Antarctica ice melting at alarming rate


The continent is now melting so fast, scientists say, that it will contribute 15cm to sea-level rise by 2100 - the upper end of what the Intergovernmental Panel on Climate Change has estimated Antarctica alone could contribute to sea-level rise this century.

University of Leeds Andrew Shepherd, a lead scientists into the investigation on Antarctica, speaks to CapeTalk's Kieno Kammies about their findings.

"Ice shelves fringe about three quarters of the Antarctic coast and they play a crucially important role in moderating sea level rise by buttressing and slowing the movement of glacial ice from the interior of the continent to the ocean".

The Pine Island Glacier's 400-metre thick ice shelf must have therefore been grounded on the ridge for several decades as the satellite images of the glacier gathered by the researchers confirm.

Another study in Nature on Wednesday found that East Antarctic ice sheet didn't retreat significantly 2 million to 5 million years ago when heat-trapping carbon dioxide levels were similar to what they are now.

Looking closer, the rapid, recent changes are nearly entirely driven by the West Antarctic ice sheet, which scientists have long viewed as an Achilles' heel. The rate at which Antarctica is losing ice has more than doubled since 2012 as per the latest available data. This has its ultimate effect on the sea level rise to half a millimetre per year. If the sea ice melts the sea would probably rise half a meter from where it was in 2000 which would wreak havoc on United States costs.

The speed that the ice melts is a key indicator of climate change. That is pushing up global sea levels by 0.6mm annually, a three-fold increase since the last assessment in 2012. This is a classic example of a global commons challenge - the consequences of a melting Antarctic ice sheet have the potential to affect most people on the planet.

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Due to increasing global warming, ice from land glaciers and Greenland's dwindling ice sheets are also melting and causing the increase in the warm water expansion.

More than 90 per cent of that frozen water sits atop East Antarctica, which has remained mostly stable even as climate change has driven up Earth's average surface temperature by a full degree Celsius (1.8 degrees Fahrenheit).

Oceans are now rising by 3.4 millimetres (0.13 inches) per year.

The accelerating pace of melting means rising sea levels could threaten coastal communities far earlier than scientists had expected.

"We can not count on East Antarctica to be the quiet player, and we start to observe change there in some sectors that have potential and they're vulnerable", said Velicogna. The scientists have finally revealed the reasons behind the thinning and melting of the enormous chunk of ice in this lovely white continent. "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".

Whether Antarctic mass loss keeps worsening depends on choices made today, argues DeConto, who co-authored a separate paper in this week's Nature outlining two different visions for Antarctica's future in the year 2070.

"The next piece of the puzzle is to understand the processes driving this change", Durham University's Pippa Whitehouse said. However, since then there has been a sharp, threefold increase.