Dedicated to the balanced discussion of global warming
The Independent – April 24, 2007
This article should give pause to anyone that does not believe that the climate on earth is changing in some way. There is no doubt about it that in certain parts of the world, glaciers are changing their shape and appear to be getting smaller. While this one data point does not mean that there is a trend, it is a very significant data point when a peninsula off of Greenland that is covered with ice turns out to be a small island that was only connected to the mainland by a glacier.
I would like to point out that this article states that the computer models were wrong on this event happening by this time which underscores my long-time rant that we need better modeling techniques.
California, EPA, glaciers, Greenland, melting, ocean, satellite, scientists, survey, temperature, water
The map of Greenland will have to be redrawn. A new island has appeared off its coast, suddenly separated from the mainland by the melting of Greenland’s enormous ice sheet, a development that is being seen as the most alarming sign of global warming. Several miles long, the island was once thought to be the tip of a peninsula halfway up Greenland’s remote east coast but a glacier joining it to the mainland has melted away completely, leaving it surrounded by sea.
The US Geological Survey has confirmed its existence with satellite photos, that show it as an integral part of the Greenland coast in 1985, but linked by only a small ice bridge in 2002, and completely separate by the summer of 2005.
But it is only one more example of the disintegration of the Greenland Ice Sheet, that scientists have begun to realise, only very recently, is proceeding far more rapidly than anyone thought.
Until two or three years ago, it was thought that the break-up of the ice sheet might take 1,000 years or more but a series of studies and alarming observations since 2004 have shown the disintegration is accelerating ….
Earlier computer models, researchers believe, failed to capture properly the way the ice sheet would respond to major warming (over the past 20 years, Greenland’s air temperature has risen by 3C).
But satellite measurements of Greenland’s entire land mass show that the speed at which its glaciers are moving to the sea has increased significantly in the past decade, with some of them moving three times faster than in the mid-1990s.
A study last year by the Jet Propulsion Laboratory of the California Institute of Technology showed that, rather than just melting relatively slowly, the ice sheet is showing all the signs of a mechanical break-up as glaciers slip ever faster into the ocean, aided by the “lubricant” of meltwater forming at their base. As the meltwater seeps down it lubricates the bases of the “outlet” glaciers of the ice sheet, causing them to slip down surrounding valleys towards the sea.
Another discovery has been the increase in “glacial earthquakes” caused by the sudden movement of enormous blocks of ice within the ice sheet. The annual number of them recorded in Greenland between 1993 and 2002 was between six and 15. In 2003, seismologists recorded 20 glacial earthquakes. In 2004, they monitored 24 and for the first 10 months of 2005 they recorded 32. The seismologists also found the glacial earthquakes occurred mainly during the summer months, indicating the movements were indeed associated with rapidly melting ice – normal “tectonic” earthquakes show no such seasonality. Of the 136 glacial quakes analysed in a report published last year, more than a third occurred during July and August.