Monday, 9 July 2007

DNA evidence indicates Global cooling killed Greenland’s forests

Global cooling strikes again! Parts of Greenland were lushly forested with spruce and pine, moths and butterflies flitted in those forests of 450,000 years ago, according to an article in science Magazine.

The boreal forests coved southern Greenland during an interglacial period of increased global temperatures, when it was warmer that it is today.

Temperatures in Greenland at the time were probably between 10C in summer and -17C in winter. When the global temperatures dropped again around 450,000 years ago, the forests and their inhabitants were covered and preserved by the advancing ice.

One of the authors Professor Eske Willerslev of the University of Copenhagen, Denmark said "We have shown for the first time that southern Greenland, which is currently hidden under more than 2km of ice, was once very different to the Greenland we see today,"

Co-orther, Professor Martin Sharp of the University of Alberta, Canada, said: "What we've learned is that this part of the world was significantly warmer than most people thought,"

The research also suggests the ice sheet is less subject to warming than previously thought.

Even during the last interglacial (116,000-130,000 years ago), when temperatures were thought to be on average 5C warmer than today, the ice did not melt, preserving trapped DNA.

At the time the ice is estimated to have been between 1,000 and 1,500m thick.

Professor Willerslev noted: "If our data is correct, then this means that the southern Greenland ice cap is more stable than previously thought," "This may have implications for how the ice sheets respond to global warming."

Current data suggests that while some regions of Greenland ice are getting thinner, others are simultaneously getting thicker.

Also two of Greenland's largest glaciers, which were thought to be shrinking, have recently stabilized, possibly even increasing in mass. Previous estimate of rapid melting were based on only a few observations over a short period. Additional more thorough found the melting period actually appeared to be an anomaly.

Previous research by Australian scientists had led them to believe that a rise of only 3C would be sufficient cause the melting of the Greenland ice sheet.

No comments: