Trees are not an abundant feature of modern day Greenland [EPA]
Ancient DNA has shown that the bleak, ice-covered landscapes of Greenland were covered with verdant forests around half a million years ago.
The climate would have been much like modern day eastern Canada or Sweden according to an international team of scientists who analysed DNA recovered from from the bottom of an ice core that indicates the presence of pine, yew and alder trees as well as insects.
The researchers, led by Eske Willerslev of the University of Copenhagen in Denmark, say the findings are the first direct proof that there was forest in southern Greenland.
Their findings were published in the journal Science on Friday and include genetic traces of butterflies, moths, flies and beetles.l
The material was recovered from cores drilled through ice two kilometres thick at a site called Dye 3 in south central Greenland.
Greenland was discovered by Vikings sailing from Iceland about 1,000 years ago. While it had an ice cap then, the climate was relatively mild and they were able to establish colonies in coastal areas.
Those colonies later vanished as the climate cooled.
"These findings allow us to make a more accurate environmental reconstruction of the time period from which these samples were taken, and what we've learned is that this part of the world was significantly warmer than most people thought," Martin Sharp, a glaciologist at the University of Alberta, Canada, and a co-author of the paper, said in a statement.
The DNA, dated to between 450,000 and 800,000 years ago, may be the oldest yet recovered, according to the team.
DNA found previously in the Siberian permafrost has been dated to 300,000 to 400,000 years ago.