Global warming is melting ice in Greenland at “unprecedented rates”, experts warned. This threatens cities such as London and Venice and entire nations such as the Maldives, which within decades could be swallowed by the rising level of the sea. Researchers provided new evidence showing the impact of climate change on Arctic melting and global sea level rises, published by scientific journal Nature. The author of the study, Dr Luke Trusel from US Rowan University, said: “Melting of the Greenland Ice Sheet has gone into overdrive.

“As a result, Greenland melt is adding to sea level more than any time during the last three-and-a-half centuries, if not thousands of years. “And increasing melt began around the same time as we started altering the atmosphere in the mid-1800s.” The study confirms ice loss from Greenland is one of the main factors contributing to the sea level rise. This man-made catastrophe has sensibly worsened during the 20th century, according to the co-author of the study, Dr Sarah Das, a glaciologist at Woods Hole Oceanographic Institution (WHOI). She said: “From a historical perspective, today's melt rates are off the charts, and this study provides the evidence to prove this.

Greenland's ice sheet is melting at an 'unprecedented' rate

“We found a 50 per cent increase in total ice sheet meltwater runoff versus the start of the industrial era, and a 30 per cent increase since the 20th Century alone.” And without a huge change of direction, Greenland “will melt more and more for every degree of warming”, Mr Trusel warned. The research team found out how intensely Greenland ice has melted in past centuries using a drill the size of a traffic light pole to extract ice cores from the ice sheet and a nearby coastal ice cap. The cores of the drilling contained records of past melts, which allowed the scientists to extend their records back to the 17th century.

The rising level of the sea threatens cities on the water such as Venice

Study co-author Matt Osman, a graduate student, said: “We have had a sense that there's been a great deal of melting in recent decades, but we previously had no basis for comparison with melt rates going further back in time. “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.” Dr Trusel said: “To be able to answer what might happen to Greenland next, we need to understand how Greenland has already responded to climate change. “What our ice cores show is that Greenland is now at a state where it's much more sensitive to further increases in temperature than it was even 50 years ago.”

Meltwater increased by 30 percent during the 20th century alone