Desperate Claim: Greenland's 2015 melt records consistent with 'Arctic amplification'

From Columbia University and the “any weather event is now proof of global warming” department comes this reach of a paper trying to claim that a northern jet stream excursion is a signature of “Arctic amplification”. I don’t put much stock in it especially when Nature had an editorial a few years ago that said:

Better models are needed before exceptional events can be reliably linked to global warming.

And in this case, they are citing a single event to claim “Arctic amplification” has set in. I’m sorry, I just don’t buy it. We are told by climate alarmists that any cold event, such as a cold winter, or a string of record low temperatures don’t mean anything in the context of climate, that it is the trends of events that matter, not the individual events. Now, we are asked to believe that one event, a cut-off high pressure system in summer of 2015 is the signature of an Arctic-scale climate change. Forecasters are well aware of this sort of blocking high.


Even the IPCC AR4 suggests that the high latitudes in the Northern Hemisphere were likely as warm, or warmer, than present in the past:


Timing and intensity of temperature deviations from pre-industrial levels during the past 12,000 years. Note that Greenland and most of the high latitudes in the Northern Hemisphere were likely as warm, or warmer, than present for multi-millennial periods since the end of the last Ice Age Source: IPCC, AR4, Chapter 6, page 462

Plus, they make the claim:

Jet stream reached northern latitudes never before recorded

We don’t have reliable weather maps that can accurately portray the position of the jet stream over Greenland prior to World War II, when the phenomenon was observed, as this reference in Wikipedia notes:

Many sources credit real understanding of the nature of jet streams to regular and repeated flight-path traversals during World War II. Flyers consistently noticed westerly tailwinds in excess of 100 mph (160 km/h) in flights, for example, from the US to the UK.[11] Similarly in 1944 a team of American meteorologists in Guam, including Reid Bryson, had enough observations to forecast very high west winds that would slow bombers going to Japan.[12]

It wasn’t until around 1950, that it began to be tracked regularly, so the “never before recorded” claim really doesn’t mean much in the scope of weather patterns for Greenland when you only have about 60 years of data.

The recent conditions in Greenland likely do not represent an aberrant fluctuation in the region’s climate or the beginning of “Arctic amplification”. Instead, events like the summer of 2015 lie within the known limits of natural variations that just haven’t been seen in the 60+ years of jet stream position data we are aware of.

Also, lead author Tedesco has made some baseless claims in the past regarding Greenland:  Ridiculous claim by Marco Tedesco: ‘Darkening of the Greenland Ice Sheet is projected to continue as a consequence of continued climate warming’ where he completely ignored the contribution of soot to the changing albedo of the Greenland ice sheet.


So, I don’t think the claim about Arctic amplification they are making is all that credible; the claim from a single event is a big stretch.

Here’s the PR via Eurekalert:

Greenland’s 2015 melt records consistent with ‘Arctic amplification’

Jet stream reached northern latitudes never before recorded


Following record-high temperatures and melting records that affected northwest Greenland in summer 2015, a new study provides the first evidence linking melting in Greenland to the anticipated effects of a phenomenon known as Arctic amplification.

Arctic amplification, in the simplest terms, is the faster warming of the Arctic compared to the rest of the Northern Hemisphere as sea ice disappears. It is fueled by a feedback loop: rising global temperatures are melting Arctic sea ice, leaving dark open water that absorbs more solar radiation, and that warms the Arctic even more. Arctic amplification is well documented, but its effects on the atmosphere are more widely debated. One hypothesis suggests that the shrinking temperature difference between the Arctic and the mid-latitudes will lead to a slowing of the jet stream, which circles the northern latitudes and normally keeps frigid polar air sharply separated from warmer air in the south. Slower winds could create wilder swings of the jet stream, allowing warm, moist air to penetrate farther north.

The new study, published this week in Nature Communications, shows that those anticipated effects occurred over northern Greenland during the summer of 2015, including a northern swing of the jet stream that reached latitudes never before recorded in Greenland at that time of year.

This animation shows changes in the polar jet stream from June 1, 2015 to July 31, 2015. The jet stream is approximated by crosses. The northerly shift of the jet stream may be linked to a warming arctic, and record melt of the Greenland ice sheet in 2015. CREDIT Marco Tedesco/Lamont-Doherty Earth Observatory

“How much and where Greenland melts can change depending on how things change elsewhere on earth,” said lead author Marco Tedesco, a research professor at Columbia University’s Lamont-Doherty Earth Observatory and adjunct scientist at NASA Goddard Institute for Space Studies. “If loss of sea ice is driving changes in the jet stream, the jet stream is changing Greenland, and this, in turn, has an impact on the Arctic system as well as the climate. It’s a system, it is strongly interconnected and we have to approach it as such.”

The Greenland ice sheet, earth’s second largest after Antarctica, holds enough ice that, if it were to melt entirely, it would raise average global sea level by about seven meters. Understanding the drivers of melting is critical to understanding how quickly and by how much sea level will rise in the future and how Greenland’s freshwater runoff will affect ocean circulation and ecology.

Northwest Greenland’s summer of melt started in June 2015, when a high-pressure ridge squeezed off from the jet stream, the study shows. It moved westward over Greenland until it sat over the Arctic Ocean and affected weather across the island through mid-July.

That high-pressure system, called a cut-off high, brought clear skies and warmed northern Greenland, helping set records for surface temperature and meltwater runoff in the northwest, the study shows. With less summer snow falling and melting underway, northern Greenland’s albedo, or reflectivity, also decreased. A less-reflective surface absorbs more solar energy, which feeds more melting, as Tedesco illustrated in a study earlier this year on the darkening of Greenland.

Northern Greenland also set an unusual July record for wind: the winds blew east to west on average, rather the usual west to east; only two other years on record show easterly winds on average in July, both slower. At the same time, the jet stream’s northernmost ridge swung farther north than ever recorded for that month, passing 76 degrees North latitude, nearly 2 degrees farther north than the previous July record, set in 2009, the authors write.

The same atmospheric pattern had a different impact on southern Greenland, where new melting records have been set over the past decade. The south saw more snow during summer of 2015 and less melting than previous years.

The authors stop short of confirming Arctic amplification as the cause of the warming, but they say the results fit the anticipated effects of Arctic amplification described by Jennifer Francis of Rutgers University and Stephan Vavrus of the University of Wisconsin in a 2012 paper.

Recent studies exploring the potential effects of Arctic amplification have showed that high-pressure blocks connected to northward swings of the jet stream have become more common near Greenland. Edward Hanna of the University of Sheffield, a co-author of the new Nature Communications paper, released a study in May using the Greenland Blocking Index to measure the strength of stationary high-pressure systems over the past 165 years and found that seven of the top 11 systems had occurred since 2007.

“The significant increase in Greenland high-pressure blocking that has occurred in the last 20 to 30 years is clearly related to recent record warming over the region, as well as jet-stream changes,” Hanna said. “This makes it more likely than not that within the next five to 10 years we will witness further record Greenland melt events like in 2012 and 2015.”

“The Arctic is full of climate surprises, and Greenland is a key player,” said James Overland, an oceanographer and climate scientist at the National Oceanic and Atmospheric Administration who was not involved in the new study. “Climate models suggest a 4 degree Celsius Arctic temperature increase by mid-century, but such jet stream related surprises acting on Greenland as reported by Tedesco et al. can accelerate Arctic climate change.”

Whether the patterns seen in 2015 will continue in the future remains to be seen. This spring, Arctic sea ice set another record low for its maximum extent for the year. “Greenland also experienced early season melt in early April of this year comparable to April 2012. Record setting melt occurred later that summer, but it is too early to tell whether the same will hold true in 2016,” said co-author Thomas Mote of the University of Georgia.

“The conditions we saw in the past aren’t necessarily the conditions of the future,” Tedesco said. “If humans change the forcing, we are going into uncharted territory.”


The other co-authors of the newpaper are Xavier Fettweis of University of Liege; Jeyavinoth Jeyaratnam, James Booth, and Rajashree Datta of City College of New York; and Kate Briggs of University of Leeds. The study was supported by funding from NASA’s Interdisciplinary Data Science Program, NASA’s Cryosphere Program and the National Science Foundation.

The paper, “Arctic cut-off high drives the poleward shift of a new Greenland melting record,” is available from the author.

91 thoughts on “Desperate Claim: Greenland's 2015 melt records consistent with 'Arctic amplification'

    • When alarmists present “ever” as the timeframe, it is presented in the context of hundreds and thousands of years. It would be more accurate if they were to state “in our record set of 65 years, this has never been recorded”. They are creating a lie of omission through either incompetence, intent, or laziness. Either way, their timeframes are horribly misleading.

      • As soon as you see ” consistent with” , it means that there is a very vague resemble from which they can not make any statistically meaningful claim or show any real correlation.
        My hair loss since 1965 is “consistent with” global warming. I don’t think that merits a pal-reviewed paper though.

    • I no longer believe any global warming studies done by any of those uber liberal pseudo think groups like Columbia. They usually begin with flawed / biased theses and digress from there. Usually!!! They used to have really bright people…, now…, not so much.

    • Considering we’ve been hearing constantly about 18 years of satellite data, I’d say 65 years is a start.
      But about those satellites – the full data record shows that lower troposphere in the North Polar region has been warming far faster than the rest of the world –
      Global = +0.13C decade
      N Hemisphere = +0.176
      N Polar = +0.337
      Also, why does this post complain that “where he completely ignored the contribution of soot to the changing albedo of the Greenland ice sheet.” in an earlier study this year?
      Here’s Tedesco discussing soot on Greenland ice sheet in The Cryosphere: “The darkening of the Greenland ice sheet: trends, drivers, and projections (1981–2100)”
      “Analysis of MAR outputs indicates that the observed albedo decrease is attributable to the combined effects of increased near-surface air temperatures, which enhanced melt and promoted growth in snow grain size and the expansion of bare ice areas, and to trends in light-absorbing impurities (LAI) on the snow and ice surfaces. Neither aerosol models nor in situ and remote sensing observations indicate increasing trends in LAI in the atmosphere over Greenland. Similarly, an analysis of the number of fires and BC emissions from fires points to the absence of trends for such quantities. This suggests that the apparent increase of LAI in snow and ice might be related to the exposure of a “dark band” of dirty ice and to increased consolidation of LAI at the surface with melt, not to increased aerosol deposition.”
      The press release posted above also provides a reference to a longer data set for the high-pressure blocking – 165 years.
      “The authors stop short of confirming Arctic amplification as the cause of the warming, but they say the results fit the anticipated effects of Arctic amplification described by Jennifer Francis of Rutgers University and Stephan Vavrus of the University of Wisconsin in a 2012 paper.
      Recent studies exploring the potential effects of Arctic amplification have showed that high-pressure blocks connected to northward swings of the jet stream have become more common near Greenland. Edward Hanna of the University of Sheffield, a co-author of the new Nature Communications paper, released a study in May using the Greenland Blocking Index to measure the strength of stationary high-pressure systems over the past 165 years and found that seven of the top 11 systems had occurred since 2007.”

      • I agree completely. We have a paper that looks at 65 years of high quality data, and 160 or so years of less accurate, but still useful data, and that stops short of claiming proof of arctic amplification, stating instead that their results would be consistent with such a thing.
        And what do we get here? They get called desperate, on the basis that it could be something else, and that they don’t have records for the entirety of history?? FFS, really?
        If that makes them look desperate, then how do you think publishing Christopher Monckton’s climate speedometer comparing surface temperate predictions with lower troposphere makes this place look?
        There is precious little actual scientific criticism in Anthony’s article, and even less information about what the paper actually says.

    • “I think somebody should document how climate change caused Donald Trump.”
      It’s related, no? Polls show that climate change is the last thing on everyone’s mind, but our elected officials make it top priority. It seems they just don’t listen to us. I do find it amusing to watch the Donald stomp through topics where others tread so lightly. Love him or hate him, he’s sure changed the landscape.

      • The models didn’t allow for equal parts methane and kryptonite hooking up to form the new molecule Trump!

  1. Interesting graphics from the IPCC (shown above): during the warm Holocene Optimum most of the tropical seas were COLDER than pre-industrial.
    If that’s correct, what could be a possible explanation for this phenomenon?

    • “…what could be a possible explanation for this phenomenon”
      Well, it’s way before the heat from man-made CO2 began hiding in the deep oceans.

    • Just as curious to me is the fact that temps BOTH colder and warmer than modern ones co-existed at mid-latitudes. Lead authors of IPCC, AR4, Chapter 6, page 462 are Jansen and Overpeck are not skeptics. The slow roll-over of ocean thermoclines underrated for effects on the earth’s atmosphere.

    • It could be an effect induced by the oceans having risen and mixed rapidly from the last of the ice sheets melting away. That mixing along with the mixing from rising waters would cool the average ocean surface, and it would then take some time for the oceans to warm up the entire system.

      • An additional though is that new currents in the oceans could have been initiated by the returning ice sheet melt. The new currents would have caused new weather/climate patterns for some time, until the energy drained out of the new currents as the original main currents reasserted themselves over time. at which point the oceans would normalize.

    • In addition: it would be interesting to know, whether the tropics stayed at the same temperature when in the second half of the Holocene the earth as a whole was cooling down. If so:
      1. this should support the idea of a maximum temperature for the tropics (Willis Eschenbach)
      2. the warming of the earth in the first part of the Holocene did result in a different transport of energy: more energy was transported to the north and to the south, and in the Pacific around the equator more to the west. Isn’t that what is happening right now also?
      Recently I read about a widening of the Hadley cells during the recent warming: the tropics were ‘growing’ north- and southward. And so creating ‘more tropics’.
      And spreading the total energy over a more extended surface?

    • Maybe you need another ‘e’ in peer, in other words “pee’er”, one who is peeing. Which brings us to some old-time colloquial expressions favored by my grandfather, “Quit piddling around and get down to business” and “You’re in a piddling business, ain’t you?” Piddling being an old term for peeing and used to express contempt for an ineffectual, pointless, or inappropriate action or activity.

    • mpcraig
      The “Peer review” system is substantially broken. Not just in the case of climate “science” but in many other disciplines as well. Several meta studies have shown that well over half of “hard” sciences papers are irreproducible.
      In my sector I know of a paper that is up for peer review, and that my colleagues – tops in the field- should get to comment on but will not be asked – they’re known to be skeptical of the approach taken by the authors, for asking difficult questions and pointing out things that don’t add up. So that particular paper will get “peer reviewed”, published, probably in some pretty prestigious publication, will then be cited but even if scientifically unsound, will likely never get retracted.
      It’s the result of the “publish or perish” that has become the hallmark of the other “complex” – the government funds all science complex- that Eisenhower warned us about in his farewell speech in 1961. Far more pernicious and dangerous to society – because so much policy is based on the bad “science”- than the much vilified “military industrial complex” that the Union of Concerned Scientists and their “progressive” ilk like to complain about.
      Ironically, the best “peer review” available today is on the web. When people like Nick Lewis or Steve McIntyre put their research / analysis / conclusions out there for everyone to have a go at, they are in fact doing just like scientists did during the Renaissance and the Enlightenment – let people criticize their work who are not compromised by the need to keep on securing grants or maintain their status in the “establishment” [Trenberth, Schmidt, etc.] or who run the risk of being academically ostracized [just ask Judith Curry] for questioning the dogma.
      Ad a consequence of the breakdown of “peer review” -supposed to work as a self-correcting mechanism- wide ranging environmental, energy and by extension economic policies are today being based on climate “science” that belongs in the same category quasi religious garbage as homeopathy or astrology.
      Sad, sad, sad…, and very dangerous..

      • I agree with and commend highly your comment on many levels, tetris, but not this particular aspect;
        “Far more pernicious and dangerous to society – because so much policy is based on the bad “science”- than the much vilified “military industrial complex” ”
        I think we are facing something akin to what the military folks call “full spectrum dominance”, when it comes to the early warnings of Mr.s Eisenhower, and Kennedy. Corruption is not easily “compartmentalized”, and few sacred cows are purebreds these days, me thinks. Though both realms (and others) surely have noble warriors who stand defiantly in the breach, thank God . . or we would not be still be able to have this conversation, it seems to me.

  2. Dinosaur farts????? (A bunch of methane in those big beasts……(OK, /sark/)

  3. Following links from this article leads to the short/informative YouTube video that tells of “Glacier girl”:

    In 1942, a squadron of US Army P-38 aircraft was forced by severe weather to crash-land on the Greenland icecap. All the airmen survived and were rescued. The aircraft remained
    One P-38 was recovered in 1992 and restored in 2007, and completed the original flight plan to England.
    When the plane was recovered in Greenland, is was buried under 250 feet of ice
    Hmmmm . . . NASA/NOAA told us in the 1970s that 30 years of global cooling was indicating a return to “Ice Age conditions”. Then the Northern Atlantic Oscillation index switched from negative to positive (as it does every 30 years or so), coinciding with the beginning of “Global Warming TM” that extended to about 2000.
    Now we have the Pause for about 18 years.
    NASA/NOAA have corrupted the past temperature record by “adjusting” the past colder and warming the present. The 1940-1970 cooling no longer exists in the NASA/NOAA record, which only shows “dangerous, accelerating warming” since 1970 to today 2016
    So when did all that snow fall on the P-38s in Greenland, and hos did all that snow get converted to ice and preserved for about 75 years??

    • Not this nonsense again?
      It’s called a glacier, because glaciers move.
      Snow falls at the top and the weight of the accumulating snow pushes the ice at the bottom out.
      That the plane was recovered under 250 feet of ice is not evidence that the ice field is 250 feet higher. In all probability the top of the glacier is within a foot or two (either way) of where it was when the plane landed in 1942.
      What has happened is that 250 feet of ice formed from new snow, while 250 feet of ice was squeezed out the bottom and has been sent down the mountain towards the sea.

      • Yea it is ok to err but if you don’t learn, you just make a fool of yourself.
        SMB is positive that is snow accumulates in Greenland.

      • Never said it didn’t.
        Just that it’s bad form to cite invalid evidence.
        The fact that this plane is now 250 ft under the surface of the ice proves nothing.

      • MarkW –
        Stop and think about what you are saying. Frankly, it matters not a whit whether the P-38s landed on the stable part of the ice cap or on part that has flowed down to the sea in the intervening 75 years.
        The fact that the aircraft were recovered from beneath 250 feet of glacial ice means that they were BURIED by far more than 250 feet of snowfall – whether they were standing still on the cap or moving glacially toward the Atlantic coast.
        Unless you are suggesting that ice formed at higher elevations somehow flowed over the P-38s (what evidence??), your point is irrelevant.
        A P-38 in the ice column that is absolutely known to have been “installed” in 1942 provides an absolute time-marker for what happened thereafter.
        You still didn’t answer the question – “So when did all that snow fall on the P-38s in Greenland, and how did all that snow get converted to ice and preserved for about 75 years??”
        Facts please, no arm-waving

      • “The fact that this plane is now 250 ft under the surface of the ice proves nothing.”
        That statement is incorrect and meaningless … but assuming you meant something else …
        Its reasonable proof that that there was more than 264 feet of accumulated precipitation that fell over the area over in the 50 year period that the accumulated snow was compressed to the 264 feet of ice that was over the plane (unless you are thinking that the plane came to rest right a sink and the adjacent ice fell in on it).
        [The plane is now in a museum]

      • Nobody has ever denied that snow falls on Greenland.
        The depth of the plane says nothing about whether snowfall in the interior is exceeding the melting at the coasts.
        Many have tried to use the fact that a lot of snow has fallen on Greenland as proof that it can’t possibly be losing ice.

    • I have posted this background on Glacier Girl elsewhere but repost it here for those interested:
      Why those aircraft were there in the first place:
      The reason those aircraft were there was because of the Battle of the Atlantic. For the US to become engaged it had to get it’s fighting forces and their equipment to where the action was. With the German U-boats sinking so many allied ships during 1942 and early 1943 shipping, especially across the N Atlantic, was a big problem. The allies would not truly gain the upper hand in the Battle of the Atlantic until May of 1943.
      In April 1942 the US Army Air Force (AAF) began it’s initial deployments to England which was the beginning of what would be come the Eighth, Ninth, and Twelfth Air Forces. The heavy bombers, at this point all B-17s, could fly over on their own but what about fighter aircraft? At the time the Lockheed P-38F and G models were the only combat worthy US fighter aircraft ready for deployment that had the range to make it to where it was needed.
      They would be staged across starting from Goose Bay, Labrador with stops in Greenland and Iceland before landing in Scotland. Of course this had to be done over vast stretches of deadly cold water across a region of the world with some of the worst and least predictable weather on the globe during a time when the tools for weather forecasting and navigational aids were nothing like what we have today. Add to that the Germans broadcasting false navigation beacon signals.
      Because of the navigation involved and the need for long range CW (think morse code) communications a B-17 was assigned to be the mother ship for each flight of six P-38 fighters.
      This was a wise decision though the fact that out of the first flight of B-17s attempting the flight across the N. Atlantic three were lost (crews recovered) gave reason for some worry.
      The situation was so desperate that the AAF determined that a loss of 10% of the aircraft and pilots in transit would be an acceptable loss.
      In the end a total of 179 P-38s made it across the N. Atlantic in 1942 out of 186 that attempted and only one pilot was lost. The N. Atlantic route was considered closed during the winter months but it was a quite impressive performance for the time.
      By the summer of 1943 the Battle of the Atlantic was well on the way to being won and the miracle of production from US yards was beginning to show up. It was much cheaper to ship the aircraft and a scheme for carrying them on the decks of oil tankers worked so well that the numbers being shipped were more than adequate so there was no reason to ferry the P-38s over the great white north again.
      However if things had not gone well and the allies had not gained control of the shipping lanes the Army already had a contingency plan to ferry 4,000 aircraft across the Atlantic in 1943.
      Most of the information above was extracted from:
      Fork-Tailed Devil
      by Martin Caiden
      An excellent history of the development and deployment of the Lockheed P-38 Lightning.

  4. Consider the sources. Tedesco is joint at Columbia Lamont and GISS. Core warmunist institutions. Not surprising that they take a single blocking high weather event and claim unprecedented CAGW. Its their standard MO.

  5. Has anyone actually ever analyzed the dark material to determine if it is carbon soot or volcanic ash? Seems to me that Icelandic volcanoes should be a prime suspect.

    • According to AGW basic theory, natural events are not able to cause anything. Please write that down before we get brought up on charges in California.

    • Go to:
      Select the August 2013 blog page from the menu on the right side of the page.
      Look at the second image on the August 2013 blog:
      The caption reads:
      boots on the ice offer a close look (and to sample) impurities concentrating at the surface. The fact is, much of this dark material is from cyanobacteria and blue-green algae. Photo J. Box.
      There you have it, ‘cyanobacteria and blue-green algae’ from Jason Box, a colleague of Tedesco.

  6. If data on the jet stream position is only available for the past 60 or so years, and in that time the jet stream position that the paper reports on has never been recorded, then how can you say that the jet stream falls within the natural variation?

      • I can’t say it’s not natural and I don’t make that claim. The authors of the study also never say that it doesn’t lie within the natural variation. They simply say it’s consistent with what is expected of polar amplification. However, this blog article does say that these events “lie within the known limits of natural variations that just haven’t been seen in the 60+ years of jet stream position data.” That’s a pretty definitive statement with no proof whatsoever. How can something be within the known limits if it’s never been seen before?

  7. Whenever you see a nice, precise, scientific term like ‘is consistent with’, you can translate it to ‘this is most likely meaningless, but we can use it to support our position’. After all, it can be ‘consistent with’ just about anything.

  8. Actually, temperatures may have been warmer in the high northern latitudes than the AR4 map suggests. As Patrick Michaels pointed out back in 2007 (, the red areas in the map are based on MacDonald, G.M., et al., 2000. Holocene treeline history and climate change across northern Eurasia. Quaternary Research, 53, 302-311. AR4 labels the red areas “Above pre-industrial by 2C or more.” But according to MacDonald et al., “During the period of maximum forest extension, the mean July temperatures along the northern coastline of Russia may have been 2.5° to 7.0°C warmer than modern.”

  9. From the article: “One hypothesis suggests that the shrinking temperature difference between the Arctic and the mid-latitudes will lead to a slowing of the jet stream,”
    Is there any evidence of a shrinking temperature difference between the Arctic and the mid-latitudes?

  10. From the article: “Northern Greenland also set an unusual July record for wind: the winds blew east to west on average, rather the usual west to east; only two other years on record show easterly winds on average in July, both slower.”
    It would make sense that winds would blow east to west if Greenland was sitting under the southern part of the high pressure system. I don’t see anything unusual here

  11. From the article: “The authors stop short of confirming Arctic amplification as the cause of the warming,”
    Yeah, it’s time to stop. You are already out on that limb far enough.

  12. Meridional Flow vs Zonal Flow
    The number of long waves is largely influenced by the magnitude of the north/south temperature gradient – when the thermal gradient is weak, typically in summer, then the westerlies are able to meander rather more than in winter and early spring, when the flow is stronger.
    So, if anything, Meridional flow is evidence that the thermal gradient is weak.

    • ferdberple wrote: “So, if anything, Meridional flow is evidence that the thermal gradient is weak.”
      That would be a good explanation for why tornadoes have been fewer and less powerful in recent years.

    • I saw your comment after I posted my comment above. Do you think the meridional component would present itself in Winter if mid-latitudes were as relatively cold as the poles? Also we must remember the jet stream is very high(usually) in the atmosphere where the gradient between high and low latitudes is already significantly less.

  13. From the article: “Recent studies exploring the potential effects of Arctic amplification have showed that high-pressure blocks connected to northward swings of the jet stream have become more common near Greenland.”
    We get high-pressure blocks here in the central U.S. all the time. Just about every summer. Like clockwork.
    Maybe the central U.S. blocking high is the controlling factor. Which came first, the central U.S. blocking high, or the Greenland blocking high? 🙂

    • On average, there are between 3 and 7 such waves in each hemisphere, and considering just for the moment the Northern Hemisphere, there are two that are regarded as semi-permanent features: one roughly downstream of the North American Rockies, and another downwind of the Himalya range. The position of these features, plus their semi-permanence, suggest that the massive mountain chains involved are the primary reason for their existence. The mechanism is almost certainly a need to conserve absolute vorticity in a column of the atmosphere that is forced to climb abruptly in this fashion.

  14. 1. CO2 causes global warming
    2. Thus, anything that does not cause global warming cannot be CO2.
    3. Peaches in the springtime do not cause global warming
    4. Thus 3 supports 2, and since 2 is equivalent to 1, 3 supports 1.
    Thus peaches in springtime are evidence that CO2 causes global warming.

  15. The self-deception the climate obsessed engage in is rather subtle. “Arctic Amplification” is an emergent phenomenon that is *always* taking place, high CO2, low CO2, warming or cooling. “Arctic Amplification” is due to the fundamental physics of air movement on a rotating globe.
    The thinking behind the alarmist assertion that a particular weather pattern is due to CO2 is not really very different than some dark ages “scholar” deciding that a particular outbreak of disease was due to the wrath of God for the sins of the afflicted region.

  16. We have drifted into the realm of – a website that dealt with the evolution/creationism controversy. On the one side conventional scientist and on the other side religious fundamentalists claiming to be scientists. You will find over 10 years worth of blogs.
    WUWT is in the same predicament. The skeptics are the scientists, the climate alarmists claim to be scientists but are essentially ideologically based. As with the evolution/creation controversy, there can be no resolution if the two side use different criteria for deciding truth.
    As Karl Popper said ” A theory that explains everything, explains nothing”.
    Burning of fossil fuels explains everything. It has become the God Zeus of Greek Mythology. All weather could be explained by the action of Zeus.

  17. Zonal Jet – Positive PDO and El Nino. Meridianal Jet – Negative PDO and La Nina. It’s not rocket science.

  18. ‘The recent conditions in Greenland likely do not represent an aberrant fluctuation in the region’s climate or the beginning of “Arctic amplification” …’.
    In an overall warming climate, whatever the causes, the temperatures recorded in the ‘30s and ‘40s would need to be, or expected to be, exceeded.
    And at the other extreme Antartica has recorded no warming in the 60 + years of Climate Change™.

  19. It’s consistent with arctic amplification then how come it hasn’t been amplified till now. They’ve been predicting arctic ice free in 2000, then 2007, 2013, 2017 now the IPCC says there may be some ice in the arctic in 2100. Why is amplification kicking in now? Did they predict that or is this new science again for the “settled science.” Do they have any reason for this or is it like all the heat from 57% of CO2 for 20 years has somehow snuck into the ocean below 1000 feet from 5000 feet in the atmosphere that they can’t explain?
    Also, maybe they could explain those warm arctic conditions in the 1930s and 40s which exceed todays. Is that part of arctic amplification back then before we had put much co2 into the atmosphere? Or is that some other amplification?
    By the way when you look back at the AMO/PDO cycles over the last 120 years at least you will notice that there is a large El Nino that occurs in both previous down phases of AMO/PDO about halfway into the downphase which happens to be right around this year/last year. It was almost predictable by looking at past AMO/PDO cycles. If the past is repeated we will go back to the rest of the down phase for another 15 years. If 5 years from now temperatures (unadjusted please) are up significantly from today then something has changed and maybe there is a leg they can stand on but as of today the climate is following the exact same cycle it has in past PDO/AMO cycles.

    • Good post, and I liked the link a lot. I read it back then, but memory fails me often so thanks for the reminder.
      The 30’s and 40’s were very warm times and the government data sets use very corrupt methods to hide that fact.

    • It’s a modeled estimate, a reanalysis. Not all that reliable from the scant data we had back then.
      As I said, jet stream tracking really didn’t take off until WWII when modern methods began to be adapted. From Weather Bureau history:

      The inability of kite and aircraft meteorographs to achieve high altitudes, operate in all weather, and provide data in real-time helped foster the development for the radio transmission of upper-air data. In the late 1920’s, scientists began suspending crude radio transmitters from free balloons and by the early 1930’s the first radio-meteorographs or “radiosondes” were being flown into the stratosphere. In 1937 the Weather Bureau established a network of radiosonde stations that has continued to the present day. Click here to see maps of current radiosonde station locations in the United States.
      World War II increased the needs for upper-air data and accelerated the development of radiosonde components and the growth of observational networks. Furthermore, advances were made in radio-direction finding or radio-theodolite technology that allowed the radiosonde to be tracked in flight so that winds aloft could be obtained. Such observations became known as “rawinsonde” observations. Initially, radio-theodolites were adjusted by hand to track the in-flight radiosonde, but by the 1950s automated radio-theodolites (ART) were implemented, which are still used today.

      So just like your “BEST” data, the uncertainty range gets very large in the past due to scant and questionable observation methods of the upper atmosphere.
      Note he huge uncertainty ranges in gray.
      So in the case of upper air data, prior to the 1937 establishment of the radiosonde network (and that was only in the USA, global adoption followed later, just like it did for the advent of the Stevenson Screen in 1890) there was not much good upper air data for the Greenland area, and reanalysis of data isn’t the same as actual observations.
      Your point fails.
      [edited to fix spelling – Anthony]

  20. Another so-called “climate scientist” who turns out to be a non-reader. Had he bothered to read my Arctic paper in Energy and Environment [1] he would know that Arctic amplification was put to rest by Polyakov. There is Arctic warming, yes, but it is neither greenhouse warming nor Arctic amplification. Its cause is warm water from the Gulf Stream directed at the Arctic as a result of a major rearrangement of the North Atlantic current system at the turn of the twentieth century. Prior to this there was nothing there except for thousand years of slow cooling. The warming started suddenly but was then interrupted by a thirty year cold spell. It resumed in 1970 and is still active. Most observations of Arctic warming start around 1980 and miss the entire history of how it got started.
    [1] Arno Arrak “Arctic Warming is not greenhouse warming” E&E(22)8:1069-1083(2011)

  21. Yikes! Greenland being warmer while Hudson Bay persistently frozen is…WHAT CAUSES ICE AGES.
    That is, when Hudson Bay is colder and icier than Greenland or Alaska, this is exactly what causes most of Canada and the Northeast/Great Lakes region to stay frozen, too. This is very scary stuff.

  22. Posted elsewhere as a rebuttal
    “I don’t think Anthony knows what Arctic amplification is”
    Polar amplification is the expected warming at both poles [repeat both poles] expected of GHG increased warming of the world.
    Arctic amplification is a phenomenon at one pole only.
    It can occur as part of Polar amplification [expected], but as the graph you provide [elsewhere] shows is not occurring.
    Arctic amplification can also occur from local factors otherwise known as weather or natural variation.
    A third possibility is that the arctic amplification is real but the Antarctic disamplification is occurring from local factors otherwise known as weather or natural variation.
    Either way, until we have a bipolar agreement[funny/sad in medical terms] on what and which form of Arctic Amplification we are talking about, WUWT does have a legitimate point.

  23. Arctic amplification behaves different to the alarmists have always claimed. High pressure around Greenland and Iceland region has lead to warmer climate there with negative AO and NAO. The climate cools in the very same region during long phases of positive AO and NAO. This is opposite to the alarmist view that a positive NAO/AO will lead to Arctic warming when the opposite actually happens.
    This is shown below using a Central England Temperature style for other parts of the North Atlantic region comparing global warming periods 1901-1930 and 1975-2004 compared with cooling period between 1931 and 1970. Representing the phases of the AMO and trends in AO and NAO.
    The England Central Temperature below shows how winter months are particular affected. (all values are in degrees c) The winters warm during global warming period episodes, but cool during global cooling period episodes related to the AO and NAO.
    —–CET——– Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
    1901-1930 4.2 4.2 5.5 7.6 11.3 13.8 15.8 15.2 13.1 9.8 5.8 4.5 9.3
    1931-1970 3.4 3.8 5.8 8.4 11.4 14.6 16.0 15.8 13.7 10.3 6.6 4.4 9.5
    1975-2004 4.2 4.3 6.4 8.2 11.5 14.3 16.6 16.5 13.9 10.6 7.1 4.9 9.9
    Areas near or in the Arctic circle show warmer temperatures during global cooling episodes and colder temperatures during global warming episodes.
    Southern Greenland
    1901-1930—– -8.5 -8.9 -7.1 -3.7 1.2 4.8 6.8 6.3 3.4 -0.9 -4.5 -6.9 -1.5
    1931-1970—– -7.1 -7.2 -6.3 -3.2 1.8 5.3 7.2 6.7 3.9 -0.2 -3.4 -5.9 -0.7
    1975-2004—– -7.7 -8.3 -8.1 -3.7 0.6 4.1 6.4 6.1 3.5 -0.4 -3.5 -6.1 -1.4
    1901-1930—– -1.5 -1.1 -0.6 1.7 5.6 9.4 11.1 9.9 7.3 3.3 0.3 -1.0 3.7
    1931-1970—– -0.7 -0.7 0.3 2.6 6.7 9.7 11.2 10.7 8.2 4.3 1.6 -0.1 4.5
    1975-2004—– -1.3 -0.7 -0.3 2.3 6.0 9.1 10.9 10.6 7.3 3.7 1.0 -0.6 4.0
    Regions in lower latitudes especially closest to Greenland/Iceland, where cold air is transferred from the Arctic during these negative AO and NAO phases show similar trends to the CET.
    1901-1930—– -2.6 -2.6 -1.0 2.4 6.5 10.3 13.2 12.0 8.8 4.2 0.5 -1.6 4.2
    1931-1970—– -2.8 -3.1 -1.0 2.5 6.9 10.7 13.2 12.7 9.4 5.1 1.5 -1.1 4.5
    1975-2004—– -2.3 -2.2 -0.2 2.9 7.5 10.9 13.3 12.9 9.2 5.1 1.2 -1.5 4.7
    1901-1930—– -8.3 -8.5 -4.8 1.2 7.2 13.1 16.2 14.2 9.3 3.3 -2.0 -6.4 2.9
    1931-1970—– -9.0 -9.0 -5.3 1.5 7.9 13.8 16.8 15.2 9.9 4.1 -1.1 -5.6 3.3
    1975-2004—– -8.5 -8.1 -3.3 2.2 8.6 13.9 16.5 14.5 9.5 3.8 -1.9 -6.5 3.4
    1901-1930—– 3.9 3.7 4.3 6.1 9.0 11.6 13.3 12.9 11.2 8.5 5.4 4.2 7.9
    1931-1970—– 3.0 3.2 4.8 6.8 9.4 12.4 13.7 13.6 11.8 9.1 5.7 4.0 8.1
    1975-2004—– 3.4 3.6 5.1 6.9 9.7 12.3 14.2 14.1 11.8 9.0 6.0 4.1 8.3
    Winters are warmer in this Arctic region when the NAO and AO are negative, but cooler in the countries in lower latitudes. The opposite also applies to when the NAO and AO are positive with winters cooler in this Arctic region, but warmer in the countries in lower latitudes. The Arctic amplification has occurred in periods before and can be seen easily in past station temperature data sets.

  24. I had written an article concerning Arctic Amplification as the authors Francis and Vavrus claimed it was tied to causing amplification of planetary Rossby waves as these latest authors suggest. But my article with an application of atmospheric science demonstrates there is no theoretical basis for these authors or the new ones here to make such a claim. Anthony published it here on WUWT last March.
    As usual, their “evidence” is nothing more than anecdotal with no proof offered for any of their claims. Like so many of the authors who publish in climate journals, the absence of any good theory is substituted with an act of faith that the authors have discovered something profound. The paper is more nonsense and no different than the flawed research paper submitted on AA by Francis and Vavrus in 2012.
    If the arctic temperatures are indeed being amplified under GHG theory ( the records also show a weak case for this ) the associated dips and bends ( amplification of planetary Rossby waves ) in the jetstream waves according to the correct physics would have to DECREASE in amplitude, develop shorter wave lengths and migrate to a higher latitude. This is the OPPOSITE of what is claimed in both of these papers.
    Apparently the desire to be dishonest about severe weather, floods and temperature extremes is important to the researchers here who want to be able to blame any sort of weather extreme on their phony “climate change” propaganda.

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