Tasman Glacier retreats further

[Grant]

The Tasman Glacier is retreating rapidly and was last week further cropped when a huge chunk of ice, estimated to cover a hectare, broke off. Discovery Tours guide Elayne Nilson-Reid estimated the chunk of ice was 200m wide and 500m long. She believed it broke off on April 1 following heavy rain.

Mrs Nilson-Reid told the Timaru Herald Tasman Lake undercut the glacier. "What you end up with is like big shelves of glacier." The firm's vantage point would shift when the broken-up ice floated away after the next big flood. As the glacier retreats, tourists will travel further up the valley via the old 4WD track to the former Ball Hut. The Department of Conservation no longer maintains the track and Mrs Nilson-Reid said if it was washed away four tourism and guiding operators would be affected. "If we cannot keep that road open it means in future people will have to fly in costing several hundred dollars or walk for quite some time."

Tasman glacier cropped as huge ice chunk breaks off - 07 Apr 2007 - NZ Herald: New Zealand and International Environment News

[Grant]

Glaciologist Trevor Chinn said the development of lakes was a tipping point for glaciers. No amount of snow at the head of the glacier, the neve, would compensate the effect of the lake.

He said wherever the lake flowed under a glacier it would be eaten away. The glacier would retreat to a point where it was above the lake. He speculated this could be somewhere around the Ball Hut (about 5km away).

Alpine Recreation guide Gottlieb Braun-Elwert said long flat glaciers, like the Godley and Tasman, lost thickness on the bottom. Once pools or puddles appeared the glacier's demise rapidly accelerated. Heat dynamics meant at 4.2C water was its most dense and sank to the bottom. As ice thawed the water became cooler and moved upwards to be replaced by warmer water.

"As soon as you have puddles or lakes forming on ice you have a huge solar collector and unrestricted access of the sun's energy to melt the ice underneath." He estimated in 15 years the lake could have expanded to cut off traditional Mt Cook access via the Tasman moraine near the former Ball Hut. As the moraine wall grew higher climber access was made harder. The loss of the glaciers also increased danger. Glaciers applied lateral pressure to the sides of mountains and when they went, instability occurred. He believed loss of lateral pressure at the base of any mountains steeper than 28 degrees, the natural angle of recession, would affect stability right to the peak. This was demonstrated by the number of slips occurring on the Haast Ridge.

There are some routes he no longer uses because of increased instability. Mr Chinn said the demise of glaciers inevitably meant that some of the grandeur and beauty of the landscape was lost.

Glacier retreating as lake claims ice - New Zealand, world, sport, business & entertainment news on Stuff.co.nz

[Grant]

One of New Zealand's outstanding tourist attractions is melting away, glaciologists say.

The tongue of the iconic Franz Josef Glacier on the West Coast will melt away in the next 100 years, a team of glaciologists from Canterbury and Victoria universities have found. The researchers used a computer model to test the effect of the predictions from the Intergovernmental Panel on Climate Change (IPCC) on the glacier. "Even with the minimum amount of likely warming over the next century, the glacier will shrink in length by 4km, and reduce in size to three-quarters of its current volume," Brian Anderson from Victoria University said.

While Franz Josef Glacier is currently advancing, that was only because it was unusually responsive to short-term climate cycles such as El Nino, he said. El Nino causes lower temperatures and greater snowfall in the Southern Alps over three to five-year periods.

Meltdown for Franz Josef Glacier - 12 Apr 2007 - NZ Herald: New Zealand and International Environment News

[Grant]

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.

Mt Cook glaciers 'permanently damaged' by climate change - 03 May 2007 - NZ Herald: New Zealand National news