Guest post by Tom Fuller
How glaciers have responded to the warming of the past 130 years is a complicated story, although many millions of words have been written to try and explain it.
How glaciers have been used to promote fears of a disastrous future is a much simpler story, but it really only gets told in skeptic weblogs. The story competes with a much easier tale, one that is told by the media strategists for environmental organisations and is repeated by politicians and others seeking temporary fame or permanent fortune through shaping our future to meet the challenges of climate change.
As a non-scientist, what I take from the many articles and papers I have read can be summarized as follows: Glaciers advance and retreat in response to a variety of forces, some mechanical, some climatic, some of each regular, some of each unusual. This has been going on as long as there has been ice. I realize that this is so vague as to be useless and vapid, but I want to start from a non-controversial position. It will probably start to get controversial with the next sentence, and will probably not stop after that.
It is my best understanding based on what I have read (and please feel free to correct errors or hints of bias), that at this point in time more glaciers are retreating than are growing, and probably by a significant percentage. However, some of those that are retreating actually began retreating before global warming started. So, many glaciers are retreating, many should be attributed to global warming, but there are many exceptions–it is by no means a universal phenomenon.
There has never been anything like a census, even using satellite photography over the past 30 years, although photographs of 100,000 glaciers are available at the National Snow and Ice Data Center. (I’d love to be proven wrong on that point, as continuous satellite coverage would be really useful.) The Assessment of The Status of The Development of The Standards For the Terrestrial Essential Climate Variables, published in 2009, references the inventory of the 100,000 glaciers, but draws no conclusions on overall status.
It is also my best understanding that those pushing the story of catastrophic global warming have used and misused glacier melt to advance their quest for political agreement to their preferred solutions. They started with the glacier at Kilmanjaro, prominently featured in Al Gore’s move An Inconvenient Truth. However, it turned out that Kilmanjaro’s glacier had been receding long before human contributions to global warming, and it sort of receded to the background.
But glaciers on a mountain make a pretty picture, and Kilmanjaro was replaced by Himalayan glaciers, which are just as pretty, and didn’t seem so controversial. The Intergovernmental Panel on Climate Change, in their 4th Assessment Report wrote, “Glaciers in the Himalaya are receding faster than in any other part of the world.
(see Table 10.9)
And, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate. Its total area will likely shrink from the present 500,000 to 100,000 km2 by the year 2035 (WWF, 2005).”
This finding was meat to a hungry press corps, and was featured prominently in print, on television and on the internet. But it was wrong, as most readers here already know. Worse, the head of the IPCC, Rajendra Pachauri, had been informed it was wrong years before.
But again, as with polar bears, Antarctic ice and pictures of flooded cities, the image and the fear it produced was too important to let go. I’m not speaking of the scientists, although the warmist weblogs keep accusing me of doing so. I’m speaking of slick media strategists working hard to keep an issue alive, donations coming in, lobbyists full of talking points and committee votes on tough issues like Cap and Trade. So although the IPCC finally admitted their report was in error, it still gets spun as a typographical error that doesn’t change the inevitability of glacial disappearance.
The warming we have experienced has caused many glaciers to lose mass–in a few cases, glaciers have disappeared entirely, or are likely to do so soon. But the issue is not as simple as the media have been spoon-fed to believe, at least not according to the articles I have read.
But complexity gets in the way of a scare story, and so the narrative must be simplified–and exaggerated.
As has been the case in each instance of symbols being hijacked for political purposes, a sober and compelling story could have been told. It would have had many qualifications, and would have probably ended with a call for further research and keeping a close eye on the situation. I honestly believe such a story would have resulted in more and more effective action than the sledgehammer horror story approach the activists took.
Thomas Fuller http://www.redbubble.com/people/hfuller
How glaciers have been used to promote fears of a disastrous future is a much simpler story, but it really only gets told in skeptic weblogs. The story competes with a much easier tale, one that is told by the media strategists for environmental organisations and is repeated by politicians and others seeking temporary fame or permanent fortune through shaping our future to meet the challenges of climate change.
As a non-scientist, what I take from the many articles and papers I have read can be summarized as follows: Glaciers advance and retreat in response to a variety of forces, some mechanical, some climatic, some of each regular, some of each unusual. This has been going on as long as there has been ice. I realize that this is so vague as to be useless and vapid, but I want to start from a non-controversial position. It will probably start to get controversial with the next sentence, and will probably not stop after that.
It is my best understanding based on what I have read (and please feel free to correct errors or hints of bias), that at this point in time more glaciers are retreating than are growing, and probably by a significant percentage. However, some of those that are retreating actually began retreating before global warming started. So, many glaciers are retreating, many should be attributed to global warming, but there are many exceptions–it is by no means a universal phenomenon. There has never been anything like a census, even using satellite photography over the past 30 years, although photographs of 100,000 glaciers are available at the National Snow and Ice Data Center. (I’d love to be proven wrong on that point, as continuous satellite coverage would be really useful.) The Assessment of The Status of The Development of The Standards For the Terrestrial Essential Climate Variables, published in 2009, references the inventory of the 100,000 glaciers, but draws no conclusions on overall status.
It is also my best understanding that those pushing the story of catastrophic global warming have used and misused glacier melt to advance their quest for political agreement to their preferred solutions. They started with the glacier at Kilmanjaro, prominently featured in Al Gore’s move An Inconvenient Truth. However, it turned out that Kilmanjaro’s glacier had been receding long before human contributions to global warming, and it sort of receded to the background.
But glaciers on a mountain make a pretty picture, and Kilmanjaro was replaced by Himalayan glaciers, which are just as pretty, and didn’t seem so controversial. The Intergovernmental Panel on Climate Change, in their 4th Assessment Report wrote, “Glaciers in the Himalaya are receding faster than in any other part of the world (see Table 10.9) and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate. Its total area will likely shrink from the present 500,000 to 100,000 km2 by the year 2035 (WWF, 2005).”
This finding was meat to a hungry press corps, and was featured prominently in print, on television and on the internet. But it was wrong, as most readers here already know. Worse, the head of the IPCC, Rajendra Pachauri, had been informed it was wrong years before.
But again, as with polar bears, Antarctic ice and pictures of flooded cities, the image and the fear it produced was too important to let go. I’m not speaking of the scientists, although the warmist weblogs keep accusing me of doing so. I’m speaking of slick media strategists working hard to keep an issue alive, donations coming in, lobbyists full of talking points and committee votes on tough issues like Cap and Trade. So although the IPCC finally admitted their report was in error, it still gets spun as a typographical error that doesn’t change the inevitability of glacial disappearance.
The warming we have experienced has caused many glaciers to lose mass–in a few cases, glaciers have disappeared entirely, or are likely to do so soon. But the issue is not as simple as the media have been spoon-fed to believe, at least not according to the articles I have read.
But complexity gets in the way of a scare story, and so the narrative must be simplified–and exaggerated.
As has been the case in each instance of symbols being hijacked for political purposes, a sober and compelling story could have been told. It would have had many qualifications, and would have probably ended with a call for further research and keeping a close eye on the situation. I honestly believe such a story would have resulted in more and more effective action than the sledgehammer horror story approach the activists took.
Thomas Fuller href=”http://www.redbubble.com/people/hfuller
This may upset some people, but let me explain some things about glaciers. We have had melting glaciers since the last Mini-Ice age.
We have had consistent sunspot activity for the last 310 years. 2 cycles tend to be weak and 7 cycles tend to be strong.
There is nothing to prove arguing over glacier melt. We are in the hottest period of global warming in 310 years.
Details: As we travel north up the USA west coast, we can begin to see mountain top glaciers above the Canadian border. As we travel on north to Juneau, Alaska, the ice field on top of the mountain has the Mendenhall Glacier reaching down to the valley.
There it now stops and recedes 60 feet a year. The Juneau Ice Field is still active and feeding the glacier. The glacier nearly reached the Juneau area during the Mini-Ice age.
The same is true farther north in Seward, Alaska. There, the East Glacier is still being fed, but the glacier is still receding 60 feet a year.
Now, in the Glacier Bay area and next to Skagway are some active glaciers, still reaching the water line, one coming 32 miles out of Canada. We are finishing the warmest period of global warming in 310 years.
Our average winter temperatures in the US hit 31.4. This is a 6 degree downward trend since 2000. We are in a 30 year cooling period.
We are in the slow descent into something no nation has experienced in modern times. Where can we look for glacier growth?
First we will find that at higher latitudes and higher altitudes first. Glacier Bay had some growth in 1967 and 2002.
There was slight growth recorded in the Alps. There is evidence of mountaintop glaciers that would have required an ice sheet glacier foundation thousands of feet below at the ocean’s water line.
One thing to add. We came out of the last Ice Age rapidly in a 10,000 year period.
And that began 20,000 or more years ago. In the last 10,000 years, known as the inter-glacial period, there has been 3 cooling periods.
We know of the Mini-Ice the most. There was another period about 2500 years ago that chased tribes men out of Glacier Bay.
They settled at Hoonah, Alaska. Somewhere in front of us is a 10,000 year slide to the next preliminary states of the next ice age.
Our axis is at about 23.66 degrees. As the Axis becomes more upright at about 22.5 degrees over the next 7,000 years and the earth moves away from the Sun in its slightly elliptical orbit, things will be drastically colder.
Going back a week or two, when we speak of the Northern polar ice cap, we are dealing with a different set of variables than the southern Polar Region. The North Pole is ground Zero. There is not much elevation, but highest latitudes.
From here, glacier activity grows to Highest elevations at lowest latitude possible. We are probably past the last peak global warming period for this inter glacial ice age.
Why? We have herds of deer in Alaska that are biologically changing.
The Bucks are taking on female characteristics and their male parts are disappearing inside of themselves. This is a defense measure and a cold measure.
The bucks travel in the group of six does. The lead doe is out in front and the buck and others follow in line.
Wolf Packs protection is my thought. Also, as biology has it, cold testicles reduces production of sperm.
Now, the testicles have moved inside the body for more warmth. An observer would have to ask,”Just how freaking cold is it going to get?”
Paul
Mike Roddy says:
September 12, 2010 at 10:05 am
“Scientific articles about disappearing glaciers are all about content, not style. Here’s one example: Glacier National Park in Montana now has 25 glaciers, compared to 150 in the 19th century. […]”
So educate me, Mr. Roddy. Was it buffalo toots or SUVs that caused the retreats in the 1800s?
In Patagonia there are is a glacier named Upsala that had retreated since 1928 several hundred meters, and is Greenpeace’s proof of glaciar melting due to global warming. You can see the pictures in an article I wrote several years back (in Spanish, but the pictures are worth thousand words).
http://www.medioambiente.gov.ar/noticias/medios/2004/m_021104_01.htm
However studies made by glaciologists R. Naruse, P. Svarka and Y. Takeuchi, tell a quite different story. The study in English is at:
http://glacier.lowtem.hokudai.ac.jp/project/patagonia/patagonia.htm
“Thinning and retreat of Upsala glacier and an estimate of changes in annual ablation in Southern Patagonia.” They prove that Upsala glacier retreat has nothing to do with temperature but is related to changes in the bottom of the lake where the glacier ends its course.
Curiously, 50 km south of Upsala glacier is Perito Moreno glacier, world famous for its size and its beautiful spectacle of huge blocks of ice calving from its front and to the breaking of an ice bridge that used collapses every 4 years, during the month of March. Thousands of tourists all over the world come to watch the show.
But the Perito Moreno is advancing so fast that now it is breaking its bridge every two years, and the last time it broke the bridge was on July, in the midst of winter!
More, on the other side of the Andes Cordillera there is the fastest advancing glaier in the world: Pio XI, whose advance keeps glaciologists wondering why it advances so fast.
Big glaciers seem to be advancing fast, while small glaciers are stable or retreating.
Mr. Fuller,
The most true statement in the post was that you are a non-scientist.
Glaciers are not terribly confusing beasts. They mostly react to summer temperature and winter precipitation. Therefore in a warming climate
(which we are in fact warming and are in the warmest year on record as confirmed today by the The European Centre for Medium-Range Weather Forecasts (ECMWF)
http://www.ecmwf.int/publications/cms/get/ecmwfnews/263 )
one can expect to see that predominantly glaciers will be losing ice and that some in fact won`t be because of increased precipitation or because they recede into the shadows of cirque backwalls and so on. The best analysis present and available show that glaciers are retreating globally. There are some outliers but the absolute and utter majority are retreating and losing ice. Including the himilayas which is losing 40 Gt year (supplementary material Bamber et al 2010, The Cryosphere Discussions, New Paper)
The aforementioned bamber paper does a great job of quantifying the state of glaciers and ice sheets globally and would be a great resource for you mr. Fuller.
It is freely available. And before any other individuals here take pot shots, read the article first, afterall it is free. Bamber is a leading glaciologist and has essentially written the book on field measurement techniques so no discrediting commentary please…
Umm, Robert, forgive me but didn’t I say exactly that in the beginning of this post?
Tom Fuller
Can I suggest you tackle another icon-that of the notion of ‘accurate global figures from…”
The idea that there can be such a thing as a meaningful global average sea level, surface temperature, sea surface temperature etc is nonsensical.
A global figure hides lots of sins, for example that there are many places still cooling in the world is cancelled out by the greater number of places that are warming. The idea that we have comprehensive enough records to go back hundreds of years and then parse those figures to fractions makes the climate industry appear much more scientific than it is. For example, our knowlege of historic Sea surface temperatures is extremely fragmentary at best, yet such organisations as CRU make money selling the data.
Tonyb
Robert, you stated:
Glaciers are not terribly confusing beasts. They mostly react to summer temperature and winter precipitation.
The following mark-up of an NSIDC image of a famous Greenland glacier suggests that there are many complex factors, the least of which is air temperature.
http://www.flickr.com/photos/26175880@N05/4753025383/
See also my earlier post: September 12, 2010 at 4:05 pm plus 4:14 pm
Any comments?
The mistake with the glacier timing was due to taking over a typo in a secondary source without checking the primary source (which is of course very bad housekeeping), in a regional chapter of wg2 (read by hardly anyone; in wg1 the glacier situation was assessed correctly).
See also
http://ourchangingclimate.wordpress.com/2010/01/28/glaciers-are-retreating-but-wont-be-gone-in-2035/
Based on surveying lots of glaciers, some 95% of them seem to be retreating.
@Fuller
Since this is a science blog and the tradition in science is to provide references instead of waving of hands saying “based on what I have read” which means nothing as it might include reading twitters from 10 year olds might I suggest you provide references? I’ll demonstrate how that works.
From what *I* have read the Little Ice Age lasted several hundred years and didn’t end until around 1800 which is, probably by design, the approximate date when your graph of one particular retreating shrinking glacier begins. Do you know how to spell “cherry picking”?
http://en.wikipedia.org/wiki/Little_Ice_Age
It’s worse than you thought. As far as we can determine over the last 10,000 years of the Holocene interglacial period the maximum extent of glaciers occurred just about 200 years ago at the end of the Little Ice Age.
http://maps.grida.no/go/graphic/overview-on-glacier-changes-since-the-end-of-the-little-ice-age
It appears reasonable to me quite reasonable that most glaciers would be in retreat in the 19th and 20th centuries given that they grew like banshees during the coldest epsode in the last 10,000 years which lasted from the 14th through the 18th centuries.
So what’s your point?
Colonial says:
September 12, 2010 at 3:34 pm
“Most importantly, don’t ask Tom to leave. He’s an invited guest, providing an invaluable service to Anthony.”
Quite right. Even the best rodeos have paid people dressed as clowns running around to fill the gaps in time between the serious competitive events.
“should be blamed on global warming”. Nothing, really nothing at all should be blamed on “global warming” because it is such an ill defined meaningless concept that any causal attribution is ridiculous. And when combined with the statement that some glaciers are expanding and other glaciers are retreating, it becomes hilarious. Moreover, the term “blamed” suggests that it is an evil development, glaciers retreating whereas I tend to believe we should get really worried once they start showing continuous growth. As said time and time again on this blog, attributing any isolated weather or regional or local geological phenomenon on antropogenic greenhouse gas is pretty daring (read wrong) and almost certainly not supported by convincing scientific evidence.
Glaciers as much as climate are fascinating puzzles, lets enjoy the puzzling and not force the non fitting pieces in place because we get impatient.
By the way, the “typo” excuse to cover the scam on the 2035 Himlayan glacier melt myth is a shameless act of PR driven contempt of integrity to cover up the equally shameless inclusion of an uneducated traveler’s concerns which unfortunately has been bought by the press.
Dave Springer says:
September 13, 2010 at 6:43 am
There is even a plot :
http://www.oism.org/pproject/Slides/Presentation/Slide2.png
Any mountain glacier that exists below the freeze line will most likely melt away. I always want to know what is the altitude of the mountain glacier so I can check what the temperature is at its location using the lapse rate formula. Most of the time mountain (Himalayian) glacier stories never give that information.
Robert September 12, 2010 at 9:30 pm states: “Including the himilayas which is losing 40 Gt year (supplementary material Bamber et al 2010, The Cryosphere Discussions, New Paper)”
I’ve got to confess that I’m confused by this statement. You cite “Bamber et al 2010”
(sic).
“et al.” is an abbreviation for et alia which means “and others” and is used when there are more than one other author beside the primary author. The only apparently similar paper I could find was Bamber and Riva 2010 at The Cryosphere Discussions. Was this what you meant? If so, it should not be cited as Bamber et al. 2010.
Assuming this is the paper you mean, their supplementary material indicates that glaciers in the Himalayas and Karakorum together are losing ~40GT/yr, which differs from what you wrote.
If you are going to chide someone, it would behoove you to be as factually correct and precise as possible.
Excuse me, yes I did mean Bamber and Riva 2010 but I forgot the name of the second author, therefore my claims are invalidated correct? Those who nitpick things like that really can’t nitpick the science.
I said the himilayas were losing 40 gt a year and so did you? I don’t understand your point? Is it because i didn’t clearly state himalayas and karakorum? Sorry, I assumed I didn’t have to specify the exact range.
So once again, you nitpick the way I word my answer but cannot refute the science behind it. Just so we are clear.
Bob_FJ says:
September 13, 2010 at 1:04 am ,
I generalized regarding glaciers. If we are talking about ice sheet dynamics and how outlet glaciers from ice sheets react to different perturbations, you can read my substantive post here.
http://www.skepticalscience.com/Part-One-Why-do-glaciers-lose-ice.html
Generally when people make discussions about glaciers, receding and melting away we are referring to land based or mountain glaciers. Ice sheets and ice caps have much more varied dynamics. But in general once again, Glaciers are extremely dependent on summer air temperatures and winter precipitation (Benn & Evans, 2010, Glaciers and Glaciation).
Tom, I am not in full dispute over what you wrote. Nor do I think that there is anything too wrong with it. I just find it a little disingenuous to make the following statement
“It is my best understanding based on what I have read (and please feel free to correct errors or hints of bias), that at this point in time more glaciers are retreating than are growing, and probably by a significant percentage.”
When it is so clear and unequivocal that 95% of the world’s glaciers are retreating. I think that 95:5 is more than just a significant percentage… Especially when those that were advancing such as in parts of southern norway where I studied only gained ice for a while because of increased precipitation associated with warming at high altitudes (Nesje et al. 2008).
Overall, no I don’t think that this post misconstrued the science really, but I felt it would be useful to post and particularly show the recent study which helps to symbolize how unequivocal the retreat is. I know it can be hard to make statements like the aforementioned ones here at this website because there are a lot of individuals who would sense that as being an AGW type remark… but it seems these days that reality tends to have an AGW bias…
Bob_FJ says:
September 13, 2010 at 1:04 am ,
I read your other comment and like I said, if you read the following series of posts:
[SNIP]
[SNIP]
[SNIP]
You will likely have a greater understanding of the issues at play in outlet glaciers particularly with respect to ice sheets. It is not a plug for another website but rather what I consider to be a useful resource for inquiring minds…
[Reply: It certainly is a plug for your blog when you repeatedly link to it, as you did three times in this comment, and in previous comments, and in your screen name. Your blog is listed in the WUWT sidebar, but it does not return the courtesy. Please stop using WUWT as a vehicle to boost your blog’s traffic, and simply say what you want to say here, in your own words. Links to peer reviewed papers, charts and graphs are fine. ~dbs, mod.]
latitude says:
September 12, 2010 at 7:25 am
Would we really want to live in a period of time where glaciers were growing?
Yes, but only long enough to get the AGW types to understand that climate and ice are cyclical. The only catch would be their flip to CO2 = cooling mode.
[Reply: It certainly is a plug for your blog when you repeatedly link to it, as you did three times in this comment, and in previous comments, and in your screen name. Your blog is listed in the WUWT sidebar, but it does not return the courtesy. Please stop using WUWT as a vehicle to boost your blog’s traffic, and simply say what you want to say here, in your own words. Links to peer reviewed papers, charts and graphs are fine. ~dbs, mod.]
It is not my blog it is John Cook’s Blog. Referring to specific articles that I wrote because they have substantive information is not the same as plugging the blog over there. I included all three because they build off of each other. Part 1-3. Unfortunately Skeptical Science is not always as organized as we would sometimes like so if I said to the individual to go find my articles where i discuss this over at skeptical science then they might have difficulty in actually finding the articles. I was not trying to increase traffic over there, just trying to specify exactly where to find the information I was referencing. Sure I could be specific and cite papers and books from which I drew my analysis but frankly a list of 20 papers won’t help anyone to better understand ice dynamics. Sure I could summarize in my own words but frankly I have done so many times here and so excuse me if I just find it easier to refer to a specific article. I just don’t really appreciate the accusation that i’m trying to increase traffic over there, if there is a resource which discusses the issues at hand, how does it matter which blog it comes from?
Mr. Fuller,
You’re not a scientist? Well, slap my side and pick up my jaw.
Let’s see, Is Al Gore? Don’t know, but he has a lot of followers and a lot of them are scientists. How can that be?
I was on a cruise through Alaska. I came away impressed that to be a national park ranger, one had to worship Gore and Obama. And they had to science or history degrees to get a job.
Was Newton a scientist? Hmmm! Nope!
Was Einstein a Scientist? Not at first.
According to Edward Blair Bolles, who authored the “Ice Finders”, the first people to discover and study the last Ice age were a Poet, a professor and a politician and I add a Barron.
I along with others discovered relationships between sunspot activity and Accumulated cyclone energy, temperatures, number of hurricanes, glacier melt and precipitation and my work is at nationalforestlawblog.com Oct. Newsletter under my name and I’m a golfer.
Can you imagine that?
A golfer knows more about climate change than any given number of people at the FEDEX Cup.
The bulk of new stars and such discoveries are by amateurs.
Mr. Fuller, your in good company. You may not want to be called a scientist. That sounds so derogatory.
Most sincerely,
Paul Pierett
Robert Reur September 13, 2010 at 12:21 pm and 12:32 pm
I presented an NSIDC image of the Jakobshavn glacier, which was iconic a few years ago when it was trumpeted as being the fastest retreating glacier in the world. However, the overall retreat rate over the past ~160 years has been EXTREMELY erratic, and it then slowed down in the latter years to the end of data shown up to 2006. One would wonder, what with the alarm expressed over recently diminishing Arctic sea-ice, why this would be the case, and why it is easy make sweeping statements about glaciers. Here it is again:
http://www.flickr.com/photos/26175880@N05/4753025383/
When I asked for: “Any comments?”
I was referring SPECIFICALLY to that image, AND in the context of my September 13, 2010 at 1:04 am which opened with:
Robert, you stated:
Glaciers are not terribly confusing beasts. They mostly react to summer temperature and winter precipitation.
Please read my earlier comments, and respond to the points therein
BTW, I no longer go to the website that you recommend.
To Bob FJ,
In the entry above yours, I posted a web site of my work.
In the numerous pages are 30 some charts and as I mentioned somewhere above:
Glacier Bay glaciers melted at half the rate during the period of the early party of the 1900s when sunspot activity was low as compared to the period when sunspot activity nearly doubled. During that latter period, glaciers melted nearly twice as fast as the early part of the century.
Paul
Here is a scientific presentation re: effects of global warming on the Pacific Walrus:
http://www.regulations.gov/search/Regs/home.html#documentDetail?R=0900006480b4b89a
For those who care about wildlife and species preservation (which should be all of us), a good read.
Robert says:
September 13, 2010 at 12:21 pm
Bob_FJ says:
September 13, 2010 at 1:04 am ,
I generalized regarding glaciers. If we are talking about ice sheet dynamics and how outlet glaciers from ice sheets react to different perturbations, you can read my substantive post here.
http://www.skepticalscience.com/Part-One-Why-do-glaciers-lose-ice.html
Generally when people make discussions about glaciers, receding and melting away we are referring to land based or mountain glaciers. Ice sheets and ice caps have much more varied dynamics. But in general once again, Glaciers are extremely dependent on summer air temperatures and winter precipitation (Benn & Evans, 2010, Glaciers and Glaciation).
—…—…
OK.
(1) There (might be! – since data is “corrected” by NASA-GISS) a maximum 1/2 of one degree change in global temperatures since 1970 that (might be) attributable to Mann-made global warming.
Any increase in temperature (and therefore theoretical glacier change-in-length) before that period cannot be due to CO2. Therefore, any change in glacier length before 1970 shows that glacier length – anywhere in the world – DISPROVES your CAGW theory. Your job? Show that this conclusion is false with data.
(2) Any (theoretical) change-in-glacier-length due to atmospheric summer-time temperature changes (caused by CO2 and not natural variations – which the CAGW theory prohibits) MUST therefore be proportional to global average temperatures. (This is because CAGW zealots use retreating glaciers to “prove” CAGW, therefore glacier length MUST be proportional to air temperatures.)
Therefore, please provide the names and data of glaciers that have BEGUN retreating in 1970, and whose retreat is consistent with global air (summertime) temperatures between 1970 and 1998, and whose length has steadied (not changed!) since 1998 – since global air temperatures have not increased since 1998. Also: Note that global air temperatures retreated (got cooler) between 1940 and 1970. Therefore, your data must show a corresponding increase in glacier length/stop of glacier retreat between these dates. If you cannot plot these relationships, your theory -though a nice high-school generality – is dead wrong.
(3) Also. From first principles of heat transfer, mass flow rate, heat transfer coefficient of air to the glacier front, and the specific size of the theoretical glacier frontal area, derive the coefficient of glacier length to air temperature.
Prove that the 1/2 of one degree change in average air temperature measured since 1970 is enough to melt ANY length of ANY glacier.