The icy realm of Greenland is getting hot under the collar.

The melting of Greenland's massive ice sheet has now accelerated, scientists announced Wednesday, and shows no signs of slowing down, according to a new study.

"Melting of the Greenland ice sheet has gone into overdrive," said Luke Trusel, a glaciologist at Rowan University and lead author of the study. "Greenland melt is adding to sea level more than any time during the last three and a half centuries, if not thousands of years," he said.

Ice loss from Greenland is the single largest contributor to global sea-level rise, which is predicted to lead to inundation of low-lying islands and coastal cities around the world over the next several decades and centuries.

Conservative estimates of global sea level rise are currently an additional half a meter or more by 2100 , according to German news agency Deutsche Welle (DW). Alun Hubbard, a professor of glaciology at Aberystwyth University in Wales, told DW that even an increase of half a meter is "a terrible disaster for humanity – especially coastal regions of the planet."

"From a historical perspective, today's melt rates are off the charts, and this study provides the evidence to prove this" said co-author Sarah Das, a glaciologist at the Woods Hole Oceanographic Institution.

Specifically, the melt rate over the past two decades was 33 percent higher than the 20th-century average, and 50 percent higher than in the pre-industrial era before the mid-1800s.

According to the journal Nature, in just one year (2012), enough ice melted into water to fill up about 240 million Olympic swimming pools.

To determine how much Greenland ice has melted in past centuries, the research team used a drill the size of a traffic light pole to extract ice cores from the ice sheet itself. Ice cores contain records of past melt intensity, allowing researchers to extend their records back to the 1650s.

Researchers say the rate of melting at their drilling sites is representative of trends across Greenland.

Another expert – NASA oceanographer Josh Willis – told Mashable that "it's one more nail in the coffin of climate denial." Willis, who was not involved in the research, added "I don’t know how many more nails we need."

The study was published Wednesday in the peer-reviewed British journal Nature.