Polar ice caps melting faster than we thought
Satellite images highlight the problem.
Thu, Sep 24 2009 at 9:29 AM
RUNAWAY MELT: Scientists use new images to chart rapid ice loss. (Photo: elisfanclub/Flickr)
MSNBC reports that polar ice caps in Greenland and Antarctica are melting much faster than scientists believed, even melting at "runaway" rates. The article summarizes the findings of a research study published in Nature, a peer-reviewed scientific journal. The study explored 50 million laser images from a NASA satellite to calculate the shrinking depth of the ice sheets, finding the edges to be particularly thin because of their proximity to the warmer water beneath.
The ice in these regions is, in many areas, more than a mile thick, so people have been slow to feel alarmed. However, since 2003, some places of Antarctica have lost 30 feet of thickness each year, the study found, which is twice the rate of melting from 1995 to 2003. MSNBC states that the findings, "confirm what some of the more pessimistic scientists thought: The melting along the crucial edges of the two major ice sheets is accelerating and is in a self-feeding loop. The more the ice melts, the more water surrounds and eats away at the remaining ice."
The article quotes study lead author Hamish Pritchard, saying the melting is more widespread than scientists thought, surprising researchers by reaching hundreds of kilometers inland. The British Antarctic Survey released a statement indicating the melting affects all latitudes of Greenland, is spreading, and has intensitifed on Antarctic coastlines. The glaciers are melting at rates faster than the precipitation can replace the ice shelves and perhaps contributing to the rise in sea levels.
The article indicated that scientists once thought the melting glaciers would add three feet to sea levels by the end of the century, but that the size of the ice sheets meant it would take centuries for them to melt entirely. Now, Pritchard indicates we have "underestimated" the sensitive ice sheets' response to temperature changes. He points to not only the warm water at the edges of the glaciers, but also the warm ocean currents contributing to the melt. Pritchard calls for greater understanding of the ice loss so researchers can better predict the future rise in sea levels.
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