The Arctic will probably face another annus horribilis in 2019 with record temperatures already registered in Greenland, scientists warned.

"It's possible that we could break the records set in 2012 for both lowest Arctic sea ice extent ... and for record high Greenland ice sheet melt. It is very much dependent on weather conditions this year," a climatologist at the Danish Meteorological Institute (DMI), Ruth Mottram, warned.

A photo taken by DMI scientist in northwestern Greenland, Steffen Olsen, has gone viral, showing his sled dogs pushing through a fjord with visible meltwater beneath them.

"The picture is striking ... because it really visualises how the Arctic is changing," Mottram told AFP.

“Locals who accompanied Olsen's expedition didn't expect the sea ice to start melting that early. They usually take that route because the ice is very thick, but they had to turn back because the water was deeper and deeper and they couldn't advance,” she said.

"There was a dry winter and then recently (there has been) warm air, clear skies and sun -- all preconditions for an early melting," Mottram explained.

Polar bears’ presence in the Arctic has decreased by around 40% in the past decade due to the reduction of ice, according to the US Geological Survey.

According to DMI, Greenland's Summit Station, located at an altitude of 3,000 metres, recorded the warmest temperature in its history (minus 1.2 degrees Celsius) on April 30, and lost 3.7 billion tonnes of ice in a single day on June 17.

Since 1972, Greenland's melting glaciers have contributed to a 13.7 millimetre increase in sea levels, noting that the ice is melting six times faster now than in the 1980s.