MODIS-Aqua Image
Last week, a massive iceberg four times the size of Manhattan broke off of the Petermann Glacier in West Greenland. It is the largest chunk of ice to calve from the glacier since 1962. It is now floating down the Nares Strait between Greenland and Canada. To give a better idea of the sheer volume of the ice chunk, Professor Andreas Muenchow of the University of Delaware said that there is enough freshwater locked up in the block of ice to keep the Hudson or Delaware Rivers flowing for two years. At the same time, Muenchow believes it’s too early to say whether rising air temperatures were responsible for the crack in the glacier. In an article for the Journal of Geophysical Research, he wrote, “The floating ice shelf of Petermann glacier interacts directly with the ocean and is thought to lose at least 80% of its mass through basal melting.” He went on to write, “The oceanic heat flux into the fjord appears more than sufficient to account for the observed rate of basal melting.” Thus, if global warming is indeed causing rising ocean temperatures, then the connection could be made that it has also caused the recent historic calving event.
This news comes just as scientists are reporting that the “entire ice mass of Greenland” could disappear with a 2 – 7 degree rise in global average temperatures. Professor Richard Alley of Penn State University told the House of Representatives Select Committee on Energy Independence and Global Warming, “Sometime in the next decade we may pass that tipping point which would put us warmer than temperatures that Greenland can survive.” This doesn’t mean that the ice will instantly melt given a rise in temperatures, but rather that a tipping point would be reached such that Greenland’s ice sheet could not be saved. At that point, it would likely take 100 years to melt away.
News links
“Greenland ice sheet faces tipping point in 10 years,” The Guardian
“Vast Ice ‘Island’ Breaks Free of Greenland Glacier,” The New York Times Dot Earth Blog
“Giant Glacier Breaks on Anniversary of Global Warming,” Discovery News
“Enorm isflage i Nares Strædet,” Sermitsiaq
