Antarctica heatwave sends temperatures 40C above normal

Antarctica, the world's coldest continent holding 70 percent of the planet's fresh water, has just experienced a freak heatwave.

Temperatures over the eastern Antarctic sheet have soared up to 40 degrees above normal levels.

Dr Kyle Clem, who is an expert on Antarctica's climate and a research fellow at the Victoria University of Wellington, said the region has just experienced "a perfect storm" from a weather standpoint over five days leading up to 18 March.

A large low pressure system extended from a north south direction, going from the east coast of Antarctica to Tasmania, he told Morning Report.

"So the northern extent of this low pressure system that was hugged up against a ridge south of New Zealand and it just started drawing moisture in from the sub-tropics from the Tasman Sea and from south-east Australia.

"Then with the extent going all the way down to Antarctica it just brought this warm moist air mass forward all the way to the coast of Antarctica and up onto the plateau of the interior."

Asked about the ramifications for the stability of the glaciers and the ice, Dr Clem said the most impressive aspect was the amount of snow it dumped on the coast as far as the glaciers are concerned.

Temperatures rose above freezing along the coast but up onto the plateau where it is over 3000 metres in elevation there was no surface melt.

"But what is alarming about this is that we learn new things every day about what this new climate that we live in is capable of and when you see heatwaves like this, even though it may not have done much damage to this part of Antarctica, this can happen in other parts of Antarctica that are much more vulnerable."

It would now be reasonable to expect repeat events in other parts of Antarctica that could mean temperatures would rise above freezing over vast parts of ice shelves along the coast.

"That can cause these ice shelves to break up and collapse and that leaves the interior ice sheet vulnerable to just blow into the ocean."