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article imageAntarctica's ice melt could redraw map of world's coastlines

By JohnThomas Didymus     Feb 28, 2015 in Environment
NASA satellite studies show that in the past decade Antarctic ice melt has been adding about 118 billion metric tons per year to the oceans. This has raised concerns about a drastic reshaping of the world's major coastlines with heavy human population.
According to a report by the Associated Press, ice sheets are melting at a rate of 45 billion metric tons every year in the northern Antarctic Peninsula alone. The calculations, based on NASA satellite images, present a worst-case scenario in which Antarctica's ice melt pushes up sea levels by 10 feet (3 meters) worldwide in one or two centuries, forcing a reshaping of the world's coastlines. This could impact adversely on major coastal cities such as New York and Guangzhou.
The melting occurs by a process in which water being warmed from below forces surface ice to retreat as it rises to the top. According to Harvard geophysicist Jerry Mitrovica, parts of Antarctica are melting so rapidly that it has become "ground zero of global climate change."
Meteorological records, according Ricardo Jana, a glaciologist with the Chilean Antarctic Institute, show that temperatures in the Antarctic region rose 5.4 degrees Fahrenheit in the past 50 years, far greater than the average for the entire world.
Location of the Antarctic Peninsula in West Antarctica
Location of the Antarctic Peninsula in West Antarctica
Anna Frodesiak
Peter Convey of the British Antarctic Survey, said, "I was last here 10 years ago. And if you compare what I saw back then to now, the basic difference due to warming is that the permanent patches of snow and ice are smaller. They're still there behind me, but they're smaller than they were."
A plant biologist Angelica Casanova, spoke of the drastic changes since her first visit to the continent in 1995. According to Casanova, plant life is spreading rapidly on earth exposed by retreating glaciers.
"It's interesting because the vegetation in some way responds positively. It grows more. What is regrettable is that all the scientific information that we're seeing says there's been a lot of glacier retreat and that worries us," Casanova said.
The observations come only a month after scientists detected in satellite images rapid expansion of a massive crack in the Antarctic peninsula ice shelf Larsen C. The crack grew about 12 miles (20 kilometers) in 2014 alone. The growth threatens to cause the detachment of a chunk of iceberg about 2,000 square miles, roughly the size of Rhode Island and Delaware.
Scientists are concerned that if the process continues it could lead to the collapse of the entire Larsen C ice shelf, about the size of Scotland. Larsen C’s sister shelf, Larsen B, collapsed through a similar process in 2002.
Recent studies describe the melting of ice in West Antarctica as "irreversible." And although ice is gaining in East Antarctica, the rate of melting in the west offsets the gain in the east to the effect that there is a net loss of ice in the entire continent.
Satellite composite image of the Antarctica
Satellite composite image of the Antarctica
Dave Pape
A NASA scientist, Eric Rignot, said that melting is "going way faster than anyone had thought. It's kind of a red flag."
Scientists have also observed that altered wind directions caused by ongoing warming have contributed to the melting of ice by driving in warmer water to replace the cold waters of the Antarctica. The inflow of water just a few degrees Fahrenheit warmer is having a dramatic impact on the Antarctic environment.
The rise of the world's oceans due to Antarctica's ice melt is about a third of a millimeter every year. If the ice sheets of West Antarctica continue to melt as projected in a worst case scenario, major coastal cities with heavy human population could face flood damage of up to $1 trillion in the next few decades.
"Changing the climate of the Earth or thinning glaciers is fine as long as you don't do it too fast. And right now we are doing it as fast as we can. It's not good. We have to stop it; or we have to slow it down as best as we can," Rignot said.
A 2012 study published in the journal Nature, concluded:
"... sea-level rise [due to a combination of factors, including climate change] will increase global flood losses to US$60–63 billion per year in 2050... the magnitude of losses when floods do occur would increase, often by more than 50%, making it critical to also prepare for larger disasters than we experience today."
The latest observations come soon after Russian scientists raised alarm that rising temperatures thawing Siberian permafrost could have triggered a process of eruption of underground pockets of methane gas that could lead to an environmental disaster.
Webb Island off the coast of the Antarctic Peninsula
Webb Island off the coast of the Antarctic Peninsula
Vincent van Zeijst
Russian scientists announced discovery of new massive craters in Siberia caused by methane gas eruptions and said that evidence from satellite imagery suggests there could be as many as 30 undiscovered holes.
Methane gas is considered a far more potent greenhouse gas than the carbon dioxide emissions of global industry thought to be pushing climate change. Sustained release of methane gas into the atmosphere could complicate the picture of the emerging effects of climate change by drastically accelerating the process and increasing the risk of runaway climate change.
More about Antarctica, Ice, Antarctic ice melt, Climate change, Global warming
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