Scientists have discovered the oldest DNA sample ever from an ice core in Greenland. They say this discovery may also mean that Greenland's ice cap could be less susceptible to melting than previously thought:
also show that between 450,000 and 800,000 years ago trees such as pines and spruce were present in south-central Greenland. The lack of more recent DNA data suggests the ice cap has been fairly stable since, according to the Danish-led team.
The study, published in the journal Science, contradicts the prevalent theory that the ice cap in southern Greenland melted completely during the last period between ice ages, when sea levels rose 5 to 6 meters (16 to 20 feet).
``Part of the ice cap is more stable than previously thought,'' said Eske Willerslev, a professor at the University of Copenhagen and the paper's lead author. The study suggests ``that the southern-central Greenland ice cap did not disappear during the last interglacial period, about 120,000 years ago, when the temperatures were about 5 degrees Celsius warmer than today.''
The scientists found evidence of beetles, flies, spiders and butterflies as well as tree species including alders and yews.
``This is the earliest evidence of forest in Greenland,'' Willerslev said in a telephone interview from Copenhagen. ``The closest analog today would be the eastern Canadian conifer forests. The presence of yews means the winter temperature cannot have been below minus 17 degrees Celsius. The presence of pines and spruce means that the summer temperatures must have been about 10 degrees.''