Surprise! Study says some glaciers actually shrank during the last ice age

The simple story says that during the last ice age, temperatures were colder and ice sheets expanded around the planet. That may hold true for most of Europe and North America, but new research from the University of Washington tells a different story in the high-altitude, desert climates of Mongolia.

The Gobi-Altai mountain range in western Mongolia is in a very dry region but ice can accumulate on mountaintops, such as Sutai Mountain, the tallest peak in the range. In the picture, friends of Jigjidsurengiin Batbaatar descend this mountain after helping to install a weather station.

CREDIT Jigjidsurengiin Batbaatar/University of Washington

The recent paper in Quaternary Science Reviews is the first to date ancient glaciers in the high mountains of Mongolia’s Gobi Desert. It compares them with glacial records from nearby mountains to reveal how glaciers behave in extreme climates.

On some of the Gobi mountain ranges included in the study, glaciers started growing thousands of years after the last ice age ended. In contrast, in slightly wetter parts of Mongolia the largest glaciers did date from the ice age but reached their maximum lengths tens of thousands of years earlier in the glacial period rather than at its culmination, around 20,000 years ago, when glaciers around most of the planet peaked.

Both trends differ from the typical chronology of glacier growth during an ice age.

“In some of the Gobi mountains, the largest glaciers didn’t happen during the last ice age,” said first author Jigjidsurengiin Batbaatar, a UW doctoral student in Earth and Space Sciences. “Some of these glaciers were starving for precipitation then. Our measurements show that they actually shrank as cold, dry conditions of the ice age became more intense. Then they grew when the warming climate of the Holocene brought more moist air, feeding the glaciers with more snow.”

Batbaatar and co-author Alan Gillespie, a UW research professor emeritus in Earth and Space Sciences, collected samples from moraines, which are long ridges of rocky debris dropped at a glacier’s edge. They used a dating technique perfected in the last 20 years that measures elemental changes in the rock that occur when the rock gets bombarded by cosmic rays after the glacier’s retreat.

“We were expecting to find rocks exposed for 20,000 years, the date of the peak of the last ice age, but these moraines were much younger. That means that these glaciers were smaller when the climate was the coldest,” Batbaatar said. “The results were so surprising that we went back to double check.”

The study was possible both because of advances in the cosmic-ray dating method, and political changes that allow more access to Central Asia.

“After the fall of the Soviet Union, Russia opened up, China opened up, and Mongolia opened up to Western researchers with these novel dating techniques. And we see a very different pattern of glacial advances compared to North America and Europe,” Batbaatar said.

The data collected in 2007 and 2010 confirm a theoretical study by Summer Rupper, a former UW doctoral student now at the University of Utah, and UW faculty member Gerard Roe. In very cold and dry environments, where rain and snow are scarce, it predicted that temperature would not always be the main factor driving a glacier’s growth.

“Because the melting is so dominant a process, and the melting is mostly controlled by temperature, people think of glaciers as thermometers. But we all know that precipitation plays a role,” Batbaatar said.

The new study confirms that so-called “starving glaciers” in dry, high-altitude environments are indeed controlled by precipitation. They grow so slowly that they seldom reach the lower altitudes where melting is possible. Instead, they shrink when sunlight hits the surface and transforms ice into water vapor, a process called sublimation. These glaciers are thus less sensitive to temperature shifts, but very sensitive to precipitation amounts.

“Generally, people have assumed from well-documented North American and European records that the largest glaciers should have come in the peak of the last ice age,” Batbaatar said. “But in Mongolia, our results show that this was not the case. Glacier behavior there was different from the better-studied areas of the Alps or the Sierra Nevada in the U.S. Even within Mongolia we observe very different behavior from range to range.”

The conditions at the Gobi-Altai mountain range are extreme, with precipitation at the five research sites Batbaatar established there ranging from roughly 50 to 300 millimeters (2 inches to 1 foot) per year. Nearby mountains in Mongolia with more precipitation have more typically behaving glaciers. But other extreme climates, for example the driest parts of Tibet or the Andes, can produce glaciers with similar paradoxical trends.

“Even in this current warming climate, some mountains are so high that the temperatures are still below freezing, and the warming ocean may provide more precipitation to drive some of the glaciers to advance,” Batbaatar said.

He is now working to interpret more measurements collected from a wider geographic area in Central Asia.

“Batbaatar has shown that glaciers growing in cold, arid, desert mountains may be out of sync with those in wetter, warmer environments such as the Alps,” Gillespie said. “His findings move us toward a more complete understanding of how glaciers advance and retreat in response to climatic fluctuations.”

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The study: http://dx.doi.org/10.1016/j.quascirev.2017.12.001

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108 thoughts on “Surprise! Study says some glaciers actually shrank during the last ice age

  1. OT but….I am expecting 20 inches of AGW tomorrow.
    bangordailynews.com/2018/03/06/news/state/noreaster-could-dump-up-to-20-inches-of-snow-in-western-maine/
    1200 lbs weight added to rear of truck to offset wet snow, 9 ft 2 inch plow on front. just gonna push it as it accumulates.

    • It’s late enough in the season so I don’t worry about it much, on March 3, 2011 we got 26 inches of the wet stuff, and 3 days later it was in the upper 60’s. My only headache was that I parked mu truck right in front of my wife’s garage door, and it took about 45 minutes with the snow thrower to get things opened up.

      • On the bright side, at least once you extricated your truck, the driveway behind her side was cleared and you didn’t need to blow snow there as well

      • we handle commercial lots so we can’t just let it sit. huge liability issues involved there (one being fedex) so we work the storm and keep stuff open.

    • Two inches of snow — er, global warming overnight, and a bit more of GW this afternoon. I shoveled the GW off my front steps, and then put bird food out at the feeding station, because the redwinged blackbirds were squawking about ‘where’s the food?’, and the cardinals were doing that ‘pik-pik-pik’ thing.
      Spring is around the next two corners. We’re below average for March this year. S/B 5.4″, and so far, just 2.0+/-, but plenty of rain. Looks like a good spring and summer ahead.

    • It’s hard to believe anything printed in the BDN these days. They are left of the Guardian and way south of Bangor these days.

      • yeah they are a clone of portland press herald owned by chellie pingree husband but I have been monitoring radar and stuff and they are prob close here.

    • lol maybe 23 inches actual falll as WELL as drifts caused from 40 +/- winds.
      then satruday am another 3 inches (commercial stuff needs to be done around 2 inches) and then tuesday another 6-8 inches.
      so….good paycheck but in 3 days prob 60 hours work.
      heavy wet snow on top of the thawed ground causes us to have to spend lot of time preventing ground damage.

  2. I’ve always maintained that the dynamics of glaciers are too complex for them to serve as reliable ‘Coal Mine Canaries’ with respect to temperature. It is obvious that temperature imposes limits on when and where they can exist; however, the idea that their retreat is correlated directly to temperature alone is an overly simplistic assumption made by alarmists.

    • Just like the fact that the Greenland ice sheet gained volume last year was seen by skeptics as a sign that temperatures must have been cold. Foolish!
      Alarmists have no monopoly on oversimplifying. Most WUWT readers (and others) have an extremely simplistic idea of the potential repercussions of climate change, a willful deafness to anything negative. And look at all the people who predict the future climate based on a few graphs and some basic math!

      • “Alarmists have no monopoly on oversimplifying” – and then you immediately follow that with a gross oversimplification about those you disagree with. Your monopoly remains unthreatened.

      • Kristi,
        Set aside the linear thinking. It’s a cyclical world, including ‘climate change’. Mile thick glaciers advancing to lower latitudes in the northern hemisphere is our cyclical planetary history… and our destiny. The comparatively brief interglacial warm periods are the exceptions to that planetary rule. Our current Holocene interglacial will end and the planet will once again be wrapped in the crushing grip of continent spanning glaciers. History also demonstrates human civilization thrives in warmer climates, yet struggles to exist when the environment becomes impoverished by brutal cold.
        Every human on the planet earth has much more to fear from ‘the potential repercussions of climate change’ back to brutal cold and crushing mile thick glaciers than we do from another 2 degrees centigrade of planetary warming within the current and aging interglacial period.
        I hope you do not exhibit a willful deafness to this historically verifiable and truly negative information diminishing the anthropogenic global warming narrative.

      • Kristi,
        Can you cite any studies to support your claims about “skeptics,” “most,” and “all the people?” It seems like a lot of self-serving hand waving.

      • J Mac “Every human on the planet earth has much more to fear from ‘the potential repercussions of climate change’ back to brutal cold and crushing mile thick glaciers than we do from another 2 degrees centigrade of planetary warming within the current and aging interglacial period.”
        This is exactly what I mean. Is this not a gross oversimplification? On what do you base your knowledge? Maybe a cooler Earth would be moister overall. We survived the last glacial period, we can always move – perhaps more easily than we can move back from the coastline. I agree that if we were heading into a glacial period and the temperature were dropping at the same rate that it is now rising, that would be a problem. But it’s not. You seem to think that a couple degrees C is not a big deal, but in the span of 100 years, it is. It’s a matter of humans and organisms being able to adjust to rapidly changing conditions. There are many ways this could affect us and the nature on which we depend. Some effects will be good, but most will be costly. They already are.
        Thomas Homer: “Alarmists have no monopoly on oversimplifying” – and then you immediately follow that with a gross oversimplification about those you disagree with. Your monopoly remains unthreatened.”
        There is no logic to your statement. Whether or not I made an oversimplification has no bearing on whether skeptics do. Besides, I made a generalization, not an oversimplification.
        I said most, I didn’t say all. It wasn’t very diplomatic, but I stand by what I said. Most warmists don’t have a very good understanding of the repercussions either, but at least they are usually willing to consider them, while in my experience many skeptics just make fun of those who take such things seriously, insult them and dismiss them. without knowing them at all. At least I’ve had a chance to see what people around here think about effects of climate change, generally speaking..
        (My graduate degree is in ecology and evolution, and I think about the big picture in ways others seldom do, no matter what their stance on climate.)

      • What are these so called repercussions that have your panties in a wad?
        “And look at all the people who predict the future climate based on a few graphs and some basic math!”
        Sounds a lot like Kristi.

      • “and I think about the big picture in ways others seldom do”
        As always, Kristi actually believes that she and she alone knows what she is talking about.

      • Tell that to the IPCC who have stated officially that up to 1.8C of warming is generally beneficial for the planet.

      • Kristi appears to be some sort of climate change chess piece. She can move North and South unaffected by temperature but movement away from water is not allowed! Is she fish or water fowl I wonder.

      • Kristi Silber,

        My graduate degree is in ecology and evolution, and I think about the big picture in ways others seldom do, no matter what their stance on climate.

        What an effin’ narcissist. My graduate degree is in geology, and I (and probably most if not all other geologists on this site) not only think about the big picture, but can also put it in a geological time scale perspective. People like you think the world started when you were born and the climate was perfect and unchanging until a few years ago.

        And look at all the people who predict the future climate based on a few graphs and some basic math!

        Kinda hard on the climate scientists, aren’t you?

      • Kristi,
        RE: “Is this not a gross oversimplification?”
        No. It is not an gross over simplification, or any other inflated evasion you may choose to employ.
        It is an unyielding fact. We know the planet will cool again and glaciers will once again advance. It is going to happen. We just don’t know how soon it will happen.
        Man made global warming is a hypothesis, much debated. ‘Catastrophic’ global warming is unsubstantiated and unlikely, as the planet has had much higher CO2 levels without catastrophe. Planetary history (reality) refutes the AGW scare mongering.
        I read your response carefully. You exude irrational fear when you attempt to equate the certainty of future glacial advances with the much debated global warming hypothesis. Historical certainty is not logically equivalent to historically unsupported, debatable hypotheses.
        I hold bachelors and masters degrees in metallurgical engineering, an education intensive in mathematics, physics, chemistry, and thermodynamics. I have more than 30 years experience trouble shooting complex materials and processing problems, as well as providing research and development solutions for same. I’m an avid outdoorsman and have hiked, camped, hunted, fished, boated, and skied across many wild areas of the USA. As a result, I have a personal relationship and a lot of experience with weather and climate. In addition, I have read widely these last 25 years on aspects of climate science and paleogeology, including many of the published papers of the most vocal AGW alarmists. All of these aspects inform my educated and experienced conclusions that ‘catastrophic’ does not apply to the variable global warming fits and starts we are experiencing in our current Holocene interglacial period.
        Set your irrational climate fears aside, Kristi. Life is toooo short to waste on climate chimera.

      • Kristi,
        You come across as a recent graduate who has been thoroughly indoctrinated. You engage in statements of opinion that you apparently believe are true, but provide no incontrovertible proof nor even reliable citations.

      • Ecology and evolution? Those were courses I took to raise my GPA. Along with a semester of psychology. We actually got to mark our own multiple choice tests. I got an A+. I ventured into the hard sciences, where I studied atmospheric chem. 25 years ago we were told, by the prof, that we had about 10 years before the climate would result in unbearable living conditions for the planet. WRONG. He’s probably saying the same BS to a new crop of Chem undergrads

      • Clyde Spencer
        ‘Kristi,
        You come across as a recent graduate who has been thoroughly indoctrinated. You engage in statements of opinion that you apparently believe are true, but provide no incontrovertible proof nor even reliable citations.”
        Well, that’s why making assumptions about people can lead to error. We all do it. I just turned 48 and my best friend is a far right conservative – and we do talk politics, climate, religion – sometimes quite loudly. But I cannot provide evidence showing you’re mistaken about my indoctrination and I feel no need to plead my case. Think what you want.
        It’s kind of funny, actually – I’ve spent FAR more time talking to skeptics and exploring their arguments than I have talking to “warmists.” The vast majority of my knowledge about climate and climate change has come through skeptic sites. And you know what? That experience has made me question my beliefs, but it has also shown me the ways belief has been propagated, the Other vilified, and discussion halted. That’s on the left and right.
        I will never have incontrovertible proof of anything. If I thought I did, I’d be a very poor scientist indeed. Science doesn’t use such terms. I’ve never had a reasonable request for a citation. Others here state their opinions without needing to provide evidence.
        Phil R: I’m sorry, I only meant that I have a specific background that makes me see things as I do, just as yours affects how you see things. I know there are ways you look at the world that I can’t imagine, and I wish I had some of your knowledge! Geology has always fascinated me. What I also find fascinating is the way microorganisms, animals, plants and fungi and many mechanisms of weathering work together to break down stone, turn it into soil, make nutrients available and enable new species to grow. They, then, slowly make conditions suitable for yet new species and the community composition changes over time. Populations spread, migrate, go through bottlenecks, adapt, die out – all the while interacting with populations of other organisms doing the same things. There are tight relationships between two species, and loose, redundant ones among scores of them. They change over the scale of microcosm to ecosystem to biome to continent. We are a part of it all. Our species spread over the habitable world and then some, interacting with the environment along the way. This is just a glimpse of how I see the world: the vast, complex web of interactions among organisms and their environment, and how they came about from an evolutionary standpoint. I use “environment” here in a specific, literal sense, as the total input from surrounding organic and inorganic products and processes. It’s “hard” science, filled with statistics and emphasis on unbiased experimental method.

      • And your point is…? During the Little Ice Age the trajectory would have been exactly the inverse.

      • The glaciers in glacier national park that are on the ‘canary list’, much like many glaciers world wide, are actually young, formed well after the end of the last ice age. The Glaciers in Glacier National Park are about 3000 years old. That IceMan that melted out of the glaciers also shows the glaciers were even smaller than now in the past. A snippet out of context graph like this just shouts the lack of knowledge context the alarmists are crowing from.

      • Do you have any graphs that indicate ANY glacier has ever been stable? That line will ALWAYS be going either Up or Down but Never straight across.
        Glaciers are Always changing mass…
        Always have…
        Always will…

      • Sure Bryan
        Ruling out humans as a significant contributor is blinkered I would venture.
        These two show a few glacial cycles and the Holocene. They are probably good enough depictions of glacial mass over the periods. There are variations like the “high-altitude, desert climates of Mongolia” for example and other chaotic fluctuations but the broader patterns are pretty clear. We appear to be nearing the end of the Holocene interglacial so you’d expect the glacial growth trend to generally be positive but instead glaciers are abruptly shrinking back towards the Holocene maximum.
        http://icecap.us/images/uploads/Glacial_eras.jpg
        https://upload.wikimedia.org/wikipedia/commons/thumb/c/ca/Holocene_Temperature_Variations.png/261px-Holocene_Temperature_Variations.png
        Move along, nothing to see.

      • John Mason,
        The National Park Service formerly had a website for Glacier NP that claimed the ice fields on the north side of the mountains had been stable for over 100 years. That is, “where the sun never shines.” That claim disappeared during the Obama administration. That was my point above. If there has been a decrease in the cloudiness, ground temperatures would increase and melt snow and ice on the south-facing slopes. However, if the average ambient air temperature had increased, then the ice fields in the shade should have melted also. Apparently, they didn’t!

      • ” nearing the end of the Holocene interglacial”…the question is, why is that last red squiggle so much thicker

      • What are the error bars on this chart of yours?
        I’m willing to bet it’s a lot bigger than the alleged drop that has you so worked up.
        Regardless, 30 years? You’ve got to be kidding.

      • Nobody has ruled out the possibility that man is a major contributer, we are just pointing out that the science doesn’t support that conclusion.

      • zazove, you do realize that the lines on your second graph cover around 1000 years. Trying to determine what the temperatures should be doing over any 10 or 20 year period based on that graph is a fools errand. And you are just the fool to try it.

      • Lattitude, what I want to know is why he is so concerned regarding temperatures returning to what they were during the Holocene Optimum.

      • In 1965 I was on vacation with myy family and made a stop at the foot of a glacier in the Columbia icefield. The visitors station had pictures showing the steady retreat of the glacier since the 1860’s. Explain please how CO2 was involved.
        Let me save you the embarrassment of trying. You can’t. It wasn’t You don’t seem to have the mental capacity or strength of will to think for yourself so you parrot the defective ideas and biases of others. That makes you a force for evil in the world.
        Your own mind is the only thing that can save you from being manipulated by others.

      • all the glaciers in the world could melt into nothingness and the world sea level would rise only 40mm.

      • But…Zazove…
        The “temperature graph” you inserted above is based on proxy data that has been interpreted to indicate the possible approximate temperature with fairly large time span smoothing. It takes over 50 years of compression to firn the ice and lock in any remaining ambient atmospheric gasses. Over that span of time some of the trace gasses escape to layers above and create only a somewhat reliable temperature proxy. Low Resolution proxy data can’t show shorter period warmer spans similar to what we’re experiencing today. Especially once the data gets smoothed. Consider that in the the displayed chart the 50,000 year time span covers around 1/2 inch (on an 8″ display) the current warming since 1950 would be but a single pixel
        And, it still shows the prior interglacial periods to be warmer than current temperatures. +3.2c at 140,000 years ago, even at the low resolution of the proxy data.

      • zazove,
        I would love to provide you with the link, but, as I mentioned, the material was removed a few years after I first read it. However, the situation isn’t very different from the Himalayas, where forecasts were made of the impending end of glaciers, and then it was found that not all glaciers were receding equally. I suspect that there is a strong correlation between the rate of wasting and the slope aspect. That is, those in shade respond more slowly or not at all. However, I haven’t seen anyone publish on that part of the problem.

    • ” however, the idea that their retreat is correlated directly to temperature alone is an overly simplistic assumption made by alarmists.”
      weirdly these same alarmists publish science saying that the retreat is NOT correlated directly.
      weirdly this paper showing that things are so simple gets published.. how did that happen
      when we know that all the science produced is just a fraud

  3. I have a question – during the last glaciation, were the massive, mile-thick glaciers only in the Northern Hemisphere, or was there significant glaciation in the Southern Hemisphere as well. If only in the Northern Hemisphere, why?

  4. “Because the melting is so dominant a process, and the melting is mostly controlled by temperature, people think of glaciers as thermometers. But we all know that precipitation plays a role,” Batbaatar said.
    Isn’t this already well known? Isn’t it what happened to the snows of Kilimanjaro; not temperature, but loss of precipitation on the mountain caused by deforestation in the area?
    It seems the only new thing here is that they cleverly found a place in ancient Mongolia where this happened also.

    • Its not just melting affecting high mountain glaciers. There is also substantial sublimation. Summer Sublimation accelerating after cloud forest deforestation is what did in Kilimanjaro’s ice cap. Illustrated in depth in essay Snows of Kilimanjaro in ebook Blowing Smoke.

  5. You mean everything doesn’t happen the same way everywhere all at the same time? Gee, I thought they did. I thought the whole world moved together in lockstep towards perfect equilibrium, with the exact right amount of rain, ice and dry everywhere, all the rabbits, lions and lambs palsy-walsies, and nary a sprig of sagebrush or blade of grass feeling neglected, until humanity came along. Since humans domesticated fire, it’s been a one-way ticket to enviro-palookaville, accelerated by the invention of the infernal confusion engine.
    Sinner repent! Go back to the Stone Age and all will be well.

  6. I can’t recall the study, but weren’t the Alaskan alpine glaciers also “starved” of precipitation during the last glacial maximum? i believe they also grew as the continental glaciers melted.

    • One would think that a colder world would be a drier world. It doesn’t seem out of the question that some glaciers might not see enough snow to sustain their lower margins.

  7. Not a surpise as the Late Glacial Maximum was mostly in NE N America and NW Europe. It is well known that savannah conditions prevailed over a large part of Siberia and Alaska (and Mongolia too by the sound of it)

  8. “The science is settled” means we know everything of importance. Clearly, since this study falls outside the bounds of settled science, they must be mistaken, their study must be repudiated, and the authors need to begin new careers in security where they’ll encounter as few people as possible.

  9. “In contrast, in slightly wetter parts of Mongolia the largest glaciers did date from the ice age but reached their maximum lengths tens of thousands of years earlier in the glacial period rather than at its culmination, around 20,000 years ago, when glaciers around most of the planet peaked.”
    That is actually true for parts of the main Eurasian ice sheet as well. The eastern part on Taimyr reached its maximum size about 110,000 years ago, 90,000 years before the western part. Once the western part grew big and high the eastern end ended up in rain shadow:
    https://www.researchgate.net/publication/223294900_Late_Quaternary_ice_sheet_history_of_Northern_Eurasia

    • According to the alarmists, because the LIA didn’t stop and start everywhere at the same time, it didn’t happen.
      You have just proven that the last ice age didn’t happen either.

      • Who ARE these alarmists? Is there a list of all their beliefs I’ve missed? What does one have to do to qualify as an alarmist?

      • Kristi really does believe that anything she wasn’t taught in her indoctrination courses, doesn’t exist.

      • An alarmist is anyone that believes that CO2 below 33C actually emits any IR. Since most of the troposphere is less than that, CO2 actually causes a little cooling when combined with water vapour. In any case even the IPCC has admitted that in the last century the average temp has increased less than 1C. Since mankind has burned fossil fuels for the greater part of the last century, even if CO2 had been the cause of most of that increase in temperature that would be a good thing. Plants need more than 400 ppm CO2 to thrive. We actually need more CO2 in our atmosphere NOT LESS. The danger level for CO2 in submarines is 8000 ppm. Mankind could burn every last ounce of fossil fuel on earth and we would never reach that amount. As for runaway global warming at that amount of CO2, water vapour would still be more important as a greenhouse gas. As for more CO2 causing more H2O you need more evaporation to cause more water vapour. To get more evaporation you need higher temperatures A trace gas like CO2 cannot 1st cause higher temperatures on its own. The physics of global warming with a planet surface of 70% water is just not viable.

  10. There was another surprising exception to the glaciation which is the Cypress Hills in Alberta and Saskatchewan. Plants survived there which are quite different from the surrounding area.
    The explanation is that the glaciers bulldozed their way down the Great Plains. (This is to say that they did not form in place due to an accretion of snow.) The Cypress Hills didn’t get glaciated because they were high enough that the advancing glaciers went around them.
    The bottom line is that the presence of a glacier at a particular spot doesn’t necessarily indicate that it is there because of snowfall in that spot.

  11. “The bottom line is that the presence of a glacier at a particular spot doesn’t necessarily indicate that it is there because of snowfall in that spot.”
    Actually it is never due exclusively to snowfall in that spot since the definition of a glacier is that the ice in it moves.

    • +10 ….there is a very interesting pattern in their graphs. They show, imo, that peak rain/snow for their area occurs at solar maximum. The opposite holds true. The lowest points on the graphs align with low sunspot numbers. This is a second direct solar connection to weather patterns with some level of cyclicity in the pattern. This is the first time that I have seen this alignment. Typically, I see the opposite in many other areas/regions fo the globe.

  12. Would reduced transpiration from plants have reduced the moisture available for the growth of Gobi glaciers?
    I ask because my peer review paper suggested that low CO2 conditions during the Last Glacial Maximum (LGM) turned the high plateaus of the Gobi into a huge CO2 desert. (Not an aridity desert, as we have now, but a CO2 desert – a location where plants can no longer grow because of insufficient CO2.).
    However, the lack of plants across the Gobi may have also reduced leaf transpiration and humidity levels. I seem to remember the same argument being made for the reducing glaciers on Kilimanjaro. In which case, glaciers around the Gobi would have been denied sufficient moisture, until CO2 levels rose again after the LGM, when plants returned the the Gobi plateau. (Most of the Gobi is pasture land, not a true desert.)
    See:
    Modulation of Ice Ages via Dust and Albedo
    https://ac.els-cdn.com/S1674987116300305/1-s2.0-S1674987116300305-main.pdf?_tid=c101b95d-2db2-477a-84f2-869fc21af49b&acdnat=1520367159_ead37b5b85dea3f0e2efd327f1f05bb6
    Ralph

    • Another possibility is, again, dust. The dust originating in central Asia is said to have prevented the build-up of ice sheets in the part of Siberia that lies to the North of it – why not also in central Asia itself?

      • Hi, Mike.
        True. That fits in even better with the ‘dust albedo’ theory. We know that the Gobi was producing copious amounts of new dust during the LGM, because the dust deposits on the Loess Plateau tell us so.
        The Loess Plateau has deep dust deposits that go back a milliion years, and precisely record the climatic changes of the many ice ages. These demonstrate that during glacial periods the Gobi was producing prodigious amounts of dust (because it had become a CO2 desert). And when that dust falls upon ice sheets, it lowers their albedo and allows them to melt.
        So any glaciers in the Gobi region could have been reduced during the LGM by two processes. Lower humidity reducing snowfall. And more dust causing increased ablation and melting.
        Ralph
        (Mike is a co-author on the Ice Age Modulation paper).
        .

      • Could be. The Taklamakan desert seems to have a key role. Even as far away as Greenland most of the dust is sourced from Taklamakan.
        Taklamakan is in the Tarim basin which is surrounded by very high mountains on all sides. So it is in extreme rain shadow and is always hyperarid, whether the climate is interglacial or glacial. And the high mountains are also an inexhaustable source of sediment to be winnowed for dust. It may be the largest contiguous sand desert on Earth (most deserts are actually mostly hammada, rock desert).
        I’ve flown over the Taklamakan several times but never really seen it – a dust veil always seems to be hanging over it.

    • To answer your question about the plants (or try anyway)… I don’t think they’d be up there. In order to transpire enough to get adequate CO2, they would have to have plenty of water in the soil. Having to struggle with dust in the air and leaves, plus a weak sun…there might be some plants that would survive – it’s amazing what conditions organisms can adapt to, and an interesting question. Haven’t found an answer yet. I’d expect them along (intermittent) watercourses and lakes, in sheltered areas…they would be low, deep-rooted, with small thick leaves if present at all. Maybe some grasses, I don’t know.
      “However, the lack of plants across the Gobi may have also reduced leaf transpiration and humidity levels.”
      Yes, definitely.
      “The author standing on the very center Baltoro Glacier in the Himalayas. Surface ice quickly melts, because the albedo-assisted daytime temperatures are quite high, even in October at 5500 m altitude, leaving a rocky ice-free surface”
      I didn’t understand this. Are you on a layer of rocks that’s on ice? Or how can you be in the center of the glacier? Is it a ring shape?
      Seems like the albedo would depend a lot on the kind of dust that’s deposited. Is it in layers, deposited seasonally? Sorry if it’s in the paper; I read most of it but not all.
      I’ve never heard of plantago grass and couldn’t find it online, except when it looked like a typo, but I didn’t look exhaustively.. Is it a true grass?
      Interesting idea. It’s pretty hard to say what was more important on balance, the dust on the snow or in the air. I guess the patterns of deposition and the amounts at different times would be
      https://i2.wp.com/www.pnas.org/content/108/15/5925/F1.large.jpg

      • You have your relationship backwards.
        The more CO2 in the air means the plants transpire less water, therefore need less water to survive.

      • >>You have your relationship backwards.
        Not so. I was not referring to the known relationship between CO2 and transpiration (which is mentioned in the paper). I was referring to the relationship between traspiration from vegetated regions, and a lack of transpiration fromdesert regions (turned to desert by a lack of CO2).
        R

      • >>I didn’t understand this. Are you on a layer of rocks
        >>that’s on ice? Or how can you be in the center of the glacier?
        Yes. The entire Baltoro glacier is a field of rocks, lying on top of the ice. The point being made is that dust (or rocks) on ice sheets remain on the surface, and are not easily washed away. And the LGM ice sheets would have had 10,000 years of dust layers within the top layers.
        So when the ice sheets finally begin to ablate and melt, at the beginning of the interglacial warming period, the dust remains on the surface of the ice sheets and concentrates on the surface, getting thicker and thicker with lower and lower albedo, as the years pass. You might notice this if you have been to Canada or Scandinavia, where they scatter grit on the roads and pavements, to give you some grip. The darker and warmer grit melts and embeds itself into the surface of the ice, and cannot be washed away, so remains effective all winter.
        R
        Modern industrial dust remaining on the Greenland ice sheet…
        https://www.motherjones.com/wp-content/uploads/box-snow-2-630.jpg

  13. ”….temperatures were colder…” I have never seen one of these (Or a hot one, blue one, green or even rainbow coloured one) Are they animal, vegetable or mineral? I have come across lower ones, higher ones and even average ones but never met any other types.

    • Mark W “You have your relationship backwards.
      The more CO2 in the air means the plants transpire less water, therefore need less water to survive.”
      Just because plants need less doesn’t mean they will use less. A happy plant could grow heaps in its CO2 fortified environment then along comes a summer drought and it’s put on so much leaf material it can’t do well even at high water use efficiency. I don’t know what you’re referring to, though. I was talking about low-CO2, low-water, low-temp conditions.

  14. I am sure precipitation (or lack of it) is the main factor in all glacier forming (sorry : perhaps a low temperature is as important!). I have heard that Eskimos were living in North Siberia, along the coast of the Arctic Ocean, during the ice age. So that ocean must have been open most of the time – to provide enough precipitation to the main ice sheets. (??)

    • “So that ocean must have been open most of the time – to provide enough precipitation to the main ice sheets.”
      Definitely not. The moisture came from the Atlantic and the Pacific. The extremely low biological productivity and extensive iceberg plow-marks clearly shows that the Arctic ocean was frozen over, much of it probably by shelf-ice. There may have been limited icecaps along the coastline north of Eastern Siberia, but that is uncertain.
      And northeastern Siberia seems to have been uninhabited for most of the last ice-age despite the fairly rich fauna. It is only after the LGM that there are signs of humans in the Indigirka and Kolyma basins.

  15. As l have suggested for a number of years now, l don’t think the lack of ice sheets in eastern Asia was just due to the lack of snowfall. The big factor l think was that it just got to warm during the summer months for any ice sheets to last.
    One of the big clues for me was that any ice sheet that did form was largely confined to the high ground. Just what you would expect in a warmer climate. Also a other factor is the fact that animals were able to use the land bridge to get from Asia to N America. For them to do be able to do so, there must have been a ready food supply at least during the summer months. Otherwise how would they have made the trip.
    The large ice sheets over NW Russia and the drying out of the climate in central Asia. Suggests to me the weather was a large part of the cause of the ice sheets. As l think large areas of low pressure over northern Russia were more common back then. Which would have dragged cold air and snow over NW Russia. When this lower pressure forms over northern Russia there tends to be high pressure over central eastern Asia. l think it was this type of weather patterning that lead to the drier climate over central Asia.

    • “One of the big clues for me was that any ice sheet that did form was largely confined to the high ground. Just what you would expect in a warmer climate.”
      And in a dry climate. Only in the mountains would there be enough orographic rain to feed glaciers.
      “The large ice sheets over NW Russia and the drying out of the climate in central Asia. Suggests to me the weather was a large part of the cause of the ice sheets. As l think large areas of low pressure over northern Russia were more common back then.”
      Ice sheets are almost invariably high-pressure areas.

  16. The glacial/nonglacial history of South America and New Zealand show big advances of numerous alpine glaciers, but no really big ice sheets as in N. America. With hundreds of 14C and 10Be dates, we now know that these glaciers were almost exactly synchronous with the N. American ice sheet and alpine chronology. The significance of this is that it means that whatever caused the Ice Ages, it acted abruptly and simultaneously in both hemispheres (ie., it can’t be Milankovitch–to slow and no lag–or CO2–lags temp).
    Every glaciologist knows that all glaciers are not the same and may behave differently. There are numerous cases where small cirque glaciers adjacent to long valley glaciers don’t react the same way to temp changes. The Mongolian glaciers are what they are–in a place of extreme dryness where they may well not react the same way as the rest of the world’s glaciers.

    • How far back to these South American chronologies go though? I don’t recall having seen anything going further back than some 20-25,000 years (but I don’t work in the field).

    • Both the Patagonian and the South Island icecaps are beatiful examples of the importance of precipitation and topography for glaciation. On the western, wet, side of the mountains the icesheets grew to the edge of the continental shelf. On the eastern, dry, side the end moraines are in the foothills or in the valley mouths. In both places there are beutiful examples of fiords on the west side and their inland equivalent moraine-dammed mountain lakes like Lago Argentino or Lake Wanaka on the eastern side.
      In both cases there were periglacial steppes to the east.

    • The significance of this is that it means that whatever caused the Ice Ages, it acted abruptly and simultaneously in both hemispheres (ie., it can’t be Milankovitch–to slow and no lag–or CO2–lags temp).
      Not true.
      The decline into each glacial maximum was not rapid – in fact it took up to 110 kyrs to reach the full glacial maximum. Plus every decline into an ice age was coincident with declining NH Milankovitch insolation (whether precession dominated or obliquity dominated), and this connection was indeed causal. In the same fashion, the decline in temperature from the recent Holocene Maximum is also in perfect phase with the decline in Milankovitch insolation (see image below). (On this occasion the decline is dominated by obliquity, because precession is currently in a quiescent era due to low eccentricity).
      The fact that the decline (and rise) in ice age temperatures is dependent solely on Northern Hemisphere Milankovitch minimums and maximums (not SH influences) is due to albedo being the primary feedback mechanism, rather than CO2, and the predominance of land masses in the NH. A SH Milankovitch minimum or maximim has very little leverage, as it is mainly acting on open water. Whereas a NH Milankovitch minimum can spread a thin ice sheet across a large portion of the NH, which will raise global albedo and reject a large proportion of the subsequent summer insolation. When calculated regionally and seasonally, this reduction in insolation absorption is significant, in the order of hundreds of W/m2. Conversely, old dust laden ice sheets (which only happens at the very end of an ice age) will have reduced albedo and absorb huge amounts of extra insolation, resulting in ablation, melting, and an interglacial.
      The ice age cycle makes no sense with CO2 as the primary feedback agent. Because when CO2 is at a maximum the world cools, and when CO2 is at a minimum the world warms. This paradoxical temperature response is difficult to explain, with CO2 as the primary feedback agent.
      But ice ages are easy to explain with albedo as the primary feedback agent. Pristine new ice sheets spreading out across the NH (due to Milankovitch cooling) have a significant albedo increasing and temperature decreasing effect. Conversely, old ice sheets covered in dust (which only happens at the end of an ice age) have a significan albedo lowering and temperature increasing effect. This also explains why interglacials reach a natural maximum temperature, instead of going into a hypothesised CO2 runaway warming condition. Albedo reaches a natural minimum when the major ice sheets have all melted, and so there is no further feedback agent to cause further warming. Thus interglacial warming has a natural maximum, and it is unlikely that modern CO2 increases will have a significant effect (because we have already demonstrated that CO2 is not the primary ice age feedback agent.)
      Ralph
      Holocene temperatures (black) are following obliquity (purple)…
      https://i1.wp.com/www.euanmearns.com/wp-content/uploads/2016/05/Figure-9.png

  17. “We were expecting to find rocks exposed for 20,000 years, the date of the peak of the last ice age, but these moraines were much younger. That means that these glaciers were smaller when the climate was the coldest,” Batbaatar said. “The results were so surprising that we went back to double check.”
    Scientists should not expect their findings or find them surprising, they should document and verify.

  18. Patrick MJD ‘Scientists should not expect their findings or find them surprising, they should document and verify.”
    Why shouldn’t scientists be surprised??? They’re human, and surprising things happen in science. That’s the wonder of it. To be surprised about something doesn’t mean one is expecting something specific, and even if one is, that doesn’t mean one isn’t a good scientist, it happens all the time. That why the scientific methodology is employed to eliminate (or at least minimize) possibility of bias. This stuff was drilled into me in college and grad school; I’m surprised scientists here don’t talk about it more.
    There’s a pervasive idea that scientists have been corrupted, poisoned by groupthink and ideological perversion, and it bothers me more than what the future will bring.

    • Kristi,
      The point that Patrick is trying to make is that the ideal researcher is what has been called the “disinterested observer.” That is, someone whose mind is open and objective and does not have preconceptions. Preconceptions open one to confirmation bias. One often sees what they expect to see, as illustrated by many artistic ‘optical illusions.’ Something that you were probably not exposed to in your undergraduate training (but many of the geologist here were) is Chamberlain’s Method of Multiple Working Hypotheses. I would highly recommend that you search for it online and read it.

      • I’m well aware of what Patrick is saying. I have made a bit of a study of cognitive errors and biases, how easily the mind is manipulated, and how it is done. That’s one reason sites like these drive me crazy: It is everywhere these days, though, not just here. But scientific bias? That’s old hat to me., both from undergrad and grad school.
        Obviously if one is surprised, one is not seeing what one expects to see.
        Scientists aren’t trained to have no bias – that would be impossible. Scientists are (or should be, as I was) trained to be aware of the propensity for human bias and to work to avoid it in the way they form hypotheses, design experiments and interpret the results. They often provide caveats, discuss contradictory work, and often weaknesses in the research. This is what I see in the best publications; some aren’t so thorough.
        Certainly it is always good to be aware of alternate hypotheses, and that ability is part of what makes a good scientist. Sometime alternates can be tested at once within the same experiment.

    • Kristi, if the IDEA that scientists have been corrupted bothers you, it is the FACT that a small number of scientists appear to have been corrupted (and that a larger number appear to have been intimidated into going along with ideas that they don’t really subscribe to in order to protect their careers), that bothers us.

      • Sometimes you have to question appearances, especially when they are actively promoted despite what the verdicts of several investigations say. When committee after committee looked into it, they could have no way of knowing there wasn’t going to be a whistle blower coming next. They aren’t going to stake all their careers on protecting a few corrupt scientists. I’ve other things to say about that fiasco, but not now.

    • Well this should bother you. Science is in a crisis. As of 2017 nearly 50% of all scientific papers have invalid conclusions or the reports couldn’t be duplicated with the submitted data.. Over the last 30 years scientific fraud has increased 10 fold. Of those 50% of bad papers 43% of those 50% are fraudulent papers. These fraudulent papers get into other reports as references and then contaminate other subsequent reports like a cancer, I shudder to think what the % of bad climate papers there is Probably approaching 99% when you consider that just to get published you have to have a line in the paper that worships global warming. Studies on drug papers have placed the fraud as high as 60 % and with cancer studies the results could not be replicated in 80%. of them.

  19. So, ice can lose mass and shrink in a cold, dry environment, anyone who has left ice cubes in the freezer for
    too long knows that. These scientists got paid how much to figure that out?

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