Greenland: enough ice melted on single day to
cover Florida in two inches of water
Data shows ice sheet lost 8.5bn tons of surface mass
on Tuesday
All-time record temperature of 19.8C in region on
Wednesday
Greenland’s melting season usually lasts from June to
August. The Danish government data shows that it has lost more than 100bn tons
of ice since the start of June this year.
Oliver
Milman
@olliemilman
Fri 30 Jul
2021 17.44 BST
https://www.theguardian.com/environment/2021/jul/30/greenland-ice-sheet-florida-water-climate-crisis
Greenland’s
vast ice sheet is undergoing a surge in melting, with the amount of ice
vanishing in a single day this week enough to cover the whole of Florida in two
inches of water, researchers have found.
The deluge
of melting has reached deep into Greenland’s enormous icy interior, with data
from the Danish government showing that the ice sheet lost 8.5bn tons of
surface mass on Tuesday alone. A further 8.4bn tons was lost on Thursday, the
Polar Portal monitoring website reported.
The scale
of disappearing ice is so large that the losses on Tuesday alone created enough
meltwater to drown the entire US state of Florida in two inches, or 5cm, of
water. Ice that melts away in Greenland flows as water into the ocean, where it
adds to the ongoing increase in global sea level caused by human-induced
climate change.
“It’s a
very high level of melting and it will probably change the face of Greenland,
because it will be a very strong driver for an acceleration of future melting,
and therefore sea-level rise,” said Marco Tedesco, a glacier expert at Columbia
University and adjunct scientist at Nasa.
Tedesco
said a patch of high pressure is sucking and holding warmer air from further
south “like a vacuum cleaner” and holding it over eastern Greenland, causing an
all-time record temperature of 19.8C in the region on Wednesday. As seasonal
snow melts away, darker core ice is exposed, which then melts and adds to sea
level rise.
“We had
these sort of atmospheric events in the past but they are now getting longer
and more frequent,” Tedesco said.
“The snow
is like a protective blanket so once that’s gone you get locked into faster and
faster melting, so who knows what will happen with the melting now. It’s
amazing to see how vulnerable these huge, giant areas of ice are. I’m
astonished at how powerful the forces acting on them are.”
Greenland’s
melting season usually lasts from June to August. The Danish government data
shows that the island has lost more than 100bn tons of ice since the start of
June this year and while the severity of melting is less than in 2019 – when
11bn tons of ice was lost in a single day – the area affected is much larger in
2021.
“It’s hard
to say if it will be a record year for melting this year but there is a ton of
warm and moist air over the ice sheet that’s causing an amazing amount of
melt,” said Brad Lipovsky, a glaciologist at the University of Washington.
“The
alarming thing to me is the political response, or lack of it. Sea-level rise
is like a slow-moving train, but once it gets rolling you can’t stop it. It’s
not great news.”
If all the
ice in Greenland melted, the global sea level would jump by about 6 meters
(20ft), and although this is unlikely to happen on any sort of foreseeable
timescale, scientists have warned that the world’s largest island is reaching a
tipping point due to the pressures exerted upon it by global heating.
Greenland’s
ice is melting faster than any time in the past 12,000 years, scientists have
calculated, with the ice loss running at a rate of around one million tons a
minute in 2019. Greenland and the earth’s other polar region of Antarctica have
together lost 6.3tn tons of ice since 1994.
This rate
of ice loss, which is accelerating as temperatures continue to increase, is
changing ocean currents, altering marine ecosystems and posing a direct threat
to the world’s low-lying coastal cities, which risk being inundated by flooding.
A 2019 research paper found the Greenland ice sheet could add anything between
5cm and 33cm to global sea levels by the end of the century. The world is on
track for “the mid to upper end of that”, Lipovsky said.
“It’s very
worrisome,” said Tedesco. “The action is clear – we need to get to net zero
emissions but also we need to protect exposed populations along the coast. This
is going to be a huge problem for our coastal cities.”

Sem comentários:
Enviar um comentário