is one of the most resistant when it comes to heat-induced melting. If the glaciers there are retreating, it is terrible news.

The Denman Glacier

This major glacier, the Denman Glacier, has lost 3 miles or 5 kilometers of length from 1996 to 2018, according to a paper in Geophysical Research Letters. Two hundred sixty-eight billion tons of its ice has melted since 1979.

The Denman Glacier has 3 percent of East Antarctica’s ice. If it melts, it can add 5 feet to the global sea level by itself.

In a statement, University of California’s Professor Eric Rignot said: “East Antarctica has long been thought to be less threatened, but as glaciers such as Denman have come under closer scrutiny by the cryosphere science community, we are now beginning to see evidence of potential marine ice sheet instability in this region.”

The ice in West Antarctica has apparently been melting faster recently. The sheer size of the Denman Glacier implies huge long-term impacts on the sea level.

Why didn’t we notice it before?

Most observers can’t see the boundary between the glacier and the Shackleton Ice Shelf and, thus, failed to notice the retreat earlier. However, the glacier has extended into Earth’s deepest continental canyon, where it touches the bedrock. This submarine component is melting and leaving a thin layer of sea-ice on the surface.

Rignot and his colleagues used the radar capacity of the COSMO-SkyMed satellites of the Italian Space Agency. They can thus study the depth of the glacier and make a comparison with earlier observations.

If the subglacial ridge was not restricting the eastern flank of the glacier, the retreat would have been more intense and noticeable. The western flank, unfortunately, does not have a similar stabilizer. The underwater trough is getting deeper and deeper and is allowing the glacier’s retreat. This will continue if the global warming situation does not recede.