Hidden ‘dark river’ could stretch more than 1,000 miles under Greenland, scientists believe

Greenland's ice sheet may be obscuring a thousand mile-long river deep beneath the frozen surface, scientists have suggested.

The island has become an increasing focus of scientific study as researchers look to reveal the hidden world beneath earth’s glaciers and the ramifications of changing ice levels on the future of the planet.

Now experts from two universities have said they may have found an undisturbed river under the ice, carrying water from the heart of the world’s largest island and into the Atlantic Ocean through the Peterman Fjord.

Scientists from the Hokkaido University, Japan, and the university of Oslo, Norway, used radar data analysing the height of rock surfaces underneath the ice to create a computer simulation of the likely lay of the land.

What they uncovered was the potential for a long valley containing liquid water that flows out towards the coast – leading scientists to hypothesise they had discovered a 1,600km river running deep underground.

If correct, it could mean the body of water stretches much of the world’s second largest ice sheet, which is 2,400km long north to south.

Naming the potential waterway "the dark river" as much of its path would be devoid of light, researchers said more work would need to be done to confirm the river’s existence while presenting their findings to a meeting of the American Geophysical Union.

“Though considerable uncertainty remains” researchers said “the results are consistent with a present day active long subglacial river system that, if confirmed with further radar bed observations, could be over 1,600km long.

“The results raise issues concerning the need to better observe, understand, and simulate the complicated basal hydrology of the Earth's ice sheets.”

Glaciology professor Jemma Wadham of Bristol University, who was not involved in the study, told The Independent: “This is a fascinating discovery.

“We know from elsewhere on ice sheets that if there is enough meltwater at the glacier bed and an obvious path, water will likely travel by fast channels, a bit like rivers, even if ice is very thick.

“That these features might extend from 1,600 km inland on the Greenland Ice Sheet to emerge at Petermann Glacier is intriguing."

She added that the discovery could help future researchers better understand how substances in Greenland’s ice might be transferred from living systems into the environment – a process known as the biogeochemical cycle.

“It’s an interesting proposal because such sub-ice rivers have the potential to influence ice flow and to enable sediments, gases and nutrients to be quickly transported from the ice sheet interior to the ocean, affecting biogeochemical cycles”

It comes after scientists discovered thick, impenetrable “ice slabs” are expanding on the inside of the ice sheet - causing vast amounts of meltwater to spill into the ocean.

To date, run off from has added less than a millimetre to global sea levels. But by 2100 this could be raised by an additional three inches in a high emission scenario, according to the study published in the journal Nature.