Everyone knows the best scare stories are those in which the most obvious and visible danger turns out to less dire than an unsuspected peril revealed only later, the deadfall that sends a shiver down the listener’s spine.
We’ve all heard about the Antarctic ice shelf melt-off that’s been taking place with increasing speed and frequency. But at least there was always a comforting swathe of East Antarctica, the thick part that wasn’t floating like a massive ice cube in a warming drink.
The Totten Glacier catchment basin (blue outline) is three-quarters the size
of Texas and holds the ice and snow that flows through the glacier.
Credit: Australian Antarctic Division via LiveScience
As it turns out, what lies beneath a large part of East Antarctica is not, as previously thought, solid earth. Rather, it appears that there might be water flowing through large subsea troughs, regions of the seabed that slope away from the ice above, allowing warmer water to melt the largest ice sheet in the world from below.
Most research to date has focused on West Antarctica. An international team of scientists carried out the study, published in Nature Geoscience, to investigate why satellite images seemed to show that the Totten Glacier was growing thinner.
Carrying out measurements by plane flyovers, the resulting cartography indicated the presence of invisible valleys and warm water carried there by heavy salt concentrations.
The aircraft that researchers flew over East Antarctica to map Totten Glacier.
Credit: Chad Greene via LiveScience
The ice is 480 m (1600 ft) thick in some places. To get to the bottom of the ice from the height of a plane, three methods were used: gravitational measurements, radar and laser altimetry.
The radar was used to measure the thickness of the ice. Gravitational pull on the plane was measured at various points to determine the location of the seafloor beneath the ice.
The next step will be to send down underwater to verify initial study results and monitor activity of Circumpoloar Deep Water at the base of the glacier.
Actually, like turning on all the lights after the end of a good scary story, the next step for me will be to remind myself that if and when the sea rises to Pliocene Epoch levels, we might have had time to develop more effective ways of living with a lot of water in places where there is now land.
I also recommend a visit this other, more benign exploration into how ice behaves, the Icicle Atlas. I think the images of icicles forming look a bit like shivers running down a spine:
A clip from the wonderful Icicle Atlas, a creation of Stephen Morris at the Physics Department at the University of Toronto that explores how icicles form. A visit to the Rogue’s Gallery of icicles is a mesmerizing and informative trip.
Source: Icicle Atlas/Univ. of Toronto