Antarctic Ice Core Sample Tells Story Of 1,000 Years Of Climate Fluctation

Using a 1,200-foot-long ice core sample, scientists have been able to reconstruct the last 1,000 years of the Antarctic Peninsula's ice melt and freeze.

The study, published in the journal Nature Geoscience, shows that summer ice melting has intensified almost ten-fold over the years, and mostly since the mid-1900s. In contrast, researchers found the region was coolest approximately 600 years ago, as observed in an annual melting and refreezing of roughly 0.5 percent of the region's snowfall; today, that number is 5 percent.

"Summer melting at the ice core site today is now at a level that is higher than at any other time over the last 1000 years," said lead author Nerilie Abram of The Australian National University and British Antarctic Survey in a press release. "And whilst temperatures at this site increased gradually in phases over many hundreds of years, most of the intensification of melting has happened since the mid 20th century."

One of the reasons summer ice melt is so important, according to the study's scientists, is that it in turn affects the stability of Antarctic ice shelves and glaciers.  

"Having a record of previous melt intensity for the Peninsula is particularly important because of the glacier retreat and ice shelf loss we are now seeing in the area," Robert Mulvaney who led the ice core drilling expedition said. "Summer ice melt is a key process that is thought to have weakened ice shelves along the Antarctic Peninsula leading to a succession of dramatic collapses, as well as speeding up glacier ice loss across the region over the last 50 years."

And while Mulvaney and Abram both agree that the picture is more complex in other parts of Antarctica, such as the West Antarctic Ice Sheet, they believe the findings are far-reaching in terms of the overall health of the area.

"This 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 degrees Celsius, such as along the Antarctic Peninsula, and this has important implications for ice instability and sea level rise in a warming climate," Abram said.

And nor is the Antarctic alone: meanwhile, scientists from the National Oceanic and Atmospheric Administration recently released an estimate that the Arctic's summer ice may disappear completely within a decade or two. 

Such changes are liable not only to result in an even greater increase in world temperature, but a drastic change in weather patterns, including the jet stream and prevailing winds, which in turn would lead to a change in storm tracks.