Planetark.org, July 6, 2007
LONDON - Scientists using DNA extracted from ice buried deep below the surface have found evidence that a lush forest once existed in southern Greenland, a finding that sheds light on how climate change affects Earth's frozen areas.
The researchers analysed ice cores 2-3 km below the surface from several locations in southern
Eske Willerslev, a biologist at the
"We have shown a principle and now you can move around to other ice cores and try to do the same thing," he said in a telephone interview. "We have limited knowledge about the Antarctic ice sheet and the biology there."
Willerslev said drilling techniques developed over the past few years allowed him and his colleagues to search far below the surface to discover evidence of an ancient forest.
Writing in the journal Science on Thursday, they said their research showed it was possible to explore and understand Earth's vast frozen areas by sampling basal ice that sits far below the surface.
Basal ice is soil trapped at the bottom of ice and, because the dirt holds on to biological material, offers a richer source of DNA to study past life and climate change than clean ice near the top.
Scientists had thought the area was last ice-free about 120,000 years ago during the last interglacial but the study showed southern
This suggests the southern
This does not change the view that climate change is problematic but could force scientists to rethink their models looking at the impact of warming temperatures, he said.
"If we have found evidence that the ice didn't melt away then people have to take that into account when modelling how ice caps might react in the future to climate change," he said.