Antarctica Is Melting Three Times Faster Than a Decade Ago

Mindy Sparks
June 14, 2018

On current trends, Antarctica could become the single largest source of sea level rise, ahead of runoff from the Greenland ice sheet and mountain glaciers, and the expansion of ocean water as it warms, the study found.

While the current ice loss measured is literally a drop in the ocean compared to Antartica's catastrophic potential to raise global sea level by as much as 58 metres (190 ft) if the ice sheets were to completely melt, the apparent acceleration in the latest satellite observations is enough to have scientists duly anxious.

West Antarctica is now bearing the brunt of this loss, as its glacial ice shelves have been melted from below by warming deep ocean water.

As part of IMBIE, Professor Shepherd coordinated with 83 other scientists, from 44 global organizations, to combine the data from two dozen different satellite surveys for this comprehensive look at the changes in Antarctica's ice mass balance.

"We now have an unequivocal picture of what's happening in Antarctica", said co-lead author Eric Rignot, a scientist at NASA's Jet propulsion Laboratory who has been tracking Earth's ice sheets for two decades.

IMBIE was established with the support of NASA and the European Space Agency, to monitor the changes in ice-sheet cover around the world.

West Antarctica lost 159 billion tons of ice a year from 2012 through 2017, compared with just 65 billion tons from 2002 through 2007.

Per the team's calculations, a high emissions scenario - in which carbon emissions rise unabated and environmental protections in Antarctica are not implemented - global air temperature would rise almost 3.5°C above 1850 levels by 2070, with sea level rise averaging somewhere between 10-15 mm every year. The latter is increasingly being viewed as posing a potential planetary emergency, because of its enormous size and its role as a gateway that could allow the ocean to someday access the entirety of West Antarctica, turning the marine-based ice sheet into a new sea.

Antarctica has lost 3 trillion tons of ice in the past 25 years, and that ice loss has accelerated rapidly over the last five years.

The findings, reported in Nature, are part of a special collection of five studies focussed on environmental change in Antarctica and the Southern Ocean.

What's happening in East Antarctica is extremely important because it has by far the most ice to give, being capable of raising sea levels by well over 100 feet. "Put simply if we can not collectively tackle climate change, then it's unlikely we will maintain Antarctica as a place for peace, nature and science".

NOAARapidly rising sea levels that inundate the coastlines where billions of people live is one of the more worrisome concerns associated with climate change. However, ice retreat today is about more than 20 times that rate - more than 3,200 feet (1 kilometer) per year. If sea level continues to change at this rate and acceleration, the researchers estimate that average sea-level rise by 2100 will be closer to 24 inches than 10 inches in 2100. Scientists can't see the future, but they do fear continuing and even worsening losses. "We will not necessarily see exclusively rapid retreat, " said Christianson, noting that as glaciers like Pine Island retreat backwards down a submarine, downhill slope, they will sometimes encounter bumps that slow down their movement.

"There has been a step increase in ice losses from Antarctica during the past decade", said Leeds University professor Andrew Shepherd, co-leader of the Ice Sheet Mass Balance Exercise (ISMBE).

Antarctica has lost about three trillion tonnes of ice since 1992 and scientists say the window of opportunity to prevent major meltdown of the icesheets is narrowing. And many of those papers showed different results. "But remember for the northern hemisphere, for North America, the fact that the location in West Antarctica is where the action is amplifies that rate of sea level rise by up to an about additional 25 percent in a city like Boston or NY".

Ekwurzel at the Union of Concerned Scientists said the study's findings mean "we have to go back and tell coastal planners that it may be worse than scientists thought before".

Rising sea levels can have a unsafe impact on coastal habitats and communities as flooding increases along with higher tides and stronger storm surges.

Other reports by Iphone Fresh

Discuss This Article