Antarctic ice is melting TEN TIMES faster than it was 600 years ago



Experts found the most rapid melt occurred in the past 50 years

Tests carried out on ice core on James Ross Island, Antarctic Peninsula

Temperatures up by 1.6 degrees Celsius over 600 years, they found

Summer ice is melting 10 times faster in the Antarctic than it was 600 years ago, with the most rapid melt occurring in the past 50 years.



Researchers from the Australian National University and the British Antarctic Survey also discovered the ice melt i s at its highest level in 1,000 years.



' It's definitely evidence that the climate and the environment is changing in this part of Antarctica,' lead researcher Nerilie Abram said.

A one-metre long section of the West Antarctic Ice Sheet Divide core, with a dark layer of volcanic ash visible. The teams drilled a 364-metre (1,194 feet) long ice core from James Ross Island in the continent's north to measure past temperatures in the area

Abram and her team drilled a 364-metre ( 1,194 feet ) deep ice core on James Ross Island, near the northern tip of the Antarctic Peninsula, to measure historical temperatures and compare them with summer ice melt levels in the area.

Visible layers in the ice core show periods when summer snow on the ice cap thawed and then refroze.

They found that, while the temperatures have gradually increased by 1.6 degrees Celsius (2.9 degrees Fahrenheit) over 600 years, the rate of ice melting has been most intense over the past 50 years.

Experts said the stronger ice melts are likely to be responsible for faster glacier ice loss and some of the dramatic collapses from the Antarctic ice shelf over the past 50 years

Scientists at the British Antarctic Survey have produced the most detailed map yet of Antarctica¿s landmass, showing a landscape of mountain ranges and plains cut by gorges and valleys much deeper than previously seen

That shows the ice melt can increase dramatically in climate terms once temperatures hit a tipping point.

This is the first time it has been demonstrated that levels of ice melt on the Antarctic Peninsula have been particularly sensitive to increasing temperature during the 20th Century.



MOST DETAILED MAP OF ANTARCTICA YET

Scientists at the British Antarctic Survey have produced the most detailed map yet of Antarctica’s landmass. Bedmap2 shows a landscape of mountain ranges and plains cut by gorges and valleys much deeper than previously seen. In addition, the map allows scientists to analyse, in much greater detail, the bed below the Antarctic ice sheet. The map reveals the volume of ice in Antarctica is 4.6 per cent greater than previously thought and that the the mean bed depth at 95 metres, is 60 metres lower than estimated.

The volume of ice that is grounded with a bed below sea level is also 23 per cent greater than originally thought meaning there is a larger volume of ice that is susceptible to rapid melting.

It also reveals the ice that rests just below sea level is vulnerable to warming from ocean currents. The new deepest point, under Byrd Glacier, is around 400 metres deeper than the previously identified deepest point.

'Once your climate is at that level where it is starting to go above zero degrees, the amount of melt that will happen is very sensitive to any further increase in temperature you may have,' Abram said.

Robert Mulvaney, from the British Antarctic Survey, said the stronger ice melts are likely responsible for faster glacier ice loss and some of the dramatic collapses from the Antarctic ice shelf over the past 50 years.

Their research was published in the Nature Geoscience journal.

In other parts of Antarctica, such as the West Antarctic Ice Sheet, the picture is more complex and it is not yet clear that the levels of recent ice melt and glacier loss are exceptional or caused by human-driven climate changes.



Dr Abram concludes: ' T his new ice core record shows that even small changes in temperature can result in large increases in the amount of melting in places where summer temperatures are near to 0°C, such as along the Antarctic Peninsula, and this has import'

This research was funded by the Natural Environment Research Council.



Dr Abram is an Australian Research Council Queen Elizabeth II Fellow.







