The UK is evacuating British Antarctic Society scientists from its Halley VI polar research base in March after a new rift developed in the ice sheet. The crack had been dormant for 35 years but became active again in 2013. Now a second crack has appeared in the shelf in October and the risk to the ice shelf’s stability prompted the decision to relocate the base.
Ice shelves are in constant motion from the rising tides, splitting off icebergs in a soupy mélange of icebergs and snow ice at its edges The ice shelf can grow again as inland glaciers feed it assuming no change in the dynamics occur with the balance of resistance between the floating ice shelf and the land based glacier. Scientists are now beginning to witness that some ice shelves are beginning to crack from the inside out due to channels carved in the ice due to a warming ocean . In the case of the Brunt Ice shelf, scientists are unsure what these cracks portend for the future of the ice shelf.
Eighteen years of change in thickness and volume of Antarctic ice shelves. Rates of thickness change (m/decade) are color-coded from -25 (thinning) to +10 (thickening). Circles represent percentage of thickness lost (red) or gained (blue) in 18 years. The central circle demarcates the area not surveyed by the satellites (south of 81.5ºS). Background is the Landsat Image Mosaic of Antarctica (LIMA).The Washington Post reports on what a melting Antarctica means for sea level rise.
Sea levels could rise nearly twice as much as previously predicted by the end of this century if carbon dioxide emissions continue unabated, an outcome that could devastate coastal communities around the globe, according to new research published Wednesday.
The main reason? Antarctica.
Scientists behind a new study published in the journal Nature used sophisticated computer models to decipher a longstanding riddle about how the massive, mostly uninhabited continent surrendered so much ice during previous warm periods on Earth. They found that similar conditions in the future could lead to monumental and irreversible increases in sea levels. If high levels of greenhouse gas emissions continue, they concluded, oceans could rise by close to two meters in total (more than six feet) by the end of the century. The melting of ice on Antarctica alone could cause seas to rise more than 15 meters (49 feet) by 2500.
The startling findings paint a far grimmer picture than current consensus predictions, which have suggested that seas could rise by just under a meter at most by the year 2100. Those estimates relied on the notion that expanding ocean waters and the melting of relatively small glaciers would fuel the majority of sea level rise, rather than the massive ice sheets of Greenland and Antarctica.
x YouTube Video HALLEY VI RESEARCH STATIONHalley Research Station is an award-winning science lab, complete with accommodation for researchers.
The modular lab, which was first constructed in 1956, is run by the British Antarctic Survey.
It was here that researchers first discovered the hole in the ozone layer in 1985.
The research facility comprises eight modules sitting atop hydraulic legs, enabling each module to be towed to a new location.
Halley sits on the 130 metre-thick Brunt Ice Shelf. The ice shelf flows slowly out onto the Weddell Sea, where chunks of ice 'calve' off as icebergs.
In its current 'VI' configuration, it has been operational since 2012.
Halley is home to 70 staff during the summer (late December to early March) and around 16 during winter.
Source: British Antarctic Survey
h/t Daily Mail