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What role did climate change play in this winter’s US freezes, heat, and drought?

Posted on 28 February 2018 by dana1981

This is a re-post from the Citizens' Climate Lobby Blog by Dana Nuccitelli and Doug Sinton, CCL Science Policy Network Team

There is growing scientific evidence suggesting that human-caused global warming is causing rapid changes in the Arctic, which in turn is altering the atmosphere, causing wavy patterns to form more frequently in the jet stream. On the West Coast, this can cause persistent high-pressure systems to form in the Pacific, exacerbating droughts by blocking storm systems. It can also allow frigid Arctic air to spill into the USA, creating especially cold winter weather. In sum, these freezes, heat, and droughts are made more likely by rising global temperatures, and as they rise further, such extremes may well become more common.

Abnormal winter weather

This winter, the eastern USA was hit by frigid cold weather, although at the same time, the western states (and most of the rest of the world) were relatively toasty:

Surface temperatures, Arctic, North America, NASA

North American surface temperatures for Dec. 26, 2017 – Jan. 2, 2018, from NASA Earth Observatory

This prompted a presidential tweet suggesting, “Perhaps we could use a little bit of that good old Global Warming.” It’s a natural reaction, when in the midst of frigid weather, to wonder how such cold conditions can strike in a world that’s being heated by global warming. However, scientific research has suggested that, counterintuitively, climate change appears to be playing a role in making these cold winter weather events happen more often in some regions.

Connecting global warming, the Arctic, and the wobbly jet stream

The jet stream plays a key role here. Jet streams are bands of fast-moving air currents about five to seven miles above Earth’s surface. The polar jet stream influences weather in North America, and in turn is influenced by changes in the Arctic due to human-caused global warming.

The Arctic is the fastest-warming part of the planet, in large part because sea ice is disappearing so rapidly. White ice is reflective, but dark oceans aren’t. When sea ice sitting on top of the ocean melts, the Arctic surface becomes less reflective, absorbing more sunlight, which in turn melts more ice in what’s known as a “positive feedback.” Because the colder Arctic is warming faster than the warmer area to its south (e.g. North America), the temperature difference between the regions is shrinking.  

That temperature difference is a big part of what normally keeps the jet stream strong and moving in a straight west-east line. When it shrinks, that allows more and larger wobbles (waves) to form in the weakened jet stream. As a result, weather patterns can get stuck as those waves slow down in the weaker jet, and the weather systems can become quasi-stationary or “blocked.” Picture a river with a slower current having more and larger meanders than a faster flowing one. (2)

Consequences: Drier West Coast, cold weather in the East

These jet stream waves (3) tend to cause different types of extreme weather in different parts of the country. On the West Coast, persistent high-pressure ridges tend to form in the Pacific Ocean, creating warm, dry weather in California as storms pass to its north. One such high pressure system, coined “the Ridiculously Resilient Ridge,” contributed to California’s 2012–2016 drought, which a 2014 study concluded was the state’s most intense in over 1200 years. A 2016 study published in “Science” found that these persistent high-pressure ridges are forming more often off the West Coast in a hotter world.

In the Midwest and on the East Coast, a southward dip in the jet stream tends to cold Arctic air to spill into those states. Rutgers climate scientist Jennifer Francis described this scenario:

“In response to the strengthened western ridge of atmospheric pressure, the winds of the jet stream usually also form a deeper, stronger trough downstream. Deep troughs act like an open refrigerator door, allowing frigid Arctic air to plunge southward, bringing misery to areas ill-prepared to handle it. Snowstorms in Texas, ice storms in Georgia and chilly snowbirds in Florida can all be blamed on the Terribly Tenacious Trough of December 2017 and January 2018.”

Jet stream trough Arctic air North America

While this is a topic of active research and significant uncertainty, a 2018 study published in “Nature Communications” found additional evidence that the jet stream has become increasingly wavy over the past 50 years, to a degree unprecedented in the past 290 years, which “can generate more frequent mid-latitude blocking patterns and facilitate persistent periods of extreme weather.”

How to accurately communicate climate-extreme weather connections

Communicating these sorts of climate-weather connections can be tricky. It’s often tempting to begin by hedging that “we can’t say that any given weather event was caused by global warming.” However, that approach emphasizes what we don’t know instead of what we do know.

A National Academy of Sciences’ Committee on Extreme Weather Events and Climate Change Attribution report tackled this question:

“A reoccurring theme of this report is the importance of the framing of any attribution question. Although climate scientists are frequently asked ‘Was a given observed weather event caused by climate change?’ we believe this is a poorly formed (or ill-posed) question that rarely has a scientifically satisfactory answer. The report discusses appropriate ways to frame attribution questions as well as the interplay between meteorological and human-made factors in the realization of extreme events.”

When Barry Bonds was setting home run records during the steroid era, people used to ask if his latest homer was due to steroid use. The same dynamic occurs after each extreme event and global warming. It’s more useful to assign a higher probability to extreme weather events because of global warming just as it was more instructive to look at Barry Bonds’ overall home run record than any single home run.

As climate scientist Kevin Trenberth noted in a 2012 paper, all weather events now happen on a planet with a climate that we’ve made hotter:

“The answer to the oft-asked question of whether an event is caused by climate change is that it is the wrong question. All weather events are affected by climate change because the environment in which they occur is warmer and moister than it used to be.”

That is the proper framing when discussing these types of extreme weather events. In this case, there is growing scientific evidence suggesting that human-caused global warming is causing rapid changes in the Arctic, which in turn is altering the atmosphere, causing wavy patterns to form more frequently in the jet stream. On the West Coast, this can cause persistent high-pressure systems to form in the Pacific, exacerbating droughts by blocking storm systems.  It can also allow frigid Arctic air to spill into the USA, creating especially cold winter weather.


  1. Volunteers should carefully consider what audience this information may be most appropriate for. For example, if presented to a “layperson,” ensure it is done in a manner that is easy to understand.
  2. Rutgers climate scientist Jennifer Francis explains these changes to the jet stream and impacts on weather systems here.
  3. A video illustrating the jet stream waves is available here.

Dana Nuccitelli is an Environmental Scientist and writes about climate change for The Guardian and Skeptical Science. Doug Sinton is a meteorology professor at San Jose State University (retired).  

The Science Policy Network is a team of CCL leaders and supporters with a diverse background in the field of climate science. These network contributors write regular guest posts, offering thorough insight into topics that fall within their expertise. This post and other resources are available in the form of white papers on CCL Community


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Comments 1 to 44:

  1. It would be good also to mention more specifically the extraordinary Arctic winter event that has unfolded this year, with temperatures above freezing at extreme lattitudes in the dead of the polar night and the lowest sea ice extent recorded for January.

    WaPo article previously referenced by OPOF on another thread. Links to the Danish Meteorological Institute. Arctic Temperatures as high as 20 deg C above normal.

    Sea ice is not tracking any better now, NSIDC shows that we are fast approcahing the max extent time and have barely made it above 14 millions square kilometers. Of all the features of climate change, I find the loss of Arctic sea ice to be one of the most worrisome; it is truly a geological scale event that we are witnessing in a blink of an eye.

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  2. A similar thing is happening now with  Europes unusually cold weather and very high arctic temperatures. This article discusses the events and the possible mechanism.

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  3. David Roberts has a few good quotes on this topic of how "climate change" is related to extreme weather. This one is from when he wrote for Grist:

    There is no division, in the physical world, between “climate change storms” and “non-climate change storms.” Climate change is not an exogenous force acting on the atmosphere. There is only the atmosphere, changing. Everything that happens in a changed atmosphere is “caused” by the atmosphere, even if it’s within the range of historical variability. Climate change is just the term we use to describe those changes.

    And more recently, writing for Vox on last year's hurricanes:

    “Did climate change cause this hurricane?” is a malformed question.

    Climate change does not cause things, because climate change is not a causal agent. “Climate change” is a descriptive term — it describes the fact that the climate is changing. What’s causing the changes is an increase in heat energy trapped in the atmosphere, due to greenhouse gases.

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  4. nigelj,

    I'm afraid some brits tell me that this cold spell is nothing like what happened in 1962

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    Moderator Response:

    [PS] and have they data to back that up? Where does "1962" come from anyway. I dont it in nigelj comment nor linked reference.

  5. that the jet stream has become increasingly wavy over the past 50 years, to a degree unprecedented in the past 290 years,

    Please could somone tell me how do we know what the jet stream was like 290 years ago when it was only discovered in the mid 20th centurey?

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    Moderator Response:

    [PS] If you had bothered to read the linked paper in the article, it would tell you. This is a site for the discussion of science of global warming. Please dont try to substitute in rhetoric instead.

    Perhaps this would be a useful guideline to create a sensible discussion since you clearly dont like the result. Which of factors here are you disputing and why.

    1/ That deep waves in the jetstream cause extreme weather (heat wave, heavy snow)?

    2/ That jetstream is currently weakening and becoming more wavy?

    3/ That climate change is causing the changes to the jetstream?


  6. Alchemyst @5

    "Please could somone tell me how do we know what the jet stream was like 290 years ago when it was only discovered in the mid 20th centurey?"

    I didn't know either, but If you actually read the research link "2018 study in nature communications" in the article you find they used tree rings.  The research is outside my knowledge, however this media article describes it in plain language.

    "The rings of trees from Britain and the northeastern Mediterranean region tell a long history of the jet stream. That's allowed a team of scientists to piece together 300 years of the flow of the North Atlantic jet stream in summer."

    "So we used the wood density, and that's been found to be very sensitive to temperature conditions. So in cold summers you'll have less dense wood, and in hot summers you'll have more dense wood," said Valerie Trouet, an assistant professor of tree-ring research at the UA."

    "Trouet said since the 1960s there have been more instances of the jet stream moving off its average position. When the North Atlantic jet stream is more north, Britain is much warmer than normal. In Italy and the Balkans, there are floods and colder conditions. That's reversed when the jet stream has a more southerly track."

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  7. Sorry for appearing to be repeating stuff,  but the moderators message wasn't there when I pressed submit.

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    People are commenting (comment 1 and 2)that this weird warming of the pole is unprescedented, Yet 1962 we had the same pattern and this minor cold wave bit of cold weather in western europe is nothing as to what happened in 1962 to 63. It was for more than 3 months. I thought it was common knowledge what had happened in Britain in 1962, indeed 1948, and 1933 also had severe weather in Britain. for whatever the reason it seems to be corrolated with low sun spot activity, but it is certainly has prescedent.

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  9. europe

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    Moderator Response:

    [DB] Image resized to 450 width.  Please limit all further images to that or less.

  10. Nijelj  I believe you live in the southern hemisphere. This unprescedented weather is well known here and yes I remember 2011 where it was some 20 C below normal temperatures, and yes the sunspots were low that winter.

    I read your newspaper report now have a read of mine. 

    "So cold the SEA froze: Current cold snap is nothing compared to -22C winter of 1963",

    In 1962-63 sea ports were frozen. This has certainly not happened this year

    The daily mirror

    This type of weather is well known in Europe and is not unprescedented as your report says. Please look at the weather map from the Royal Met office and yes it does seem that the arctic get the atlantic weather and western europe gets frozen. other similar instances are documentad in the report. please note the comment, that the meteorologist expects these events to become rarer with climate change. somehow you just can't win.

    “The winter of 2010/11 was a rare weather event, even in the context of the 352 years of the Central England temperature record. Yet while the odds of such an event have lengthened as a result of human influence on climate, such unlikely events can still happen, as the winter of 2010/11 demonstrated.” – Nikolaos Christidis and Peter Stott, Bulletin of the American Meteorological Society , July 2012

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  11. A slew of high-quality articles about the recent heat wave in the Arctic and its impact on weather in the Northern Hemisphere have been published around the world over the past few days. I have posted links to some of them on the SkS Facebook page. Here's listing of the links I have posted to date.

    Has the Arctic Finally Reached a Tipping Point? by Brian Kahn, Science, Earther, Feb 23, 2018

    Really extreme' global weather event leaves scientists aghast by Peter Hannam, Sydney Morning Herald, Feb 26, 2018

    North Pole surges above freezing in the dead of winter, stunning scientists by Jason Samenow, Capital Weather Gang, Washington Post, Feb 26, 2018

    Arctic warmer than much of Europe is a worrying sign of climate change by Stuart Braun, Deutsche Welle (DW), Feb 27, 2018

    Arctic heat spasm caused by stratosphere warming has a southern cousin by Peter Hannam, Sydney Morning Herald, Feb 28, 2018

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  12. alchemyst may not notice that he raises a common issue we layperson's often deal with on a science site.  Let me explain: A peer-reviewed "discovery" will present a set of facts (with or without causality).  The evidence support the facts, even though there is a slight chance that another set of evidence might support the facts.  To me the problem is connectivity.  Let me eplain this problem:  Your dog gets hit and killed by a car.  The "evidence and facts" that cause the death of your dog won't change the fact that your dog is dead, but oftentimes people go on and on about the efficacy of their given set of facts and argue their set of facts against your set of facts.  Meanwhile, the dog is still dead.  I think Alchemyst owes us a lot more corroboration (and proofs) that his "climate events" in the 1960s are of the same "pedigree" as the climate events described by the CCL people above or that his 1960s climate events make the 2018 climate events the result of sunspots (etc) rather than increases in average planetary temp (etc).

    Am I "all wet" about this point of view?

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  13. Swampfox, there is a reference to the royal metrological office, from the  Imperial College London the top science university in Britain (OK Cambs is pretty good to). Now you cannot get more authority than that. However if you wish to dispute the met office and Imperial college! The data from the met office report is all peer reviewed

    Seemingly 2011 had a warmer Greenland (7.8 C) than this year, it is only a blog but it refers to a danish met office document. that was the same winter as the last big freeze in europe.

    As to sunspots, there is a peer reiew out there that these events in western europe have a strong corrolation, that does not give any link though it is intriguing is it real effect or hocus pocus, I do not no, for me its a bit spooky, I do not want to believe it. but there it is

    I'm not really bothered if you do not give creedance to the fact that this weather pattern occurs regularly, it does. Warm air goes up Greenland cold air comes through Europe first law of thermodynamics.

    the pattern in the 1962-3 winter temperature anomalies in the imperial college match closely the current situation.  

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  14. swampfoxh

    I have never stated that there is any causal link between cold winters in W europe and sunspots.

    here is the peer review report linking sunspot activity with cold weather in England,


    Please read the royal met office report warm air every so often slip up by Greenland, 1962 and 2017 and seemingly 2011(not checked).  These pulses in cold temperature have been going on for over 300 years and the last three have had warm temperature anomalies in Greenland.

      I think that the onus to link this effect to climate change is on the proponents at the moment sunspots has more credibility, but if you want my opinion it is probably stochastic. 

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  15. Alchemyst @8 - 10.

    I didn't personally call anything 'unprecedented'. The article I referenced described how this current stormy cold weather in Europe is well explained by changes to the polar vortex and jet stream and this in turn is caused by climate change. The theory does fit the evidence pretty well.

    I dont know whether the research paper linking cold weather in europe to sunspots has gained wide acceptance. However cold weather In Europe could be partly influenced by sunspot activity as well as changes to the jet stream. 

    The more important point is the arctic has been warming for decades here . There were some hot individual years back in the 1940s, however temperatures are clearly higher now "on average" than at any point in the last 100 years and this is the most important thing to understand. This can all potentially change weather systems a lot, because of how weather systems originate. And arctic temperaturtes are predicted to get a lot higher yet by 2100.

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  16. Moderator,

    now do you know the significance of 1962 weather in Britain? I find it exraordinary that 

    "Arctic warmer than much of Europe is a worrying sign of climate change"

    is the headline in the ref  niegelj posted.

    The headline of the newspaper article states that the reversal of temperature between W Europe
    is linked with climate change, yet this pattern of weather has been observed
    (or has got proxies worked out by Mann!) for 350 years.

    page 17 of the Burt report shows that in 1962. Greenland was significantly warmer than normal and Britain had an extremely anomalously low temperature.

     A pattern of weather that peridically hits europe and has been recorded in 26 winters in 350 years with very strong correlation with the low of sunspots activity

    I have never attribted a causal link, yet swampfoxh is strongly insinuating it.

    I think you should moderate others.

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    Moderator Response:

    [PS] You appear to arguing a strawman. The "unprecedented" statement in the linked paper states

    "We further find an unprecedented increase in NAJ variance since the 1960s, which co-occurs with enhanced late twentieth century variance in the Central and North Pacific Basin."

    It does not state that jetstream events have not happened in past or that other cold/ warm events have not happened for other causes. Nothing presented so far by you contradicts the paper conclusion.

     Misunderstandings with other commentators would be less likely if you took the approach I suggested further down: State what you accept. State what you disagree with and why.

  17. nigelj

    Sorry if I caused offence, it was your reference that was taking liberties with the data. I think that the original article in this site is balanced. The problem starts when these papers are mis reported.  

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  18. Alchemyst @17

    No offence taken. I realise comments get rushed sometimes, but I wanted it made clear I never made such a claim.

    Basicially you are not reading what I say and responding directly to it. Therefore you totally fail to convince me of anything. Instead you are just repeating yourself.

    You are also contradicting yourself. If you believe the sunspot thory is "just stochastic" ( I assume you meant just a random sort of correlation)  why do you keep repeating it? If you go on repeating it, I will interpret this as meaning you support it.

    The article I referenced took no liberties with the data. Climate scientists have apparently postulated that the current cold weather in Europe is related to current high arctic temperatures and jet stream changes thats all. Its quite a good theory. Are you saying they are not entitled to postulate a theory? Remember we have empirical evidence that the jet stream has changed.

    Nobody has claimed all storms in Europe are being caused  by recent climate change. The recent warming trend in the artic is probably just making them more frequent or longer lasting, as the changed jet stream lets more cold air move south than normal. This may also have happened in the 1940s and 1960's, but its pretty obvious that higher temperatures in recent decades can only make it happen more frequently now.

    The article I mentioned also references Europe and the arctic as a whole, not the UK and greenland. I mean, theres a pretty significant difference.

    And Dana is talking about artic warming is causing je stream changes that are affecting North Americas weather. It seems plausible that if this is the case in America, it could also be the case in Europe. Its stupid to dismiss this, just because we had one particularly cold year in 1962.

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  19. Sunspot cycles in recent decades barely cause a wobble in increasing global temperatures.They might affect winter weather, but aren't by definition the only factor.

    Temperatures in the artic are currently 35 degrees above historical averages, and are affecting fundamental circulation patterns. This seems far more likely to be the most important factor in europes current storms, especially given that a mechanism has been explained by the experts.

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  20. Speaking of severe weather events in the US during the current Winter season...

    Once-in-a-generation flooding possible in Boston — for the second time this year by Matthew Cappucci, Capital Weather Gang, Washington Post, Mar 1, 2018

    'Bomb cyclone' forms as flood threat sparks 'LIFE & DEATH' warning by Faith Karimi & Joe Sterling, CNN, Mar 2, 2018

    Major Coastal Flooding, Hurricane-Force Wind Gusts Expected From Friday's Nor'easter by Jeff Masters, Category 6, Weather Underground, Mar 1, 2018

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  21. The top post states: "White ice is reflective, but dark oceans aren’t. When sea ice sitting on top of the ocean melts, the Arctic surface becomes less reflective, absorbing more sunlight, which in turn melts more ice in what’s known as a “positive feedback.”

    It's not that simple. That's not the whole truth. The people who wrote that must live in quite another place, where the sun is above their heads.

    Here are a couple of factors that work in the other direction:  1.Ice covered by snow also acts like a blanket, and protects the relative warmth underneath it from escaping.  2.There is almost no sunshine in the winter to be absorbed in the Arctic; the angle of incidence of the few hours of sunlight available is just a couple of degrees, at which angle almost all radiation is reflected from the water surface.

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    Moderator Response:

    [DB]  "there is almost no sunshine in the winter to be absorbed in the Arctic"

    There is almost no darkness in Arctic summer.  Winter and summer cancel out, inconveniently for you.  Over the course of the year, water without ice absorbs more energy from the sun than water covered by ice.  This is well-understood and not contentious in any way.

  22. Argus@21,

    In addition to the Moderator's correction regarding your comment, when the ice covers the arctic waters in winter it acts as insulation keeping the warmth in the water. So winter maximum extents not declining can actually lead to even smaller summer minimum extents.

    The ice cover is getting thinner. More of it is only new ice rather than thicker multi-year ice. That makes it easier for the trend of minimum extent in each new summer to be significantly smaller as the 24 hour sunshine warms the larger area of uncovered waters. And that significant downward trend of summer minimum extent is indeed what is observed.

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  23. The post was talking about winters ("Abnormal winter weather"), and I was talking about the winter sun, or lack of sun – but you and the moderator are talking about summer, with midnight sun and all that. A slight misunderstanding.

    Ok, so just now the ice cover seems to get thinner, and covers a smaller area in the summer. The sun does what it's meant to do, shine. So does it shine more now than 20 years ago, or 50 years ago? If so, why? Maybe this is just a period where ices are smaller, and 20 years from now maybe they will be thicker and bigger again. What's the problem? Fluctuations have always occurred.

    Everybody in this forum seems to be climate pessimists.

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  24. Argus @23,

    The sun is shining less now than 20 years ago. Refer to "its the sun" under climate myths at the left hand side of the page. So quite obviously the warming arctic and decreasing ice can't be attributed to solar activity.

    Natural fluctuations have always occured, but that obviously doesn't mean they are always particularly strong, or that humans can't have an influence.

    I don't know about other people, but I try to be a "climate realist".

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  25. Alchemyst brings our attention to the 1962 event that showed an apparently similar weather patern as the one we're experiencing this year.

    I looked at the archives of the DMI and found the Arctic temperatures above 80 deg lattitude for that year. The highest temp for the first 55 days of the year in 1962 are arond 252 deg K. For 2018 they are approximately 264 deg K, 12 degrees warmer.

    Arctic temp North of 80 deg

    In comparison, this is 1962:

    Arctic temp North of 80 deg

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  26. Philippe Chantreau @25,

    You might be interested in the daily DMI data available in spreadsheet form courtesy of 'Tealight' at Arctic Neven's Forum. 'Tealight' runs CryosphereComputing website. The numbers (1960-2017) are very handy for comparing the inter-year DMI data. Thus in early 1962 the temperature is given as peaking at 251.72K on 14th Jan & 252.53K on 29th Feb (evidently some form of leap year handling process is in use), these being the 3rd & 4th warmest excursions of the 1960s (exceeded by one in 1960 & one in 1965).

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  27. Glad to see that my 252 eyeballing was that close. Thanks for the link. I looked at the entire DMI archive and did not see a year with a spike as high as 2018 in the first 55 days, although the lows may be the more remarkable story. The level of the minimum Arctic temp in this year's first 55 days is quite interesting.

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  28. Philippe Chantreau and MA Rodger,

    It is my understanding that while the high temperature this year in Northern Greenland was not the highest ever recorded it was above zero for much longer than had ever been recorded.   (Sorry no cite, it was a newspaper article)  Eyeballing the graph at 25, the temperature was above 260 for several days.  That is not the same as Greenland but it does support the claim that the heat wave this year was extraordinary.

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  29. >>I'm afraid some brits tell me that this cold spell is nothing like what happened in 1962<<

    I don't have the data to hand, but I was flying training in 1962/3 and subjectively it was in the same category as this winter: days on end of cancellations and life-threatening cold.

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  30. The DMI 80N daily data is exceedingly wobble-ridden. To get a sense of seasonal trends, I have plotted out decadal 31-day rolling averages. This does show significant change but only since 2000. The graphic linked here (usually 2 clicks to 'download your attachment') shows the freeze season (Oct-Dec) was +3ºC warmer in the 2000s. And the 2010s have show additional warming with the height of the freeze (Jan-Mar) is on average+ 5ºC warmer. In that context, the 2018 season is probably averaging +7ºC warmer. Interestingly, the DMI data shows the summers over the last couple of decades with lower temperatures than in the 1960s.

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  31. MA Rodger (r.e. "Interestingly, the DMI data shows the summers over the last couple of decades with lower temperatures than in the 1960s.")

    I'm going to guess that more exposed water slows the warming of the air as summer sets in because you get more heat exchange between water and air than ice and air. Whereas having ice-covered water basically insulates the air from the moderating effects of the water. Just a guess...

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  32. P Chantreau

    hanks for the graphs,  You hoverer do not compare one cold period with the other.

    You need also to compare like with like.

    The 62 winter freeze extended through from  December to March 63.

    The temp at the begining of December in Greenland according to your graphs was 262K at 2017 it was 264 K  quite close!

    Is it possible to see a graph of these? also is it possible to see a graph  of feb 2011 to get a good comparison.  The cold snap this year has lasted 6 days The 62 lasted some 70 days and the sea was frozen in  UK ports.

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    Moderator Response:

    [PS] It would still help this discussion if you made it clear what you are trying to establish.

  33. M A Roger at 5:04 am 4 March

    thanks for the tables. You missed the excursion!

    please read that the highest winter peak was 261.33 K on  21 Nov 1962 not 252K in February.

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    Moderator Response:

    [PS] And??? What point are you trying to make?

  34. This was the headline that nigelj posted

    Arctic warmer than much of Europe is a worrying sign of climate change

    however we now have established that in 1962 that a similar excursion took place in which the arctic was warmer than europe. a couple of degrees lass possibly, But these temperature reversals have a long history, so how can they be sign of global warming.

    The headline is therfore misleading.

    The fact that the arctic is warmer than europe at times is a sign of weather.

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    Moderator Response:

    [PS] But a change in trends is a sign of climate change, and that article went on to explain not the significance of one event but the underlying changes. As did the paper that is main focus of this blog article. Noone disputes that one event by itself is insignificant and just weather. Persistant changes to jetstream variability are another thing altogether.

    Quoting Nigelj article (did you read down that far)
    But such "intrusion events" are happening with increasing frequency, says Adamson. And they "are linked to increased temperatures and reduced sea ice cover."

    Global warming may be to blame.

    "There is now a large and strong body of evidence that the major changes we are seeing are linked to climate change," Adamson said. "Changes in one part of the ocean-atmosphere system can have major impacts on another."

    Note the "increasing frequency"?

  35. I don't understand what Alchemyst is talking about. My initial post makes it clear that my concern is about the Arctic and the changes taking place there. I am comparing apples to apples, namely the temperature north of 80 degrees lattitude during the first 55 days of the year in the DMI archive. So, it is definitely comparing a cold period of the year with another cold period of the year.

    There may have been a similar weather situation in 1962 as in  2018 but the temperature in the Arctic was nowhere close to what it has been since the beginning of this year, as is totally obvious from the graphs. As I stated above in another post, I looked at the entire archive and did not find a single year with temperatures looking like what was just recorded in 2018. I may have missed one, anyone is free to look for themselves, the archive is freely accessible. 

    I did not consider European weather, my comment was about the Arctic temperatures and state of the sea ice, which saw the lowest January extent on record, and retreating ice in the Bering sea. Sea ice extent shows no sign of improvement, barely exceeding 14 million at a time where the interdecile range is between 15 and 16 million It appears likely that we are going to see the lowest max winter extent on record for a given year.

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  36. Seth Borenstein's below article is chocked full of information about records that have been set in the Arcitic this winter. Here are the introductory paragraphs of his in-depth article.

    Winter at the top of the world wimped out this year.

    The Arctic just finished its warmest winter on record. And sea ice hit record lows for this time of year, with plenty of open water where ocean water normally freezes into thick sheets of ice, new U.S. weather data show.

    Scientists say what’s happening is unprecedented, part of a global warming-driven vicious cycle that likely plays a role in strong, icy storms in Europe and the U.S. Northeast.

    “It’s just crazy, crazy stuff,” said Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colorado, who has been studying the Arctic since 1982. “These heat waves, I’ve never seen anything like this.”

    It’s been so unusually warm that the land weather station closest to the North Pole — at the tip of Greenland — spent more than 60 hours above freezing in February. Before this year, scientists had seen the temperature there rise above freezing in February only twice before, and only ever so briefly. Last month’s record-hot temperatures at Cape Morris Jesup have been more like those in May, said Ruth Mottram, a climate scientist at the Danish Meteorological Institute.

    Science Says: Arctic not so chill this record warm winter by Seth Borenstein, AP News, Mar 6, 2018

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  37. my initial comment was against a newspaper article that nigelj quoted. and as you would have read my comments. 

    It has had nothing against the main article. So please do not try and divert the point of my comment.

    The headline is what people remember and it is misleading.

    It is extraordinary that to raise a sinle error on a websit has raised so much opposition.

    It would bring one to the conclusion that no dissent is tolerated.

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    Moderator Response:

    [PS] And my second quote was also from the newspaper article that nigelj quoted which explained that it was about trend. My moderation though was about trying to get you to be more explicit about what point you were trying to make instead of having everyone guess because it appeared you were tilting at windmills.

    [JH] Moderation complaint snipped. 

  38. My summary as a layman of this whole post, with its attached discussion, is as follows:

    We have seen unusual winter weather in several areas this winter: in some places warmer, in other places colder. These variations in temperature, humidity, and wind used to be called weather, but are now increasingly blamed on climate change.

    I think Alchemyst summarized the topic post nicely in #13: "Warm air goes up Greenland - cold air comes through Europe - first law of thermodynamics". The recent cold winter weather is only interesting because it can be discussed in relation to global warming. Nobody writes reports about the unusually cold winters (in northern Europe) of 1867, 1871, 1881, 1888, and 1942, because those cannot be connected to global warming.

    The warmer Arctic is interesting because it rhymes with AGW theories. What about Antarctica then? Not interesting. Near the south pole it's now -45, and that is supposed to be their summer, with the sun up 24/7. "In stark contrast to the sharp decline in Arctic sea ice, there has been a steady increase in ice extent around Antarctica during the last three decades, especially in the Weddell and Ross seas." (

    I can sympathize with Alchemyst's reaction at the end of #37, but I think it is not that "no dissent is tolerated". More likely it is that most writers in this forum are so skilled in advocating the AGW theory that they immediately can jump on any aberrant opinion, fully equipped with diagrams and reports that support their belief.

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    Moderator Response:

    [PS] Alchemyst could rightly argue that the headline in nigelj newpaper article could mislead someone how only read headlines. However, the blog post, the science paper and the substance of the newpaper article were all about the increasing frequency of jetstream variability (climate) and statements that amount to "its been cold/warm before" do not address trend. By all means present dissenting views, but argue against the real premise, not some strawman and present evidence. Ie a real counterpoint is some evidence that similar frequencies of jetstream variability occurred when artic basin had more ice.

    Also note that try to say Arctic seaice loss is okay because something different is happening in antarctica (and you may want to check most recent data) is a logical non-sequitor. Look at what is causing the changes in both places, but argue in an appropriate place.

  39. Argus  @38

    You claim theres been a steady increase in Antarctic sea ice. Your reference is to old data. The following national geographic article shows antarctic sea ice at record lows in 2017.

    Global temperatures and sea level rise have been incresing for decades, we have seen more heatwaves and heavy rainfall events and so on. The arctic has been warming now for decades, and its not guesswork or belief to suggest this has implications for regional weather.

    Scientists have a good explanation for the changes in agw climate change with over 12,000 scientific papers on the issue, but you  prefer to claim all this science is just a 'belief'. Do you not know the difference between a belief and massive scientific evidence?

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    Moderator Response:

    [PS] please put any further discussion of Antarctica on an appropriate thread.

  40. Nigelj  7:22 am 2 march 2011

    "The article I referenced took no liberties with the data. Climate scientists have apparently postulated that the current cold weather in Europe is related to current high arctic temperatures and jet stream changes thats all. Its quite a good theory. Are you saying they are not entitled to postulate a theory? Remember we have empirical evidence that the jet stream has changed.
    Nobody has claimed all storms in Europe are being caused by recent climate change. The recent warming trend in the artic is probably just making them more frequent or longer lasting, as the changed jet stream lets more cold air move south than normal. This may also have happened in the 1940s and 1960's, but its pretty obvious that higher temperatures in recent decades can only make it happen more frequently now."

    Nigel, please read page 2 of the ref

    In it there is a red graph that shows the 1962 incedent in context with historical events of which there were many at about 12 year intervals.  It also shows that there has been no further similar events in the UK since 1963 date. the graph also show a slight hockey stick. Compared with the pre 1963 events, the 2011 event hardly registered in the graph.

    The argument has not been that the arctic is getting warmer but that this  is affecting western europe. The graph shows clearly that the so called more frequent events are not materialising. this is not computer modelling papers but real measurements. This is not surprising since as the arctic is warming, there is less difference in the temperature between the arctic and europe.

    Please read the document fully as it predates all this new stuff by 4 years, we have seen documentaries about it 

    If you notice a set of headlines is given in another paper on this topic 7 march

    None of the British Papers did the same mistake of DW and linking the Beast from the East to Climate Change, because all of the Brits know that these storms were worse and more frequent before climate change. they have either lived through them or had their grandad/dad tell them and every so often theBBC will have a documentory.

    We have empirical evidence that since global warming these storms are less frequent and milder.

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    Moderator Response:

    [PS]" The graph shows clearly that the so called more frequent events are not materialising"

    It does no such thing. You cant make any statement about jetstream variability from one set of temperature measurement.

  41. Moderator thank you for your comment
    The graph indicates cold weather arriving in Britain, not jetsteram events.
    The tile says "Central England Winter mean temperature 1660- 2013"
    It says nothing of jetsreams so why do you imagine jetstreams.
    Now what it does say is that the knock on from polar warming that is supposedly happening according to the molelers is not happening to the any extent as it did before global warming happened.
    This is what I have been saying all along but somehow you and the bloggers do not seem to have understood it.
    Ah well horses to water is what I say

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    Moderator Response:

    [PS] I "imagine jet streams", because that is the topic of this article, the topic the paper referenced and the substance of nigelj newspaper article. As I keep suggesting, you seem to be tilting at another windmill. Similarly, modellers are not much involved. The variability of jetstream is directly observed in recent times and inferred from proxies in past. What modellers do is look at why jet stream variability appears to be increasing. If you do not want to discuss jet stream variability, then you are offtopic.

    Sorry, I think I will make a longer comment to explain my lengthy moderation. It seems to me that if someone made the claim "We are having some extreme weather, and this is a sign of climate change", then your comments would make more sense. But that is not what is claimed. Instead, what has been observed is that jetstream "loopiness" has become more frequent, and incidentally, that brings some kinds of extreme weather (but it is not the only cause). Is this unusual and how do you tell when jetstreams havent been observed for that long? Well someone figured out how to extend the record by using paired tree ring data, and yes, it turns out to be unusual. Modellers meanwhile notice arctic changes give more loopiness in the models. Is this the cause? Well that bit is still uncertain science but what we observe is consistant with it. Discovering that unusual to have loopiness over a 300 year record is reason for concern.

  42. Alchemyst @40

    Thank's for the link on Britains weather trends.

    Firstly with respect its really hard understanding your points at times. Possibly english is your second language. 

    Secondly I want to clear one issue up. You said the article I quoted was misleading.  In hindsight, the title of the article "Arctic warming more than much of europe is a worrying sign of climate change" is not a great title, and is unclear. However that is typical of the media, as  they use clickbait deceptive, silly headlines all the time.

    More importantly, the body of the article was more nuanced and not misleading to me, because they said that the warming arctic was almost certainly a climate change process, and that this "could" be causing the cold weather in Europe. Please note they acknowledged it is simply a hypothesis, and we don't have enough time data yet on recent changes in the Jet stream and arctic oscillation to be sure. But personally I think its a good hypothesis.

    Thirdly regarding your link on Britains cold weather history. I dont dispute its possible that if anything cold snaps like the one in the early 1960's  have lessened over the last century. This is what is expected overall in a warming climate of course. Your linked article is however hard to follow and I'm just assuming its correct in its data.

    Its also entirely possible that sunspots have a relationship to winter weather.

    None of this is the real point. The phemomena in the arctic over the last decade appears to be a great deal of warming and changes to the jet stream and the behaviour of the polar vortex that is all quite recent. This may be now causing a new trend of colder weather periods to start in Europe, so is a recent thing. That was my understanding of the article. Clearly we need years more of data to be sure. It might not cause more cold periods either, and instead the effect may simply be longer ones that linger. 

    But one thing is for sure. The rate of warming in the arctic is very high any way you look at it, and we have seen a few individual years now with very high seasonal temps, and the consequences could be disastrous for the planet.

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  43. nigelj #39:

    I did not "claim" – I quoted an exact statement from an article, as is evident from both the quotation marks, and from the link.

    You say my "reference is to old data". It is from 2016, and your reference is from 2017. So, in a year my reference is already too old? Is that really how fast the facts are changing? I thought it would take decades, before you could make completely different statements about climate.

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  44. Argus @43, the moderator said the antarctic is off topic on this page. I will post a response on the page below.

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