Climate Change Update (10 Jan 2007)

Earlier satellite photograph of Ellesmere Island.
Satellite photograph from 13 Aug 2005 showing the now-free Ayles Ice Shelf.
NASA’s Terra satellite took these photographs. In the first image, the ice shelf is still attached to the island. In the second photograph, from 13 August 2005, the now-free ice shelf can be seen near the top middle of the image. Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC.

In a dramatic, alarming event, CNN and NASA reported that scientists have just discovered a sixty-six–square kilometer (twenty-five–square mile) ice shelf, the Ayles Ice Shelf, broke free from northern Canada’s Ellesmere Island last year. This was one of only six major ice shelves in Canada. The shelves are ancient, having been present for at least three thousand years; the loss of one is unprecedented. The event was discovered by scientist Laurie Weir who had been examining 2005 satellite data. After she noticed the break and alerted other scientists, satellite images were used to pinpoint the event to 13 August 2005; a retrospective examination of seismologic data confirmed this.

Richard Fisher of New Scientist reports on a study published in Science (vol 315, p 95) studying a fish population (Zoarces viviparous) over the past ten years (also read the report by Katharine Sanderson of Nature News). They showed that rising temperatures in the North Sea have led to a decreased oxygen supply but increased oxygen demand, causing the population to drop sharply. As would be expected, the fish are best adapted to function at the temperatures at which they evolved, not at the warmer temperatures of the last decade.

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