July 12, 2014
The West Antarctic Ice Sheet: Why Is It So Important To Climate Change Research?
redOrbit Staff & Wire Reports - Your Universe Online
Much of the climate change-related research published recently has focused on the impact of warming temperatures on the West Antarctic ice sheet – but what is it about this region that causes scientists to be so interested in it?
According to the US National Oceanic and Atmospheric Administration (NOAA), the West Antarctic ice sheet contains two major slabs of frozen water (the Ronne and Ross Ice Shelves), as well as several small and flat plates that are floating at sea level on the Southern Ocean.
Since the ice sheet is exposed to both atmospheric and ocean-related changes, the agency explained that it is “particularly vulnerable” to the effects of climate change. Satellite and ground-based observations of the glaciers and the floating ice surrounding the Pine Island Bay region indicate that significantly more ice has been melting and flowing into the ocean (a phenomenon known as flow acceleration) over the past four decades.
In May, NASA posted an online primer on the area surrounding the West Antarctic ice sheet, explaining that one of the major reasons for the region’s instability is the fact that most of it is “grounded” or resting on land located beneath sea level. Furthermore, a second factor is that there are ocean currents beneath the edges of the ice sheet which can deliver warm water to its bottom, especially at the grounding line or the area where the ice first begins to float.
That warm water begins a chain reaction, according to scientists. The currents melt the ice, causing the grounding line to retreat inland and causing the ice shelves to lose mass. As the ice shelves shrink, they lose the ability to prevent inland glaciers from traveling towards the sea allowing them to gain speed in their journey. This cycle repeats, shifting water and ice from land to ocean eventually causing the sea level to rise.
Climatologists and other specialists are attempting to determine whether or not the West Antarctic ice sheet completely melted away some 125,000 years ago – the last time the planet reached temperatures as high as those anticipated within the next 200 years. If it melted at that time, it will most likely do so again – and if it does, experts believe it could raise the sea level by as much as four meters, which could impact several coastal cities.
“One technique that can help reveal Earth’s climate history is to drill into the ice sheets with a hollow tube and remove long cylinders of ice called ice cores,” NOAA said. “Layers in the ice are like snapshots of the past snowfall, air, and climate, anywhere from a few months to a few years for every inch along the core.”
“After analyzing enough ice core slices, a researcher can identify patterns and track changes in the atmosphere's composition and temperature, and in many cases can determine what activity on Earth caused these changes,” the agency continued, adding that current research suggests that the Pine Island Bay region is “almost certainly headed toward inevitable collapse.”
A study appearing online in the journal Geophysical Research Letters in March confirmed that glaciers surrounding the Amundsen Sea had continually been gaining speed for the past 40 years, while a second paper published two months later indicated that this acceleration is expected to continue and ultimately lead to the collapse of the ice sheet in this particular area – which by itself could cause a sea-level increase of more than three feet.
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