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New Zealand's famed Mount Cook glaciers are so affected by a warming climate they will never return to their former splendour, a New Zealand glaciologist has said.
Glaciologist Dr Trevor Chinn, who has been studying the Mount Cook structures since the 1960s, said some had already shrunk up to five kilometres, about 20 per cent, and it was too late for any of them to completely recover.
He said that while some of the world's glaciers would grow back if the climate cooled to its pre-global warming levels, those fronting lakes, like some at Mount Cook, would not.
"You can't get a re-advance that will come back if you apply the previous climate ... a re-advance across a lake is difficult because the ice breaks off the front of the glacier and floats away," Chinn said.
He said local warming since the 1890s had started the trend, but man-made climate change in recent decades had exacerbated the effect.
"They will never completely go. For that to happen the climate has to warm enough for the snowline to rise clean above the mountains, but they will retreat quite a bit more," he said.
He said the retreat had made it tough for tourists wanting to see the spectacle.
"It makes access much more difficult, to get a track up beside the glaciers any more because the sides are falling in."
But it was not all bad news for those wanting to see the glaciers, he said.
Chinn said the big glaciers were typically covered in gravel and didn't look spectacular, but the melting ice had created lakes covered in floating icebergs that were more impressive.
He said if global warming continued, eventually the floating icebergs would also disappear, although probably not for decades to come.
Mount Cook, also known as Aoraki, is New Zealand's highest peak and stands about 3,800 metres above sea level.
There are thousands of glaciers in the New Zealand alps and the ones on Mount Cook are among the best known.
- AAP
