Researchers have found that the Greenland ice sheet, currently the biggest source of new water added to oceans, is melting at unprecedented levels in the modern era, according to a study published in the scientific journal Nature on Wednesday.

Run-off from the ice sheet now occurs at a volume 50 per cent larger than during the pre-industrial era and 33 per cent greater than the 20th century alone, scientists from American and Dutch universities found.

The Greenland ice sheet is in places over 1.6 kilometres thick and contains enough ice to raise global sea level by seven metres.

"Greenland's ice is melting more rapidly in recent decades than at any point in at least the last 350 years, and likely more than any time in the last 7,000-8,000 years," Rowan University's Luke Trusel, the study's lead author, said.

"Greenland is more sensitive to temperature change today than just a few decades ago. Warming matters more than ever," Trusel added.

The researchers have reconstructed over three hundred years of melt patterns by using ice core data, creating the most comprehensive study of the phenomenon yet.

"By sampling ice, we were able to extend the satellite data by a factor of 10 and get a clearer picture of just how extremely unusual melting has been in recent decades compared to the past," Trusel said.

In June, another study published by Nature found that Antarctica has lost about three trillion tonnes of ice since 1992 and that the rate of melting had accelerated threefold in the last five years.