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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Are glaciers growing or retreating?

What the science says...

Select a level... Basic Intermediate

Most glaciers are retreating, posing a serious problem for millions who rely on glaciers for water.

Climate Myth...

Glaciers are growing

“[R]eports are coming in from all over the world: for the first time in over 250 years, glaciers in Alaska, Canada, New Zealand, Greenland, and now Norway are growing.”(JamulBlog)

At a glance

Glaciers are wonderful things, as any high mountain-climber will agree. Trekking up a glacier at sunrise to reach the start of a climb is one of the truly awesome experiences in mountaineering. They also act as vast cold-storage facilities, capturing and holding winter snowfall. People, animals and crops in the valleys below benefit from this meltwater supply when the warmer season arrives. That makes them really important. So let's take a look at what makes glaciers tick.

Glaciers form when perennial snow-cover starts building up, year upon year. Freeze-thaw cycles and compaction gradually turn the accumulated snow into glacial ice. The process takes years and for the glacier to survive, conditions need to remain cold, with a continual ample supply of new snow, year in year out, over the decades.

Because a glacier is a slow-moving river of ice with its motion driven by gravity, it will typically exhibit a distinctive set of physical features. There will be the break-line along which it pulls away from its headwall. This is marked by a system of large crevasses that divide the moving ice below from the static ice above.

Crevasses also form in the moving part of the glacier where the ice undergoes flexure and splits. Such features are commonest where a glacier is flowing over uneven ground or is rounding a bend. Where a glacier encounters a major steepening in its downhill course, it will break up into a chaotic system of unstable, crevasse-bounded blocks known as an ice-fall.

For a glacier to be stable, snowfall needs to be in balance with 'ablation'. Ablation is the term that covers the ways in which a glacier loses its snow and ice. If the glacier is going to endure, snow gain clearly has to be at least equal to ablation. Forms of ablation include surface melt, meltwater run-off, strong winds blasting snow away, sublimation (solid to vapour direct transition) and avalanches. In addition, ablation can also occur within and beneath a glacier. When meltwater is running along beneath the ice, it acts as a lubricant, so the glacier's flow may suddenly speed up, or surge, as it's called.

With any glacier, its status in terms of whether it is gaining or losing mass is termed its 'mass balance'. Mass balance is a mathematical expression of whether a glacier is retreating or advancing. It is based on various careful and long established measurement techniques, Unfortunately, mass balance measurements tell us that a very high percentage of Earth's mountain glaciers are in retreat. It is wrong to single out the few glaciers that are growing in the face of the overall trend of steep decline, in order to argue there is no global warming. It's the scientific sin of cherry-picking.

Please use this form to provide feedback about this new "At a glance" section, which was updated on May 27, 2023 to improve its readability. Read a more technical version below or dig deeper via the tabs above!

Further details

Compared to the great ice sheets of Antarctica and Greenland, mountain glaciers make up a small fraction of global ice volume. The figure is less than 1%: if they all vanished the resulting amount of global sea level rise would be around 0.32 metres. Of much greater importance is their role as freshwater storage reservoirs and their potential loss represents a serious threat to countries where this water supply is regarded as vital.

Glaciers occur in the higher mountain ranges worldwide and at lower altitudes in the higher latitudes, meaning they exist within a range of climatic conditions. The processes that determine their behaviour over time are recorded on an ongoing basis, both on the ground and remotely via satellites and as our understanding of such things improves, we are able to model that behaviour with greater and greater accuracy.

Mass balance of glaciers is measured through a variety of techniques. Direct glaciological methods include deployment of ablation stakes, graduated rods inserted several metres into an augered hole in the ice. The distance from the top of the stake to the surface of the ice is recorded and then the site is revisited at regular intervals for repeat measurements to see how much ablation has occurred. In the accumulation zone, above the Equilibrium Line Altitude, snow pits and snow probing are utilised to find out the amount of accumulation in a similar, regular manner.

To figure out the mass balance of a glacier, regularly-spaced traverse lines, with regular-spaced stakes or pits, are set out across its width. These data are then combined with independent geodetic surveys, using tools like the satellite-based Global Positioning System – GPS – and is collated and published by the World Glacier Monitoring Service (WGMS).

Monitoring glaciers has a long pedigree. Collection of data about ongoing glacier changes began in 1894, with the foundation of the International Glacier Commission at the 6th International Geological Congress in Zurich, Switzerland. Back then, the focus was on the idea that long-term glacier observations would give insight into processes of climatic change, but of a different kind - the formation of ice ages. As can be imagined, the goals of international glacier monitoring have since evolved and expanded.

The WGMS took over the curation of such data - standardised observations on changes in mass, volume, area and length of glaciers with time - in 1986. Within the data, it is not surprising that the highest information density is with regard to the Alps and Scandinavia, easily accessible to Europeans for over a century so that long and uninterrupted records are available. But in more recent decades, data coverage has spread around the world, so that the highest quality glacier observations are ongoing, continuous and long term.

Today, the WGMS is pushing towards reaching global coverage from space-borne geodetic surveys. These geodetic observations can provide geodetic mass changes over decadal to multi-annual time periods but are hampered at shorter time scales by the required density conversion. The glaciological method is able to fill this gap by providing mass-balance observations with annual or seasonal resolution.There are 30 glaciers in 9 different mountain ranges that have seen special attention, having been continuously measured since at least 1950 and are considered 'reference glaciers'. Figure 1 shows the annual mass change of reference glaciers monitored since 1950.

Global annual mass change of reference glaciers

Figure 1: Annual mass balance of reference glaciers with more than 30 years of ongoing glaciological measurements. Annual mass change values are given on the y-axis in the unit meter water equivalent (m w.e.) which corresponds to tonnes per square meter (1,000 kg m-2). Source: WGMS (2021, updated and earlier reports).

As a consequence of all this work, the answer to, “are glaciers growing or retreating?” is not only clear but definitive and based on the scientific literature. Globally, glaciers are losing ice at a rapid rate (fig.1). There are still situations in which glaciers advance: these are confined to parts of the world with high enough precipitation to keep accumulation in a predominant position over ablation. In these cases, the advances may continue where warming leads to increases in precipitation and therefore glacier ice accumulation, such as displayed in part of southwestern Norway during the 1990s (Nesje et al. 2008). The long term trend though is that most mountain glaciers are shrinking worldwide (figure 2).

Global mass balance

Figure 2: Global averages of observed mass balances from 1930 to 2019. Cumulative annual averages are relative to 1960. Geodetic balances were calculated assuming a glacier-wide average density of 850 kg m-3. Graph adapted from WGMS Global Glacier Change Bulletin, No. 4, 2021, available here (PDF, 36 Mb).

Through such detailed work, it is now possible to estimate glacial retreat for almost all of them worldwide. Since 2000, glacier retreat was the predominant pattern in the Southern Andes, New Zealand, Alaska, Central Europe, and Iceland. By 1990, glaciers had already lost 7 to 28% of their 1901 mass and the decade 2010-2019 saw the highest recorded glacier mass loss since the beginning of observations. The amount? Some 267 billion tonnes per annum (Hugonet et al. 2021). There are even signs of ice-loss starting to take over in some ranges where, up to now, the glaciers were holding their own, such as the Karakoram (Hugonnet et al. 2021 op cit).

Changes in glacier properties are in most cases predominantly caused by variations in both temperature and snowfall, since without sufficient snow they cannot gain mass and ablation takes control of the situation. That looks to be the case for the years to come, even if we curb our emissions enough to stabilise temperatures: there's a time lag between temperature rise and glacier response, so that there are decades of retreat baked-in under any emissions pathways.

Like other climate topics, changes to glaciers are best examined in a global and multidecadal manner. Misinformers have sought to spread confusion here with one of their favourite techniques - cherry-picking from the much smaller number of individual glaciers that are advancing – in other words ignoring those long-term trends. Diversions such as these do not address the most important question here: what is the real state of glaciers globally?

Last updated on 18 June 2023 by John Mason. View Archives

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Further viewing

Time lapse photography of shrinking glaciers:

Myth Deconstruction

Related resource: Myth Deconstruction as animated GIF

MD Glacier

Please check the related blog post for background information about this graphics resource.

Denial101x video

Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial


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Comments 1 to 25 out of 49:

  1. John This is a strange claim: Global warming causing California glacier to grow (Wednesday, July 9, 2008) "the seven glaciers on Shasta, part of the Cascade mountains in northern California, seem to be benefiting from the warming ocean"
  2. Can the list of increasing glaciers be subdivided, by explanations, in a meaningful way? I. WARMER POLAR SEAS GW EXPLANATION The increased snowfall in central Greenland and Antarctica is due to the increased evaporation from the warmer polar seas around them. Could this same reason apply to western Norway (Briksdal Glacier) and the west coast of South New Zealand (Franz Josef Glacier, Fox Glacier)? "But Salinger said New Zealand glaciers were boosted by extremely high rainfall, with more than 10m a year falling west of the Southern Alps' main divide. "Most glaciers, except for some in parts of Norway, were in areas of lower rainfall and were affected more quickly by rising temperatures." Taipei Times And PIO XI Glacier(Chile) , and Perito Moreno Glacier(Argentina), are even further south... Iam making my argument despite the following article...which goes into greater detail. I am referring to the higher temperatures after several decades of GW. And simply extending the analogy: IF warmer seas lead to increased snowfall on Greenland and Antarctica, THEN... "RECENT GLACIER ADVANCES IN NORWAY AND NEW ZEALAND... "Norway and New Zealand both experienced recent advances, commencing in the early 1980's and ceasing around 2000, which were more extensive than any other since the end of the Little Ice Age. Common to both countries, the positive glacier balances are associated with an increase in the strength of westerly atmospheric circulation which brought increased precipitation..." Norway=f(North Atlantic Oscillation) New Zealand=f(Interdecadal Pacific Oscillation, El Nino/Southern Oscillation) II. MISCELLANEOUS GW EXPLANATIONS The Karakorum Mountains are mentioned above. ???Alaska's increasing coastal glaciers??? "...Hubbard Glacier is the largest of eight calving glaciers in Alaska that are currently increasing in total mass and advancing. All of these glaciers calve into the sea, are at the heads of long fiords, have undergone retreats during the last 1,000 years, calve over relatively shallow submarine moraines, and have unusually small ablation areas compared to their accumulation areas." "...were retreating throughout the Little Ice Age (AD1350 or 1450 to AD 1900) when most glaciers were growing." Jan 2003 Icy Bay glaciers, Alaska: "puzzled by the glaciers' advance because all three glaciers moved forward at the same time, possibly because of a high snowfall year in the upper reaches of the glaciers, or rainfall down low, that could lubricate the glacier's sliding surface, the bedrock beneath them." June, 2007 (January 2007 was the warmest globally, I believe, so the La Nina hasn't started yet.) Icy Bay is located near the Hubbard Glacier, on the Gulf of Alaska. Note that all eleven of these increasing glaciers are located on the coast. I couldn't find an Alaskan map locating its glaciers. But Google Earth suggests that the largest glaciers are on the coast, and behind it; in an arc around the Gulf of Alaska. Winter Land and Ocean Surface Temperature trend maps seem to indicate cooler water near the Gulf of Alaska, but warmer water way out in the north Pacific. NOAA Wind Direction vectors for January pass thru the warm Pacific area, and head toward this coast. Could the increasing Alaskan glaciers be attributed to Global Warming via the warmer waters in the north Pacific? III. OTHER (NON-GW) EXPLANATIONS Mount Shasta is mentioned above. The Mount Shasta explanation would also cover two small glaciers nearby in the Trinity Alps. "Since 1980, there has been an advance of more than 55% of the 625 mountain glaciers under observation by the World Glacier Monitoring Group in Zurich..." A skepticalscience listing on this page, it is from a 2007-12-23 dated website. Obviously, '1980' seems pretty irrelevant. And,from the table above, 7% are increasing. "Crater Glacier" is inside the Mount St. Helens crater. "Shadowed by the crater walls and fed by heavy snowfall and repeated snow avalanches, it grew rapidly..." This sounds like a special case, to me...a 'shadow' glacier. "In addition, since 2004, new glaciers have formed on the crater wall above Crater Glacier, feeding rock and ice onto its surface below." "Very high-elevation Mont Blanc glaciated areas not affected by the 20th century climate change..." "...the mass balance of the glaciers is strongly controlled by precipitation, not temperature." This list is from a skeptic website that, among many other things, lists articles about 'GROWING' glaciers. I have not included the more recent, post La Nina, situations.
  3. ........SKEPTIC SOURCES My focus above was on increasing glaciers that were referred to by skeptics. I got them from an endless skeptic bibliography...that's split up into a hundred subdivisions. index.php?showtopic=2050 GW skepticism being what it is, the counter argument was often also there, in the same article. In addition, there'd be some "google words", on which to continue. The other skeptic source I know about is also subdivided; and includes some text, with a literature review. A neophyte believer blogger's first source would likely be a skeptical argument website, like skeptical Is appinsys the first source for a neophyte skeptic blogger? It would be useful to know where the other blogger is getting his information. For example, I've always been amazed at skeptics' ability to produce weather related fatality statistics. When I've never seen any. Until... There's no hope for the cynical skeptic, who'll cherrypick anything anywhere. And the gullible skeptic can probably be reached only on his own entry level conspiracies. But I think the more open-minded ('skeptical') skeptic would eventually see through this disjointed collection of counter arguments...that don't add up to a realistic whole. Are there any other useful skeptic sources?
  4. Another collective datapoint: Almost 90 percent of Austrian glaciers shrank in 2009, some by as much as 46 metres (150 feet), the Austrian Alpine Association (OeAV) said Friday. In a report, the OeAV said 85 out of 96 glaciers had shrunk over the past year. The biggest changes were seen in the Oetz valley in western Tyrol province, where three glaciers retreated by over 40 metres, and eight by over 20 metres. "The ice is very thin over large areas, so the glaciers are retreating very quickly," noted Andrea Fischer of the University of Innsbruck, who conducted the measurements for the alpine club. One glacier bucked the trend and expanded, but only by a few dozen centimetres. Temperatures were higher than average by about 0.2 degrees Celsius in the winter of 2008-2009 and by 2.1 degrees last summer, the OeAV noted. More: Almost all Austrian glaciers shrank in 2009
  5. I have seen this graph you posted abopve, but the data you reference cuts off in 2006. I have seen researching the web that the Western Himilyas, Argentine Mountains and most of N America Glaciers have shown growth and stopped what amounts to a 250 year trend in the last 3-4 years, can you verify? I don't want to trustingly believe everything that I read elsewhere, but your information does not deal with 2007, 2008, 2009 and 2010. The Arctic Ive has certainly recovered in area and thickness since 2007, but it is not talked about?
  6. Dave, I've not read of the sort of broad glacier recovery you're speaking of. There are in fact a few glaciers currently in a state of growth thanks apparently to variations in snowfall but the vast majority continue to retreat. Perhaps you could cite where you read of regional increases? As to the Arctic, if you look at the record you'll see many instances where an observer focused on a 2 or 3 year span might think a recovery was beginning, but those little bumps are overwhelmed by a steady downward trend.
  7. Dave D: Unfortunately there's not a "real-time" glacier observing system, so we'll have to wait for 2009-2010 data to be made available. But the WGMS website does have updated information on glacier mass balance through 2007-2008: Overall, mass balance of the observed glaciers continues to be negative, but the loss of mass in 2007 and 2008 was less than in 2003 or 2006. I'm not sure what you mean by "The Arctic [Ice] has certainly recovered in area and thickness since 2007, but it is not talked about?" Are you referring to sea ice? The 2008 and 2009 minumum Arctic sea ice extent was above 2007, but still below the long-term downward trend (and far below the levels of the 1980s). I wouldn't call that a "recovery" unless it continues long enough that late-summer sea ice extent actually returns to normal. As for Arctic sea ice thickness, it clearly has not shown any sign of recovery; instead, it continues its downward trend:
  8. Dr. Tim Ball was interviewed by Kim Greenhouse on her program on Dec. 10, 2010. He said world glacier ice mass is currently growing, and he talked about the contribution undersea vulcanism is making to oceanic warming. Can you address these issues?
  9. rockpicker - As addressed on this topic with multiple papers and lots of data, glaciers are not growing. There's also no indication that the level of undersea volcanism has changed in the last 100 years or so - and geothermal inputs are on the order of ~1% those of greenhouse gas effects. So changes in undersea volcanism isn't driving oceanic warming. Dr. Tim Ball is not what I would call a reliable source - he chairs the Natural Resources Stewardship Project, which is apparently run by energy industry lobbyists, as well as being one of the best known members of the Friends of Science group. He's a well known climate change skeptic with ties to industrial groups. I'll also point out that a show which " a broadcast vehicle for introducing new and ancient knowledge, solutions, discoveries, and compelling stories" doesn't sound like a great scientific forum - it sounds like something closer to "Ripleys Believe It Or Not!".
  10. rockpicker - "Dr. Tim Ball.....He said world glacier ice mass is currently growing" The World Glacier Monitoring Service say otherwise: Given that the last decade is the warmest in the instrumental record and 2010 the warmest year in that decade, Tim Ball's assertion seemed unlikely from the get-go. Does make you wonder why he would make such an erroneous claim, when it's so easy to check its' veracity.
  11. I checked the WGMS and their data is from 100 monitored glaciers. Since there are over 100,000 glaciers world wide this can lead to an entierely new discussion on how or why these were chosen. Trying to figure out the science of climate is still in its infancy and so many things are based on simulations that are based on limited data and potentially flawed assumptions that what impact an additional 100 - 200 ppm of CO2 is doing to the world is truly just a guess for now. When short term climate models(3-5 year) are consistently correct then we can start looking at longer term modeling systems. I don't doubt we need to be better shepards of our planet, but the only way to not impact the planet is to not be on the planet and that is not going to happen (at least any time soon regardles of any zombie movies you may watch). An interesting fiction novel to read is by Michael Chrichton - STATE OF FEAR. He makes many interesting points on the science and politics of Global Warming and Climate Change. While it is fiction, he does add many true facts to the story line.
  12. Starnut: Yawn. You're going to trust Crichton but not climate science. Lovely. Don't you think it's odd that someone would write a novel trying to scare people about a project designed to scare people? Where did you get that "over 100,000 glaciers" number, btw? And you don't think that monitoring, say, 10 glaciers in 10 different areas of the world will give us useful data? Or you think that these particular glaciers in the WGMS have been carefully selected by scientists who are in on the hoax? Also, what's a "short-term climate model"? Climate is 30 years, according to climatologists. Finally, speaking of zombies, the science of climate is, by most measures, about 150 years old. The basic radiative physics of CO2 have been established for about that long as well. It's established science. The remaining questions we have are mainly about ocean heating and and cloud effects.
  13. Starnut, can you give a reference for the number of glaciers you state ? While doing that, please read the following study : International glacier monitoring has produced a range of unprecedented data compilations including some 36000 length change observations and roughly 3400 mass balance measurements for approximately 1800 and 230 glaciers, respectively. The observation series are drawn from around the globe; however, there is a strong bias towards the Northern Hemisphere and Europe. A first attempt to compile a world glacier inventory was made in the 1970s based mainly on aerial photographs and maps. It has resulted to date in a detailed inventory of more than 100000 glaciers covering an area of about 240000 km2 and in preliminary estimates, for the remaining ice cover of some 445000 km2 for the second half of the 20th century. This inventory task continues through the present day, based mainly on satellite images. WGMS. 2008. Global Glacier Changes: facts and figures. Zemp, M., Roer, I., Kääb, A., Hoelzle, M., Paul, F. and W. Haeberli (eds.), UNEP, World Glacier Monitoring Service, Zurich, Switzerland
  14. @Starnut, I suggest you read less airport literature and more actual science in order to form a valid opinion on climate science.
  15. Anyone left clinging to the glacier growing myth? Explain the emergence of ice mummies. The discovery of Mr. Pabón’s partially preserved remains was one of a growing number of finds pulled from the world’s glaciers and snow fields in recent years as warmer temperatures cause the ice and snow to melt, exposing their long-held secrets. ... “It looks like the warming trend seen in many regions is continuing,” said Gerald Holdsworth, a glaciologist at the Arctic Institute of North America in Calgary, Alberta. “There are still some large snowbanks left in promising places, and many glaciers of all different shapes, orientations and sizes, so the finds could go on for a long time yet.”
  16. Glaciers hold only 1% of the planet’s ice. Antarctica and Greenland hold the rest, with the greatest amount in glaciers being in the Himalayas. I don't know how Cogley weighed his data. That the vast majority of glacial volume is in the Himalayas and that soot is causing more melting there than warming ( provides additional pause. A map is here: So, a chart of a sampling of ice loss from glaciers world wide says very little about what to expect from what really matters: temperature or sea level rise. That we are in a temperature peak that I believe to be mostly natural makes loss of loss from tiny glaciers that lack thermal inertia in extremely cold locations in isolated climate zones does not impress me as much as the idea that world sea ice is starting to melt in an actually meaningful manner. That the IPCC claimed the Himalayas would melt by 2035 means that unless those who allowed such a claim to pass through their peer review process need to go or I have little trust in current claims of impending doom. Addendum: The 5x5 temperature grids around the Himalayas actually do show a hockey stick shapes, adding a whopping 2 degrees since 1990!: So no wonder glacial melt is surging. Local heating over the Himalayas. This has been suggested to be due to local land use changes as a sudden 2 degree jump certainly isn't due to a local spike in CO2. Can I find this warming in a map? Nope! Evidently it must be a very local effect then if it doesn't show up as a very large super red region above India: But boy oh boy look at the extreme *cooling* in Antarctica where 90% of world ice is contained!

    [DB] Nice Gish Gallop.  This thread is on 'Are glaciers growing or retreating?'; please stay on-topic to ensure your comments do not get deleted.

    For the casual reader, appinsys is well-known to be a site of active disinformation on matters related to climate and climate change.  The other graphics that Nik provides to further his narrative are of unknown provenance and should be regarded as questionable.

    A reliance on primary sources is best.

  17. NikFromNYC @16, I am unsure what point there is to your post other than to sow confusion. The topic of the main article above is the ongoing retreat of glaciers world wide, something you do not dispute. You do attribute the retreat of Himalayan glaciers to black carbon (soot) from the Indian industrialisation, and indeed that is probably a factor; but it is hard to dispute that they would continue melting in a warming world, even in the absence of black carbon. More importantly, the ongoing retreat of Andean, African, North American and New Zealand glaciers shows the primary cause of retreat is a global factor, specifically the rise in temperatures through the 20th century. You throw out a couple of of topic canards. First you suggest that Antarctica is cooling. In fact it is warming: The map on the left is from O'Donnell et al, a team closely associated with Climate Audit, and one of the very few pieces of actual science produced by people associated with Climate Audit. It is not without its problems, including a number of methodological choices that introduce a cooling bias to their study, but even so it shows a clearly warming Antarctica with some cooling regions. You also mention the IPCC's error with regard the Himalayan glaciers. The incorrect prediction of glacial melts was made by the IPCC Working Group 2, which looks at the impacts of global warming, not the science of global warming. It therefore is no reason to call into question the very high standard of the IPCC Working group 1 reports. What is more, it is just one error from among tens of thousands of factual claims across 3000 pages of the IPCC report. An error rate of less than 1 in 10,000 is no reason to doubt the general reliability of the IPCC. In contrast, many of the more highly touted denier documents struggle to keep their error rate down to 1 per sentence. Having said that, may I suggest you take comment about that error to the appropriate topic (which I suggest you read).
  18. NikFromNYC, you need to look at the story closer. As I recall, the 2035 claim was discussed on this site. The search engine works well. It turned out to be another molehill made into a mountain through the usual disingenuous methods. Tom addressed the Antarctic cooling canard. Overall, your post adds little that is of value for one seeking good information. Your claim that the Himalayan temperature increase is due to land use changes is not only unsubstantiated but unplausible considering how much is actually there to use and how long it has been used in one way or another. It's not like forests are being cut down on the icy slopes. As for what is useable, it is scarce and has been used by the locals for a very long time. Ramanathan has shown that, at the altitudes where the brown cloud aerosols are found, they exert a strong positive radiativce forcing. This forcing is a much better candidate for the temperature increase than your land use hypothesis. The glaciers get a double whammy from the black carbon deposited on their surface and the atmsopheric BC heating them up.
  19. Some grist for the mill: I’ve come across an interesting easy to read general paper on AGW by the glaciologist Lonnie Thompson titled Climate Change: The Evidence and Our Options. “Glaciers serve as early indicators of climate change. Over the last 35 years, our research team has recovered ice-core records of climatic and environmental variations from the Polar Regions and from low-latitude high-elevation ice fields from 16 countries. The ongoing widespread melting of high-elevation glaciers and ice caps, particularly in low to middle latitudes, provides some of the strongest evidence to date that a large-scale, pervasive, and, in some cases, rapid change in Earth’s climate system is underway. This paper highlights observations of 20th and 21st century glacier shrinkage in the Andes, the Himalayas, and on Mount Kilimanjaro. Ice cores retrieved from shrinking glaciers around the world confirm their continuous existence for periods ranging from hundreds of years to multiple millennia, suggesting that climatological conditions that dominate those regions today are different from those under which these ice fields originally accumulated and have been sustained. The current warming is therefore unusual when viewed from the millennial perspective provided by multiple lines of proxy evidence and the 160-year record of direct temperature measurements. Despite all this evidence, plus the well-documented continual increase in atmospheric greenhouse gas concentrations, societies have taken little action to address this global-scale problem. Hence, the rate of global carbon dioxide emissions continues to accelerate. As a result of our inaction, we have three options: mitigation, adaptation, and suffering.”
  20. muoncounter:The finding of the ice mummy, Otzi, does this indicate the present melting of the glaciers are now back to the level where they were when this mummy was first frozen? So, this would represent natural climate variability.
  21. oneiota: Glaciers may or may not be a good indicator of climate change. Uniform melting of mountain glaciers, excluding Greenland and Antarctica, is an indicator. About 65% of all mountain glacial ice worldwide as noted above, is found in Canada. So, if Canadian glaciers are all melting, in unison,then, yes, a good indicator of global warming. It is my understanding that Mt Kilimanjaro's source of moisture for glacier building was a forest at its base, which had been cut down, so the glacier disappeared. Many glaciers have sublimated even when the temperature above the glacier was still below freezing. Can someone vouch for the temps over each of these declining glaciers? That data appears missing? So, the many causes for glacial decline are not even mentioned.
  22. Henry justice @20, you are assuming that Otzi died in an ice free area that later became glaciated. That would be near impossible, and is contrary to the evidence. Rather, he died above the permanent snowline, and has remained above the permanent snowline ever since.
  23. So Henry, perhaps you would like to look at Mt Kilimanjaro for some discussion on this. Also: "Many glaciers have sublimated even when the temperature above the glacier was still below freezing" Now why do you think this is? You seem to be trying to say that glacier melting isn't a sign of temperature warmings, but actually temperature rise is symptom of increased surface radiation. Might not that have something to do with the ice melt.
  24. Tom Curtis: Antarctic warming- Could some erupting undersea volcanoes in the warming areas of West Antarctica be the cause of the warming there?

    [DB] There simply is no evidence to support that assertion.  And much to the contrary (example here).

  25. scaddenp: Thanks for your comment and reference. I believe action was taken to replant the forest. Sadly, it may prove very true that it will not do the trick. Sublimation may indicate a change in atmospheric air streams to a drier air. Glacier melting from increased warming via conduction is certainly a factor, not necessarily air temps increases. For the last 200 yrs the slight upward temp trend has been declared at about +0.5 deg C. Increase in IR (i.e.8-15 microns) will cause 10 deg F insol (Bragg Equation foldback effect) and yes, that will cause melting. But that is for snout ice, not hard ice underneath the glacier, which might be at a much lower temperatue. So, what are we talking about for all these melting glaciers, softer snout ice or hard glacial ice?

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