CLAIM: Melting of Arctic mountain glaciers unprecedented in the past 400 years

From AGU and the “one mountain is not the planet” department. I wonder if they considered natural ocean cycles as a driver here? I wonder if they considered soot deposition on snow. Probably not. They go straight to the industrial revolution. What’s ironic is that without the industrial revolution and fossil fuels, they wouldn’t be able to fly there in helicopters (see video below) to measure and complain about it.


WASHINGTON D.C. — Glaciers in Alaska’s Denali National Park are melting faster than at any time in the past four centuries because of rising summer temperatures, a new study finds.

New ice cores taken from the summit of Mt. Hunter in Denali National Park show summers there are least 1.2-2 degrees Celsius (2.2-3.6 degrees Fahrenheit) warmer than summers were during the 18th, 19th, and early 20th centuries. The warming at Mt. Hunter is about double the amount of warming that has occurred during the summer at areas at sea level in Alaska over the same time period, according to the new research.

Scientists spent a month in Denali National Park in 2013 drilling ice cores from the summit plateau of Mt. Hunter. The ice cores showed the glaciers on Mt. Hunter are melting more now than at any time in the past 400 years. Credit: Dominic Winski.

The warmer temperatures are melting 60 times more snow from Mt. Hunter today than the amount of snow that melted during the summer before the start of the industrial period 150 years ago, according to the study. More snow now melts on Mt. Hunter than at any time in the past 400 years, said Dominic Winski, a glaciologist at Dartmouth College in Hanover, New Hampshire and lead author of the new study published in the Journal of Geophysical Research: Atmospheres, a journal of the American Geophysical Union.

The new study’s results show the Alaska Range has been warming rapidly for at least a century. The Alaska Range is an arc of mountains in southern Alaska home to Denali, North America’s highest peak.

The warming correlates with hotter temperatures in the tropical Pacific Ocean, according to the study’s authors. Previous research has shown the tropical Pacific has warmed over the past century due to increased greenhouse gas emissions.

The study’s authors conclude warming of the tropical Pacific Ocean has contributed to the unprecedented melting of Mt. Hunter’s glaciers by altering how air moves from the tropics to the poles. They suspect melting of mountain glaciers may accelerate faster than melting of sea level glaciers as the Arctic continues to warm.

Understanding how mountain glaciers are responding to climate change is important because they provide fresh water to many heavily-populated areas of the globe and can contribute to sea level rise, Winski said.

“The natural climate system has changed since the onset of the anthropogenic era,” he said. “In the North Pacific, this means temperature and precipitation patterns are different today than they were during the preindustrial period.”

Assembling a long-term temperature record

Winski and 11 other researchers from Dartmouth College, the University of Maine and the University of New Hampshire drilled ice cores from Mt. Hunter in June 2013. They wanted to better understand how the climate of the Alaska Range has changed over the past several hundred years, because few weather station records of past climate in mountainous areas go back further than 1950.

Researchers drill an ice core at their camp on the summit plateau of Mt. Hunter.

Credit: Dominic Winski.

The research team drilled two ice cores from a glacier on Mt. Hunter’s summit plateau, 13,000 feet above sea level. The ice cores captured climate conditions on the mountain going back to the mid-17th century.

The physical properties of the ice showed the researchers what the mountain’s past climate was like. Bands of darker ice with no bubbles indicated times when snow on the glacier had melted in past summers before re-freezing.

Winski and his team counted all the dark bands – the melt layers – from each ice core and used each melt layer’s position in the core to determine when each melt event occurred. The more melt events they observed in a given year, the warmer the summer.

They found melt events occur 57 times more frequently today than they did 150 years ago. In fact, they counted only four years with melt events prior to 1850. They also found the total amount of annual meltwater in the cores has increased 60-fold over the past 150 years.

One of the ice cores taken from Mt. Hunter in June 2013. The bands of dark ice represent times when glacier snow melted and refroze in past summers. Credit: Dominic Winski.

The surge in melt events corresponds to a summer temperature increase of at least 1.2-2 degrees Celsius (2.2-3.6 degrees Fahrenheit) relative to the warmest periods of the 18thand 19th centuries, with nearly all of the increase occurring in the last 100 years. Because there were so few melt events before the start of the 20th century, the temperature change over the past few centuries could be even higher, Winski said.

Connecting the Arctic to the tropics

The research team compared the temperature changes at Mt. Hunter with those from lower elevations in Alaska and in the Pacific Ocean. Glaciers on Mt. Hunter are easily influenced by temperature variations in the tropical Pacific Ocean because there are no large mountains to the south to block incoming winds from the coast, according to the researchers.

They found during years with more melt events on Mt. Hunter, tropical Pacific temperatures were higher. The researchers suspect warmer temperatures in the tropical Pacific Ocean amplify warming at high elevations in the Arctic by changing air circulation patterns. Warmer tropics lead to higher atmospheric pressures and more sunny days over the Alaska Range, which contribute to more glacial melting in the summer, Winski said.

“This adds to the growing body of research showing that changes in the tropical Pacific can manifest in changes across the globe,” said Luke Trusel, a glaciologist at Rowan University in Glassboro, New Jersey who was not connected to the study. “It’s adding to the growing picture that what we’re seeing today is unusual.”

###

This research article is available for free for 30 days. A PDF copy of the article can be downloaded at the following link: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017JD027539.

Advertisements

113 thoughts on “CLAIM: Melting of Arctic mountain glaciers unprecedented in the past 400 years

    • So is the flooding of the East Side highway in Manhattan, so are the droughts in Northern Cali, so is the snow in the UK

  1. So it is warmer now than 150 years ago? It was the end of the Little Ice Age then, so of course it should be warmer.

    • I was thinking the same thing. It is always good to check but, this study just confirms what many thought already regardless of CAGW.

      • I find it interesting that their core was 200 meters deep down to bedrock and was found to be 400 years old at the base of the glacier. Does this mean that the glacier wasn’t there 400 years ago? It would also seem to indicate that the glacier grew at a rate of around 1/2 meter per year (though probably faster due to current melting)

    • Suggested new title for their paper: “Arctic Ice Cores Provide More Evidence of the Extent of the ‘Little Ice Age'”.

      • …but these core provided evidence of a global phenomena … the Little Ice Age was a local phenomena

      • Neo:”…but these core provided evidence of a global phenomena … the Little Ice Age was a local phenomena”
        False!

      • Yes, it is also interesting to note that they attributed much of the melting to the warm North Pacific Ocean. The warming in the North Pacific is directly related to the effects of El Nino and all folks (both Skeptics and Alarmists) agree that El Nino is related to the Solar effects on the ocean and is NOT related to CO2 at all. Also, this ties directly to the effect of melting occurring multiple times over a long time-period. Doesn’t this tell us that the AGW is non-existent since CO2 has been increasing at a relatively constant rate since the 1950’s.

    • Never mind the ‘little ice age’ how about the warminess compared to the last ice age and apparently the warming was all natural…..or was it? Perhaps those damned neanderthals got their just deserts.
      /sarc

    • As I always ask True Believers: “We’re coming out of an Ice Age, what should the climate be doing if not warming?”
      But I refuse to believe this report out of hand as I’m unsure that, in the #METOO era, I can’t tell if it has been approved by feminist glaciology.

      • Yup, but as sure as eggs are eggs, we’re heading back in to another full scale Ice Age eventually. Probably not in our lifetimes, but the geologically short warming periods in the current inter-glacial seem to be getting progressively cooler, from the Holocene Climate Optimum to the Minoan, Roman, Medieval and the current Modern Warming periods. The next hemisphere wide freeze is nearer then the last. The, relatively benign, warming interludes have seen the flourishing of civilisation, technology and agriculture and are to be rejoiced. The cooler periods in human history are more synonymous with pestilence, crop failures and premature deaths. What faces the generations to come is much darker and much more frightening. Sadly, few governments, and very few of the scientists that are ‘allowed’ to advise them now, seem to have even learned the lessons of our geological history or to be even planning for the inevitable colder future. Our surviving descendants will be shaking, no, shivering in disgust at the bizarre groupthink that has so hijacked the ‘so called’ most intelligent species on the planet that has led to the majority of our current leaders in the West in to believing that cool is ‘good’ and warm is ‘bad’. A fact clearly disputed by the increase in crop yields and human health in warm periods. In dictating that the modern warmth is so dangerous and harmful, unfortunately, their current policies have then crippled our future Western children’s ability to survive the forthcoming climatic viscitudes of this restless planet by denying them access to cheap, reliable and dispatchable energy. In the meantime, the Russians, Chinese and Indians etc are paying lip service to ‘climate change’ and carrying on regardless with their expansionist fossil fuel based programmes. When the temps drop, the sun doesn’t shine and the wind stops blowing what would you rather, a few solar panels and a windmill or a coal, gas or nuclear powered station? Thought so.

      • Given that Glacier Bay was frozen over with (wait for it) …glaciers… all the way to its mouth when the first ships went there in the late-1700’s, one would think that it obvious that the LIA at least extended to Alaska.
        According to naturalist John Muir those glaciers had reportedly retreated nearly all the way up the Bay by the 1880’s, well before warming from greenhouse gas emissions could have been a factor.

  2. Did the drilling go down deep enough to measure the rate of warming or melting 1100 to 1200 years ago
    or did they hit rock at the 400-500 year mark?

    • From the ‘supporting information files ( https://agupubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2F2017JD027539&attachmentId=2197340478 ), the glacial thickness at the ‘saddle’ center was 200 – 250m thick. Two cores are referenced: Core 1 ~ 100m, Core 2 ~ 150m. The ‘melt layer’ analyses only extend back to ~1785CE. The visual appearance of individual melt layers becomes more diffuse with increasing depth and the temporal spacing before 1935 gets quite wide.

    • My guess is that they had no interest in observing what must have been occurring during the 4-500 years leading up to, and thru, the LIA. Likewise, they’d have no interest in finding out how much worse the melt was during the MWP.
      A clue to this can be found here,
      Ancient trees emerge from frozen forest ‘tomb’
      Retreat of the Mendenhall Glacier reveals the remains of trees which grew more than 2,000 years ago:
      http://juneauempire.com/outdoors/2013-09-13/ancient-trees-emerge-frozen-forest-tomb#.UzBGVPldWjs
      Some, at the Exit Glacier in Alaska, were carbon dated to as recently as 700-800 years ago – before they were buried by hundreds of years of advancing ice. Perhaps soon, this warm cycle will last as long as the MWP, such that trees may once again take root and grow into beautiful life giving forests at those altitudes.
      It’s my understanding that most all of the glaciers in the CA Sierra’s disappeared during the MWP.

      • I mentioned the melting mendenhall glaciers a few years ago over at Skeptical Science which indicated that the MWP was far more widespread that the “regional” nature of the MWP.
        I got accused of A) cherry picking facts B) presenting facts that in no way disputed the scientific conclusion that the MWP was confined to the North atlantic and northwestern europe
        It also got me banned from posting at Skeptical science – Seems they dont appreciate legitimate questions of the science.

    • They drilled the cores 200 meters deep Down to Bedrock at the base of the glacier, as deep as they could go, so apparently ALL the ice in the glacier is no older than 400 years

      • Bingo.
        So the headline in the ‘abstract’ should be, “findings are that glaciers haven’t melted as much during this warming cycle as in the last one. If history repeats itself, then we should, naturally, see much more melting before the cold returns.”

      • I don’t spend much time thinking about this stuff, so forgive my stumbling ignorance: If the transit time of the glacier from the mountain top to the ocean is 400 years, wouldn’t that mean that only 400 years of ice were in the vertical column? (A rhetorical question, to be sure, now a real one or two) If the glacier moves more slowly, isn’t it necessarily older and all things equal, taller too? And isn’t it not necessarily true that 400 years of ice in a glacier doesn’t mean that the mountaintop was dry when the glacier began its descent?
        Thanks for any info!
        Another Joe

      • Joe – The non climate scientist
        The 200 meters down to bedrock was directly from the accompanying video presentation at the 0.46 mark

      • Thanks bryan
        That tends to confirm what we already know
        A) that we are warming since the end of the last ice age, and the rate of melting is consistent with a warming world
        B) that the elevated mwp was far more widespread than the gods of climate change are willing to admit. Though We skeptics already knew that.

  3. I have to admit I missed the paper on how oceans are warmed by CO2. Don’t understand what the mechanism might be. The oceans have far more influence on the atmosphere than the other way around.

    • Oceans aren’t warmed by CO2, they are warmed by the sun.
      However if the air above the oceans is warmer, then the energy being put in by the sun can’t get out as easily.

      • Doubt that warmer air above oceans retards heat loss. Oceans lose heat primarily by IR emission and water evaporation. Water saturated air above oceans would retard heat loss.

      • MarkW
        Not per our warmists friends, somehow they think CO2 in the atmosphere warms the ocean even before the air above is warmed. This has always been my beef about CO2 warming the oceans, i agree it MAY be possible but not without atmospheric warming first.

      • donb April 10, 2018 at 10:56 am
        “Doubt that warmer air above oceans retards heat loss.”
        Let’s look at a real world scenario. In February the Gulf of Mexico is generally at its coolest, usually in the mid to upper 50’s F due to colder, north winds passing over the water. This year we had a strong southerly air flow in February, air temp got into the 80’s F and the Gulf warmed up into the 70s F. When the wind shifted in March back to a colder, northern flow the water temps went back down into the 60s F.
        So, the Sun was able to warm the waters because the warmer air above retarded the heat loss to create a net heat gain. When the winds changed, the colder air above allowed more of the heat to be lost resulting in a net heat loss and the water temp went down. It is notable that the CO2 ppm didn’t change and the Sun angle was changed only slightly, to a higher angle, yet the water temps went down. Air temps matter.

      • @Tom in Florida;
        Are we talking the top couple of meters here or are we talking down to 50 or 100 meters?

      • D. J. Hawkins April 10, 2018 at 1:05 pm
        I don’t know what method they are using, but they label it “Gulf Temperature”.

      • Tom In Florida
        To extend that outcome, when warm winds from the mid latitudes travel to the Arctic (as they should) this would have the same affect on Arctic (and Antarctic) sea surface temperatures.
        The same apples to the sea surface temperatures where the warmer atmosphere travels during its transport to those destinations.
        So when we see a warm patch in the middle of the Pacific, Indian or Atlantic oceans, this same affect is occurring. The atmosphere may warm the surface skin of the water, but importantly it stops the release of heat from the deeper water, and gives a temperature anomaly.
        Please offer comment or guidance on my conclusions.
        Regards

      • re: Ozonebust April 10, 2018 at 2:43 pm
        I don’t think the air warms the water. Only the Sun’s energy can do that. However, it seems obvious that the air temperature can retard or hasten the heat flow from the water to the air. It’s all about the balance between what the Sun puts in and what the air temperature lets out.

  4. Does this study not imply that the ice/snow levels are continuing to rise on the glacier?
    And would not a period of heavy melting would not leave a record at all? So how do hey establish the age of any particular layer?
    If you are counting melt rings, then you are counting accumulation. A period of extreme melting could erase 1, 2, 3 or more layers in a summer!

    • Glaciers take in snow at the top, and expel ice at the bottom.
      The fact that new snow continues to fall at the top is not evidence that the glacier is growing.

    • Melting of Arctic mountain glaciers unprecedented in the past 400 years

      You do make a point!
      But then the title says “melting .. (is) unprecedented”. It doesn’t mention whether it was also accompanied by “unprecedented” deposition which would result in a net-net. It does make sense that if warmer air from the Pacific is causing more melting events, it would also be causing more snow events in the winter.
      I would have thought the research would be looking at the total picture or did they just decide to announce one side of it?

  5. If true, not surprising, since Earth has been warming for over 320 years, since the depths of the LIA during the Maunder Minimum.

  6. Four hundred years ago was in the middle of the Little Ice Age. It has been warming since the depth of the LIA. Glaciers melt when it is warmer. Duh.

  7. Scientists spent a month in Denali National Park in 2013 drilling ice cores from the summit plateau of Mt. Hunter.
    ==========
    Correction: scientists spent a month polluting the mountain with hydrocarbon emissions and waste heat and found they were melting the ice. News at 11. Researchers find fungus killing frogs.

    • I recall seeing a map that showed the steady expansion of moose range Northward across Alaska from approximately 1800 to the present. It has been warming there for over two hundred years. Besides that, 400 years? Who cares? What is the record for the last 4000 years? Glaciers have been much smaller in the not so distant past with no contribution from mankind. They refuse to look back beyond the “Anthropogenic Age” but extrapolate not fearlessly but with maximum terror into a future that they actually know nothing about. They seem to have pathetic little lives without any ability to see positive possibilities.

  8. Meanwhile, Hubbard Glacier, the largest calving glacier on the North American Continent in Alaska (25 percent larger than Rhode Island), advances. https://pubs.usgs.gov/fs/fs-001-03/
    Cherry picking mountain glaciers, like I just did, always gives nefarious results. Mountain glaciers are dependant on many criteria, such as aspect, elevation, micro climate, amongst other such many site specific details. It is not surprising that a south facing glacier on one side of the mountain would be losing mass, while a north facing glacier on the other side of the same mountain, would be growing. Making broad statements about long term climate prediction from such observations is a mugs game.

    • I think you are mostly correct but we have seen many, many instances of very deliberate cherry-picking by the alarmists on these kinds of situational facts. It is never an accident.

  9. “It’s adding to the growing picture that what we’re seeing today is unusual.”
    =========
    Unusual as compared to what???? Where is your baseline to establish “normal” climate.
    Maybe the climate yesterday was unusual and today is usual. If it rains today and yesterday was sunny, which day is unusual?

    • “If it rains today and yesterday was sunny, which day is unusual?” The one that doesn’t promote your agenda?

  10. The natural climate system has changed since the onset of the anthropogenic era,” he said. “In the North Pacific, this means temperature and precipitation patterns are different today than they were during the preindustrial period.

    The juxtaposition of natural climate system and preindustrial period cleverly lets us know the author’s unstated opinion that the changes in temperature and precipitation are due to mankind’s industrial activities. The possibility that the changes would have occurred regardless of human activity is casually dismissed as being unworthy of consideration.
    Are these scientists or priests?

  11. Were they REAL REAL scientists or activist “scientists”? Are all the people doing this kind of research at their core political activists?

  12. This report is further evidence that natural climate variability is far greater than the climate impact of humans. The warming started 70-80 years before the increase in atmospheric CO2 became significant. Any warming since then may have a human component, but it may also be largely a continuation of the natural warming.
    Like Edwin, above, I call foul when increasing atmospheric CO2 is blamed for warming the oceans, especially when the ocean started warming 80 years before the CO2 began to significantly increase!
    Overall, it sounds like these folks did some legitimate science for a change. Good for them! Their work may eventually be useful in studying climate change. But as long as a man-made climate crisis is the paradigm that pays for these expeditions, all observations, no matter how round, will be forced into that square hole, even when it is scientifically irrational to do so.

    • Yes this report points out that the warming in this area over the last 400 years has largely been due to changes in the weather. lf that’s the case in this area, then why not across other parts of the globe as well.?
      l also call BS on the claim that its CO2 levels that have caused ocean warming. But what this report does do is point out what may have been the real reason for the warming both in the Pacific and Alaska.
      Which is that there has been a general increase in higher pressure forming over the northern Pacific during this time leading to less cloud cover and lighter winds. At least during the summer months.

  13. “The ice cores captured climate conditions on the mountain going back to the mid-17th century”
    If the ice moves down the mountain to melt and provide drinking water for the area then how did they manage to get an ice core containing ice formed almost 400 years ago?.

  14. So it’s over a degree warmer than it was 400yrs ago. Yeah, I could have told you that. Where have these people been? I’ve come to recognize a type of prose that I call ‘hyperventing style’ – most unseemly for scientific communication.
    Here’s what you have. A very expensive research project is funded and mounted. Trump has put clime studies under a load of pressure. It takes a season’s work and the prof wants to get a paper out of it this year. After hundreds of thousands of dollars expended in the hope that the last couple of decades have witnessed imminent terminal extinction of the Hunter glacier, they come up with bupkis. Okay, let’s save what we can here. We have a smoking gun that it was colder and more icy during the Little Ice Age. In fact this warming is a hyperventilation emergency.
    I’ll bet the classic way of doing research in which one records the objective of the investigation is not done in clisci. They use the throw-the-crap-at -the-wall technique and see what terrible findings they can make stick.

  15. 57 times as fast? A number that high should make researchers step back and question the result. Even global warming theory shouldn’t support a number that high. Something else is happening.

    • ..bodies too…..they called it the Canada Ice Man…..and dated it right before Columbus got here

      • The local Yukon-BC Athabaskan people were more welcoming of scientific study of his remains than were my Yakima, Walla Walla, Umatilla and Cayuse neighbors of those of ~9000 year-old Kennewick Man, discovered a few years earlier, with the site promptly buried under tons of rock by the Army Corps of Engineers.

  16. So they same snow cores near the peak of Mt Hunter that determined that there has been a drastic reduction in snow. A drastic decrease in snow and 57 times more melting, and yet no mention of how they actually age dated the layers. Snow is quite stable at the base of a high mountain peak, right?

  17. It’s only going to get worse. Much, MUCH worse. I predict that we will see a 40-50 degree F rise very soon. By August at the latest. It’s already too late to stop it!
    At that rate, by next January or February, temperatures will be averaging around 120F. This is so unprecedented, who can say if the rise will be linear? Maybe we will have molten lava on the surface by December.
    Then you deniers will be sorry, won’t you?

  18. Archaeologists in Norway who are following a receding glacier and surveying the newly exposed ground for artefacts have so far retrieved more than 2000 items, dating from 4000BC to the medieval era. What does that suggest about the extent of the glacier at the start of that range?

      • Their mindless adherence to a morbid outlook in solidarity with climate alamism is hilarious!

        Many alpine snow patches are now melting away and important cultural and climatic specimens and information are being subjected to exposure and deterioration

        1. If the snow had not melted no one would have ever known about most of these artifacts in the first place.
        2. These artifacts were obviously subjected to exposure and deterioration BEFORE they were covered by snow thus supplying even more proof of a warmer period back then than now.

  19. First, they are playing fast and loose with the start of the industrial revolution. If I recall my history correctly, it began in the early 19th Century, more than 150 years ago. What happened closer to that date? The American Civil War of course! So that must be the cause, right? Climate never changes unless humans are involved.
    I recall seeing a video discussing unexplained archaeological finds. One was what certainly appeared to be a human footprint in rock with dinosaur prints in the same rock. I’m surprised that it isn’t used as proof that human activity caused the extinction of the dinosaurs 65 million years ago!

  20. Convenient…the LIA was fading away when they started the timeline. Pffft. Who paid for this ?

  21. Love the Alaska Range. The view of the Moonflower buttress on Hunter in the video brings back lots of memories. Mugs Stumps did the first ascent. What an amazing climb. It’s hard to appreciate the size until you stand under it. Alas, Mugs got buried while guiding on Denali. I’ve trids the West Ridge and SW Ridge of Hunter. Got buried in snow on the West Ridge. Scary place to be with avalanches kicking off all around. I also froze my ass on a winter attempt on Denali. Brrrrrr. Nice standing on the summit though.
    Just a FYI. If the helicopter is at the drill site, the drill site it isn’t on the summit plateau. The helicopter is sitting on the Kahiltna Glacier. I know the area very well. I didn’t watch the video

    • “….to drill the ice core, …” Simple question, since you’ve been there how representative do you think it is of what is going for the whole glacier? These sure get lots of pages and references and pretty graphs out of one sample, but did they take another for the deeper/older part? I live at 28° N latitude on the other side from Tom in Florida and a geologist friend showed up on his motorcycle with a heavy coat on this morning. Some days heat seems good since some of their cold is down here. Been quite a while since we had ice on the bay, but it did snow a little this winter. Gulf temperatures are usually given for the surface, some get influenced by inlets and wind.

  22. 400 years. Wow!!! That would mean since . . Umm 2018-400 years is 1618. It seems I’ve heard something about a cold spell called the Little Ice Age happening about then? Anybody?
    Bueller?
    Bueller?
    Bueller?

  23. Warmists just love the “melting glaciers” gambit, because it provides physical evidence of warming. But skeptics/climate realists don’t deny that there has been some warming, although the temperature record has been skewed, naturally towards warming. Still, the “disappearing glaciers” is good emotion-laden grist for the Warmists mill. The children won’t know what glaciers are! Oh my, think of the children.

  24. From the post:
    “The more melt events they observed in a given year, the warmer the summer.
    They found melt events occur 57 times more frequently today than they did 150 years ago. In fact, they counted only four years with melt events prior to 1850. They also found the total amount of annual meltwater in the cores has increased 60-fold over the past 150 years.”
    1850
    Golly that is about the time the LIA ended!
    Snicker……………

  25. Alaska was not iced over during the last ice age – animals grazed its grassy plains. It tends to seesaw the other way to the rest of US climate. So not a great bellwether of global climate.

  26. Claim: use of the word “unprecedented” is unprecedented in the last 40 years. It was invented by Paul Ehrlich.
    It’s the end of the world 🌍 as we know it and I feel fine.

  27. There is also a preoccupation with the US and ENSO here, that’s regional weather, a significant contributor perhaps, but not net global change, nor typical of the global situation, obviously as that isn’t the case elsewhere, on the facts. Just saying.

  28. “The physical properties of the ice showed the researchers what the mountain’s past climate was like. Bands of darker ice with no bubbles indicated times when snow on the glacier had melted in past summers before re-freezing.”

    Maybe…
    One small possibility is refrozen melt pools.
    A greater likelihood would be rain puddles that froze.

    “Scientists spent a month in Denali National Park in 2013 drilling ice cores from the summit plateau of Mt. Hunter. The ice cores showed the glaciers on Mt. Hunter are melting more now than at any time in the past 400 years.”

    Without wasting time searching for the “summit plateau” altitude, we can start with Mt. Hunter’s altitude of 13,900 feet (4,260 meters). Considering Mt. Hunter’s location Latitude at 63.4°, it is very doubtful that much melting occurs during their short summers.
    However, a warm front could dump liquid water that would likely freeze quickly.
    There is also the curiosity regarding the geological instability of the Denali range. How does one trust the data they gather from unstable mountains?
    https://pubs.usgs.gov/fs/2003/fs014-03/images/fig1.gif
    Once again, eager students, activist professors get a fun vacation while confirming their own confirmation bias.

  29. “Melting of Arctic mountain glaciers unprecedented in the past 400 years”
    Let’s see, what was happening 400 years ago? Oh, yeah, the depths of the last mini-ice age.

  30. Bloggers here blithely assert that the world is warmer now than a couple of hundred years age because we are recovering from the Little Ice Age.
    By what mechanism?
    Are we drawing on a reserve of stored heat?
    Or are we intercepting more heat from the sun?
    Or has Nature reduced the duration or extent of cloud cover?
    Some other way? Like???
    If you are to be a credible sceptic, you have to support your assertions with mechanisms and evidence. Geoff

    • Actually you don’t have to propose a mechanism to observe the fact of a warmer world, if it be a fact, as virtually all paleo proxy and unadjusted instrumental data show.
      The correlation between solar activity and climate however suggests a causal link.

      • Millennial-band climate spectrum resolved and linked to centennial-scale solar cycles
        https://www.sciencedirect.com/science/article/pii/S0277379104003063
        Spectral comparison of the Hulu Cave, GRIP, and GISP2 δ18O records suggests that the single dominant period centered on 1470 yr in the GISP2 spectrum, the so-called ‘1500-yr cycle’, is an artifact of the age model. The 230Th-dated Hulu Cave record indicates a millennial-band spectrum with a weak spectral peak near this period flanked by two stronger peaks centered on 1667 and 1190 -yr, similar to the GRIP δ18O record. All three millennial-band cycles may derive from heterodynes of centennial-band solar cycles as observed in the Holocene record of atmospheric 14C production. This suggests a link between centennial-scale solar variability and abrupt climate change at the millennial time scale.

      • As per Javier, 2017:
        https://judithcurry.com/2017/12/02/nature-unbound-vi-centennial-to-millennial-solar-cycles/
        Holocene climate has been affected in different periods by several centennial to millennial solar cycles. The ~ 1000-year Eddy solar cycle seems to have dominated Holocene climate variability between 11,500-4,000 years BP, and in the last two millennia, where it defines the Roman, Medieval, and Modern warm periods. The ~ 208-year de Vries solar cycle displays strong modulation by the ~ 2400-year Bray solar cycle, both in its cosmogenic isotope signature and in its climatic effects. The Centennial, and Pentadecadal solar cycles are observable in the last 400-year sunspot record, and they are responsible for the present extended solar minimum that started in 2008.

      • Cyclic rapid warming on centennial‐scale revealed by a 2650‐year stalagmite record of warm season temperature
        https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2003GL017352
        A 2650‐year (BC665‐AD1985) warm season (MJJA: May, June, July, August) temperature reconstruction is derived from a correlation between thickness variations in annual layers of a stalagmite from Shihua Cave, Beijing, China and instrumental meteorological records. Observations of soil CO2 and drip water suggest that the temperature signal is amplified by the soil‐organism‐CO2 system and recorded by the annual layer series. Our reconstruction reveals that centennial‐scale rapid warming occurred repeatedly following multicentenial cooling trends during the last millennia. These results correlate with different records from the Northern Hemisphere, indicating that the periodic alternation between cool and warm periods on a sub‐millennial scale had a sub‐hemispherical influence.

      • Millennial- to centennial-scale climate periodicities and forcing
        mechanisms in the westernmost Mediterranean for the past 20,000 yr
        http://www.ugr.es/~grupo179/pdf/Rodrigo%20Gamiz%202014.pdf
        Cyclostratigraphic analysis conducted on a continuous high-resolution marine record from the western most Mediterranean reveals well-identified paleoclimate cycles for the last 20,000 yr. The detrital proxies used (Si/Al, Ti/Al, Zr/Al, Mg/Al, K/Al, Rb/Al) are related to different sediment-transport mechanisms, including eolian dust and fluvial runoff, which involve fluctuations in the atmosphere–hydrosphere systems. These fluctuations are accompanied by changes in marine productivity (supported by Ba/Al) and bottom-water redox conditions (Cu/Al, V/Al, Zn/Al, Fe/Al, Mn/Al, U/Th). Spectral analysis conducted using the Lomb–Scargle periodogram and the achieved significance level implemented with the permutation test allowed us to establish major periodicities at 1300, 1515, 2000, and 5000 yr, and secondary peaks at 650, 1087, and 3000 yr. Some of these cycles also agree with those previously described in the North Atlantic Ocean and circum-Mediterranean records. The periodicities obtained at 2000 and 5000 yr support a global connection with records distributed at high, mid, and low latitudes associated with solar activity, monsoonal regime and orbital forcing. The 1300- and 1515-yr cycles appear to be linked with North Atlantic climate variability and the African monsoon system. Thus, the analyzed record provides evidence of climate cycles and plausible forcing mechanisms coupled with ocean–atmosphere fluctuations.

      • Cited in the above paper:
        Holocene climate variability of the Norwegian Atlantic Current during high and low solar insolation forcing
        https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2010PA002002
        A high‐resolution sediment core from the Vøring Plateau has been studied to document the centennial to millennial variability of the surface water conditions during the Holocene Climate Optimum (HCO) and the late Holocene period (LHP) in order to evaluate the effects of solar insolation on surface ocean climatology. Quantitative August summer sea surface temperatures (SSSTs) with a time resolution of 2–40 years are reconstructed by using three different diatom transfer function methods. Spectral‐ and scale‐space methods are applied to the records to explore the variability present in the time series at different time scales. The SSST development in core MD95‐2011 shows a delayed response to Northern Hemisphere maximum summer insolation at ∼11,000 years B.P. The record shows the maximum SSST of the HCO to be from 7.3 to 8.9 kyr B.P., which implies that the site was located in the regional warm water pool removed from the oceanic fronts and Arctic waters. Superimposed on the general cooling trend are higher‐frequency variabilities at time scales of 80–120, 210–320, 320–640, and 640–1280 years. The climate variations at the time scale of 320–640 years are documented both for periods of high and low solar orbital insolation. We found evidence that the submillennial‐scale mode of variability (640–900 years) in SSST evident during the LHP is directly associated with varying solar forcing. At the shorter scale of 260–450 years, the SSST during the LHP displays a lagged response to solar forcing with a phase‐locked behavior indicating the existence of a feedback mechanism in the climate system triggered by variations in the solar constant as well as the role of the thermal inertia of the ocean. The abruptness of the cooling events in the LHP, especially pronounced during the onsets of the Holocene Cold Period I (approximately 2300 years B.P.) and the Little Ice Age (approximately 550 years B.P.), can be explained by a shutdown of deep convection in the Nordic Seas in response to negative solar insolation anomalies. These cooling events are on the order of 1.5°C.

    • No, I disagree. Stating one does not find any of the proposed explanations credible, and stating one’s reasons why they are not credible, is sufficient. One does not have to come up with one’s own credible explanation. What you are tending towards is a version of the ad ignorantium fallacy==> because no one has a good argument explaining cycles between Milankovich cycles, it must be CO2.

  31. At 13000 ft what is the range of actual air temperature, and does it go above 32 Dec. For any extended periods during the summer?
    [The mods point out that very little air extends past 31 Dec. .mod]

  32. We are now in the Modern Warm Period and what is happening is what one would expect. How does glacial melting during the Modern Warm Period compare to what happened turing the previous Medevial Warm Period? There is no real evidence that what is happeing has anything to do with Mankind’s burning of fossil fuels.

  33. A paper on the last 2000 years of glacial advance and retreat. (just the abstract here)
    http://www.whoi.edu/cms/files/solomina16qsr_238964.pdf
    “A global compilation of glacier advances and retreats for the past two millennia grouped by 17 regions
    (excluding Antarctica) ”
    “The timing and scale of glacier fluctuations over the past two millennia varies greatly from region to
    region. However, the number of glacier advances shows a clear pattern for the high, mid and low latitudes
    and, hence, points to common forcing factors acting at the global scale. Globally, during the first
    millennium CE glaciers were smaller than between the advances in 13th to early 20th centuries CE. The
    precise extent of glacier retreat in the first millennium is not well defined; however, the most conservative
    estimates indicate that during the 1st and 2nd centuries in some regions glaciers were smaller
    than at the end of 20th/early 21st centuries. ”
    and
    “Other periods of glacier retreat are identified regionally
    during the 5th and 8th centuries in the European Alps, in the 3rde6th and 9th centuries in Norway,
    during the 10the13th centuries in southern Alaska, and in the 18th century in Spitsbergen. However, no
    single period of common global glacier retreat of centennial duration, except for the past century, has yet
    been identified. In contrast, the view that the Little Ice Age was a period of global glacier expansion
    beginning in the 13th century (or earlier) and reaching a maximum in 17the19th centuries is supported
    by our data.”
    So the question is are we actually seeing exceptional glacial retreat globally now?
    Maybe not.

  34. Unprecedented means it’s NEVER happened before. “Unprecedented in 400 years” is an oxymoron.

Comments are closed.