Asia-Pacific

In just nine days 20 per cent of this Antarctic island's snow has melted

The photo on the left of Eagle Island, Antarctica was taken 4 February. The image on the right taken 13 February. Source: NASA Earth Observatory

New satellite photos from NASA's Earth Observatory show ice on the cap of Eagle Island has almost disappeared after less than 10 days of extreme heat.

As Antarctica became the latest place on Earth to smash its high-temperature record, it's now been revealed nearly a quarter of one island's snow cover melted at that time.

On 6 February, weather stations recorded the hottest temperature on record for Antarctica.

Thermometers at the Esperanza Base, on the northern tip of the Antarctic Peninsula, reached 18.3C - about the same temperature as Los Angeles that day.

The warm spell caused widespread melting on nearby glaciers.

A satellite image of Eagle Island in Antarctica, taken 4 February.
A satellite image of Eagle Island in Antarctica, taken 4 February.
NASA Earth Observatory

NASA's Earth Observatory has released two photos taken during the heatwave, just nine days apart, showing melting snow on the ice cap of Eagle Island.

The images were acquired by the Operational Land Imager (OLI) on Landsat 8 on 4 February and 13 February, with snow visibly absent in the latter picture. 

Mauri Pelto, a glaciologist at Nichols College, said during the weather event about 1.5 square kilometres of snow became saturated with melting water.

“I haven’t seen melt ponds develop this quickly in Antarctica,” he said. 

According to climate models, Eagle Island experienced a melting peak on 6 February, and by 11 February 106mm of snow had melted. 

A satellite image of Eagle Island in Antarctica, taken 13 February.
A satellite image of Eagle Island in Antarctica, taken 13 February.
NASA Earth Observatory

“You see these kinds of melt events in Alaska and Greenland, but not usually in Antarctica,” Mr Pelto said.

He noted that such rapid melting was caused by sustained high temperatures significantly above freezing. 

This February's heatwave was the third major melt event of the 2019-2020 summer, following warm spells in November 2019 and January 2020.

“If you think about this one event in February, it isn’t that significant,” Mr Pelto said.

“It’s more significant that these events are coming more frequently.“

Studies show what rising sea levels could mean

January 2020 was the hottest January scientists had ever witnessed, and Earth's poles are warming quicker than much of the rest of the planet. 

Two recent studies have sounded the alarm on what rising land and sea temperatures could mean for the continent's vast ice sheets.

One study in the Earth System Dynamics review found that Antarctic melting could raise sea levels up to 58cm by the end of this century - constituting a trebling of last century's pace. 

A fractured and melting iceberg is seen in Antarctica.
A fractured and melting iceberg is seen in Antarctica.
Barcroft Media

"The 'Antarctica Factor' turns out to be the greatest risk, and also the greatest uncertainty, for sea-levels around the globe," lead author Anders Levermann said from the Potsdam Institute of Climate Impact Research.

A second study by Australian researchers in the PNAS journal, looked into the deep past to predict future sea-level rises.

They studied the last of Earth's inter-glacial periods, between 129,000 and 116,000 years ago.

Measuring isotopes from volcanic ash in ice samples, the team identified a gap in the ice sheet record that indicated mass sea-level rise as temperatures warmed.

At the time, Earth's oceans were roughly 2C hotter than currently, and the team estimated the effect that had on Antarctica's vast western ice sheet.

The sheet rests on the sea bed and so is extremely vulnerable to temperature rises.  

Chinstrap penguins walk by a scientific station where melting ice has posed a problem on Fildes peninsula, King George Island, Antarctica.
Chinstrap penguins walk by a scientific station where melting ice has posed a problem on Fildes peninsula, King George Island, Antarctica.
AFP

Earth and Climate Science Professor Chris Turney from UNSW said: "The melting was likely caused by less than 2C ocean warming – and that's something that has major implications for the future, given the ocean temperature increase and West Antarctic melting that's happening today". 

The United Nations Intergovernmental Panel on Climate Change says that melting ice sheets have already contributed 15cm to sea levels since the start of the 20th Century.

As a consequence, by mid-century more than one billion people will live in areas particularly vulnerable to storm surges made worse by higher seas.

With wires... 

Stay up to date with SBS NEWS

  • App
  • Subscribe
  • Follow
  • Listen
  • Watch