Glacier loss

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RWood
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Glacier loss

Unread post by RWood »

http://www.niwa.cri.nz/news/mr/2007/2007-11-18-2

Have posted this as a matter of interest and importance. I do not intend however to get into arguments with trollers,if any are lurking.
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NZstorm
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Re: Glacier loss

Unread post by NZstorm »

Interesting that an 0.5C increase in NZ's mean temperatures over the last 50 years will change the dynamics of the glaciers so dramatically. You would think an 0.5C rise in temperature would lead to increased rainfall and thus make it more possible for the volume of a South Island glacier to be sustained.
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tgsnoopy
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Unread post by tgsnoopy »

I watched a documentary this morning on Greenland where they reported the average temperature has risen 2°C in the last decade. It was an interesting watch. They can now grow crops and graze stock that they couldn't previously.

The amount of glacier and permafrost melt occuring presently is scary and it's accelerating. It doesn't look good for the future and lets not think about the potential increase in sea level.
Andrew Massie
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Re: Glacier loss

Unread post by Andrew Massie »

We went on a walk up to a pseudo glacier in Arthur's Pass (Bealey Glacier) last month that my Fiance hadn't seen since she was a child. She was very surprised how far it had receded.

Don't worry about trollers, RW, they're easily ignored! :roll:
southernthrash
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Re: Glacier loss

Unread post by southernthrash »

It's the glaciers of longer response time that are generally showing the greatest shrinking. Trends are very different in some of the smaller shorter response times.

Glacier size is not the immediate concern for NZ though, as our main reliance on the Southern Alps as a hydrological system is for the hydro schemes, seasonal snow contributes far more water to the hydro lakes than the glaciers, and is much more variable, but as was mentioned in the article, the end of summer snowline has not changed significantly (some areas are seeing greater volumes lasting longer lately). The accelerated melting is generally occuring entirely in the ablation zones of glaciers, and the boundary between accumulation and ablation is remaining pretty static position-wise.

Interesting side note, the Main Divide recieved 12 metres of snow in the Mt Cook region during October this year, making for the best climbing conditions in years, and one of the most consistent and continuous late winter snow covers most people can remember.
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sthguy
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Re: Glacier loss

Unread post by sthguy »

It's the glaciers of longer response time that are generally showing the greatest shrinking. Trends are very different in some of the smaller shorter response times
Thank goodness someone has the sense to point out the facts.


The western glaciers are very steep and respond quickly to increased snowfall - around 5 years - and the larger eastern glaciers have response time as long as 100 years.

New Zealand's fastest glacial retreat in the last century occurred in the 1950's. In the last 20 years the major western glaciers have recovered some 40% of the ground they lost in the 20th century. It is clear that the eastern glaciers will eventually start advancing as a response to the snowpack increases but this may not be for another 20-30years. Until then we will have varying degrees of hysteria over glacial retreat.

For an interesting report by Chinn, Winkler,Salinger and Haakenen

http://climatesci.colorado.edu/publicat ... nnetal.pdf
the end of summer snowline has not changed significantly (some areas are seeing greater volumes lasting longer lately). The accelerated melting is generally occuring entirely in the ablation zones of glaciers, and the boundary between accumulation and ablation is remaining pretty static position-wise[/quote]

Exactly. There has been a mean lowering of the snow line by 67m since the 70's {Chinn 1999}

I
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RWood
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Re: Glacier loss

Unread post by RWood »

Hysteria? I simply quoted the article, which contains the following from Salinger - you can take the matter up with him if you like:

“The twelve big glaciers with these pro-glacial lakes have passed a ‘tipping point’. 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. And 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.”

As to whether anyone is being hysterical, we'll let the future decide that.
Andrew Massie
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Re: Glacier loss

Unread post by Andrew Massie »

Don't worry, RW, I think somebody answered his own post with a new user to try and sound intelligent! :lol:
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sthguy
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Re: Glacier loss

Unread post by sthguy »

=D>

Touchy place! Nothing like letting a few facts stir people up. Pardon me.

AM you couldn't be more wrong. In fact that is a very unusual and revealing conclusion to jump to.

As for Salinger, interesting guy, check out his press statements over the last few years on glacial advance/retreat and you might find him rather confused and contradictory, but I wouldn't characterise him as hysterical...but certainly there are varying degrees of hysterical reaction from all points of the compass when trying to discuss the facts of these matters, rather than opinions.....
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RWood
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Re: Glacier loss

Unread post by RWood »

I've seen more than enough posts in various forums to recognise which category you belong to. Therefore I won't waste any more of my time on your musings. ](*,) [-(

Well said, Andrew!
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sthguy
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Re: Glacier loss

Unread post by sthguy »

the Main Divide recieved 12 metres of snow in the Mt Cook region during October this year,
I guess 900m or warm rain [melting level around 2700-3000m] will have dealt to much of that....
recognise which category you belong to


[-X

Love it when people just box you up... amazing. Must have been that lightning rod word 'hysteria that did the trick. You'r entitled to your own opinions, but not your own facts.
The twelve big glaciers with these pro-glacial lakes have passed a ‘tipping point’. 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. And 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.
This is a fair opinion, but that's all it is.
My view is that our great great great grandchildren may be able to grow grapes at 10,000ft if warming continues.
But its also a perfectly valid opinion, based on snowfalls and glacier responses over the last 20yrs that at some point in the next 20-30yrs the eastern glaciers will show an advance to some degree or the other. But there are 100 different outcomes possible as well. Time as you say will tell.

Talking about never letting facts stand in the way of a good story, Campbell Live the other night - 'Antartica melting, penguins dying'. Interesting story, but Campbell would have earnt far more credit if he'd covered all sides to that story. Antartica sea ice reached the largest extent this year since measurements began, and as of the end of Nov it was still the size it was in June 07. Sure, its shrinking around the Antarctic Peninsula but the picture is far more complex than the media presents.
Climate is what you expect. Weather is what you get.
dogmelon
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Re: Glacier loss

Unread post by dogmelon »

I'm enjoying the warm weather, long may it continue so boo hoo to the glaciers.
Weathermad
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Re: Glacier loss

Unread post by Weathermad »

So many different aspects to the glacier discussion

Recently I had a chat with a mountaineer who has been climbing for 40 years over the S.I. glacial region and he said the thickess and width of the glaciers are more obvious now than ever before and he wasn't sure what all the fuss is about. His fellow climbers have spoken similarly.

I suppose it's difficult to make generalisations but yet again there seem to be two very different viewpoints on the matter
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sthguy
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Re: Glacier loss

Unread post by sthguy »

40 years over the S.I. glacial region and he said the thickess and width of the glaciers are more obvious now than ever before
A top older mountain guide at Mt Cook whose name escapes me? has opposite recollections {was interviewed on tele a few months back}
At the time I was thinking his points didn't seemed to match the increased snowfalls and ice accumulations over the last 20yrs....but the piece was about the crumbling and retreating eastern glacier snouts.
Of course there are always some people whom beleive things have 'changed' from the 'old days' irrespective of any evidence to the contrary. This is especially true of weather, where older people always claim the summers were 'hotter and drier' in their youth.

Southern sea ice anomolies...

http://arctic.atmos.uiuc.edu/cryosphere ... .south.jpg
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southernthrash
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Re: Glacier loss

Unread post by southernthrash »

It really annoys me the way there seems to be an "old guard" on this board, who dismiss anyone with an argument against their own. How does a forum function without discussion and differing opinion. RWood, you really need to be a bit more accepting when presented with conflicting information, you are rather dismissive.

Mountaineers in the Mt Cook region (and the Southern Alsp in General) have all been talking very excitedly about how this spring has been the best climbing in a along long time due to increases in snow and ice volume.

Another point RWood - and why I'm not a fan of Salingers discussion on the topic - he accepts that snowlines and the border between ablation and accumulation have remained static, but gets in a panic over the retreat of the snout (which is significant, but can't be considered in isolation, and I hope some of the FACTS presented here have opened your eyes a bit), but I personally would not be terribly worried until the snowline and accumulation/ablation boundary sees a rapid retreat.

I wish Gary were here so he could cry too.

Mt Cook climbing conditions:
http://www.stuff.co.nz/4269939a6010.html
RWood
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Re: Glacier loss

Unread post by RWood »

Refer to my original post - stating that I didn't want to get into arguments. If you want to chew the fat with Salinger et al, get in touch with him/them. The "glacier issue" is not one of huge personal concern to me, I merely gave the link as a reference to those interested.
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sthguy
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Re: Glacier loss

Unread post by sthguy »

From Stuff '...Alpine Recreation owner Gottlieb Braun-Elwert...'
Thats the guy. Thought he must have only been guiding on the crumbling faces of the lower Tasman. :)

Salinger Aug 2005
New Zealand glaciers continue to recover
......Glaciers in New Zealand’s Southern Alps gained ice mass again in the past year. Fifty glaciers are monitored annually by the National Institute of Water & Atmospheric Research (NIWA).....
"Over the last three years, the glaciers have gained in mass, halting the declines seen between 1998 and 2002. This past year was the seventh largest gain since we started aerial surveys in 1977," said Dr Salinger. "Since 1977 overall for the Southern Alps there has been little change in size of the glaciers...[/b]

Salinger Nov 2007
New Zealand glaciers shrinking
New Zealand’s glaciers are shrinking and twelve of the largest glaciers in the Southern Alps are unlikely to return to their earlier lengths without extraordinary cooling of the climate......the volume of ice in the Southern Alps has reduced by about 5.8 cubic kilometres, or almost 11%, in the past 30 years. More than 90% of this loss is from 12 of the largest glaciers in response to rising temperatures over the 20th century......The iconic Franz Josef glacier is still much shorter now than in 1900,” says Dr Salinger. “Franz Josef glacier retreated about 400 metres from 2000–2005, then advanced 170 metres to 2007, but this recent gain does not compensate for the large overall losses seen over the past century {My italics}

The problem I have with his Nov presser is not the facts presented, rather that he downplays the quite extraordinary advance and thickening of the western glaciers and has gone to some effort to do so. In fact he omits to mention the total advance in the last 20 odd years, instead selectively refers to a 400m retreat followed by a lesser advance. That is classic cherry picking

And when stating this this loss is from 12 of the largest glaciers in response to rising temperatures over the 20th century he doesn't state the fact that reduced precipitation amounts must have some influence as well. He can't argue that precip is a factor for the advances depsite temperature rises yet discard the possiblilty of lower precip preceeding retreats.

It's complex of course and doesn't suit the media frenzy for sensationalism.
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NZstorm
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Re: Glacier loss

Unread post by NZstorm »

Another way of looking at this is to look at temperature data from the West Coast. I might have a look at the historical temp data when I get the chance just for my own interest . And if temperatures are higher then it follows that rainfall will be higher as well.
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NZstorm
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Re: Glacier loss

Unread post by NZstorm »

I had a look at the mean temps from Auckland Airport a few months back for the period 1970 to 2006.
If you remove from the data two extraordinary years, 1982 cold El Nino and 1998 warm La Nina, the temperature trend line was static, no change over that period. Just an observation here.
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Re: Glacier loss

Unread post by RWood »

That's simply consistent with NZ having been under the influence of an El Nino-favouring regime for most of that period (1977+). During that period, we have had less net warming than the planetary average, while Australia (which is slightly larger!) has had more.

I don't intend to answer the points made by others about glaciers without first getting some feedback from Jim Salinger.

Re Auckland airport - the NZ wide averages show the 4 warmest years as 1999, 1998, 1971 and 2005.
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NZstorm
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Re: Glacier loss

Unread post by NZstorm »

Yes, NZ hasn't had the warming that other parts of the world has experienced in recent decades. And I think NZ's temp rise occured mid 20th century before the 1970's. So if the Glaciers are receding I suspect we need to go back to mid last century to find the rise in temp behind the thaw.
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