New Zealand's changing glaciers

[Kiwithrottlejockey]

Warming catches up with big glaciers

By RUTH LAUGESEN - Sunday Star Times | Sunday, 18 November 2007


DISAPPEARING ICE: The Tasman Glacier, the biggest of New Zealand's
twelve largest glaciers, all of which are rapidly shrinking in response
to regional climate warming.

CLIMATE CHANGE is making New Zealand's biggest glaciers melt twice as quickly as comparable ice masses overseas, according to research released today.

The Southern Alps' 12 biggest glaciers had crossed a "tipping point" into faster melting as they respond to regional warming, said National Institute of Water and Atmospheric Research principal scientist Jim Salinger.

"These have now passed a threshold, where the ice is collapsing, rapidly expanding lakes at the foot of the glaciers," he said.

"It is not yet clear whether the glaciers will disappear completely with future warming, but they are set to shrink further as they adjust to today's climate."

The findings come as the UN's Intergovernmental Panel on Climate Change releases a synthesis report in Valencia today on climate change, its likely impacts, and what can be done to mitigate it or adapt to it.

The report, which builds on the findings of three IPCC reports this year, will arm policymakers as they go into the UN Climate Change Conference in Bali next month. Those talks will begin work on an international agreement for responding to climate change to replace the Kyoto Protocol when it expires in 2012.

The Niwa research, which is the first long-term study of ice mass in the Southern Alps, found 5.8cukm of ice had been lost in the past 20 years. That was almost 11% of the total ice mass. More than 90% of this loss was from the 12 largest glaciers.

Those glaciers Tasman, Godley, Murchison, Classen, Mueller, Hooker, Ramsay, Volta/Therma, La Perouse, Balfour, Grey, and Maud had lost an average of 22m in ice thickness since 1986. In comparison, figures from the World Glacier Monitoring Service found that a sample of large world glaciers had lost an average of 9.6m in ice thickness since 1980.

Smaller glaciers, having rapidly adjusted to regional warming earlier, had not receded much in the past 20 years or in a few cases have slightly advanced. They include two well-known West Coast glaciers, the Fox and the Franz Josef.

Salinger said the glaciers overseas had responded more quickly to rising temperatures, and had thus already experienced substantial melting. New Zealand mean air temperatures have risen 0.4C since 1950 but the big glaciers here would probably not disappear any sooner than those overseas because they had taken longer to respond to warmer temperatures typically being covered in an insulating blanket of thick rock debris.

However, Salinger says, "it is already clear that they will not return to their earlier lengths without extraordinary cooling of the climate because the large lakes now block their advance".

www.stuff.co.nz/sundaystartimes/4277239a6442.html

[Kiwithrottlejockey]

Glacier to go in 20 years

NZPA | Thursday, 24 April 2008


MELTING ICE: The terminal lake of the Tasman Glacier complete with icebergs that have calved
from the terminal face as viewed from a skiplane on Easter Monday, 24 March 2008.

CLIMATE CHANGE will see most of the Tasman Glacier in the Southern Alps melt away over the next 20 years, scientists say.

"In the past 10 years, the glacier has receded a hell of a lot," said glaciologist Martin Brook.

"It's just too warm for a glacier to be sustained at such a low altitude — 730 metres above sea level — so it melts rapidly and it is going to disappear altogether."

The Tasman Glacier is the biggest in the Southern Alps and, at 29 kilometres, was one of the longest in the world's temperate zones.

In 1973, there was no lake in front of the Tasman Glacier. New measurements taken last week indicate the lake at its foot is now 7km long, 2km wide and 245m deep.

The lake has attracted regular excursions by boatloads of tourists, but Dr Brook warned yesterday that they may be at risk from huge chunks of ice unexpectedly breaking loose underwater and surfacing as far as 60m from the glacier face.

"There's actually a sub-surface apron of ice that slopes away under the water for at least 50m or 60m from the front of the glacier," Dr Brook said. As this ice-apron melted, blocks of ice broke off and floated to the surface.

"This happens pretty quickly and is potentially a hazard for the tour boats that cruise up to the cliff: the blocks just pop out on the surface and some are between 5m and 10m in size."

The lake has been formed as the ice which makes up the glacier melts, and is a key factor in its destruction: the deeper the lake, the faster the retreat of the glacier.

According to another glaciologist, Trevor Chinn, the development of the lake was a tipping point: no amount of snow at the head of the glacier, the neve, can compensate for melting triggered by the lake.

The last major survey of the glacier was in the 1990s. Since then, the glacier has retreated 180m a year, exposing a basin carved out of rock more than 20,000 years ago when the glacier was a lot larger and more powerful.

www.stuff.co.nz/dominionpost/4494166a6479.html

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Tasman Glacier could go in 20 years

Hot air blamed for Tasman Glacier's melt

By JOHN KEAST - The Press | Thursday, 24 April 2008


MELT DOWN: The Tasman Glacier is melting fast
and will ultimately disappear, experts fear.
— DAVID HALLETT/The Press.

THE TASMAN GLACIER in Aoraki-Mount Cook National Park is retreating at an alarming rate and will ultimately disappear, experts at Massey University warn.

Dr Martin Brook, lecturer in physical geography, said that in 1973 there was no lake in front of the glacier, but new measurements last week indicated the lake was now 7km long, 2km wide and 245m deep.

The lake is formed as ice in the glacier melts.

"In the last 10 years the glacier has retreated a hell of a lot. It's just too warm for a glacier to be sustained as such low altitude, 730 metres above sea level, so it melts rapidly and it is going to disappear altogether.

"Significantly, the deeper the lake, the faster the retreat of the glacier."

The lake could only grow to a length of 16km, which would mean a further 9km of glacier retreat.

"Using the empirical relationships between the water depth and glacier retreat rate, we could expect further retreat of between 477m and 822m each year. At these rates, it would take between 10 and 19 years for the lake to expand to its maximum," Brook said.

His work indicated that an extreme scenario for the future retreat of the glacier, developed by Dr Martin Kirkbride in the 1990s, was correct.

"The last major survey was in the 1990s and since then the glacier has retreated back 180m a year on average. This has exposed a huge rock basin which was eroded more than 20,000 years ago when the glacier was a lot larger and more powerful."

Research students are studying the glacier and lake using a new towfish sonar and echo-sounding equipment.

"The glacier followed a slow retreat phase for a while, in that a thermo-erosional notch in the ice cliff face would develop at the water line, melt back into the glacier undercutting the ice above, causing the ice to collapse into the lake.

"But what is happening now is that a short foot of ice is extending out into the lake away from the ice cliff, and the glacier is now in a period of fast retreat. This is because as the water depth increases, sodoes the speed of retreat — simply, a much larger part of the glacier is submerged and the water, even at only 2°C, is still able to melt the glacier ice," Brook said.

As well as looking at the Tasman Glacier, the team is analysing the newly exposed sub-surface landscape.

www.stuff.co.nz/thepress/4495365a24035.html

www.stuff.co.nz/4494061a7693.html

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Tasman Glacier retreat extreme

Created: Wednesday, 23 April 2008 | Last updated: Thursday, 24 April 2008
Massey University News


From left: technician David Feek, senior lecturer Dr Ian Fuller and PhD student
Claire Robertson looking at sub-bottom sediment using the towfish sonar.
In the background is a high-precision GPS transmitter attached to the
towfish, which gives its location to about 5mm accuracy.


PhD student John Appleby (left) and Honours student Rob Dykes (right)
in a boat on the lake measuring depth with an echo sounder.

THE TASMAN GLACIER is retreating faster than ever and will ultimately disappear, glaciologists are warning.

In 1973 there was no lake in front of the Tasman Glacier, says Dr Martin Brook, lecturer in physical geography in the School of People, Environment and Planning. New measurements taken last week indicate the lake, formed by ice melt from the glacier, is now 7km long, 2km wide and 245m deep. The lake has been formed as the ice which makes up the glacier melts.

“In the last 10 years the glacier has receded a hell of a lot,” Dr Brook says. “It’s just too warm for a glacier to be sustained at such a low altitude, 730m above sea level, so it melts rapidly and it is going to disappear altogether. Significantly, the deeper the lake, the faster the retreat of the glacier.”

Dr Brook says the lake can only grow to a length of about 16km, which would mean a further 9km of glacier retreat.

“Using the empirical relationships between water depth and glacier retreat rate we could expect further retreat of between 477m and 822m each year. At these rates it would take between 10 and 19 years for the lake to expand to its maximum.”

His work indicated that an extreme scenario for the future retreat of the Tasman Glacier, developed by Dr Martin Kirkbride in the 1990s, was correct.

“The last major survey was in the 1990s and since then the glacier has retreated back 180 metres a year on average. This has exposed a huge rock basin which was eroded more than 20,000 years ago when the glacier was a lot larger and more powerful.”

Dr Brook and a number of research students are studying the glacier and the lake using a new towfish sonar and echo sounding equipment to measure the depth and analyse sediments under the lake.

“The glacier followed a slow retreat phase for a while, in that a thermo-erosional notch in the ice cliff face would develop at the water line, melt back into the glacier undercutting the ice above, causing the ice to collapse into the lake.

“But what is happening now is that a short foot of ice is extending out into the lake away from the ice cliff, and the glacier is now in a period of fast retreat. This is because as the water depth increases so does the speed of retreat — simply, a much larger part of the glacier is submerged and the water, even at only two degrees celcius, is still able to melt the glacier ice.

“The result is large pieces of ice fracturing off the ice foot and floating on the surface — the debris on the icebergs on the surface of the lake and the icebergs are a reflection of this.”

As well as addressing the future of the Tasman Glacier, which is in Aoraki Mount Cook National Park, the team is analysing the newly exposed sub-surface landscape. The project is also interested in the glacier because it is very different to the clean-ice glaciers on the West Coast. Tasman is covered in rock and debris, and has a different relationship with climate, Dr Brook says, as well as different patterns of retreat.

“In particular, although there’s a near-vertical ice cliff at the front of the glacier that terminates in the lake, there’s actually a sub-surface apron of ice that slopes away under the water for at least 50m or 60m from the front of the glacier. As this ice-apron melts, blocks of ice break off and float to the surface. This happens pretty quickly and is potentially a hazard for the tour boats that cruise up to the cliff — the blocks just pop out on the surface and some are between 5m and 10m in size.”

www.massey.ac.nz/massey/about-us/news/article.cfm?mnarticle=tasman-glacier-retreat-extreme-23-04-2008

[Kiwithrottlejockey]

Heavy snow likely to bolster southern glaciers

By PAUL GORMAN, Science Reporter - The Press | Monday, 15 September 2008


GLACIAL FUTURE: Heavy alpine snowfalls in the South Island this winter
could temporarily halt or even reverse the continuing decline of some
glaciers in the Southern Alps. Meanwhile, Franz Josef Glacier (pictured)
and the nearby Fox Glacier in Westland National Park both buck the
worldwide trend as they continue to advance. — ALAN WOOD/The Press.

HEAVY ALPINE SNOWFALLS in the South Island this winter could temporarily halt or even reverse the continuing decline of glaciers in the Southern Alps.

The latest survey by the National Institute of Water and Atmospheric Research (Niwa) draws the gloomy conclusion that the country's glaciers are shrinking at an alarming rate.

The total ice volume of the Southern Alps' glaciers is 44.9 cubic km, the least since the annual survey began 32 years ago.

The 50 glaciers in the survey lost 2.5 cu km, or 2.2 billion tonnes, of permanent ice in the 12 months from April 2007, the fourth greatest annual loss on record. That was reflected in a mean South Island snowline over the period of 1960m above sea level, 130m higher than the 1976-2008 average.

However, the stormy winter means the snowpack in some parts of the Southern Alps is the greatest it has been for about a decade.

Power company Meridian Energy is eagerly awaiting a large spring thaw and the boost it will give to its southern hydro-lakes, which are only just starting to recover from very low levels throughout the winter.

Niwa principal climate scientist Jim Salinger said that extra snow could boost the ice mass quite quickly in some smaller glaciers but would not show up in larger glaciers for years.

"It depends what happens over the summer. We've still got the snow melt to come that's November to February and maybe March. If it's a cold summer, it might halt the decline a little, but the general trend is downward."

There was also a chance of late spring snowfalls.

The shrinking of the glaciers was due to climate change, Salinger said.

"Temperatures have increased a degree over a whole century, and by about three-tenths of a degree since 1960."

The melting trend in New Zealand matched that globally.

"International monitoring of mountain glaciers by the World Glacier Monitoring Service in Switzerland shows most glaciers are retreating," Salinger said.

"Of the glaciers where continuous data is available, the mean annual average loss in ice thickness since 1980 is close to half a metre per year."

www.stuff.co.nz/thepress/4692591a19753.html

[Kiwithrottlejockey]

NZ glaciers smallest since records began

By TOM CARDY - The Dominion Post | Monday, 15 September 2008


WARMING SIGN: Marion Glacier in Arawata Valley has recently withdrawn
from its proglacial state. Most of New Zealand's glaciers are the smallest
they've been since records began. — DR TREVOR CHINN/NIWA.

MOST OF New Zealand's glaciers are now the smallest they have been since records began — and they continue to shrink at a rapid rate.

The National Institute of Water and Atmospheric Research, which made the discovery, said global warming was the main culprit.

Between April last year and March this year, glaciers in the Southern Alps lost about 2.2 billion tonnes of permanent ice — the equivalent in weight to the top section of Mount Taranaki. It is the fourth highest annual loss since monitoring began 32 years ago.

The total ice for the glaciers now comprises an estimated 44.9 cubic kilometres — the lowest on record. The volume of ice dropped by 50 per cent during the last century.

NIWA principal scientist Jim Salinger said glaciers were fed by snow, but because of the La Nina weather system over New Zealand, more easterly winds and warmer than normal temperatures during the period, there was less snow in the Southern Alps and more snowmelt.

Dr Salinger said while the glaciers were sensitive to changes in wind and precipitation as well as temperature, global warming was a big factor in their shrinking.

"It's one of the clearest signs that our climate is warming and that [the shrinkage] is a definite physical response. To have that amount of melting you would have to reduce the precipitation at least by a half or more or warm a degree," he said.

"We know that precipitation has not gone down in the Southern Alps. In the last quarter of a century it's gone up. So to make them retreat you've got to have more melting, which is higher temperatures.

"This is certainly a definite sign of warming in the New Zealand area."

Niwa has surveyed 50 glaciers in the Southern Alps for the past 32 years, recording the height of the snowline at the end of each summer. On average the snowline this year was 130 metres above where it would need to be for the glaciers not to shrink, Dr Salinger said.

It was unlikely the glaciers would disappear entirely, as that would require a temperature rise of 7 degrees celsius and no snow even at the top of our highest mountain, Aoraki Mount Cook.

But they would continue to retreat. Another sign of warming were 12 glacial lakes, including ones at Marion Glacier and Tasman Glacier.

"They are definitely a sign of warming. There is no doubt about it. You get a very rapid loss of snow and ice and that's what's been happening."

www.stuff.co.nz/dominionpost/4692547a6479.html

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Media Release

Glaciers continue to show significant ice loss

15 September 2008
National Institute of Water & Atmospheric Research (NIWA)


The large Tasman Glacier in Aoraki-Mount Cook National Park.
— Photo: Dr Trevor Chinn, Alpine and Polar Research, Hawea.

NEW ZEALAND'S GLACIERS are showing the lowest total ice mass on record and most are continuing to shrink at a rapid rate.

Research released by the National Institute of Water & Atmospheric Research (NIWA) shows the Southern Alps glaciers have lost 2.5 km³ (2.2 billion tonnes) of permanent ice from April 2007 to March 2008, the fourth highest annual loss since monitoring started.

The 2008 total ice volume estimate for the Southern Alps glaciers of 44.9 km³ is the lowest on record.

For the past 32 years NIWA has been surveying 50 glaciers in the Southern Alps, using a small fixed wing aircraft, to record the height of the snow line at the end of summer.

NIWA Principal Scientist Dr Jim Salinger says the photographs taken on this year’s survey showed the glaciers had lost much more ice than they had gained during the past glacier year.

“As a result of La Niña conditions over New Zealand, more easterlies, and warmer than normal temperatures, there was less snowfall in the Southern Alps and more snowmelt.

The higher the snow line, the more snow is lost to feed the glacier. On average, the snow line this year was about 130 metres above where it would need to be to keep the ice mass constant,” Dr Salinger says.

Dr Salinger says these results match trends of ice mass lost globally. International monitoring of mountains glaciers by the World Glacier Monitoring Service in Switzerland shows most glaciers are retreating. Of the glaciers where continuous data is available, the mean annual average loss in ice thickness since 1980 is close to half a metre per year.

For more information contact:

Dr Jim Salinger
NIWA, Auckland
Tel: [phone]
Mob: [phone]

______________________________________

Background Information:

Worldwide, glaciers are regarded as a useful indicator of global warming, but New Zealand’s glaciers are more complicated because they have their source in areas of extremely high precipitation. West of the Main Divide in the Southern Alps, more than 10 metres (10 000 mm) of precipitation falls each year as clouds are pushed up over the sharply rising mountain ranges. This means the mass and volume of New Zealand’s glaciers is sensitive to changing wind and precipitation patterns as well as to temperature. So, for example, the glaciers advanced during most of the 1980s and 1990s when the area experienced about a 15% increase in precipitation, associated with more El Niño events and stronger westerly winds over New Zealand. The glaciers in parts of Norway are similar.

Despite the sensitivity of New Zealand glaciers to changes in both precipitation and temperature, the volume of ice in the Southern Alps dropped by roughly 50% during the last century. New Zealand’s temperature increased by about 1°C over the same period.

Globally, most glaciers are retreating. Of the glaciers for which there are continuous data from the World Glacier Monitoring Service, the mean annual loss in ice thickness since 1980 remains close to half a metre per year. The Service has said that the loss in ice mass “leaves no doubt about the accelerating change in climatic conditions”. For world glacier data, see www.geo.unizh.ch/wgms.

The level of the glacier snow lines is not necessarily closely related to the amount of snow that falls on the country’s ski fields during winter. Most of the popular ski fields are east of the Main Divide, or in the North Island. Mount Hutt, for instance, gets its snow from big southeasterlies, whereas most of the glaciers are fed by westerlies.



www.niwa.co.nz/news/mr/2008/2008-09-15

[Kiwithrottlejockey]

Kiwis unlock glacier secret

The Dominion Post with NZPA | Friday, 01 May 2009

RESEARCH BY by three New Zealand scientists may have solved the mystery of why glaciers behave differently in the northern and southern hemispheres.

New Zealand researchers, geologist David Barrell of GNS Science, Victoria University geomorphologist Andrew Mackintosh, and glaciologist Trevor Chinn, of the Alpine and Polar Processes Consultancy, have helped provide definitive dating for changes in glacier behaviour.

The three were part of a team of nine scientists, led by Joerg Schaefer of Lamont-Doherty Earth Observatory, which used an isotope dating technique to get very precise ages for glacial deposits near Aoraki-Mount Cook.

They measured the build-up of beryllium-10 isotopes in surface rocks bombarded by cosmic rays to pinpoint dates when glaciers in the Southern Alps started to recede. The technology is expected to be widely applied to precisely date other glaciers around the world.

Glaciers are sensitive indicators of climate changes, usually advancing when it cools and retreating when it warms.

The first direct confirmation of differences in glacier behaviour between the northern and southern hemispheres, the new work topples theories based on climate in the northern hemisphere changing in tandem with the climate in the southern hemisphere.

The research argues that at times the climate in both hemispheres evolved "in sync" and at other times it evolved differently in different parts of the world.

Dr Barrell told NZPA their research presents "new data of novel high precision" though the team has so far chosen not to roll out wider interpretations too quickly.

He said much of it reinforced work done 30 years ago by Canterbury University researcher Professor Colin Burrows, who used NZ glacier data to highlight some of the similarities and differences between northern and southern records over the past 12,000 years.

The paper published in Science magazine today showed the Mount Cook glaciers advanced to their maximum length 6500 years ago, and have been smaller ever since — but glaciers in the Swiss Alps advanced to their maximum only in the past 700 years — during the northern hemisphere's "Little Ice Age", which ended about 1860.

During some warm periods in Europe, glaciers were advancing in New Zealand. At other times, glaciers were well advanced in both areas.

In a commentary which accompanied the research, Greg Balco, from the Berkeley Geochronology Center in California, said the conclusion that glacier advances in the northern and southern hemispheres were not synchronised was "unexpected".

Dr Barrell said the paper presented only the first instalment of the dating work, and more will be revealed at an international workshop on past climates to be held at Te Papa on May 15.

"We expect that much progress will result from this new work and the discussions at that meeting," he said.

"The New Zealand findings point to the importance of regional shifts in wind directions and sea surface temperatures," he said.

Regional weather patterns such as the El Nino Southern Oscillation (ENSO) were superimposed on the global climate trends reflected in the behaviour of glaciers.

www.stuff.co.nz/dominion-post/news/2378376/Kiwis-unlock-glacier-secret

[Kiwithrottlejockey]

NZ glaciers continuing to shrink

NZPA | 10:55AM - Monday, 23 November 2009

NEW ZEALAND'S GLACIERS are continuing to shrink, the National Institute of Water and Atmospheric Research (NIWA) says.

NIWA's annual end-of-summer survey of the snowline on key South Island glaciers showed they lost much more ice than they gained between April 2008 and March 2009.

Scientists flew over 50 glaciers in the Southern Alps and Kaikoura area and photographed the positions of snowlines on glaciers during the survey.

NIWA snow and ice scientist Jordy Hendrikx said above-normal temperatures, near or below-normal rainfall and above-normal sunshine were among the reasons for the continued shrinking.

This year's snowline was, on average, 95 metres above where it needed to be to keep the ice mass constant, NIWA said.

This indicated the loss of glacier mass observed in the 2007-2008 survey had continued.

Over the past 33 years, there had been an overall decrease in the glacier mass balance, despite periods where the balance had increased for a few years.

www.stuff.co.nz/environment/3088709/NZ-glaciers-continuing-to-shrink

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Glaciers continue to shrink

New Zealand’s glaciers lost significant ice mass again last summer.

National Institute of Water & Atmospheric Research | 23 November 2009


When one portion of snow melts, it takes about two equivalent portions of snow fall
to keep a glacier's mass balance the same.

THE National Institute of Water & Atmospheric Research (NIWA) has just released the results of its annual end-of-summer survey of the snowline on key South Island glaciers, showing continued loss of glacier mass.

The survey uses a small fixed wing aircraft to fly over 50 glaciers in the Southern Alps and Kaikoura. Scientists take photographs and then analyse the images to determine the position of the snowline after the summer melt but before the first winter snowfall. This provides an index of the mass balance or ’health’ of the glaciers of New Zealand. The survey has been going since 1977.


ROLLESTON GLACIER

NIWA Snow and Ice Scientist Dr Jordy Hendrikx says weather patterns over the course of the year from April 2008 to March 2009 meant that overall the glaciers had lost much more ice than they had gained. This was mainly due to the combination of above normal temperatures and near normal or below normal rainfall for the Southern Alps during winter, and La Niña-like patterns producing more northerly flows creating normal-to-above normal temperatures, above normal sunshine, and well below normal precipitation for the Southern Alps particularly during late summer.

The higher the snowline, the more snow is lost to feed the glacier. On average, the snowline this year was about 95 metres above where it would need to be to keep the ice mass constant. This indicates that the loss of glacier mass observed in 2007-08 has continued.


GODLEY & CLASSEN GLACIERS


AORAKI-MOUNT COOK, TASMAN GLACIER & HOCHSTETTER ICEFALL


AORAKI-MOUNT COOK & TASMAN GLACIER TERMINAL LAKE

When studying and reporting what is happening to glaciers, it is important to look at more than one factor. The position of the end of summer snowline is only part of the story; in New Zealand, an estimated 90% of ice loss from glaciers since 1976 is due to down-wasting and lake calving. NIWA’s snowline surveys show an overall decrease in the glacier mass balance (and thereby volumes) over the past 33 years — but this is punctuated by periods where the prevailing weather conditions caused the glacier mass balance to increase for a few years.

Similarly, glacier terminus position (the “length” of a glacier) can be misleading when considered on its own because total volume can be decreasing even while terminus length is increasing.


BONAR GLACIER & MOUNT ASPIRING


PARK PASS


MOUNT TUTOKO & DONNE GLACIER

For more information, contact:

Dr Jordy Hendrikx
NIWA Snow & Ice Scientist
Mob: [phone]

For images:

Large sized high resolution glacier photographs and graphs showing the changes in glacier ice mass can be downloaded from here.

Background information:

1. Worldwide, glaciers are regarded as a useful indicator of global warming, but New Zealand’s glaciers are more complicated because they have their source in areas of extremely high precipitation. West of the Main Divide in the Southern Alps, more than 10 metres (10 000 mm) of precipitation falls each year as clouds are pushed up over the sharply rising mountain ranges. This means the mass and volume of New Zealand’s glaciers is sensitive to changing wind and precipitation patterns as well as to temperature. So, for example, the glaciers advanced during most of the 1980s and 1990s when the area experienced about a 15% increase in precipitation, associated with more El Niño events and stronger westerly winds over New Zealand. The glaciers in parts of Norway are similar.

2. Despite the sensitivity of New Zealand glaciers to changes in both precipitation and temperature, the volume of ice in the Southern Alps dropped by roughly 50% during the last century. New Zealand’s temperature increased by about 1°C over the same period.

3. Globally, most glaciers are retreating. Of the glaciers for which there are continuous data from the World Glacier Monitoring Service, the mean annual loss in ice thickness since 1980 remains close to half a metre per year. The Service has said that the loss in ice mass “leaves no doubt about the accelerating change in climatic conditions”. For world glacier data, see www.geo.unizh.ch/wgms.

4. The level of the glacier snowlines is not necessarily closely related to the amount of snow that falls on the country’s ski fields during winter. Most of the popular ski fields are east of the Main Divide, or in the North Island. Mount Hutt, for instance, gets its snow from big southeasterlies, whereas most of the glaciers are fed by westerlies. The melt season is also of critical importance, so while a glacier may receive “normal” snow accumulation, it could be subject to above normal melt and the net result is a higher snowline and less ice.

5. An estimated 90% of the ice loss from New Zealand glaciers in the Southern Alps since 1976 is due to down-wasting and lake calving mainly from 12 of the largest glaciers on the eastern side of the main divide. These processes are:

• Down-wasting: ice melts from the top surface of the trunk. Trunks go from their original convex shape to near-straight or even concave (slight hollow in the centre).

• Lake calving: ice melting at the foot of glaciers & meltwater forming lakes. Some chunks of ice ‘calve’ off glaciers into the lakes (like icebergs).

www.niwa.co.nz/our-science/climate/news/all/glaciers-continue-to-shrink2

[Kiwithrottlejockey]

Shrinking glaciers curtail climbing trips

By FLEUR COGLE - The Timaru Herald | 5:00AM - Tuesday, 24 November 2009

AORAKI-MOUNT COOK'S shrinking glaciers are forcing climbers to think more carefully about their excursions into the national park.

The National Institute of Water and Atmospheric Research (Niwa) yesterday released the results of its annual end-of-summer survey of the snowline on key South Island glaciers, showing the glaciers continue to shrink. The news is no surprise to those who know the national park.

Veteran mountaineer Gordon Hasell, who has been climbing in the area since the 50s, said that during the 60s the lake at the base of the Tasman Glacier was the same size as the duck pond in Timaru's Botanical Gardens.

"It's now about 4km long."

With a new lake and the increased exposure of the glacier's moraine walls, climbers were being forced to change the way they approached the park.

Mr Hasell said climbers no longer have as easy access to parts of park as they once did.

"Now the major effect excess recession has had is a greater dependence on air access."

Department of Conservation ranger Ray Bellringer said the changes had been "very spectacular and very noticeable over a period".

www.stuff.co.nz/timaru-herald/news/3090706/Shrinking-glaciers-curtail-climbing-trips

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Cold spell needed for Mount Cook

By JEFF TOLLAN - The Timaru Herald | 5:00AM - Monday, 07 December 2009

HOT WEATHER is threatening a thriving climbing season in the Aoraki/Mount Cook National Park.

Alpine guides say their books are bulging with customers, domestic and international, but Conservation Department staff are praying for a cold snap to hit the area in the coming weeks.

Ranger Ray Bellringer said a storm from the south would prolong the climbing season. Without it, large crevasses in glaciers open up, the risk of rockfall increases, routes become more challenging and climbing or guiding will eventually become impossible.

"If we get another hot period then the season would be over by the middle of January. We've been in the equinox for some weeks, [it has been] raining, nor'west and windy. There were some reasonable amounts of snow around, but it's melted back quite a bit," Mr Bellringer said.

Police Mid-South Canterbury Area Commander Inspector Dave Gaskin urged any climbers to use common sense and climb when the conditions were right.

He said each season, search and rescue teams were put at risk, rescuing "foolhardy" people who tried to climb in bad weather, or who climbed areas that were beyond their experience.

However, guides in the area have said there has been no shortage of people booking with them, to take advantage of the skills of people who know the park well.

One of the area's largest guiding companies, Alpine Guides, has a 10 per cent increase in bookings for this season, filling the diary until January 20.

Managing director Bryan Carter said between 180 to 200 people had booked in for the summer season, with the Australian market still going strong.

"[People are choosing] short haul travel more than long haul. A lot of people have decided it has been a bit of a tough year, so they're going to take a break."

Dave McKinley of Mountains New Zealand said while the weather had been "playing games", it was still good to be out in the hills and there was no shortage of business.

"We are pretty heavily booked through to almost March, it's quite a healthy season. For the start of the season, the conditions are better than last year," he said.

Whether climbers had a guide or not , Mr Gaskin said police and DOC staff were unable to stop them, which made it important to keep a close eye on the weather. He estimated there would be 20 or 30 rescues from the Aoraki/Mount Cook National Park every year and three or four deaths. Rescue or recovery missions were not a nice part of the job, Mr Gaskin added.

"People who fall off mountains are generally knocked about. You're falling down a hill and when your body comes into contact with some unforgiving objects ... it's difficult."

He said the region's police had an annual budget of about $30,000 for helicopter SAR operations and while there was no such thing as a "standard" rescue, an average cost of getting someone off the mountain was about $2000 to $5000, not including costs to DOC and police staff.

ACC picked up a large part of the bill for rescues, if there was an injury involved. People only had to pay the helicopter bill if they decided they could not carry on their journey and wanted to be airlifted out, rather than walk.

www.stuff.co.nz/timaru-herald/news/3131118/Cold-spell-needed-for-Mt-Cook

[Kiwithrottlejockey]

Tasman Glacier about to calve

By JEFF TOLLAN - The Timaru Herald | 5:00AM - Tuesday, 03 August 2010


READY TO ROLL: The terminal face of the Tasman Glacier
has risen 20 metres out of water and is now 50 metres high.
Its original depth can be seen by the notches cut by the lake.
— Photo: GLACIER EXPLORERS.

A 20-METRE RISE in the height of the Tasman Glacier's terminal face is "a prelude" to an iceberg calving — a year after the largest recorded calving.

Aoraki/Mount Cook Alpine Village tourism general manager Denis Callesen said the latest change of the glacier's appearance was amazing. It followed a 250 millimetre downpour in the weekend.

"We've never ever seen the face rise up like that. The whole process that's going on at the moment is incredible."

"In the coming weeks it's inevitable there's going to be a massive calving."

In February 2009, a giant slab of ice, estimated to be 250m long by 250m wide and 80m high, plunged into the lake. It sent a three-metre surge of water down the terminal lake. A second iceberg about a quarter of the size calved from the face shortly afterwards.

The glacier is the country's largest, at just under 30km long, 600m deep in the middle and 1.6km wide. At its deepest point it sits below the bottom level of Lake Pukaki.

Its face is now 600m across by 100m deep by 50m high.

While it is a popular tourist attraction, Mr Callesen said boats touring the glacier would not be allowed to go within 1.5 kilometres of the terminal face. Up until now they had been able to travel to within 800 metres of it.

In spite of the risk of a 3 or 4 metre swell, he said it would not be a big issue if boats were on the lake, as the crews were trained.

"It's not a breaking wave and the boats are relatively safe."

"As it comes through the first thing that happens is the jetty grounds out on the bottom of the lake and then bounces up."

Speaking to the Herald last night, glaciologist Trevor Chinn said the rise in the face was likely to be caused by extra water getting in between the ice and the bedrock. "Ice is one-tenth lighter than water. The ice is so deep, with a bit more water in the lake, the central ice is held down by the sides and if the ice on the bottom gets water under it then it floats."

Mr Chinn said it was likely the part that rose out of the water could have broken from the glacier already.

"It's dreadfully unstable because it's probably leaning back against the glacier."

"When it's floating, there's nine times more underneath."

Mr Chinn said the climate was no longer playing a part in the Tasman's retreat and large chunks would continue to calve off until it reached equilibrium, to which it was about "half way there". "It's going to go on for another decade really. It's far too big for this climate, it's quite dramatic, this change. It's a tipping point."

"You can't reverse this. If the climate got colder, no, you wouldn't get your glacier back for years and years. Huge bits coming off is to be expected."

www.stuff.co.nz/timaru-herald/news/3983628/Tasman-Glacier-about-to-calve

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Tasman Glacier calving awaited

The Timaru Herald | 5:00AM - Saturday, 14 August 2010

ALL EYES are still on the rising face of the Tasman Glacier, waiting for the birth of an iceberg.

Aoraki-Mount Cook Alpine Village Ltd tourism general manager Denis Callesen said the only movement on the glacier front had been vertical, as the face of the 20-kilometre-long ice flow continued to rise out of the terminal lake.

Mr Callesen said plans to install a camera to watch over the glacier had been hampered by power supply problems and the weather.

"Our problem at present is access, as the Tasman Valley Road beyond Blue Lakes has a very high avalanche danger."

At the beginning of the month a 250mm deluge of rain caused the face of the glacier to rise 20 metres out of the water — a prelude to the face snapping off, a process known as calving. The broken ice would then be an iceberg.

In February 2009, a giant slab of ice, estimated to be 250 metres long by 250 metres wide and 80 metres high, fell into the lake. It sent a three-metre surge of water down the terminal lake. A second iceberg about a quarter of the size calved from the face shortly after.

The glacier is the country's largest, at just under 30km long, 600 metres deep in the middle and 1.6km wide.

www.stuff.co.nz/timaru-herald/news/4024293/Tasman-Glacier-calving-awaited

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Glacier wait ‘a bit like Jaws’

The Timaru Herald | 5:00AM - Tuesday, 17 August 2010


WAITING FOR THE BIG ONER: Glacier Explorers'
manager Bede Ward looks over the rising face of
the Tasman Glacier after the closest glimpse in
days at what is happening at the terminal face.
Part of it is expected to shear off and become
an iceberg. — Photo: GLACIER EXPLORERS.

AFTER RAIN and avalanche threats, conditions have cleared to allow a closer look at the rising, cracked face of the Tasman Glacier.

A team from Glacier Explorers, which gives tours of the terminal lake, yesterday got within 690 metres of the ice floe that recently gained international attention following reports the face will soon break off into an iceberg.

Heavy rain in the Aoraki/Mount Cook National Park has seeped underneath the base of the glacier, pushing the terminal face up by 30 metres since August 02. As a result, millions of tonnes of ice are expected to snap from the rest of the glacier, and become one or more large icebergs.

A chunk of ice, about 250 metres long, 250 metres wide and 80 metres high, fell into the terminal lake in February last year, generating a 3 metre surge of water.

Denis Callesen, tourism general manager of Aoraki/Mount Cook Alpine Village, said a lowering of the avalanche risk allowed several staff members to get alongside the glacier, though from the safety of the moraine wall above it.

"The scope is enormous. There were cracks in the glacier before, but they've certainly gotten bigger, possibly as wide as one or two metres."

While the wall of ice keeps climbing out of the water, Mr Callesen said there was still no idea when it would calve off into an iceberg. "The fellow upstairs will decide that. It's a new phenomenon, there's no telling what will happen."

He said it was the magnitude that made this event unique — a much smaller rise happened following torrential rain in 1994 — and so far the event was "running as predicted".

Glacier Explorers' manager Bede Ward said it was "a bit like the movie Jaws; it's what is below the water — and you can't see — that you worry about".

www.stuff.co.nz/timaru-herald/news/4030214/Glacier-wait-a-bit-like-Jaws

[Kiwithrottlejockey]

Massive ice chunks split off from glacier

By AL WILLIAMS - The Timaru Herald | 5:00AM - Monday, 23 August 2010


GLACIAL EVENT: Thirty to fifty million tonnes of ice have broken off the Tasman Glacier forming around 20 icebergs now floating in the Tasman Lake.

A LARGE SECTION OF ICE, estimated to weigh 30 million tonnes, has broken off the Tasman Glacier, resulting in a number of icebergs entering the lake.

Heavy rain in the Aoraki/Mount Cook National Park had caused the glacier's terminal face to tilt and lift up, signalling a fresh round of dramatic calving activity at the weekend.

Discovery Tours chief guide Vernon Reid, who had been watching events unfold, said he had never seen such a large amount of ice and calving activity on the Tasman Glacier in winter in the 18 years he had been in the Aoraki/Mount Cook region.

Mr Reid said he believed the unusual winter activity of ice breaking up was due to the ever-increasing volume of the Tasman Glacier's terminal lake. "We may see an increase of such large-scale ice-calving events."

Aoraki/Mount Cook Alpine Village Ltd tourism general manager Denis Callesen said it was the biggest calving yet.

"Certainly everything above the water has gone. Based on my calculations, around 30 million tonnes."

A team from Glacier Explorers, which gives tours of the terminal lake, managed to get close to the ice floe last week following heavy rain and avalanche threats.

Heavy rain in the region had seeped underneath the base of the glacier, pushing up the terminal base by 30 metres.

"It has been exciting and fascinating for both our guides and clients to witness these dramatic events unfold over the past two months from high on our tour viewpoint, which is directly above the terminal ice face," Mr Reid said. "This was also the first time in 18 years where the lake surface didn't freeze, just the lower section of the lake froze and the water in the terminal lake looked a very blue hue rather than the common muddy colour."

He said guides now had a clear point of view, enabling them to see the glacier's calving activity including the entire lower 12km surface of the glacier, the thermokarst lakes, moraine-covered surface and ever-increasing ice cracks, giving people the opportunity to truly appreciate the glacier's rapid retreat.

"When I first arrived in 1992, the Tasman Glacier was around 29km in length. Today it is around 25km long and will continue to retreat until a new equilibrium is reached.

"There are now a number of complex processes which influence whether a glacier advances or retreats but, for now, the Tasman Glacier terminal lake is the biggest single factor and many exciting changes will occur in the next few years."

A chunk of ice — about 250m long, 250m wide and 80m high — fell into the terminal lake in February last year, generating a 3m surge of water.

www.stuff.co.nz/timaru-herald/news/4049150/Massive-ice-chunks-split-off-from-glacier

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Glacier calving changes landscape

The Press | 2:19PM - Monday, 23 August 2010


BEFORE: The terminal face of the Tasman Glacier prior to the huge break-off of ice.


AFTER: Thirty to fifty million tonnes of ice have broken off the Tasman Glacier.

THIRTY TO FIFTY MILLION TONNES OF ICE have broken off the Tasman Glacier forming around 20 icebergs now floating in the Tasman Lake — adding more drama and spectacle to an already dramatic landscape.

The process began earlier this month when the terminal face rose 20 to 40 metres thanks to a rain downpour which lifted millions of tonnes of ice from the water across the entire 600m width of the face.

On August 18, a small section of that ice calved resulting in a massive and spectacular iceberg separating from the face. Sometime over the weekend, the rest of the uplifted ice broke away from the terminal face in the biggest ever calving in the lake's 35 year history.

Glacier Explorers, which takes passengers on cruises on the Tasman Glacier Terminal Lake, will resume operations on 03 September, one month ahead of schedule due to an early spring melt and to take advantage of the opportunity to see the magnificent new icebergs.

Denis Callesen, General Manager Tourism for Aoraki Mount Cook Alpine Village Ltd said the coming season promises visitors the most spectacular iceberg and glacier cruising season yet.

"The scale of what's happening here is just enormous. The biggest iceberg is about 300m by 200m and 40m high — and that's only the 10% of the 'berg that we can see. Ninety percent is below the waterline."

Callesen said the Tasman Lake is now full of icebergs with more than 20 that are 50m by 50m above the waterline.

"These 'bergs now take on a life of their own, flipping, turning and moving as natural forces take action."

Callesen said he and Glacier Explorers staff were "incredibly excited' about the coming season.

"We are expecting the most spectacular season ever here, with stunning viewing of nature in action. Visitors will be able to get out onto the lake from early September and they will be in for a trip of a lifetime with sensational iceberg viewing. The current calving will give us ice to study for the next two seasons at least."

The season will open with two trips a day increasing to five as the season develops.

www.stuff.co.nz/the-press/news/south-island/4051422/Glacier-calving-changes-landscape

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• More photographs at: The Hermitage Hotel's Facebook page.

[Kiwithrottlejockey]

New Zealand's glaciers face great melt

By KIRSTY JOHNSTON - Stuff.co.nz | 11:42AM - Monday, 10 January 2011


UNDER THREAT: Franz Josef glacier could lose up to 75 per cent
of it's mass by 2100.

NEW ZEALAND'S GLACIERS could shrink by more than 75 per cent by the end of the century, contributing to an expected 12 centimetre rise in sea levels, a study says.

The research, published in Nature Geoscience this week, predicts that, globally, mountain glaciers and ice caps will lose 15 to 27 per cent of their volume by 2100.

One of the first such studies to provide detailed projections by region, it warns "ice loss on such a scale may have substantial impacts on regional hydrology and water availability".

Worst hit will be glaciers in the European Alps and New Zealand, with glaciers expected to shrink by more than 70 per cent due to the altitude, the nature of the terrain and the susceptibility to localised warming.

Glaciers in the Caucasus, western Canada and the western United States were projected to lose more than 50 per cent of their current ice volume.

Only 10 per cent shrinkage was predicted in Greenland and high-mountain Asia.

The scientists, from the University of British Columbia, say the melt-off will be responsible for increases in sea levels of between 8.7 and 16.1cm by 2100, supporting the change predicted by the UN climate change study from 2007.

Study leader Dr Valentina Radic said they were surprised at the amount the glaciers and caps contributed to the predicted rise in sea levels.

Currently, melt from smaller mountain glaciers and ice caps was responsible for a disproportionately large portion of sea level increases, even though they contained less than one per cent of water in glacier ice.

"What is surprising here is the contribution to sea level rises of up to 16cm just from the melting of small glaciers and ice caps. This may still be a low estimate as we did not include ice loss from calving — when a piece of ice breaks off into the sea," Radic told The Guardian newspaper.

Total sea level rises were likely to be considerably higher, however, due to the effects of melting Greenland and Antarctic ice sheets and thermal expansion of water, which were excluded from the results.

The scientists arrived at their conclusions by modelling volume loss and melt off from 120,000 mountain glaciers and ice caps. It is one of the first to provide detailed projections by region.

However, its projections didn't include glacier calving — the production of icebergs. Calving of tide-water glaciers may account for 30 per cent to 40 per cent of their total mass loss.

"Incorporating calving into the models of glacier mass changes on regional and global scale is still a challenge and a major task for future work," Radic said.

New Zealand has hundreds of glaciers, in both the North and South islands, with the most famous the Fox and Franz Josef on the South Island's West Coast.

Most of New Zealand's largest glaciers are in the Southern Alps, which have the highest mountains and heaviest rainfall. Glaciers in the Mount Cook area include the 29-kilometre-long Tasman and the Murchison (18 kilometres).

South of Mount Cook, the Bonar and Volta glaciers are centred around Mount Aspiring. Many, including the Olivine Ice Plateau, lie in the upper catchments of the Arawata, Matukituki, Dart and Hollyford rivers. The only glaciers in the North Island are found on Mount Ruapehu.

www.stuff.co.nz/national/4525379/New-Zealands-glaciers-face-great-melt

[Kiwithrottlejockey]

Mount Cook glacier's rare display

Glacier visitors witness ‘blue ice’ event

By NICOLE MATHEWSON - The Press | 1:26PM - Friday, 14 January 2011


COOL ADVENTURE: Visitors on a Glacier Explorers trip were surprised to come up close and personal
with the “blue” iceberg.

VISITORS near Mount Cook witnessed a rare sighting of ‘blue ice’ at the base of a massive iceberg that rolled over in the Tasman Glacier Terminal Lake yesterday.

Photographers have only two hours to capture images of the crystal-clear blue ice on the base of an iceberg before it turns white after exposure to air.

Visitors on a Glacier Explorers trip yesterday were surprised to come up close and personal with the iceberg, even touching the coffee-cup sized crystals.

"This ice is so dense and compressed, it's five times harder than the ice you might have in your gin and tonic," said Denis Callesen, tourism general manager for Aoraki/Mount Cook Alpine Village Ltd.

The visitors were "luckier than they could possibly imagine" to see the phenomena, he said.

"In Disneyland they spend millions of dollars creating shows like this, but here this is simply nature at work."

The iceberg was created when 50 million tones of ice ‘calved’ off the Tasman Glacier face in July and August last year.

"As they melt down, they become unstable, especially in this warmer weather. This is the second significant iceberg rollover we've had this week, and on Monday another one-million tonnes of ice calved off the terminal face," Callesen said.

www.stuff.co.nz/the-press/news/south-island/4542307/Mount-Cook-glaciers-rare-display