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https://theconversation.com/meltwater-is-hydro-fracking-greenlands-ice-sheet-through-millions-of-hairline-cracks-destabilizing-its-internal-structure-207468>
"I’m striding along the steep bank of a raging white-water torrent, and even
though the canyon is only about the width of a highway, the river’s flow is
greater than that of London’s Thames. The deafening roar and rumble of the
cascading water is incredible – a humbling reminder of the raw power of nature.
As I round a corner, I am awestruck at a completely surreal sight: A gaping
fissure has opened in the riverbed, and it is swallowing the water in a massive
whirlpool, sending up huge spumes of spray. This might sound like a
computer-generated scene from a blockbuster action movie – but it’s real.
A moulin is forming right in front of me on the Greenland ice sheet. Only this
really shouldn’t be happening here – current scientific understanding doesn’t
accommodate this reality.
As a glaciologist, I’ve spent 35 years investigating how meltwater affects the
flow and stability of glaciers and ice sheets.
This gaping hole that’s opening up at the surface is merely the beginning of
the meltwater’s journey through the guts of the ice sheet. As it funnels into
moulins, it bores a complex network of tunnels through the ice sheet that
extend many hundreds of meters down, all the way to the ice sheet bed.
When it reaches the bed, the meltwater decants into the ice sheet’s subglacial
drainage system – much like an urban stormwater network, though one that is
constantly evolving and backing up. It carries the meltwater to the ice margins
and ultimately ends up in the ocean, with major consequences for the
thermodynamics and flow of the overlying ice sheet.
Scenes like this and new research into the ice sheet’s mechanics are
challenging traditional thinking about what happens inside and under ice
sheets, where observations are extremely challenging yet have stark
implications. They suggest that Earth’s remaining ice sheets in Greenland and
Antarctica are far more vulnerable to climate warming than models predict, and
that the ice sheets may be destabilizing from inside.
This is a tragedy in the making for the half a billion people who populate
vulnerable coastal regions, since the Greenland and Antarctic ice sheets are
effectively giant frozen freshwater reservoirs locking up in excess of 65
meters (over 200 feet) of equivalent global sea level rise. Since the 1990s
their mass loss has been accelerating, becoming both the primary contributor to
and the wild card in future sea level rise."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
