Wednesday, April 1, 2015

Melting Ice Makes Antarctica Ground Zero for Climate Change

Although melting ice sheets in the Western Antarctic has received the bulk of concern, it would appear that a similar forces are at play in the Eastern Antarctic. Warm water is eating away at the ice from underneath, this in turn exposes more ice to the water. As the ice above the water melts it collapses into the water and melts as well.

The melting of the West Antarctic ice sheet is accelerating at an unprecedented rate and this has very significant implications for flooding around the world. If the entire West Antarctic ice sheet were to melt sea levels would rise 11 feet (3 meters) and thirteen million people would be at risk. The cost in property damage would exceed $2 trillion.

According to an ENN article early last year reports revealed that the Pine Island Glacier, located in West Antarctica was showing signs of thinning and sliding into the sea. Scientists observed that warmer water from the melting ice makes its way into a cavity beneath the ice shelf melting even more ice from below. Observations in January 2012 show ocean melting of the glacier was the lowest ever recorded. The top of the thermocline (the layer separating cold surface water and warm deep waters) was found to be about 250 meters deeper compared with any other year for which measurements exist.

According to scientific observations ice loss from West Antarctica has increased nearly three times faster in the past decade than during decade that preceded it.

Reports released in February 2015 show that melting water is indeed behind this accelerating melting trend in the ice sheets of Western Antarctica. According to NASA satellite images, a total of 118 billion tonnes of water is pouring into the sea each year.

Temperatures on the Antarctic peninsula have risen 3 degrees Celsius in the last half century and they are expected to keep climbing melting even more ice. This phenomenon has led Harvard Geophysicist Jerry Mitrovica to describe Antarctica as, "ground zero for global climate change."

The Antarctic is changing rapidly with glaciers retreating entire valleys are now ice free and plants are taking root.

As reported in the Washington Post, a paper published in March 2015 edition of Nature Geoscience is shedding new light on East Antarctica. An international team of scientists representing the United States, Britain, France and Australia flew a number of research flights over the Totten Glacier of East Antarctica — the fastest-thinning sector of the world’s largest ice sheet. Their findings reveal that like the Pine Island Glacier of West Antarctica, the Totten, is also losing ice because warm ocean water is getting underneath it. The Totten glacier holds back a much more vast catchment of ice. If it were to melt it could cause sea levels to rise more than 11 feet (3 meters) just like the glacier in the West Antarctic. Together this represents 22 feet (6 meters of sea level rise).

The impact of ice loss in the Antarctic is not only from the added water created by melting ice.The gravitational effect of Antarctic ice pulls the ocean towards it keeping sea levels in the Norther Hemisphere lower. If that ice melts the gravitational pull would relax and this would exacerbate sea level rise. In the US this could cause sea levels to rise 25 percent more than the global average.

NASA ice scientist Eric Rignot said the melting "is going way faster than anyone had thought. It's kind of a red flag."

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