WASHINGTON, July 5: Scientists probed two kilometres through a Greenland glacier to recover the oldest plant DNA on record and discovered that the planet was warmer than believed during the last Ice Age, according to a study released on Thursday.

DNA of trees, plants and insects including butterflies and spiders from beneath the southern Greenland glacier was estimated to date to 450,000 to 900,000 years ago, the remnants of a boreal forest that existed before the Earth cooled.

That sharply altered the previous view that a boreal forest existed in Greenland only as recently as 2.4 million years ago, according to a summary of the study, published in the journal Science in its latest edition.

The samples suggest the temperature probably reached 10 degrees C in the summer and minus 17 degrees C in the winter.

They also indicated that during the last period between ice ages, 116,000-130,000 years ago, when temperatures were on average five degrees C higher than now, the glaciers on Greenland did not completely melt away.

“These findings allow us to make a more accurate environmental reconstruction of the time period from which these samples were taken,” said Martin Sharp, a glaciologist at the University of Alberta, Canada, and a co-author of the paper.—AFP