With the potential to cause sea levels to rise by more than 11 feet and unleash the ice of the East Antarctic Ice Sheet, the massive Totten Glacier has come to be known as the ‘sleeping giant.’
And now, scientists have discovered that strong winds over the Southern Ocean could be causing it to wake up.
A new study has found that East Antarctica’s largest glacier is melting from beneath, as winds transport warm water to the ice – and, these winds are expected to intensify with climate change, the experts warn.
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The research revealed that the glacier’s flow speeds up when winds over the Southern Ocean are strong. These winds pull warm water up from the deep ocean, in a process known as upwelling
EAST ANTARCTICA MORE STABLE THAN THE WEST
A recent study conducted by researchers based at Indiana University-Purdue University Indianapolis has found that the central core of the East Antarctic ice sheet should remain stable even if the West Antarctic ice sheet melts.
The West Antarctic ice sheet is a marine-based ice sheet that is mostly grounded below sea level, which makes it much more susceptible to changes in sea level and variations in ocean temperature than the East Antarctic Ice Sheet.
By contrast the East Antarctic ice sheet has been considered relatively stable because most of the ice sheet was though to rest on bedrock above sea level, making it less susceptible to changes in climate.
In the study, led by researchers at the University of Texas at Austin, used satellite images and wind stress data to investigate the effect of wind on the water beneath the glacier.
While the glacier is known to speed up some years, it also slows down in others.
The research revealed that the glacier’s flow speeds up when winds over the Southern Ocean are strong.
These winds pull warm water up from the deep ocean, in a process known as upwelling.
The warm water climbs to the continental shelf – and, once it reaches the coast, it circulates beneath a floating chunk of the glacier, and causes the ice sheet to melt from below, according to the researchers.
‘Totten has been called the sleeping giant because it’s huge and has been seen as insensitive to changes in its environment,’ said lead author Chad Greene, a PhD candidate at the University of Texas Institute for Geophysics (UTIG).
‘But we’ve shown that if Totten is asleep, it’s certainly not in a coma – we’re seeing signs of responsiveness, and it might just take the wind blowing to wake it up.’
Wind strength varies from year to year, the researchers explain.
But, climate change is expected to intensify the winds over the Southern Ocean, which could, in turn, effect the melting of the Totten Glacier.
The process does not require the air or ocean temperatures to rise – instead, upwelling occurs as the wind displaces the surface water, making way for the deeper, warmer water.
‘It’s like when you blow across a hot bowl of soup and little bits of noodles from the bottom begin to swirl around and rise to the top,’ said Greene.
The new study follows up on previous research led by a team with the Australian Antarctic Division at the Antarctic Climate & Ecosystems Cooperative Research Center.
That research found that the warm water below Totten causes the glacier to detach from the seafloor, and instead float.
This can cause the flow to further accelerate.
With the potential to cause sea levels to rise by more than 11 feet and unleash the ice of the East Antarctic Ice Sheet, the massive Totten Glacier has come to be known as the ‘sleeping giant’
‘The remaining question was, why do the canyons beneath Totten get flushed with warm water some years and cold water other years,’ said Jason Roberts, a glaciologist who led the earlier study.
The findings suggest melting at Totten could become more extreme as winds grow stronger with climate change.
‘Ice sheet sensitivity to wind forcing has been hypothesized for a long time, but it takes decades of observation to show unequivocal cause and effect,’ said Donald Blankenship, a senior researcher at UTIG who contributed to this study and Roberts’ study.
‘Now we’re at the point where we can explicitly show the links between what happens in the atmosphere, what happens in the ocean, and what happens to the Antarctic Ice Sheet.’