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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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Argument Feedback

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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

Comments

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Comments 26 to 48 out of 48:

  1. [DB] I disagree, there is an active under the ice volcano in the area where the warming is graphically shown. Your reference did not address Antarctic underice/sea volcanoes.
    Response:

    [DB] "there is an active under the ice volcano in the area where the warming is graphically shown"

    Citation, please?  Also please quantify how much heat is melting how much ice causing how much warming.  Please include in your citation the paper the peer-reviewed study you cite appeared in.

    "Your reference did not address Antarctic underice/sea volcanoes"

    Quite frankly, it doesn't need to.  Volcanoes are not magical creations possessing the higher intellects needed to discern between hemispheres, like say, polar bears and penguins.

    [Not DB] In my opinion, volcanoes are not really on topic for this post, which focused on the plain and simple fact that glaciers overall are not growing. Evidence for and against that particular point is welcome.
  2. "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." And the evidence for this what? And where is the extra heat from conduction coming from? Almost of all of glacier melt is in the ablation zone, and in many cases, ice loss is accelerated by calving. As to the sudden appearance of volcanoes causing melting where it wasnt before, leaving aside the question that heat flow from volcanoes is very localised, in what ways would such melting be different than that caused by warming? And how does that compare with observation?
  3. Henry Justice @26, you continue to make a string of claims with no attempt to either justify, reference or defend them. That is called trolling. Forum rules forbid me from saying what I think of trolls. Take your claim about about Arctic volcanoes. A troll says "arctic volcanoes" ergo heat from volcanoes is melting the ice. Somebody with intellectual integrity, in contrast, would seek to answer several questions. a) The volcanoes are newly discovered, but are they newly existing? If they are not new volcanoes, then their presence is not a change to the Arctic heat budget and therefore cannot explain changes in Arctic ice extent. b) Can the heat from the volcanoes reach the surface? The answer here is not obvious. The Arctic is the location of a strong down welling current as part of the thermo-haline circulation. Therefore heat from subsurface volcanoes in that region are likely to be carried in the subsurface current into the depths of the Atlantic, and hence to the Antarctic rather than to simply be carried to the surface. c) Can the volcanoes significantly effect the surface temperature? There is a lot of water between the volcanoes and the surface, and water can absorb a lot of heat. To raise the temperature of surface water significantly, the volcanoes must raise the temperature of the entire water column. It is very unlikely that they have enough heat to do so. d) Do the volcanoes have enough heat to melt the ice? As it happens, summer Arctic sea ice reduces in volume by about 100 km^3 every year. That would require 3.34 x 10^19 Joules to melt. The heat from those undersea volcanoes comes to about 0.45 W/m^2 or less: That means there would need to be 2.35 million square kilometers of these under sea volcanoes to melt the ice. So are there? Have they found 2.35 million square kilometers of previously non-existing under sea volcanoes in the Arctic? Or is this just another trolling drive by. Trolling only works because the troll needs make no intellectual effort, while the rebuttal of the trolling does! I don't like that ratio, so if you are not a troll, you need to answer all four of my questions above, with linked or properly cited sources, and with the steps of your arguments clearly laid out. If you are not prepared to do so, then you clearly are a troll, which is sufficient rebuttal of any point you pretend to make. Trolls have no intellectual integrity - they have put no effort into forming their "opinions". Therefore they need be given no intellectual credence. Over to you.
    Response: I've deleted Henry Justice's comment you are responding to, because not only was it trolling, it was not really on topic.
  4. Sorry, I forgot to properly explain the map in my previous post. It is the map of the geothermal energy (including from volcanoes) of various part of the Earth. The units are mW/m^2, so need to be divided by a thousand to show values of Watts per meter squared. Source
  5. If I can't defend my comment by posting a reference, then would you please delete comments 26, 28, 29 and 30 in their entirety. Especially comment 30, since I see no mention of anything about the Arctic.
  6. Tom Curtis at 22: "you are assuming that Otzi died in an ice free area that later became glaciated." Here is what I stated: "Does this indicate the present melting of the glaciers are now back to the level where they were when this mummy was first frozen?" This does not state or indicate an ice free area!
  7. Here are my requested references : For the undersea volcanoes: (-Snip-) For the Under-Ice Antarctic Volcanoes and its effects: (-Snip-) Finally, here is a reference for a good discussion on melting glaciers: Behavior of World's Glaciers Fails to Prove Global Warming Theory by John Carlisle, Feb 1999.
    Response: [DB] Please note that volcano's have been determined to be off-topic on this thread.
  8. Henry, don't you think the title of Carlisle's work is a little, well, ignorant? Decline in glacial mass is not cited as evidence for the theory of AGW. No scientist would say, "glacial mass is declining and this proves AGW." Carlisle: "Glaciers are influenced by a variety of local and regional natural phenomena that scientists do not fully comprehend. Besides temperature changes, glaciers also respond to changes in the amount and type of precipitation, changes in sea level and changes in ocean circulation patterns. As a result, glaciers do not necessarily advance during colder weather and retreat during warmer weather." What a revelation. Glaciers "do not necessarily" shrink or grow in response to changes in global temp, but in general they do, as evidenced by the change in global mass balance. The analogous situation is global sea ice. Area of both poles are subject to regional fluctuations from year to year, but Arctic extent, area, and volume are, across the entire Arctic region, rapidly decreasing. Antarctic sea ice extent is slightly increasing, even while ice shelves show signs of increasing deterioration.
  9. Henry, you surely arent mistaking articles by right-wing think tanks for science? Looking at published science we note for instance here, we find temperature is the predominant influence. Modelling on the franz joseph when advancing showed it needed a 40% increase in precipitation to offset a 1 degree increase temperature at the terminus. The worldwide glacial retreat is consistent with established climate theory. All of us want to find evidence that supports what we would like to be true. The development of science has showed that we need find a discipline that protects us from this normal human reaction. Try thinking about what evidence would convince that your views are wrong and see if there is evidence to support this. Look for that evidence in peer-reviewed science publications. There is plenty of fairy-dust about on the net for those just want to be fooled.
  10. DSL at 33: Yes, I do agree. However, come lately, the glaciers, via mass balance analysis, are disappearing at an alarming rate due to increasing air temps, lack of snow and shifting jet streams. Water supplies are adversely affected. While in Arequipa, Peru, I watched the 19,100 ft snow cap disappear. Water is a big problem down there and elsewhere. The mass balance analysis is now supporting the retreat of the glaciers. This is so bad in Peru that they are painting the rocks white.
  11. scaddenp at 34: Thanks, you have restored my confidence. Yes, I seem to remember that. But I thought that the terminus ice not being compacted melts much faster. My take on glaciers is that of a hard tongue of ice where temperatures may be 50-80 or more degrees F below freezing: i.e. Greenland and Antarctica, the bulk of the world's frozen water. The temps, density and melt rate of snout ice glaciers are all different. Rapid retreat is expected in "shallow iced" glacial areas (i.e.compared to Greenland or Antart.) So, yes, climate is changing for now and the glaciers clearly indicate this. But will this trend last into the upcoming decades? Anyway, I will make an effort to shake off the fairy dust. Thanks.
  12. In the very few places in the world where glaciers are advancing (or have some oscillation), then for most it is due to more precipitation in the neve overwhelming the increasing temperatures at the terminus (which by definition is where temperatures are too hot for ice to persist unless its terminating into water). The ones I know about are in NZ Alps and southern Andes where warmer oceans are increasing precipitation from westerlies blowing onto the mountains. With precipitation, temperature and flow rate monitored, you can model the effects of changing terminus temperature and changing snowfall. Will it last? Will if the amount of radiation warming the surface increases, then yes it will. With increasing GHG concentrations, then that is a measurable increase. For it not to continue in face of increasing emissions, then you must have either less sunlight entering or more sunlight reflected (higher albedo or more aerosols). The sun going into really deep minimum would cive us a reprieve but if we didnt use that time to reduce GHG concentrations, then we would suffer badly when the minimum was over.
  13. Hi, I have an honest question. I read an article here: climate-skeptic.com that basically claims that glacial melting history is being cherry picked by climate change theory advocates and ignores that glaciers have been melting for 200 years, since before the onset of CO2 emissions. I dismiss most denialist stuff, but haven't seen any rebuttals to this argument. Is this just a new argument? What's going on ? Thanks!
  14. Chef, what evidence was given for the claim? Some glaciers have cycled through gain and loss over the course of the current interglacial, but most of the world's ice hasn't been monitored until fairly recently. To use those few glaciers that have 200-year old records to make a claim about global ice mass loss--that's a cherry pick itself. The World Glacier Monitoring Service has more detail: http://www.grid.unep.ch/glaciers/ The sharp reduction in global ice mass over the last 30 years is well-documented. Not all glaciers are retreating. The overwhelming majority are--Antarctica most alarmingly. Interestingly, increased atmospheric water vapor should mean more available snow, and thus an increase in glacial mass. Nope. Too warm. As a proxy for AGW, it's pretty good. After all, what could be causing this ice loss? It's not increased insolation, because there hasn't been increased insolation. It's not volcanic activity under the ice, because that's not happening either. Further, whatever alternative theory that might be proposed for such loss, it would still have to take into account increased global energy storage via increased CO2. If it were discovered that black carbon was the culprit, that wouldn't suddenly negate the known physics of atmospheric CO2.
  15. Oh, and Chef, did you click on the "intermediate" tab above? That has information on the number of glaciers monitored -- directly relevant to the cherry-pick claim.
  16. wealthychef @41, figure 1 in the basic article represents a full rebutal of the fake skeptic claims. If you look at it, you will see a gradual loss of glacial ice from 1850, which represents the ongoing glacial retreat for some glaciers since the little ice age. However, two features stand out. First is the much more rapid loss of ice since 1970. If glacial ice loss simply represented the restoration of equilibrium after the LIA, glacial ice loss would gradually slow as it approached that equilibrium. Hence, the recent very rapid ice loss shows clearly that the cause is a recent warming rather than the warming that accompanied the end of the LIA. Second is the brief accumulation of glacial ice from 1950-1970. Global temperatures actually cooled slightly during that interval, primarily due to the rapid accumulation of sulphate (SO4) in the atmosphere from the burning of coal. The important factor here, however, is that that brief cooling could not have resulted in an overall gain in glacial ice unless the glacial ice was very close to equilibrium. That gain in glacial ice therefore contradicts the fundamental assumption of the fake skeptic argument, which is that glacial ice balance is far from equilibrium, and continues to be lost because of a warming episode that ended over a century ago. Typical of fake skeptic arguments, the argument presented at climate-skeptic.com is depends on superficial knowledge of the data to retain its plausibility.

  17. Ok, so what if I were to say the rapid decline(rate of change) after 1990 was also seen at the start of the graph in figure1(Basic). Does the graph in figure1 actually make any statment keeping this in mind?

  18. The mass loss from 1996 to 2005 is more than double the mass loss rate in the previous decade of 1986 to 1995 and over four times the mass loss rate over 1976 to 1985.

    A regular doubling period is the exact definition for exponentiality... can anyone please tell me when the saviour of sinusoidality kicks in??

  19. Aerosols were likely the biggest contributor to glacial retreat in Europe from 1850 to 1910. Aerosol loading in the Himalayas due to Indian, European and African fossil fuel consumption are likely the largest contributors to glacial retreat in the Himalayas. There are uncertainties if aerosols from China make their way into the Himalayas.

    Aerosols reduce albedo and increase the skin temperature. This same effect, surface darkening effect (SDE), is also leading to a reduction in boreal forest snowpack accumulation (video). It is also having an effect on the Sierra Nevadas in California. The Himalayas is the largest reserve of ice outside of the polar regions. Anthropogenic aerosol forcing is largest contributor to this glacial retreat – not anthropogenic GHG forcing. There are many uncertainties regarding the role of aerosols in global warming; it is also the largest source of uncertainty regarding anthropogenic radiative forcing (IPCC chart).

  20. Supplemental reading:

    Preliminary data reported from the reference glaciers of the World Glacier Monitoring Service (WGMS) in 2018 from Argentina, Austria, China, France, Italy, Kazakhstan, Kyrgyzstan, Nepal, Norway, Russia, Sweden, Switzerland and United States indicate that 2018 will be the 30th consecutive year of significant negative annual balance (> -200mm); with a mean balance of -1247 mm for the 25 reporting reference glaciers, with only one glacier reporting a positive mass balance (WGMS, 2018).

    Alpine glaciers: Another decade of loss, Guest Commentary by Mauri Pelto, RealClimate, Mar 25, 2019

  21. New data on glaciers:
    Global glacier mass changes and their contributions to sea-level rise from 1961 to 2016
    https://www.nature.com/articles/s41586-019-1071-0
    "Present mass-loss rates indicate that glaciers could almost disappear in some mountain ranges in this century"

  22. Recommended supplemental reading:

    Scientists have found warm water beneath Antarctica's "doomsday glacier," a nickname used because it is one of Antarctica's fastest melting glaciers. While researchers have observed the recession of the Thwaites Glacier for a decade, this marks the first time they detected the presence of warm water – found at a "vital point" beneath the glacier.

    A news release on the findings called it an alarming discovery.

    "The fact that such warm water was just now recorded by our team along a section of Thwaites grounding zone where we have known the glacier is melting suggests that it may be undergoing an unstoppable retreat that has huge implications for global sea-level rise," David Holland, director of New York University's Environmental Fluid Dynamics Laboratory and NYU Abu Dhabi's Center for Global Sea Level Change, which conducted the research, said in the news release.

    Scientists alarmed to discover warm water at "vital point" beneath Antarctica's "doomsday glacier" by Sophie Lewis, CBS News, Feb 1, 2020

  23. The recent article Antarctica melting: Climate change and the journey to the 'doomsday glacier' by Justin Rowlatt, BBC News, January 28, 2020, complements and supplements the items linked to by John Hartz @47.

    A relevant supplement provided in the article is the presentation showing that the elevation of a substantial portion of the ‘grounding surface’ under Antarctica’s ice, and almost all of the ‘grounding surface’ at the base of the Thwaites Glacier, is below sea level.

  24. Please note: the basic version of this rebuttal has been updated on June 18, 2023 and now includes an "at a glance“ section at the top. To learn more about these updates and how you can help with evaluating their effectiveness, please check out the accompanying blog post @ https://sks.to/at-a-glance

    Thanks - the Skeptical Science Team.

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