Impact of declining Arctic sea ice on winter snowfall

by Judith Curry

Liu, Curry et al. have a new paper published in PNAS entitled “Impact of Declining Arctic Sea Ice on Winter Snowfall.”

Impact of Declining Arctic Sea Ice on Winter Snowfall

Jiping Liu    Judith A. Curry    Huijun Wang    Mirong Song    Radley M. Horton

Abstract.  While the Arctic region has been warming strongly in recent decades, anomalously large snowfall in recent winters has affected large parts of North America, Europe, and East Asia. Here we demonstrate that the decrease in autumn Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation that have some resemblance to the negative phase of the winter Arctic Oscillation. However, the atmospheric circulation change linked to the reduction of sea ice shows much broader meridional meanders in mid-latitudes and clearly different interannual variability than the classical Arctic Oscillation. This circulation change results in more frequent episodes of blocking patterns that lead to increased cold surges over large parts of northern continents. Moreover, the increase in atmospheric water vapor content in the Arctic region during late autumn and winter driven locally by the reduction of sea ice provides enhanced moisture sources, supporting increased heavy snowfall in Europe during early winter, and the northeastern and mid-west United States during winter. We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters.

PNAS abstract is [here]; full text manuscript is [pnas].

Georgia Tech press release

A new study led by the Georgia Institute of Technology provides further evidence of a relationship between melting ice in the Arctic regions and widespread cold outbreaks in the Northern Hemisphere. The study’s findings could be used to improve seasonal forecasting of snow and temperature anomalies across northern continents.

Since the level of Arctic sea ice set a new record low in 2007, significantly above-normal winter snow cover has been seen in large parts of the northern United States, northwestern and central Europe, and northern and central China. During the winters of 2009-2010 and 2010-2011, the Northern Hemisphere measured its second and third largest snow cover levels on record.

“Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation,” said Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech. “The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents.”

The study was published on Feb. 27, 2012 in the online early edition of the journal Proceedings of the National Academy of Sciences. The research was supported by NASA and the National Science Foundation.

In this study, scientists from Georgia Tech, the Chinese Academy of Sciences and Columbia University expanded on previous research by combining observational data and model simulations to explore the link between unusually large snowfall amounts in the Northern Hemisphere in recent winters and diminishing Arctic sea ice.

The researchers analyzed observational data collected between 1979 and 2010 and found that a decrease in autumn Arctic sea ice of 1 million square kilometers — the size of the surface area of Egypt — corresponded to significantly above-normal winter snow cover in large parts of the northern United States, northwestern and central Europe, and northern and central China.

The analysis revealed two major factors that could be contributing to the unusually large snowfall in recent winters — changes in atmospheric circulation and changes in atmospheric water vapor content — which are both linked to diminishing Arctic sea ice. Strong warming in the Arctic through the late summer and autumn appears to be enhancing the melting of sea ice.

“We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere,” explained Jiping Liu, a senior research scientist in the School of Earth and Atmospheric Sciences at Georgia Tech. “These pattern changes enhance blocking patterns that favor more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and Midwest regions of the United States.”

Diminishing Arctic sea ice can cause changes in atmospheric circulation that lead to a circulation pattern that is different than the “negative phase” of the Arctic Oscillation.

In addition to analyzing observational data, the researchers also assessed the impact of the diminishing Arctic sea ice on atmospheric circulation by comparing the results of model simulations run with different sea ice distribution. They ran one experiment that assumed seasonally varying Arctic sea ice and utilized sea ice concentration data collected between 1979 and 2010. Another simulation incorporated prescribed sea ice loss in autumn and winter based on satellite-derived Arctic sea ice concentrations.

The simulations showed that diminishing Arctic sea ice induced a significant surface warming in the Arctic Ocean and Greenland/northeastern Canada, and cooling over northern North America, Europe, Siberia and eastern Asia. The models also showed above-normal winter snowfall in large parts of the northern United States, central Europe, and northern and central China.

The consistent relationships seen in the model simulations and observational data illustrate that the rapid loss of sea ice in summer and delayed recovery of sea ice in autumn modulates snow cover, winter temperature and the frequency of cold air outbreaks in northern mid-latitudes.

Huijun Wang and Mirong Song of the Chinese Academy of Sciences Institute of Atmospheric Physics and Radley Horton from the Columbia University Center for Climate Systems Research also contributed to this work.

This project was supported by the NASA Energy and Water Cycle Study and the National Science Foundation (NSF) (Award No. ANT-0838920). The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of NASA or the NSF. 

Other press

The paper is getting pretty good coverage by the media and in the blogs.  A few samples

Joe D’Aleo has posted a a critique at WUWT.

JC comment:  Several people have asked why I have not posted on this paper earlier.  Last week I was on travel and was totally swamped, and was not able to interact with the press at all on this, or even keep up with it.   Jiping Liu has been very busy interacting with media and other email queries.  This week is slightly better for both of us but not much, so I am apologizing in advance if our interaction in the discussion in the comments is limited.

291 responses to “Impact of declining Arctic sea ice on winter snowfall

  1. “The proof of the pudding is in the eating”. If you have a hypothesis, or theory, as to what is causing what, then the thing to do is to use this information to predict what is going to happen in the future. This is what I mean that the main use of models is to design the next experiment. So, Judith, what is the prediciton as to what is going to happen next winter in the northern hemisphere? And then what will happen for subsequent winters.

    • Well, our idea implies that autumn sea ice extent can be useful as a predictor for DJF NH snowfall. So at best this is useful for seasonal forecasts, unless someone is forecasting sea ice extent on longer time scales.

      • my anomaly bets at Lucia’s of course!

      • Judith, you write “Well, our idea implies that autumn sea ice extent can be useful as a predictor for DJF NH snowfall.”

        Fair enough. When it comes to autumn 2012, are you going to issue a forecast for DJF NH snowfall?

      • We do provide seasonal forecasts for clients in the private sector, that is one factor that is considered in our winter forecast. We do not make public forecasts.

      • Dr. Curry and Jim Cripwell, all those details and predictions what lack of ice on Arctic’s water makes I have commented on many blogs, including on yours. CORRECT details that every scientist needs to learn (maybe they have being wiped of; but there are tons of real proofs on my website on the exact subject) Many off your visitors have read it also. I even pointed details to Vukcevic – he hates me for it.

        When you people learn how it functions; you can have even this small new prediction: Because river Danube water catchment areas had big snowfall, when the snow melts – will drain extra water in Black sea – that will slow down the ”Gulf Stream” – which means: in near future Texas will get more rain. Before Gibraltar and English Chanel were opened – there was no gulf stream. At that time, warmed water in Mexican Gulf was staying there and producing lots of extra moisture – with planet spinning eastward – that moisture was going west – lots of oil in Texas created. Now as soon as water is warmed – surface warm-water instantly goes east, no time to produce big moisture west. More water by Danube to replenish the deficit from evaporation in Mediterranean > gulf stream slows.

        The big ice age was created by people rubbing two sticks and turning Sahara into a desert. Plimer says that” human cannot change the climate” WRONG, human triggered the big ice age! At that time was no Gibraltar opening – Mediterranean, Black, Caspian, Aral systems dry. Made river Rheine to a trickle, same with Nile – that system decreased a lot the rainfall / snow in the Russian rivers; which freshwater spreads on the top of the Arctic’s salty heavy water and decreased protecting the ice from the salty water – was NO ice left on Arctic’s waters. No ice on Arctic ocean made Alaska permafrost, but lots of ice in Europe / USA. I have given it a name in my book ”THE ICE DOUGHNUT EFFECT”’ Now same ice age is impossible, because Gibraltar and Bosporus are opened for business, to bring water from Atlantic and prevent Mediterranean drying – but because of strong ”gulf stream” speeding up – worse and more devastating ice age… the idiots are still threatening with their PHONY GLOBAL warming…?! – The rest of details, lots of it, on my blog See why the big Ice age wasn’t on both hemisphere and much more. Inform the shonky ”researchers” + NASA that plagiarizing is illegal. All the proofs, dates are on record .

      • Thank you, Professor Curry, for your effort to walk “the razor’s edge” – between warring factions in the global climate scandal.

        Thanks to your tolerance of strident opinions from both sides, we may finally be able to condemn:

        a.) Deceit in Government Science, and
        b.) Elimination of the First Amendment

        Without vilifying politicians and scientists who could find no better way to avoid the dangers of:

        1. Mutual Nuclear Annihilation;
        2. Pollution of the Environment;
        3. Overpopulation of the Earth; and
        4. Natural Aggressiveness in Humans

        Those noble goals were apparently behind decades of government deceit over my research career (1960-present) that culminated in the release of Climategate emails and documents in November 2009.

        See: “Video Summary of Research Career”

        And: “House Resolution (H.R.) 347”

        With kind regards,
        Oliver K. Manuel

  2. Did you not read the post, Jim? Unusually large snowfall in the winter in the affected areas. On average.

    Clear enough?

    • Unusually large and on average are meaningless pseud-statistical concepts as stated. You need to specify periods for both. BTW we have had an almost snow-less winter in Virginia. have to work to get that average up if this is the first winter in the prediction. Are you also predicting that ice extent will stay low, or go lower?

      The actual prediction is just that winter snow will be predictable from autumn ice. It is a meta-prediction, as with any claimed regularity or law of nature.

      • I am making no prediction about long term trends in sea ice. Eurasia was buried in snow this last winter. the geographical distribution of the sea ice anomalies influences the location of the snowfall. And other things besides sea ice influence the arctic circulation regimes.

      • I am making a long term prediction.
        Earth cannot get much warmer than now. If it tries, it will melt more Arctic Sea Ice and the resulting more snow will cool Earth. We are near the upper limit for Earth Temperature that has been in place for ten thousand years.

      • Markus Fitzhenry

        Alexander, we got HOT near on a decade ago and have been warm for some time. The Earth disseminates heat over long time scales. We have had lengthy heating phase caused by a spurt of insolation, now we have had a big El Nino, a subsequent shift to La Nina and the resulting warm currents moving up the the Western Pacific, causing warming polar oceans and changes in atmospheric water vapor content.

        With decreasing Sun is now warming Earth less, we will eventually see the ice cover return. There is no confusion that the uniform distribution of heat results in the poles becoming warmer with a reduction in ice cover, and increased snow from additional water vapor. Snow is a weather effect.

        Bear in mind the current out letting of heat in the waters below Australia, heat that did not have thermal capacity to reach the Antarctic.

        Snow doesn’t ‘cool’ Earth, decrease in insolation and changes to albedo does. The effects of our cooling world will be sensible at the poles in a decade.

        I expect the more dominate El Nino system to return June 2013, a mild heating of at ENSO with a ‘negative’ system appearing at the poles in about 2018 -20, when the oscillation switches to the next La Nina.

      • Markus

        You say: Snow doesn’t ‘cool’ Earth, decrease in insolation and changes to albedo does.

        Snow is the most important thing that causes change to albedo.
        More Snow cools Earth and Lack of Snow allows the sun to warm Earth.

      • Markus Fitzhenry

        ‘Snow is the most important thing that causes change to albedo’

        Yes, Herman. I should have been clearer and said “falling snow doesn’t cool Earth. I agree about the albedo effect of snow, but the way albedo is formed has been given some insights with the new Svensmark paper on cloud formations.

      • Markus, you are right, falling snow does not cool earth.

        Well, it likely really does. It sure feels like that to me.

        Snow falls when it is cloudy.

        The snow that fell while it was cloudy, that is still on the ground when the sun is shining, is what does cool earth.

        Do you have some data that shows this to be not true? I do want to see that data.

      • Markus Fitzhenry

        Hi Alexander you said;

        “Markus, you are right, falling snow does not cool earth.
        Well, it likely really does. It sure feels like that to me.”

        What I think you can feel is a cooling atmosphere from falling snow. That water vapor that turned into snow clouds causing snow was generated from a warmer surface, from when the snow landed back on it.

        The water vapor cooled the Earth, the snow cooled the atmosphere with resulting increase in surface albedo which does reflect radiative heat, meaning the Earth gets less warm, not colder because of it. Snow, per se, doesn’t cool Earth. Snow is a weather effect of a cooling Earth.

      • “Unusually large and on average are meaningless pseud-statistical concepts as stated.”

        Failing to read the paper and then demanding numbers is foolish.

        You’re in no position to criticize something you haven’t read.

      • I thought the Earth’s orbit around the Sun makes the Earth warm and cold, true?

      • @ Herman Alexander Pope | March 5, 2012 at 11:46 pm |
        Herman, your observation that: snow cools the planet; is coincidental.
        The reason more snow Europe / USA got for the last 3-4 years is: lets go back 5-10 years first; the moisture / water vapor North Atlantic / Mediterranean – produces – half of it drops as 0,5m of snow in Europe / USA – the other half goes to replenish the deficit of the ice on Arctic’s water (that ice seats on currents of SALTY WATER – gets constantly melted from below, NOT FROM THE TOP – needs replenishing.

        What started happening 3-4 years ago is: by demolishing more and more of the Arctic’s ice by the ice crusher ships – to get the shonky experts and bias media further north – when corridors separate the ice is as cutting 10 corridors in the window glass = easy the currents to demolish 1000 times more ice – those ”cuttings” go south and innocently melt. BUT, much more water is exposed in Arctic ocean to the winter coldness. Ice as polystyrene full of air was insulating the water from the winter coldness – minus ice; water absorbs extra coldness – in combination of the coldness from the air and extra coldness in the water = that double coldness as ripples goes south – intercepts 95% INSTEAD OF 50% of the moisture and is dropping it in Europe / USA – end result: SOUTH MUCH MORE SNOW AND COLDNESS – NO MOISTURE TO REPLENISH THE ICE DEFICIT ON ARCTIC. Simple arithmetic: more snow in Europe / USA – less moisture left for replenishing Arctic’s ice. That means; the chain reaction has started.

        Alarmist theory is: white ice reflects the sunlight – less ice = global
        warming. The truth is completely the opposite: 6monts of no sunlight white ice to reflect; but ice absent to shield the water from the unlimited coldness in the air during winter – water absorbs much more coldness – currents are distributing that ”extra” coldness south as on a conveyer belt. That’s why their followers are for a big shock. They were expecting with less ice at-least a small GLOBAL warming – to get them out of trouble – but nature is controlled by the laws of physics – not by their
        wishful thinking. So; more snow and coldness is because is less and less ice on Arctic as shield / insulator for the water. Cheers

    • Robert writes “Did you not read the post, Jim?”

      Yes I read the post very carefully. If this idea has any merit, then what we need to see is a series of forecasts made year after year, until it is clear whether what was observed is just by chance, or whether there really is a realtionship between open sea in the autumn, and snowfall in the NH the next winter.

      This is precisely what Grey and Klotzbach did with their December forecasts of the next hurricane season. After 20 years of trying, they found their idea had no merit.

      • “If this idea has any merit, then what we need to see is a series of forecasts made year after year”

        That’s nonsense, Jim. The short-term variability from year-to-year may obscure the long-term trend.

        There are a number of ways you can test a prediction against data. Using a climate hypothesis for weather prediction is rarely going to be one of them.

  3. Judith

    We had a similar decline of ice from 1918 to 1939. Presumably you could test your hypothesis against the snow records for that period. I suspect that there might be sufficient records available for the 1818 to 1860 melting as well?

    • “We had a similar decline of ice from 1918 to 1939.”

      That’s nonsense. Care to cite a source?

      • Robert, Tony will likely have better sources, but I remembered this paper:

        See Fig. 3, it’s only ice around Iceland, but the decline there was from ~1880 to ~1940.

      • Surely you are not serious in not being aware of that period of melt?

        Google ‘the arctic heats up’ and you will come to a book. This cites the newspaper reports of the time. Such as bob Bartlett on the morissey made a good living taking people there to explore the melting, somewhat equivalent to the cruises that celebs make today. He was filmed for pathe newsreels that your ancestors would have seen in cinemas during the 1920’s and 1930’s.

        The period will be part three in my ‘historic variations in arctic ice ‘ series. I am currently working on part two that covers the seven arctic warming periods that can be identified during the Holocene.

      • “it’s only ice around Iceland”

        You see the problem with that?

        “Surely you are not serious in not being aware of that period of melt?”

        Since you’re already having to change your story from “a similar decline of ice” to a vague “period of melt” I’d say you’ve effectively conceded your first assertion was nonsense.

        But please, just as a formality, would you please either prove “a similar decline of ice” or concede that you exaggerated?

      • I see no problems with that. Ice around Iceland (the number of weeks when ice was observed in this case) must correlate very well with the arctic sea ice extent/area, at least with the annual maximum. To claim otherwise requires extraordinary evidence.

      • “must correlate very well”


    • Tonyb,
      AGW true believers rely on historical illiteracy implicitly. The history of weather variability is one that AGW community avoids at every opportunity.

    • I really wish we had good sea ice and snow cover records during the early part of the 20th century

      • Dr. Curry,

        Aren’t there historical records of local sea ice extent (like the one referenced in my comment above) from different places in/near the Arctic (Iceland, Russia, Scandinavia, Japan…). Those should be good proxies. Snow too. There must be such records.

      • Tonyb is working on assembling the historical records of sea ice

      • Judith

        I will send you the sea ice records but I have never had cause to seek out snow records

      • Try the Admirality Records, the RN ran convoys to Russian from 1941 and tried to keep as close to the ice pack as possible. After WWII British and American spy ships monitored the Soviet Navy pretty much non-stop.
        The USN will also have all the yearly records their submarines got of the Arctic ice.
        It wasn’t until relatively recently, with the commissioning of USS San Juan (SSN-751; 1988) that US submarines were able to break through thick ice. Prior to this period, they would spend a lot of time looking at ice thickness.
        So both the RN and USN have a LOT of data on ice-pack thickness and extent. You could ask really nicely.

      • By all means ask the Navy for their sea-ice thickness data, but I don’t think we were up there primarily to study sea ice thickness. And the sonar systems on Los Angelos class fast attack submarines, like the one I went under the ice on, that could measure ice thickness, were of the active variety, projecting sound and listening to the echos, and were rarely, if ever used up there. In all the voyages I made on that sub, I do not remember ever going active.

        Even if the subs up there took constant ice thickness measurements, it would still be an incomplete picture, a series of snap shot pictues of local conditions, which wouldn’t sum to big picture measurement of total ice volume.

      • Agreed. Cool that you were on the subs :)

      • Phyllograptus

        I remember reading a paper using admiralty logs from whaling ships in the Antarctica to gauge ice extent. Knowing the biota food source relationship to ice and what whales fed on what biota, the researchers were able to take the position of the whale kills from the admiralty records and map the decadal long position of the southern ice coverage. Not sure if the same thing could be done for the Arctic, but it could be looked into

      • The warm Arctic peak around 1940 seems to have corresponded with snow in Britain. There are some anecdotal things on British winters here.;sess=
        Notably “1937-42: These years were all snowy, with numerous falls of 1-2ft, and occasional falls (such as 194-41) in which snow depths of up to 16 foot (drifts) were recorded. Places worst affected by this mini outbreak of snowy winters were Scotland and Northern England, but the South was also quite badly affected, more particularly the South West and Wales. 1939-40 saw the supposed ‘blizzard of the decade’ in Scotland and England when in late January snow fell widely, excluding only some areas. The snowy period ended in 1942-43, when little snow was recorded the next 2 winters. “

      • scepticalWombat

        You might like to look at “A changing Arctic seasonal ice zone: Observations from 1870–2003 and possible oceanographic consequences” 2007 by Kinnard et al. You will find the abstract at

      • Dr. Curry,
        Your paper is intriguing and thank you for writing about it.
        IRT records of ice- it seems that proxy data (obviously with large error bands) could be made from news reports and local records kept. You could attempt to link your study of decreasing ice yielding increasing snow with the inverse condition of increasing ice and decreasing snow. It seems from several paleo studies that at least on regional basis Arctic ice cover has been very dynamic over the long term. Also, what are the energy budget implications of the increased evaporation from more open ocean?

    • Captain Kangaroo

      These are Russian observatons from four Arctic Seas

      Here are the Arctic temps. –

      Here are the US temps – watch for the change

      Why do they look like that? Why the hell should I tell you.

      Best regards
      Captain Kangaroo

  4. It seems there are unusual things going on in both the southern and the northern hemisphere. New Zealand has just had a summer without much sun and Australia is having higher rainfalls than normal. There is nothing unusual in the southern sea ice except maybe a bit higher than the long term average. We’ve also been through a deep solar minimum and in early 2009 also announced the lowest value ever measured for the top of the atmosphere. How do you segregate out the solar / upper atmoshperic affects from ice extent effects when both things are going through some extraordinary cycles?

    • sean,
      Australia fluctuates between extreme drought and extreme wet. If you look at long term records, you will see that the current wet cycle is not unprecedented at all.

    • Sean

      Google ‘I love a sunburnt country’ a great poem about Australian weather written in 1903, nothing strange going on at all.

  5. Not that I doubt that sea ice cover affect atmospheric circulations but I wondering about that chicken and egg thing or cart before the horse.
    Does the current winter season detract from your conclusions, given the opposite nature of the AO and NAO in comparison to 09/10 and 10/11 (or any winter in the last 60 years)?
    Or is it more likely that wind circulations determine where the ice is or not as the case may be. For example last year Hudson Bay and around Baffin Island had a very late start due to a very strongly negative AO. While this year the very stongly + AO and NAO has the ice levels at normal levels in those areas but the Barents and Kara Seas have the negative sea ice anomolies while the Bering Sea has a positive anomoly.
    Last thought, are your conclusions non-falsifiable?

    • The current winter had several things going on, resulting in positive sea ice anomaly in Bering Sea and negative anomalies in the Barents and Kara Seas. Interestingly, Eurasia (under the influence of Barents and Kara) had lots of snow, whereas U.S. (influenced by the Bering Sea) had very little snow. The chicken and egg are impossible to sort out; at best you can identify a chain of events and gain some predictability from this.

  6. Latimer Alder

    So the unusually cold and snowy winters we’ve been having the last few years in England are due to global warming. And if we have a warmer than normal one next year that’ll no doubt be proof positive of global warming too. Ten years ago we were warned – in all seriousness by a guy from the Met Office – that snow would be a thing of the past because of global warming.

    It is no wonder that the general public is losing faith in climatology and climatologists when they hear such stuff advanced with a straight face. They may not be experienced scientits, but they can evaluate a ‘having your cake and eating it argument’ as well as anybody else.

    Let’s have a quick competition. What conceiveable weather event in the UK will not be taken as proof of global warming?

    Unusually Hot & Dry = global warming
    Unusually Cold and Snowy = absolute definite proof of global warming.(theory above)
    Lots of rain = global warming
    Drought = global warming
    Just the same as last year – tediously boring = a temporary lull in the the otherwise inexorable global warming
    Colder than last year. = cherry picking by the well-funded big oil denier conspiracy…….

    and so it goes…….

    • Latimer old boy,

      Dr. Curry never assigned GW to the ice deficit. Just that if ice extent was low during the NH autumn, then there was a probability that there would be higher then average snowfall in certain NH areas.

      The ice extent could be low for numerous reasons, wind, wave action, seal farts, whatever.

    • Now is not the time to lose faith in climatology and climatologists. When some come out with something different from what they were telling us before, it gives us confidence that they are still scientists and they are still skeptical and they are still looking at every different idea that might prove something they believed before was wrong. If this idea turns out to be wrong it is still scientists who are still thinking.
      They are not wrong! This is correct science!
      This is “SCIENCE” without the consensus. This is what we have been hoping for!
      These are heros of Climate Science.
      Jiping Liu Judith A. Curry Huijun Wang Mirong Song Radley M. Horton
      Some more scientists need to get off their consensus butts and start thinking.

    • Latimer,

      I think Dr. Curry made it clear above that all she expects is a partial (all other things equal) negative correlation between artic sea ice extent and NH snowfall totals. There’s nothing there about GW per se being the lurking third variable: Could be seal farts, as DeNihilist puts it.

      • Latimer Alder

        @de nihilist, @nw

        Thank you both for your suggestions. I am sure that , in the strictest sense, you may be right. Judith’s paper may not explicitly make that link.

        But I am not holding my breath waiting to see that nice lady from the Met Office (Julia Slingo??) come onto breakfast telly every time it snows and announce to a hushed nation that the snow is all due to seal farts. Nor that we need to invest zillions of scarce pounds in a new supercomputer to investigate those anal effusions. Instead she will stick to her line that any unusual weather is entirely down to global warming alone. Including snow and cold.

        The UK public is increasingly sceptical of global warming claims. This is just one more that will evoke a guffaw of disbelief rather than a groundswell of concern.

      • andrew adams


        You seem to have a very low opinion of the British public’s intelligence.

      • Latimer Alder

        @andrew adams

        ‘You seem to have a very low opinion of the British public’s intelligence’

        No indeed. A very high one. Eventually they see through even the best of showmen and illusionists. And AGW is now so much last year’s problem that even our own Minister for Energy and Climate Change hardly dares to utter its name. The mantra now is ‘energy security’, not ’emissions reduction’.

        Remember Transition Towns? The idea that we would all collectively work together to solve the climate change problem?
        Here’s this quarter’s agenda for a group near me.

        I merely observe that with its emphasis on cake making and sewing it seems to have morphed from the great campaigning organisation it set itself up to be – to a new version of the Women’s Institute. Worthy and laudable though both may be, they ain’t going to change the world.

        So everywhere I look around UK I see that AGW is fading away from public concern. The Prime Minister is casting doubt on the vast subsidies we pay for ‘renewable energy’. Fifteen years ago the buzz word was ‘Community’. And everybody in local and central government had to be working on ‘Community’ projects. I have personal experience that a failed grant application to the local council became successful just by adding that one magic word wherever it could be fitted

        Five years ago the new buzz word was ‘global warming’. Who knows what tomorrow’s will be. But I’ll take a wager that it won’t be ‘climate change’.

      • actually, the correlations aren’t with total NH snowfall, but rather certain regions, see fig 1 of the paper.

      • Ah yes, and I understand why you want that clear. Thanks.

      • andrew adams


        First of all, my comment on the intelligence of the British public related to their ability to hear a claim such as global warming could cause more severe winters and understand that just because it sounds counter-intuitive it shouldn’t necessarily be dismissed out of hand.

        But on your wider point I think you have it wrong. If there is not much public debate about climate change I don’t think it’s because it’s no longer considered to be a concern, in fact it’s the opposite – it’s become such a mainstream, widely accepted part of the public conscience that it’s no longer controversial, despite the attempts of some to portray it as otherwise.
        At the last election all three major parties were pushing their “green” credentials, particularly their concern about climate change – even our Tory Prime Minister promised that his government would be the “greenest ever”. Of course they are not living up to their own rhetoric, they never do, but they recognised where public opinion is on the subject. When they did publish their ambition targets for cuts in CO2 emissions there was the usual squealing in the right wing press but no great outcry from the public. Similarly businesses are keen to promote their “green credentials” (which usually involve reducing their caron footprint) because again they recognise that this plays well with the public.

        I can’t pretend to be particularly knowledgable about “Transition Towns” but I looked at the link you provided. Of course it’s easy to mock initiatives like this but they seem to do more than just cake making and sewing and there are a lot of such schemes across the country, and they can’t operate without a certain level of acceptance from the public, businesses, local authorities etc. Similarly the 10:10 campaign was well supported across the country. Of course a lot of people do not get involved in such things, for a number of reasons, and given the country’s other problems it’s not surprising that AGW has slipped down the list of personal priorities for some people, but that doesn’t necessarily mean they do not accept there is a problem.

      • Latimer Alder


        You might find the linked article below quite interesting. A sceptical commentator, used t being vilified and shunned by the media discovered that a radio phone-in on LBC – the London commercial talk radio station – could hardly find anybody to disagree with him.

        (Note to US readers – commercial talk radio in UK is not a politically polarised thing as it is in the states. They are obliged by their licence to broadcast to maintain a generally impartial stance)

      • I have read Delingpole often enough to believe that there’s never lack of people who disagree with him on whatever subject he chooses.

        There may be some reason that kept others out of the radio discussion, but that cannot be the lack of disagreement.

        The introductory words of his blog: James Delingpole is a writer, journalist and broadcaster who is right about everything. lead naturally to the style that he has chosen to use.

    • Hi Latimer

      I don’t think that was anyone from the Met Office warning that “snow would be a thing of the past” was it? The quote “Children won’t know what snow is” seems to be generally attributed to David Viner at UEA. I don’t know for sure whether he really said that or not either, but I’m pretty confident nobody from the Met Office said it.



      • Richard Betts

        From The Independent;

        ‘However, the warming is so far manifesting itself more in winters which are less cold than in much hotter summers. According to Dr David Viner, a senior research scientist at the climatic research unit (CRU) of the University of East Anglia, within a few years winter snowfall will become “a very rare and exciting event”.

        “Children just aren’t going to know what snow is,” he said.

      • Richard Betts

        Mind you it seems the Met office do have some form on disappearing snow…I would be surprised if David Parker said what is attrbuted to him here;

      • Latimer Alder

        Hi Richard

        You are right. The guy in question was from the CRU at UEA…so a colleague of Phil Jones and Trevor Davies, rather than at the Met Office so a colleague of yours. His point was also reinforced by David Parker, from the Hadley Centre for Climate Prediction and Research in Berkshire.

        Here’s the article from The Independent in 2000.

        And though the fine distinction between these various institutions may be very apparent to insiders, they are not so to the general public. For whom you are all part of the consensus among the vast majority of climatologists.

        So apologies to the Met Office if I have maligned you. I’m sure you agree that any blame attached for this daft statement should be attributed to the CRU/UEA.

      • Hi Richard,

        As the UK government’s meteorological agency, presumably you took appropriate steps at the time to rebut Viner’s egregiously misleading prediction?

        Care to point us to where/when/what you said?

      • Correct- and new to me, the last part of the article ‘Heavy snow will return occasionally, says Dr Viner, but when it does we will be unprepared. “We’re really going to get caught out. Snow will probably cause chaos in 20 years time,” he said.”- yep that about sums up our ability to cope with snow.

        I am not big on the science but it seems logical and at face value, expected that cold wet sea in the north rather than frozen dry freezing sea will generate very different weather. In west Britain warm sw winds bring damp winters, NE winds used to be just cold, but now I expect snow.

  7. Dr. Curry,
    I will certainly read your paper. But knowing how it is sometimes difficult to spot all the important implications of technical scientific papers (especially for a layman), I would like to ask two questions first.

    The post (maybe part of the press release) states: “The simulations showed that diminishing Arctic sea ice induced a significant surface warming in the Arctic Ocean/ . . .and cooling over northern North America. Europe . . .” Does your new paper address what caused the diminishing Arctic sea ice, e.g., increasing Arctic surface air temperatures?

    Have you and your co-authors perhaps found a new and powerful negative feedback?

    • Leigh, we do not address the causes of the sea ice decline in our paper. And yes, what we propose is arguably a negative feedback. This general idea is not original with us however, it was proposed by Ewing and Donn (refer to wikipedia

      • Anything is possible

        A broad outline of Ewing and Donn’s theory, which proposes that the Arctic was ice free during the last glaciation, can be found here :

        Interesting line of thought……..

      • Dr. Curry,

        Thank you for your reply. I read your paper a couple of hours ago. At least relative to my questions above, what struck me was the possibility of starting with your reduction and analysis of the snow cover/fall anomaly data to come up with a research project based on some quite complicated but fascinating calculations on net TOA energy balance as a result of your conclusion about the relation of Arctic sea ice loss to NH snow cover/amount anomaly.

        I have made a list of (up to this point) 15 different factors rhat would need to be included in a further analysis, time differentiated against seasonal and, for the entire period you study, yearly time changes in radiative effects.

        Looking at your graphics, what struck me most was how far south these major snow anomalies have occured. Just this alone generates at least 3 relevant variables: (1) Additional snow/ice area coverage through time; (2) resurfacing of snow/ice coverage through time affecting lowered albedo of aged snow/ice; and (3) persistence through spring and increased area coverage in early autumn.

        The point of all this would be to see what the net TOA radiative loss/gain of this process was. Observationally, we are currently arguing [in fact in a war] about a possible radiative imbalance of approx. ,6 – ,85 W/m^2 (with a satellite error range of 3 to 4 W/m^2.) While strictly speaking a radiative negative feedback from the Arctic sea-ice-loss/land-snow-increase-gain might not be a feedback on global surface temperature, if after reasonable calculation it were either quite large in terms of energy gain or loss, that would “give ’em somethin’ to talk about”.

        My gut feeling is that this process is a very strong negative feedback. If so, at least over the temperature and climatological conditions we are now facing, working this out quantitatively would stand “transient/equilibrium responses” or “fast/slow feedbacks” ruminations on their head. Remember, you never get to the mighty positive slow feedbacks unless you first have to confront sufficiently large and positive fast feedbacks. Dr. Curry, the fast feedback your recent research points to is a fast negative feedback.

        And so, paradoxical as it may seem, Al Gore, Monbiot, Revkin, Romm, et. al. and et. cet., may all be right: warming (in some forms and in some places) causes cooling, but not in the form and quantity they dimly imagined.

      • Leigh, agreed, there is a potential negative feedback here, esp if the snowfall melts later in the spring.

      • A.I.P., thanx!

        very interesting paragraph this one (remember, this article is from 1958) –

        “Modern man’s hunch that the Ice Age has gone for good is based on what he firmly believes to be common sense. How, we ask, can a new Ice Age possibly be shaping up when everybody knows that existing glaciers — like those in the Swiss passes and Alaska — are melting? How could new ice hulks creep in upon us while weather experts are announcing that even the North Polar ice caps are thinning? And what about the fact that weather records show the weather has been growing warmer over the years – so warm in fact that certain glaciers are melting fast enough to raise the level of the world’s oceans? Can such signs really foreshadow the coming of a new Ice Age?”

      • Leigh, read AIP’s pointer to the 1958 article. These scientists were envisaging an ice free artic as a major cause for glacation. Kinda cool way of looking at things!

        Works if you believe that CO2 follows warming of the planet. As CO2 climbs, temps get coupled and climb higher faster, thus melting the Artic ice cover, thus allowing more and more snowfall in the NH, thus creating glaciers, thus creating a negative feedback, thus starting cooling, thus CO2 starts to drop , thus cooling picks up, thus finally the Artic freezes again, thus starts less snowfall, etc.

        I like this theory and it is now my official stance on AGW! We have to drop our CO2 output before we freeze most of the NH!!!!!!

      • There are fast positive and negative feedbacks all through the system.

        Warm Arctic winters, for example, are degrading the ozone over the Arctic, which leads to greater heat loss. The open sea, obviously, absorbs more solar energy than the ice. Positive feedback. The glacier ice exposed by early-season melting is darker and absorbs more solar energy. Positive. There are both positive and negative cloud feedbacks.

        In total there are hundreds if not thousands of feedbacks, and if you think you can eyeball one hypothesized negative feedback and proclaim victory over “Al Gore, Monbiot, Revkin, Romm, et. al” and their “dim imaginings” you are deluding yourself.

    • scepticalWombat

      A negative feedback yes. A powerful one – probably not. Snow on land in winter is not going to have the same impact on insolation as ice on sea in summer.

    • DeNihilist
      CO2 is a trace gas and, if anything, it has a trace effect.
      If you cut manmade CO2 you just kill the green things that grow and life that depends on green things.
      Earth temperature has little to do with manmade CO2.

      This climate cycle that Dr Curry’s team has found will cool the earth, no matter what you do with CO2. When earth is cool the arctic will freeze and the extra snow will stop and earth will start warming again.

  8. Judith,
    I’m wondering if you’d consider asking Joe D. to put up a guest post as a way to get a conversation going between two experts….instead of just posting a link as you did. It’s very difficult…if not impossible….for a lay person like myself to make any kind of scientific judgement based on a paper. But actual dialogue between two human beings with differing views can be very illuminating.

    Joe makes his living in the cut throat field of private long range forecasting. If you guys have come up with something he can use on a practical basis to get a leg up on the competition, I’m certain he’dl use it. And yet it sounds like he’s rejecting your hypothesis.

  9. This year in Manitoba (north central NA) there was no snow on the ground until late Feb, and Feb temperatures reached 12 degrees C (totally unheard of in my life). I know that means nothing with climate or even short term observations like this, and I’m not panicing (TM), but it did make me hunt for charts on snow cover after reading this. I found:
    …which may not be the right thing to look at – I’d be grateful for better links/analysis. After clicking through all of them, it didn’t seem to me that there wasn’t really significant extra snow? I also wonder how that measures snow that falls on the ocean, which must be a significant portion (do years with randomly more blizzards over land overtake the signal being looked for?).

    Mostly I wonder if it’s the amount of snow outside university windows in the north east US and north west Europe that cause people to look so close at this question in the first place? If this same cold and snow fell over Sibera and mid west Canada would people have noticed an anomaly in the data? Genuine question, probably yes, but I can’t seem to find a good confirmation.

    • Huge amounts of snow this winter in Eurasia

      • Hector Pascal

        In my town (northern Honshu, Japan) the snow blanket depth peaked at about 2.6 metres in late February. Checking my record, (back to 1959) that puts us at around 15-16 metres of daily accumulation since mid-December. If so, it will be the 7th 14 metre+, and 3rd 15 metre+ snowfall in 53 years. Unusual, but not unprecedented.

        Normally, local authorities are able to budget for road clearing and snow removal. This winter the snowfall across northern/western Japan has been so severe, the national government has stepped in to provide extra funding.

      • I understand there has been more snow in Eurasia this year, but overall NH seems to be down for the last 10 years or so, including 2011. I did get the impression that there was more snow overall from the paper (“snowier conditions in large parts of northern mid-latitudes”, “more persistent snowstorms over northern continents during winter”), but rereading I see it doesn’t say that specifically. I stand corrected. I noticed in the models and measurements there was significantly less snow in places like Tibet that balance it out, I guess that is just less interesting to people : ).

        (the source of the snow data as per the methods section)

        Thanks for the paper and chance to discuss it : )

      • Jack Hughes

        Where is Eurasia ?

        (Except in the pages of Orwell’s Climate Primer)

      • Markus Fitzhenry

        Jack Hughes | March 6, 2012 at 4:18 am |
        Where is Eurasia ?””

        Don’t know, but on the other side of Asia there is Australasia.

      • Hector Pascal

        “Where is Eurasia ?”
        If you look at a map, or maybe an atlas, you will see a continent in the northern hemisphere which stretches from western europe to east asia. This continent may be usefully described as “Eurasia”.

        Hint to the geographically challenged: this continent is not the USA.

  10. Congratulations on getting another paper published. This one looks like it might have been fun, as well. How do you find time to blog?

    • Judy – Could I ask the converse of that question? How do you find time to do science?

      The question is asked sincerely, not as snark. In your leadership position, you have administrative responsibilities, teaching obligations, committee responsibilities, invited talks, and invited articles, and you also follow media and blog items on climate in some detail, as well as paying extensive attention to your own blog.

      I’m impressed that you are continuing to work in an area of climate science where you have previously established a reputation for expertise, and so obviously you haven’t lost touch with that area, but I also expect the demands on your time limit your ability to concentrate on the science unless you are superhuman. I would be interested in your perspective on how you manage your time.

      I would also be interested in the separate roles of each of the five authors of the article.

      I have a couple of other unrelated comments on the article, which I think is a very nice contribution to our understanding of these regional effects. The first is that it illustrates the point that if one reads the general science and climatology literature on climate phenomena, the vast majority of papers are not designed either to prove or disprove “AGW”, and so the notion that in publishing one must either pay tribute to the “consensus” or risk ostracism and defunding is refuted by that evidence. Obviously, there is always some resistance in any science to unorthodox views, but one can remain comfortably funded by avoiding unorthodoxy without endorsing orthodoxy. The second is that the notion that there is something unseemly about using models as an instrument of understanding signifies a profound misconception about our ability to study any type of complex physical phenomena (or even simple ones) without some sort of model. Each use of models must be judged on its merits rather than via pejorative generalizations, but I hesitate to trigger another landslide of commentary about the deficiencies of models, so I won’t pursue that point further.

      • Fred

        It’s obvious, the denizens are so brilliant that we continually provide Judith with top class peer reviewed material thereby saving her lots of time. :)


      • Fred, I have published 4 first authored papers this past year, 3 of which were discussed on this blog. The 4th is outside the domain of what we discuss here, but FYI here is the other paper:

        Mostly, I am 2nd or 3rd author on papers with collaborators, some from my own research group and some are other collaborators. At this point in my career I do not write code or run models, so my contribution as coauthor typically involves conceptualizing the research problem and analysis methods, writing, and occasionally some theory.

        With regards to the latest Arctic paper, I do not know anything about the contribution of the last two authors, but Jiping Liu did most of the work. I contributed substantially to the writing.

        At this stage of my career, I find writing blog posts and textbooks to be more rewarding than working on journal articles (I am coauthor of a new textbook that is under contract, and contemplating 2nd edition to my thermodynamics text). I am working to understand broader aspects of the climate problem (many areas of which i am unlikely to publish in), rather than digging deep in my own specialties.

      • Fred, What you say about models is a good point and I think few would disagree. We use them all the time in structural analysis, fluid dynamics, cosmology, medicine, weather and may other fields. The problem I think is the assumption that is implicit in the climate science activist community and that is somewhat reflected in the IPCC that models are adequate for “projecting” or “predicting” (depending on what rather irrelevant semantic nuances you want to use) what will happen in 100 years. This is especially true when the track record of the models is decidedly mixed on even decadal time scales. Weather models (basically GCM’s) are very useful on daily and in some cases weekly time scales even though not particularly accurate. But they are terrible on yearly time scales. This is obvious just by looking at the National Weather Service forecast discussions produced for all major cities in the United States, where it is clear these issues are well known to virtually every meteorologist. So lets be clear on this. The problem is not about the models but the climate science establishment’s absurd defense of them and what they can tell us. Now I know about what I call the “doctrine of the attractor” and it doesn’t change the observations above.

      • An interesting follow on question is related to going over to RC, C-A-S etc. and finding all sorts of comments about how “Curry gets all the science wrong” etc etc. They even happen on this blog and it’s to Judith’s credit that she doesn’t borehole them.

        I would be very interested in Judith’s perspective on why people take this tone in light of her impressive record of publications etc. etc.

    • I actually ask because I tend to reward myself with time for blogging if I get everything else done to my satisfaction. The fact that I’m down to two posts a week is an indication of things not going well…

  11. Markus Fitzhenry

    ABC NEWS – Science
    By Clayton Sandell
    Feb 27, 2012 9:35pm
    Disappearing Arctic Sea Ice & More Powerful Storms?
    “”Liu says the new research may also help connect the dots between human-caused global warming, vanishing ice and our changing weather.””

    ( What? climate research still in the process of ‘connecting dots’ )

    “”Climate researchers believe that the three-decade decline in Arctic sea ice cannot be explained by natural causes alone. The National Center for Atmospheric Research, for example, recently found that roughly half of Arctic sea ice decline from 1975 to 2005 can be blamed on the increasing amount of climate-changing greenhouse gasses, including carbon dioxide, that humans are releasing into the atmosphere.””

    ( You counted the number of joules to make this happen, Dr Curry? Or, could we assume that statement has no statistical support? Were previous decade increases in cover, not explained by natural causes?

    Even if the author did not attribute the statement above to your study, the reporter draws a clear inference that your paper directly suggests CO2 as a duel driver with natural variability for the phenomena you studied. Is it? )

    “Is Arctic ice in a death spiral? Maybe not yet, but it’s in big trouble,” Mark Serreze, director of the National Snow and Ice Data Center, recently told ABC News, pointing out that the five lowest amounts of Arctic sea ice on record (since 1979) have all been recorded in the last five years.””

    I detest climate studies that correlated what is happening in the NH directly to the SH, suggesting global effects, and especially ones that denote a signal from short time spans, then correlating the span with global warming, rather than global cooling.

    Well, make up your mind Dr Curry. Is the effects of Co2 global, or when taking into account the SH ice trends, is climate change warming restricted to the NH?

    Is it not, the opposite phonemna would be occuring in the SH, with warmer and drier wheather over continents?

    In my opinion the study is alarmist in suggesting the praochial effects of weather phonenma in the NH can have any wider application. Absolute rubbish.

    • I will defend/discuss what we wrote in the paper and in the press release issued by Georgia Tech. I am not going to defend what other people say about our paper or about arctic sea ice in an interview.

      For my take on the broader issues associated with arctic sea ice, see these previous posts:

      • Judith, if you’re happy for your paper to be correctly interpreted by experts, but misinterpreted by the multitudes, this is fine.

        If, on the other hand, you would prefer that the multitudes, to the extent that they understand your work at all, understand it correctly, it may be a regrettable fact that you have to anticipate the interpretation likely to be placed upon it by the media through which it is, in most cases, going to be received.

        Like it or not, papers such as yours are of genuine interest to many who cannot understand them in detail, and must rely on “the media” to interpret their burden. Experience tells us that the MSM, with few exceptions, has a Pavlovian catastrophist response to climate stories, and will interpret them in a catastrophist way unless the authors preempt their bias by a clear statement about what is NOT being proposed. It shouldn’t be necessary, but….

      • Well I’ve despaired of communicating effectively with the masses that just read the headlines; rather I am focusing on engaging at Climate Etc. with the technically educated group that cares enough to dig in a bit. Hoping that will have a trickle down effect.

      • Tom,

        I recently asked a question in similar vein to Isaac Held, got an even shorter response ;)

    • Markus, I share your dim view of the CAGW interpretation of the paper, but that is not the paper. The paper’s hypothesis is relatively limited. The fact that one’s work will be twisted this way is not a reason not to do it.

      • Markus Fitzhenry

        But if it has been twisted David, is it the responsibility of the Authors to be clear and unambiguous in a rebuke of the misleading news article

        I respect what Dr Curry would be likely to do here.

        We seem to be fond of claiming science acts for a better public good but used this way, it serves the public no good at all.

      • You don’t rebuke the press for reporting what a lot of scientists believe.

      • Markus Fitzhenry.

        ABC NEWS – Science
        By Clayton Sandell
        Feb 27, 2012 9:35pm
        Disappearing Arctic Sea Ice & More Powerful Storms?
        Liu stresses that many factors are at play when it comes to winter weather and insists that more research is needed to better understand the connections.
        “We want to know, is this due to human induced greenhouse gasses, or natural variability? We want to figure this out,” he told ABC News.
        I believe a lot of scientists don’t know what to believe, more confusion reigns than belief.

    • Bob Ludwick

      This is a bit of a cheap shot and I am certainly not going to argue science with Dr. Curry, but isn’t 1975, the reference point for the start of the alarming decline of arctic sea ice, about the time when we were awash with warnings about the imminent ice age? And wasn’t the UNPRECEDENTEDLY LARGE AND GROWING extent of arctic sea ice cited as incontrovertible evidence that an ice age was nearly inevitable unless action was taken immediately? I recall (among other remedies) plans to spread soot over the ice cap to melt it before the onslaught of the ice age became unstoppable.

      And for a little historical perspective:
      “It will without doubt have come to your Lordship’s knowledge that a considerable change of climate, inexplicable at present to us, must have taken place in the Circumpolar Regions, by which the severity of the cold that has for centuries past enclosed the seas in the high northern latitudes in an impenetrable barrier of ice has been during the last two years, greatly abated.

      (This) affords ample proof that new sources of warmth have been opened and give us leave to hope that the Arctic Seas may at this time be more accessible than they have been for centuries past, and that discoveries may now be made in them not only interesting to the advancement of science but also to the future intercourse of mankind and the commerce of distant nations.”
      President of the Royal Society, London, to the Admiralty, 20th November, 1817 ”

      In 1817 the melting of the ice cap was, unlike now, apparently considered to be a GOOD thing. Oh well, times change.

      • “the reference point for the start of the alarming decline of arctic sea ice, about the time when we were awash with warnings about the imminent ice age?”

        No, we were never “awash with warnings about the imminent ice age.” That’s a bit of propaganda the denialists cooked up long after. SkS has a post, I believe:

      • @Robert: I stand corrected.

        Not being a climate scientist, and not realizing in the mid-70’s that there WAS such a thing, I’m sure you will forgive me for noticing that all the articles in the ‘popular press’, like ‘Newsweek’, ‘Popular Science’, ‘Popular Mechanics’, ‘Science Digest’, newspapers, et al warning us of an imminent ice age and proposing methods of staving off disaster were simply being made up out of whole cloth by science editors to drum up circulation while the real Climate Scientists were frantically trying to warn us that we were about to be rendered into cracklings by anthropogenic CO2. Of course the climate scientists at NOAA quoted here: actually said nothing to imply that the earth was cooling rapidly and potentially disastrously and Gwynne just made it up, but how was I to know, not being an actual climate scientist or climate scientist in training at an accredited university? Likewise headlines such as ““U.S. Scientist Sees New Ice Age Coming,” ‘Washington Post’, July 9, 1971 (the scientist in question being a colleague of Dr. Hansen) or Holdren in 1971 predicting an ice age (, (although, to be fair, in the same book he simultaneously predicted global warming), or books from 1977 quoting the CIA: “The studies conclude that the world is entering a difficult period during which major climate change (further cooling) is likely to occur.” Professor Schneider was one of the leading ‘coolists’ in the 70’s, but of course he ‘saw the light’ and became a leading ‘warmist’, which I suppose proves that he is a true scientist. The ‘NY Times’ ran several stories in ’74 and ’75 warning of the coming cooling, citing multiple authoritative references, thus misdirecting us unwitting non-climate scientists. The initial ‘Earth Day’ kicked off with a warning about the coming ice age: “1970: First Earth Day Promoted Ice Age Fears – Excerpt: At the first Earth Day celebration, in 1970, environmentalist Nigel Calder warned, “The threat of a new ice age must now stand alongside nuclear war as a likely source of wholesale death and misery for mankind.””

        So yeah, not being a scientist, I was duped by a bunch of ‘pop science scare pieces’ in a gamut of national media that I foolishly trusted into thinking that legitimate climate scientists were warning of an imminent ice age when all along they were warning against CO2 driven overheating.

        I may have been DUPED by the warnings, but I didn’t imagine them.

        I’ll be more careful next time.

      • apologies, this was sent to spam for some reason

  12. How does one measure the winter snowfall level of the entire NH? This sounds like another area-averaged statistical boondoggle, like global temperature anomaly.

  13. Judy et al., very nice paper (except for the “loaded dice” quip in the discussion).

    Allow me to present some thoughts from the Numerical Weather Prediction point of view.

    I agree that the Arctic Oscillation (AO) is a major player in Northern Hemisphere winter from daily to seasonal time scales. However, I’d contend that the variance explained or variability of the mid-latitude flow attributed to the AO is not well understood to infer anything much about the derivative of such variability due to Arctic Sea Ice change.

    Recent review literature by Tim Woollings: see 2010: “Dynamical influences on European climate: An uncertain future, Phil. Trans. A, 368, 3733-3756.”

    summarizes the current literature on the predictability of European winter on seasonal time scales. The prevailing wisdom combined with woeful MetOffice forecast examples suggests that European blocking is not predictable. The onset of North Atlantic and European blocking episodes does not show satisfactory skill on 7-10 day time scales in the current ECMWF operational deterministic model. The natural variability and reddened state of the North Atlantic (poorly defined mean state) jet is directly related to the NAO phase, which is not well predicted past 7-10 days (synoptic time scales).

    Similar conclusions are reached in a numerical weather prediction context by T. Jung et al. at ECMWF (GRL 2011: ) who performed very detailed sensitivity analysis of the origin of the very persistent negative NAO (blocked phase) during the winter of 2009-10. They used the very advanced ECMWF seasonal prediction model at high resolution and prescribed various sea-ice concentrations, ENSO states, as well SST and solar forcings. They could not reject the null hypothesis that natural variability was the main cause of the 09-10 negative NAO.

    As the AO loading pattern shares the North Atlantic (Icelandic Low) node of the NAO, the current PNAS study by Liu et al. presents a potentially contradictory result to previous studies performed at ECMWF in the past 2-years.

    • Ryan, we have have been using ECMWF to make regime forecasts on timescales 1-15 days and 16-32 days for the past 4 years. The ensembles are far more useful than deterministic at timescales beyond a few days. The AO during winter 2009-2010 was of a different origin from winter 2010-2011, with 2009-2010 showing stratospheric origin and 2010-2011 showing a more surface origin. The problem with the ECMWF winter seasonal forecasts has been the specification of climatological sea ice. The Liu et al paper identifies a new pattern that is not AO, and may provide some insights into the blocking.

      • I agree with those comments.

        Bonus points for the Liu et al. paper referenced the Thompson and Wallace (2001) Science paper with the awesome paragraph:

        “The notion of blocking and cold air outbreaks being orchestrated on a hemispheric scale was anticipated by Namias and collaborators in early investigations of the so-called “zonal index cycle”, but was abandoned nearly 50 years ago for lack of evidence of statistically significant relations between climate anomalies in the North American and Eurasian sectors ”

        As a follow-on suggestion for future research, I would be interested in the origin and type of the blocking episodes found in your climate simulations. The importance of wave-breaking (cyclonic vs. anti-cyclonic) with respect to explosive extratropical cyclone activity and block onset is right up my alley.

  14. John Kannarr

    I was just noticing a post at NOT A LOT OF PEOPLE KNOW THAT:

    “There was a very sudden climatic shift in Iceland in 1965, with temperatures falling dramatically. The following six years were known there as the “Sea ice years” and saw major economic upheaval as a result.”

    I was wondering if those years, roughly 1965 – 1971 were years of low snowfall in Europe, northern Asia, or North America?

  15. “We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere,”

    Really? You guys get paid for this?


    • “We think the recent snowy winters could be caused”

      Anyway, I think this is gramatically incorrect. Should be “could have been caused”.


  16. A physicist

    Per last week’s NOAA article Temporal and spatial variability of Great Lakes ice cover, 1973-2010, does the remarkable multi-decade decline in winter ice on America’s Great Lakes evaporate more moisture from warmer unfrozen lakewater into winter air, thus increasing snow coverage? Are there other increasingly-unfrozen lake systems in the northern hemisphere, that similarly are evaporating more moisture into winter air-masses?

    • If you live in Buffalo NY, you will understand lake effect snowfalls.

      • A physicist

        Yes, that set me wondering if perhaps the Buffalo NY snow effect is now being seen on a global scale? Because as Google Earth shows us, lakes, rivers, and bogs are abundant in Canada and Siberia … are they staying unfrozen longer, similar to the Great Lakes?

      • Dr. Curry,

        I only get a slightly significant upward trend in median total snowfall in Buffalo over 70 years (quantile regression on years), and not on other quantiles of the distribution, nor anything with a robust regression. Is there a place to download yearly ice cover on the great lakes?

  17. Judy, do you think the moving of most sooty/sulfurous heavy industry from Western Europe to SEA/China is going to alter snow fall trends?

    • The impact of soot and pollution on precip is complex. There is a field experiment in the next year to look at the impact of the asian brown cloud on monsoon rains. The impact on snowfall would be more complex and we are in early days of understanding the microphysical impacts of soot/pollution on snowfall. This kind of problem is right up my alley, actually. But my field experiment days are over, relying on theoretical analyses with my Russian colleague Vitaly Khvorostyanov

      • Dr. Curry,
        Based on your study of a link between Arctic ice and snow, have you considered that since soot increases snow and ice melt significantly, the impact of soot is more than simply acting as nucleation for precipitation?

  18. Fred from Canuckistan

    You had best look at the implications of increasing Arctic ice . . . the regular 30+ year Arctic Ice Pulse, the one that peaked in the late 1970’s and waned since then is now quickly turning around to the rapid arctic ice accumulation period.


  19. Peter Davies

    The Arctic ice melting certainly releases more moisture into the atmosphere and subsequent increases in snowfalls certainly seems linked.

    I wonder if heavier snowfalls will generally then lead to the formation of more ice on the Arctic Ocean and less snowfalls and so the cycle goes on?

    The whole ice-snow phenomenon looks very much like the negative feedback such as that being suggested by our Alex Pope.

    • the heavier snowfalls will increase the albedo of earth, which will cool the land and the oceans. at some point the ocean temperature will not be warm enough to keep the arctic sea ice melted and the sea ice will increase and halt the cooling.

  20. Five years ago I was told that the earth was warming, and we needed to spend billions to study it. And we needed to live as peasant farmers.

    Four years ago, I was taunted, “don’t you know the diffence between weather and climate?

    Three years ago I was told no more snowy winters, which seemed like a weather thing.

    Two years ago, was told that more snow was due to global warming.

    This year, the tornadoes and our lack of snow is due to global climate change.

    dr Curry, do you sense my skepticism?

  21. Judith-

    I can accept that a reduction of sea ice will enhance fluxes of moisture,etc from the ocean to the atmosphere. What I don’t understand is what physical mechanism is responsible for altering the flow (say, at 300 hPa) and changing the meridional structure of the mid-latitude circulation. Do any papers outline any convincing physical explanations for this?

    I don’t have strong background in this field, although I think this marriage between climatology and synoptic dynamics is at the frontier of atmospheric science research. Jiping Liu gave a talk about this paper to our department though, and several of the synoptitians weren’t buying it, but it will be interesting to see how this area progresses in the next few years.

    • My simple, perhaps wrong, interpretation is that a warmer Arctic reduces the NH temperature gradient, hence it reduces the mean westerly flow, hence supports more of the easterly anomalies that lead to European snow episodes.

    • Chris, Just wondering if you want to retract some of your recent comments on Real Climate denegrating Judith’s scientific knowledge and work. I won’t quote them just so I don’t embarrass you.

      • You can quote away, and I don’t retract anything I’ve said.

      • Markus Fitzhenry

        ‘You can quote away, and I don’t retract anything I’ve said.’

        Chris, you might not retract anything you have already said but what you have ‘said’ will detract from anything you are about to say.

      • Chris

        Can you post up here half dozen of your science papers as I would be interested to see what area you are specialising in. Thanks for that

      • Tony,
        Try here,
        or here.

        Do you think a scientific publication record should be a requirement to comment here?

      • Markus Fitzhenry

        Nick says;
        Do you think a scientific publication record should be a requirement to comment here?”

        Well, I suppose it could depend on the genre of specialization of the Author,

        Your examples for Chris were,

        1. A transient simulation.
        2. A synthesisation.
        3. The falsification of a physics argument by use of a global
        climate model (GCM)

        My reading of Judith’s paper is that the data was derived from observations. It matters.

      • Nick

        You have obviously taken my comment as snark. It wasn’t. I have seen Chris commenting a number of times and merely wanted to get a handle on his areas of expertise. Thanks for the links, I shall read them with interest.

        No of course I dont think a scientific publication record should be a pre requisite to post here or otherwise we would miss out on a lot of interesting information (and a lot of interesting silliness too :) )


      • Latimer Alder

        @nick, david, tony

        We should also not forget Colose’s (in)famous remark on this blog:

        ‘Nobody without a PhD in Radiative Physics is even entitled to have an opinion about Global Warming’.

        Not , I suggest, a man with an inquiring, nor an open mind.

      • Tony,
        apologies for the misunderstanding.

      • Latimer,
        Here you are attributing that quote to Easterbrook. Did anyone ever say it?

      • From the blog rules:

        Respond to the argument, not to the person. What another participant stated on another blog in another context should not be used to discredit or otherwise challenge the participant. Changing your mind in response to new evidence and arguments is valued here.

        So while I’m sure Chris is willing to have it out, it’s explicitly not what this blog is about. So before you play teacher’s pet and try snitching on Chris to play up to our host, you might want to consider that she has very specifically asked us not to do that.

      • Nick Stokes

        No ptroblem. And just to prove I read them I noticed the reference to you-good stuff


      • Thanks, Nick (though I note I had nothing to do with the second publication).

        I also note that Latimer made that quote up.

      • Latimer Alder

        @chris colose

        If I have indeed misattributed that quotation to you then of course I apologise unreservedly.

        But I did not make it up – it seared itself on my brain at the time. as a humdinger of smug arrogance from a climatologist.

        If I could find a good way to search Climate Etc since its inception I will try to identify the exact source. Can anybody make any suggestions on how to do so?

      • So in summary, you don’t have a source, you don’t know who said it, but you’re sure somebody did, because it made you wery, wery mad.

        That’s less than persuasive. I suggest you get your facts straight and have your sources in hand before you start something like this laughable excuse for a witch hunt.

        At it stands you’ve scored an own goal against your own credibility.

      • You’re free to play gotcha games, but if I recall correctly, I was trying to get the point across that it’s very difficult for non-specialists to evaluate the fine points in climate science (just as with any other discipline). At some level, we need to take medical professionals, engineers, scientists, etc at their word unless you want to pay tuition and go to graduate school. Or you can read a few blogs….

      • Latimer Alder

        @chris colose

        You write:

        ‘You’re free to play gotcha games, but if I recall correctly, I was trying to get the point across that it’s very difficult for non-specialists to evaluate the fine points in climate science (just as with any other discipline)’

        Are we to understand that you did in fact make the quote I attributed to you? Or something very very close?

        It is difficult to read your remark above in any other way. Please clarify.

      • steven mosher


        About this need to take people at their word. Yes, at SOME point you may decide to take someone at their word. Also, at some point you may decide to check everything they say.
        A properly executed paper should provide the data and tools necessary to check the work performed.

        I decide to take somebody at their word when they first and foremost provide the data and tools necessary to check their claims. If they don’t provide this, then I’m not inclined to believe the words they write merely because they wrote them and merely because they passed through a process where no double checking of results was performed. If they do provide this, then I like to check a few of their claims. After a while, I might decide to take them at their word.

        If they have ever lied, if they have ever failed to correct a known error, if they have ever failed to properly credit another, if they defend lying, if they brush off errors that “don’t matter” then I never take them at their word. They either get ignored or double checked.

        For the record, do you condemn lying for the AGW cause?

      • steven,

        I never condone lying for scientific purposes.

        In general, I would support the ideal situation of complete transparency in science, though I also recognize that it is not often practical in the real world, and I’ve had headaches before getting data in a user-friendly format—- climate related or otherwise (of course, I would never support the null hypothesis of manipulation when such data/code is unavailable or not in a friendly format). Even more, getting to the point where you can interpret the data beyond standard statistics, and then put it in a context that relates to previous work on the issue (and in physics) requires some background in the topic.

        I also believe there are cases that can be justified when data requests should not be honored, but there’s endless blogs about this sort of stuff, and a lot of people have their disagreements on ethics/politics, other people’s motives, etc. and I’m not terribly interested in it. I prefer physics.

        You can go to ClimateAudit to self-validate all the conspiracy theories that you can handle, get all the latest news on who said what over e-mail, what legal procedures are relevant for this or that case, what code was/was not available, who did what about it, where Mike Mann slept on July 28, 2005 etc. It’s all pretty lame to me. Sometimes it’s amusing to get into briefly, and I made some comments regarding Gleick’s case on a couple blogs, but for me (and most people) the interest level fades within a couple days and at some point you need to put the event into the broader context of what thousands of scientists are doing, and what they’ve been doing for decades. You need to read the literature and attend academic conferences.

        I have no respect for people who only throw potshots at scientists, but don’t have the integrity to publish their results in the traditional scientific way or attempt to help further our understanding on that topic. This is true even if they found some minor issues with their methods (or expressed disagreements on methods where inherent subjectivity and uncertainty exists).

      • Latimer

        I think it might have been S Easterbrook that made that specific quote originally.

        Chris has certainly said something very broadly similar on Climate Etc because I remember wincing at the time, but I don’t think he used the same form of words. Chris is young and needs to be cut a little slack (don’t mean to be patronising) but he does come over as over confident sometimes. When he is posting straightforward material he is worth lisening to.

        I’m not sure its worth pursuing, lets just hope that all of us here show due respect to other denizens no matter what ‘side’ they are on.


      • Latimer,

        The closest thing I can find on this site to that PhD quote is:

      • steven mosher



        I never condone lying for scientific purposes.


        But that is not the question I asked Chris. I will ask it directly. Do you
        condemn Gleick’s lying to Heartland and his lying to the journalist he sent the documents to. Yes or no, Up or down.

        You continue:

        “In general, I would support the ideal situation of complete transparency in science, though I also recognize that it is not often practical in the real world, and I’ve had headaches before getting data in a user-friendly format—- climate related or otherwise (of course, I would never support the null hypothesis of manipulation when such data/code is unavailable or not in a friendly format). Even more, getting to the point where you can interpret the data beyond standard statistics, and then put it in a context that relates to previous work on the issue (and in physics) requires some background in the topic.”

        Nobody asked for a user friendly format. If you used data, and wrote code that read that data, which you HAD TO, then that is enough.
        Look, if I wrte a paper saying that my proxy data proves the MWP was Huge and then refused you access to the data on the grounds that the format wasnt user friendly, or that you couldnt understand it, what would you make of my claim?

        “I also believe there are cases that can be justified when data requests should not be honored, but there’s endless blogs about this sort of stuff, and a lot of people have their disagreements on ethics/politics, other people’s motives, etc. and I’m not terribly interested in it. I prefer physics.”

        Well, Imagine how your physics career would go if people didnt give you data and said “you are just a grad student” wait till you get your PhD. If people didnt share data, you wouldnt be able to do Physics.

        “I have no respect for people who only throw potshots at scientists, but don’t have the integrity to publish their results in the traditional scientific way or attempt to help further our understanding on that topic. This is true even if they found some minor issues with their methods (or expressed disagreements on methods where inherent subjectivity and uncertainty exists).”

        That’s nice, but it has nothing to do with your stance on honesty or data or code.

      • steven:
        I’m sorry if I did not immediately infer that you were referring to the Gleick incident. Believe it or not, my world does not revolve around the latest in climate change politics, legal stories, gotcha games, conspiracies, shenanigans, etc., nor am I a spokesperson for everyone who accepts that humans can change the climate. But for the record, I do not condone Gleick’s actions, nor do I think that these sorts of methods should serve as a template in the future, for whatever reason.

      • steven mosher


        I would start there. It appears you got confused in indented thread.
        Memory is a tricky thing. What I have found is that If I have a doubt about
        the exact wording, I try to check first.

        Not that Chris or others will ever hold everyone to the same standard.

      • MattStat/MatthewRMarler

        Chris Colose: You can go to ClimateAudit to self-validate all the conspiracy theories that you can handle, get all the latest news on who said what over e-mail, what legal procedures are relevant for this or that case, what code was/was not available, who did what about it, where Mike Mann slept on July 28, 2005 etc. It’s all pretty lame to me. Sometimes it’s amusing to get into briefly, and I made some comments regarding Gleick’s case on a couple blogs, but for me (and most people) the interest level fades within a couple days and at some point you need to put the event into the broader context of what thousands of scientists are doing, and what they’ve been doing for decades.

        That attitude is what has allowed scientists to get away with fraud, sometimes (as with Sir Cyril Burt) over long time spans. Steve McIntyre’s work should be read with unflagging attention. I do not know how the Mann “case” (my word) will play out in the long run, but Steve McIntyre makes a good case that Mann is getting a lot of play out of loose and contradictory claims. It’s not about where anyone slept on July 28, 2005, but whether claims of what was included in analyses are always concordant. McIntyre does not seem to be correct all the time either, but his efforts are valuable, and your disparaging inattention is an invitation to disaster.

      • MattStat-

        No, that “attitude” is what allows people to actually get research done, rather than focus on blog stories and countless accusations that crop up on the internet. But if people want to make formal accusations of fraud, they can, just as was done with Wei-Chyung Wang at my department at the University of Albany. It was quickly found to have no basis in reality.

        Moreover, Mike Mann has been investigated to a very high extent, and has become the chosen target-point of skeptics; his work has been scrutinized, developed upon, and independently analyzed in the literature. In no cases, has any convincing evidence of fraud arisen, and his scientific work has been broadly supported by later studies. The cheap potshots coming from dishonest cowards who can’t do their own paleo-reconstructions (that can stand the test of time) is not how science advances, not how ‘fraud’ should be uncovered, or anything else. Moreover, ignoring the continued witch-hunts that continue after no evidence of fraud has been uncovered is not my idea of ‘letting people get away with it’ blindly.

      • Chris, you are full of it on Mann and McIntyre. The recent exchange in Annals of Statistics shows that at the very least, expert opinion disagrees violently with Mann’s primary statistical methods. The response of Schmidt et al is weak and its bound to be, coming from relative amateurs in the field of statistics. To characterize it the way you do is immature and implies a bias that you should try to eliminate. The climategate emails show that in fact all kinds of experts disagreed with Mann and saw McIntyre’s point. That this fact was corruptly kept out of the literature is a shame and a violation of scientific ethics and rather close to “fraud” in my opinion even though I would not be the first to use that word myself.

        This is the other thing that is disturbing about climate science. I’ve been subjected to it here by the encyplopaedic but narrow Fred, viz., that if you are not a climate scientist, you can’t have a valid opinion. Get over it Chris, climate science is a relatively immature field with very large uncertainty. Other competent people can have opinions too.

      • Brandon Shollenberger

        David Young:

        Chris, you are full of it on Mann and McIntyre. The recent exchange in Annals of Statistics shows that at the very least, expert opinion disagrees violently with Mann’s primary statistical methods. The response of Schmidt et al is weak and its bound to be, coming from relative amateurs in the field of statistics. To characterize it the way you do is immature and implies a bias that you should try to eliminate.

        If I may add something to this, I’d like to point out there is practically no support for Mann’s actual work. Yes, you get lots of papers which say they get the same result, but that’s a far cry from saying Mann did it right. The only thing which said Mann did it right, other than RealClimate, is Wahl and Ammann, and it’s so full of obvious errors it beggars description. Even the NAS panel which supported Mann’s conclusions did not support his actual methodology. They made excuses for it, but in the end, they accepted the criticisms of his work.

        And that’s just for his original hockey stick. Mann’s 2008 hockey stick hasn’t even received that much support. Even Gavin Schmidt admits it is wrong. Despite this, Mann still sticks to his Alice in Wonderland (h/t Amac) defense of denying he used proxies upside down.

        Even now, Chris Colose isn’t defending Mann’s methods. He isn’t even defending Mann’s behavior. All he’s doing is saying Mann isn’t guilty of fraud. So what if he isn’t guilty of a criminal offense. His papers were wrong, and he was dishonest. Whether or not fraud was involved is completely irrelevant to whether or not Mann helped corrupt the science.

        And here’s the thing. People like Colose can say Mann’s work has been “independently” verified all they want. They have to ignore the fact these later works are practically never independent in any reasonable sense of the word, but that’s their call. If two of the most important papers for the hockey stick turn out to be based entirely upon unreasonable methodology which is dishonestly defended, why should anyone trust other papers in the field to be correct?

        When climate scientists reject bad and dishonest work for what it is, they’ll gain credibility. In the meantime, all they’re going to be able to do is blow smoke and convince people who already agree that they’re right.

      • Brandon Shollenberger

        By the way, Chris Colose is completely full of it when he says:

        The cheap potshots coming from dishonest cowards who can’t do their own paleo-reconstructions (that can stand the test of time) is not how science advances, not how ‘fraud’ should be uncovered, or anything else.

        Those “dishonest cowards” generally believe it’s impossible to get meaningful results from reconstructions extending back a thousand or more years. The fact he insults them for holding a legitimate belief, one supported by any reasonable examination of the field, is pathetic.

      • MattStat/MatthewRMarler

        Chris Colose: Moreover, ignoring the continued witch-hunts

        McIntyre’s work is not a “witch-hunt”, but instead it is a careful analysis of Mann’s claims; he has shown those claims to contain unresolved (so far) contradictions. Initially (MBH98) that was probably mere sloppiness; with Schmidt, Mann and Rutherford in the Annals of Applied Statistics it’s almost pig-headedness (but a simple characterization is contra-indicated by some of the respectful interchanges between Schmidt and McShane and Wyner in the SOM), and subsequent comments (quoted with sources on ClimateAudit) begin to seem at least willfully negligent.

        The public evidence is that the investigations of Mann at UVA and Penn State were superficial.

    • Chris, see one of my earliest papers

      Agreed that the marriage between climatology and synoptic dynamics is important, and is a sorely missing ingredient in attempts to attribute extreme events to AGW.

      • billc,

        Judith can run her blog how she sees fit, and it’s her choice if she moderates people who criticize her or not. While she does, I will criticize her if I feel she says something worth criticism. Admittedly, I have much less patience than, say, Fred Moolten. I’m also pretty apathetic toward debates about who runs their blog the best. Actually, I don’t think free-for-all moderation is the best way to go, and one of my favorite blogs on climate change (from Isaac Held, a technical one for a graduate student or professional audience) is extremely strict in moderation.

        Whether Judith has more publications than me is irrelevant- I fully expect her to at the very different stages in our careers, but I also have the technical background to make judgments on much of what she writes about here. We could apply this same “argument from authority” logic to people who criticize Hansen, Schmidt, etc, and skeptics frequently remind us that ‘argument from authority’ is not very good (but then people like Lindzen always have the right answer, hmmm?).

        But related to what other people have said, I certainly agree Judith has the capacity to do great work, and has done so. It’s precisely because of this that I bother to comment here to the extent I do, and criticize her to the extent that I do. I have higher expectations for her, and feel that her word is at least worth listening to.

      • Chris, thanks for your reply.

        Substantive criticism is always merited, and I’m not referring to how the blog is run. In asking you this question that I asked Judith above, I had in mind a comment that I think you made on the “Teaching the controversy” thread which I recall went something like “Judith has lost her right to continue teaching science”.

        Unfortunately since Judith seems to have removed that thread, so I can’t back that up. If I am wrong my apologies.

        Also, I didn’t mean that Judith has more publications than you – she’s a lot farther along in her career. I was referring to her record in itself, which is of course a type of “argument from authority”.

      • billc- It doesn’t really matter what I think regarding what Judith should/should not teach. Personally, I think she has a number of unconventional views (specifically on climate change, not necessarily other atmospheric science subdisciplines), many of which have not been clearly thought out and could do a disservice to a students education. I note that any reasonable climate change class should highlight appropriate sources of uncertainties (e.g., in future projections of hurricane changes, cloud feedbacks, etc) and I prefer when they open up discussing to students, but I find that Judith carries this further into making up uncertainties based on her gut feeling, interpreting them in ways that make little sense, and most importantly, failing to recognize the errors in flawed sets of reasoning on fundamental topics.

        This, of course, is my opinion in characteristics that I wouldn’t want in a professor in any field. But one of the simultaneous strengths and weaknesses of academic freedom for college professors is that they can outline the class how they see fit.

      • Chris,
        “This, of course, is my opinion in characteristics that I wouldn’t want in a professor in any field. But one of the simultaneous strengths and weaknesses of academic freedom for college professors is that they can outline the class how they see fit”.

        This seems to imply a settled argument which is surely in your objective analysis no possible. How many have you been asked which defy an answer. Developing and critical thinking would seem to be a desired outcome in any enviroment?

      • billc, the Chris Collose’s trick is to be polite here and then run over to the alarmist blogs to try to point score with the believers. Its some sort of abnormal ego thing.

      • well to be clear, I wasn’t referring specifically to comments Chris made on RC and C-A-S, since there are many others who say the things I referenced on those blogs. I re-asked Chris a question I had actually asked Judith above, because I recalled his comments earlier on this blog. So he has responded, and I don’t know how much point there is in carrying this on. I just disagree with his assessment of Judith’s reasoning.

  22. Beth Cooper

    Hunter@ 5/12 5.31 pm
    ‘Unprecedented.” Say, isn’t that a favourite word of demagogues?

    • Beth,
      Apparently anything that disputes with the believer narrative is demagoguery. So it seems historical records are demagogue’s tools. And ditto for critical thinking.
      The list must be quite long.

  23. Judith,

    1) Why PNAS? (less important but curious)

    2) Why is this the right way to use models?

    3) Why very little uncertainty expressed in this paper when your blog seems to focus on it? Specifically
    “While natural chaotic variability remains a component of mid-latitude atmospheric variability, recent loss of Arctic sea ice, with its signature on mid-latitude atmospheric circulation, may load the dice in favor of snowier conditions in large parts of northern mid-latitudes.”

    The first part of this sentence seems to demand a high level of uncertainty with respect to the later assertion, especially when one considers that the work seems to be based on 4 years of observational data, the post-2007 ice decline. Yet the paper doesn’t seems to dwell on that much. In fact there seem to be very few caveats at all on this work.


    • PNAS was not my personal choice, I personally prefer not to publish in Science, Nature and PNAS because of the press embargoes. However the fact remains that these are the highest impact journals. Further, papers in these journals have stringent word/figure limits, which restricts the amount of discussion and broader interpretation of the results.

      Models can be used for many different applications. Here we chose to use a climate model to conduct controlled experiments with different sea ice configurations to test our hypothesis.

  24. Is the Arctic ice melting in place or is it migrating to a warm place to melt, or both? If it is melting in place then something must be getting cold or heat from outside the system is arriving in unusual but sufficient amounts to melt an Egypt-size sea ice floe. Where is that cold going or where is that heat coming from?

  25. steve fitzpatrick

    Interesting paper. One thing I wonder about is if there might be a heat balance calculation which would be relevant. Lake effect snow near the great lakes results from substantial warming of the lakes in the summer months and heat carryover causing evaporation into the early part of the following winter. But I wounder, is enough heat being collected in the Arctic ocean as a result of lower ice cover to account for the increased (total mass of) snowfall? The arctic doesn’t really warm very much above 0C over the summer.

    The final figure in the paper shows modeled deviation of snowfall. The units say ‘mm’, but I am guessing mm equivalent water not actual mm of snowfall. Do I have that right?

    • Steve, yes mm equivalent water. The major impact on increased snowfall is from the circulation changes; secondary from the open water in the Arctic Ocean. The later needs more investigation. Cold winter air (maybe 30C) blowing over open water even at 0C will give a large evaporative flux.

      • That is of course true and very interesting. Are there some sort ratios or equivalents than can give a picture as to how much evaporation, relative to humidity, water temperature, air temperature and wind speed?

        I realise this must be very basic science but I have never heard or seen it discussed and if anyone knows I would interested share that knowledge.

    • The warmest it ever gets in the Arctic will not melt much sea ice.
      The Arctic does not warm enough to make any difference.
      The Warm Water that flows into the Arctic melts the sea ice.
      Warm oceans and warm ocean currents that flow into the Arctic melt the sea ice.

  26. one would assume, with ‘a new record coming up’ (of ice extent), that the next NH winter will have smaller snow storms.

  27. @ JC: The study was published on Feb. 27, 2012 in the online early edition of the journal Proceedings of the National Academy of Sciences. The research was supported by NASA and the National Science Foundation.

    In my book are many pages on the subject, in details, copyrighted 2y ago. 2] on my website is a page on the subject, posted august lat year. 3] on many blogs I left many comments on the subject. 4] On this blog I have written 5-7 comments with REAL PROOFS ON THE SUBJECT, for the last 4 months 5] many people visiting this blog, have read on my website extensive proofs in details on the exact subject. 6] last my comment on other blogs AND here was, me winging about: ”Russian nuclear ice crusher ship taking spectators and shonky researchers direct to the north poll. Because the whole ice moves clockwise – the crusher ship doesn’t use same corridor; but makes slices of ice as slices of cake – those slices float south and melt. Exposing large areas, then ruff water brakes 100 times more. They were hoping: less ice = global warming… WRONG!!!

    Where the openings, water absorbs more coldness – with double strength radiates extra coldness south – intercepts the moisture south = more ice in Europe / USA = less moisture left to replenish the ice on arctic ocean = chain reaction started few days after the ”Copenhagen flop” That makes those ”researchers” and NASA, not just liars, but thieves as well.

    Plus: many of the damages could have being prevented / minimized; if the whole truth is excepted from me!!! One of the reasons they avoid is: because I have proven beyond any reasonable doubt that their theory off: ”ice is white reflects sunlight – no ice = GLOBAL warming” is completely WRONG AND back to front!!! Including plagiarizing is a double crime. First person that ridiculed me for telling the truth was ”the Scottish Skeptic” on his blog. Same on JOANNE NOVA’s, same on Anthony Watt’s blog. Up your’s too Scottish Skeptic!!! Two separate PAGES are on my website, on the subject. People, go back to my website and get all the proofs: COLDER= MORE ICE, and another one including ”Ian Plimer’s mistakes”. expose those shonky ;;researchers” + NASA for plagiarizing and pretending that is ”their research” ++++ If is not excepted the truth 100%,from me – to be blamed for devastating cold snow in central Europe included. Now you guys have real proofs, see how much you are honest and concerned / interested in the truth.

    Judith, I have repeated many times even on your blog that: the truth will win – time is on my side – climate doesn’t use ”OSTRICH TACTICS”

  28. Ted Carmichael

    Hi, Judy.

    I am intrigued that the moisture content rises with melting sea ice. Or rather, I am surprised that it seems to be (from the description of your paper) a multi-year phenomenon. Intuitively I would think that a year starting with less sea ice and ending with less would put about the same amount of moisture in the air as a “normal” year. Does this mean that the minimum extent is decreasing faster than the maximum extent? (Or minimum and maximum volume, which may be more relevant?) If so, is this based on empirical evidence? Thanks in advance.

    • Ted Carmichael

      Ah … I had a look at the paper and answered my own question. For anyone else interested (and please correct me if I get this wrong, Judy) the reduction of sea ice extent for September is more pronounced than any other month over the last ~30 years. Also, it seems the condition of more exposed and warmer arctic waters also adds to the moisture content, regardless of how much ocean was covered by ice at the beginning of the cycle.

      Interesting paper, Judy. Congratulations!


    This post proves that: all of you have being mislead by prof. Plimer = your proofs are back to front and wrong – I was correct 101%.

    Your proofs: medieval ages GLOBAL warming – Norwegian explorer went further north / because was less ice = was warmer- WRONG, time to join me! 1] medieval was milder climate in the ”old world” not stupid GLOBAL warming! Was warmer nights / cooler days. 2] When the Norwegian explorer got further north – it was colder! COLDER = LESS ICE. 3] river in London was freezing; because was less ice on Arctic’s waters as insulator for the water from the tremendous winter coldness in the air. You are all back to front. 4] than climate improved. Plimer is telling you that human cannot change the climate = he is COMPLETELY WRONG!!! Correct: human cannot produce GLOBAL warming; but human is capable to destroy and improve the climate; because H2O controls the climate, not CO2!!! Here: human made Suez Canal = small percentage less water was needed for the Mediterranean system; which comes from Mexican gulf – that positive contribution is cumulative – Mexican gulf needs to siphon less water from Arctic ocean – Arctic needs to get less salty /warm water from north Pacific via Bering straights.

    Warm / salty water eats the ice from below – stronger currents – what the ice sacrifices from itself to separate with freshwater between the salty water – stronger currents take it away. Evaporation in Mediterranean is high / Sahara close – deficit cannot come from river Nile, which is to a trickle. Must come from Danube and from Arctic ocean via Mexican gulf. When I pointed to Vukcevic on this blog that human / Suez canal stopped the little ice age – he ridiculed me that: ”short circle, Panama Canal made short circle from Atlantic to Pacific”!! Until I pointed to him that Pacific doesn’t have physical contact with Atlantic; because on the west coast of Panama the ships are LOWERED on same way as they do on river Danube at Gerdap Gorge.

    For the Warmist: captain James Cook was commissioned to map the north-west passage – BECAUSE THEN WASN’T MUCH ICE (same as today). He would have done it, he was a good sailor – if he didn’t run out of luck. Skeptics, stop the ignorance that medieval ages was warmer PLANET – that and all similar gives oxygen to the Warmist / that gives them to believe that they can manipulate you forever. As I have proven you all wrong, both camps on this subject – I’m correct on all the other subjects – time is on the side of the truth. Climate doesn’t use ”Ostrich Tactic” Time to join me and proudly promote real proofs; instead of Plimer’s crap.
    Time for you to swallow your ego and join me to see the end of the misleading propaganda. What Judith found for this post – you had it on my website with much more precise details. When you learn CORRECTLY how things function in nature; you can make your own correct predictions – not as the shonky science from Hansen / Gore and from the other treads for brainwashing you go to.

  30. Ha ha, once again you get (scientifically) nailed by WUWT :)
    Do you guys ever get over the fact you’re ALWAYS getting nailed by much smarter ppl who look at the REAL science data rather than ‘cherry pick’ (how many times have I heard warmists use that term!)?
    Don’t stress it, I hear McDonalds is still looking for staff…

    • Willis’ post shows that in general snow fall amounts have been fairly constant while Arctic sea ice has declined. I believe the Liu et al paper focuses on the distribution of snow fall under various sea ice conditions. There is a significant difference I would think.

      • Yes there is a substantial difference. I now have the published version of the paper posted (with figures); this seems to be allowed by PNAS copyright policy.

  31. Here’s what the IPCC AR4 SPM said about snow:
    “Mountain glaciers and snow cover have declined on average in both hemispheres”.
    In an attempt to justify this claim (which is not entirely true) they included a graph showing Northern Hemisphere only, months of March/April only.

    On projections, it said
    “Snow cover is projected to contract”.

    Now the story seems to be changing, and as usual it’s retrospective, a response to recent events, rather than a genuine prediction.

    The cynicism expressed by Latimer and geek49203 is entirely understandable.

    • Latimer Alder

      @paul matthews

      The cynicism expressed by Latimer and geek49203 is entirely understandable’

      Thank you for your kind words. I prefer ‘realism’, but I’m glad you got the gist of my argument. Cheers

  32. The full text manuscript is missing all the figures of the paper. It does have the figures of the supplementary material, but not those of the paper itself. The legends are there after the list of references.

  33. Dr Curry,

    Over at WUWT Willis has a post that makes a pretty good point, and I would love to have your take on it.
    – there does not seem to be a very good correlation between declining sea ice and snow extent.
    – my own impression is that the abstract sounds a bit too certain. I agree that the mechanism is highly plausible, probable even, but “we conclude” seems too strong if you only have one short period to base those conclusions on. Given your laudable insistence on communicating uncertainty, this seems at the very least, out of character.

    Finally, it would be helpful to have characterized sources of moisture that then precipitate as snowfall, since my understanding (which is undoubtedly in need of correction) was that it was cold dry air mass that are normally kept at bay by the jet stream that creep over land mass and meet moist air that was carried north from lower latitudes.

    So is moist air carried from the arctic sufficient to create the extra snowfall? By that I mean is the extra humidity alluded to in the paper contain sufficient moisture to create the extra snowfall?

    • The criticism of Willis seems to be directed against claims that are not made in the paper as the paper refers always to regional changes in snowfall, not to changes in the overall snowfall over the Northern Hemisphere. The papers is directed to more detailed study of what has happened during the last few years comparing the observations with phenomena that are seen in the model.

      Having said that, I agree that the period studied is short and that drawing conclusions from such a short period may easily lead to erroneous conclusions. Some important factors can easily be neglected and random fluctuations may play a large role over such a period. The conclusions appear, indeed, to be presented in a way that does not reflect properly such uncertainties. There’s, however, also the following sentence in the discussion:

      While natural chaotic variability remains a component of midlatitude atmospheric variability, recent loss of Arctic sea ice, with its signature on midlatitude atmospheric circulation, may load the dice in favor of snowier conditions in large parts of northern midlatitudes.

      Furthermore the text that follows this sentence contains words like can, if, speculate, and may.

      • Joe's World


        Yesterday, the media was still reporting that “scientists say” that in 50 years much of Canada will have to play hockey in indoor rinks due to global warming.

      • “Willis seems to be directed against claims that are not made in the paper as the paper refers always to regional changes in snowfall”

        I actually I noted that myself and I have asked Willis to clarify in comments there. The paper actually talks about total snowfall, not extent and it does point out that it is autumn sea ice extent that is the important factor, whereas Willis has looked at total annual sea ice area and snow extent as opposed to total fall.

        I also did notice that the body of the article included uncertainty that and appropriate equivocations, but the abstract does not.

      • Nikolay N Damyanov H Damon Matthews and Lawrence A Mysak. Observed decreases in the Canadian outdoor skating season due to recent winter warming. Environmental Research Letters, 2012; Volume 7 Number 1

    • This study was based on short term data because of the fantastic quality of the short term data. The ice core data for the past 800k years does support this study. Give them a little time to tie it all together. This theory was developed over 50 years ago by Ewing and Donn, before much quality data was developed. There is plenty of data. This is a new era in Climate Science. CO2 will soon be put out in the cold. It does not matter if CO2 can do major warming. The Open Arctic Ice Machine can keep a lid on temperature in the face of all the other forcing.

    • Agnostic, look at figure 1 from the paper. There is nothing there to infer anything quantitatively about NH total snow cover, which is what Willis analyzed. Most notably, our analysis clearly says nothing about any change in large regions of Russia and Canada. The moisture source from the open water in the arctic ocean is secondary to the atmospheric circulation change.

      In the conclusion, the words used are “The results of this study add to an increasing body of evidence . . .” are the appropriate words in my opinion. The “we conclude” statement in the abstract (where word numbers are limited) comes across a bit strong, but I think the more thorough statements in the the Discussion are appropriate. Again, some of these words are not mine such as “load the dice”.

      IMO the significance of this paper is in understanding seasonal snowfall variability, which is a goal of seasonal forecasting.

      • Thanks for the reply Dr Curry.

        I made similar points to Willis over at WUWT. Having read the paper more thoroughly I also noted that the sea ice extent during autumn was the important factor. I also noted the greater caution in the text in the discussion, but the abstract is so often the ‘take home message’.

        This area of climate science really interests me – I may have some more questions…. :-)

      • Multiple seasons go together to form climate.
        If it snows more when oceans are warm and the arctic is open, that has to cool the earth. if it snows less when oceans are cold and the arctic is closed, that has to allow the sun to warm the earth.
        This puts limits on earth temperature that other forcing cannot violate.

  34. Do you think a scientific publication record should be a requirement to comment here?

    No, but respect and courtesy always helps.

  35. Joe's World


    You still miss the mechanical components of circulation and many other factors are occurring as well. Some changes occurring are atmospheric density changes which would effect the insulation value of the atmosphere. Another study was on the changes of cloudcover closer to the planets surface in the last 10 years.

  36. Joe's World


    What is very interesting in studying velocity and rotation is the parameters that can be incorporated or taken away.
    An active sun spews out a great deal of material that our atmosphere can pick up passing through which would add density to it for protection. But also too more density would be less heat actually reaching the planets surface.
    A weak sun activity means that our atmosphere is still losing mass which would loose insulation value to the colder vacuum of space which is closest at the poles to the density at the equator.

  37. The temperature of Earth for the last 600 million years supports this study. There is an upper limit that Earth Temperature pushed against and could not cross. That limit is there because Earth is blessed with a lot of ice and water. That set point is established by the temperature that melts Arctic sea ice and that is what turns on the Arctic Ocean Effect Snow Monster

  38. On the lower side. There is another limit that temperature cannot cross. When all this Arctic Water is frozen, there is much less moisture to produce snow, and the sun is allowed to warm the Earth.
    The limits for the past ten thousand years has been plus or minus 2 degrees C all the time and plus or minus 1 degree for most of the time. This limited cycle will continue. The Arctic is open, the snows have started, temperature is at or near the current upper limit, the oceans have risen to or near their upper limit, the alarm can be turned off now.

    • Billy Ruff'n

      OMG, a negative feedback! But don’t all the models treat water vapor as a positive feedback?

    • It changes sides. When the arctic is open, it snows and ice advances and earth cools. When the arctic is closed, it don’t snow much and ice retreats and earth warms.

  39. Having now read

    I understand why our hostess is reluctant to use her hypothesis to make predictions. If she did, in a very few years it would be obvious that the hypothesis was wrong.

    • ceteris non paribus

      But she IS quite willing to make predictions – “for clients in the private sector”.

      You must ante-in to play the climate betting game with Dr Curry.

      • cnp you write “But she IS quite willing to make predictions – “for clients in the private sector”

        Precisely. These private predictions dont get into the public domaine, so few people would realise how wrong they are. IMHO, if a hypothesis is worth anything in science, then it’s authors should be so proud of it, that they would make the forecasts public.

      • ceteris non paribus

        These private predictions dont get into the public domaine, so few people would realise how wrong they are.

        I take it from this that you have paid your money, and seen the Truth by the pale moonlight?

      • Making predictions that give the public the perception of being right is not the way of testing scientific results.

        There are better ways of comparing the predictive power of theories and models. Those methods require scientists to do the testing as perceptions may easily be misleading.

        If the theory is definitive enough, it can equally well be tested in hindsight without predictions that are made in advance. If the theory is not that definitive then even tests based on pre-recorded predictions test rather the person or organization who makes the predictions than the theory alone. If one meteorological institute is more successful than another it may tell about something else than the quality of their atmospheric model.

      • Pekka, you write “Making predictions that give the public the perception of being right is not the way of testing scientific results.”

        I have said it before, and I will say it again. The only thing we can rely on in physics is observed, measured, preferably independently replicated, data. That is all that we can actually be sure of.

        So, if you have a hypothesis, it has to be tested against observed data. Hindcasting data only calibrates a hypothesis, it tells you it might be correct. It can never validate a hypothesis. The “scientific method” is get some data, form a hypothesis, and predict what the hypothesis says ought to happen. Then go out and see if it actually does happen. Anything else is just pretending that you are doing physics.

      • Jim,

        I was not arguing against testing, I was arguing for correct testing, for testing that looks what is the real scientific content of the theories and hypotheses, and that is then testing those features using scientifically justified tests.

        Making public predictions may lead to seriously erroneous conclusions in either direction.

        Physics must always be justified by empirical observations, but very often the valid tests are much less obvious than non-scientists seem to think. A good test is defined very precisely and allows for well specified determination of the significance of the results. It’s also very common that most of the tests concern specific details and combine to form a test of the whole. Testing is always related to some theory and may take advantage of other theories that have already been verified well enough.

      • IMO this is actually something that confuses many people including many professional scientists: The experimental (or observational) designs (and resulting data) that are most useful for hypothesis testing on the one hand, versus estimation, prediction and forecasting on the other, are frequently very different. Indeed an experiment that give a clean and strong test of a hypothesis can be absolutely worthless for estimating quantities needed for useful forecasting and prediction, and vice versa.

        But I also think that “good theories” need to survive both kinds of interrogation: That is, they need to survive sceptical hypothesis testing, and they also need to show usefulness in prediction to a holdout sample (or the future) once they are instantiated with their supposed parameters.

    • That’s not your best comment Jim.

      As Dr JC has already pointed out, Willis is looking at extent not volume and the paper explicitly points out the sea ice extent in autumn is important. And I don’t think Dr Curry would be concerned if the hypotheses turned out to be wrong. It’s not like she is proposing re-ordering the world economy on the back of it or anything,

  40. Its ante up. But I am grateful you pointed out J.C. is involved in private forecasting as I’d missed that. Raises her street cred substantially as far as I’m concerned.

    • ceteris non paribus

      Its ante up.

      All depends on which game you be playin’, pardner… :-)

      As for “private” forecasting and your view of Dr Curry’s street cred – I’m with Jim Cripwell – There is no such thing as “private science”.

      If you’re selling it – it’s a product – not a scientific hypothesis.

      • I want anyone who says “ante-in” at my table.

        And you’re conflating weather forecasting as a private enterprise, and scientific research. If private forecasters made their forecasts available to the public, who the heck would pay for them?

      • ceteris non paribus

        If private forecasters made their forecasts available to the public, who the heck would pay for them?

        Who will pay for the horse-fodder when cars are everywhere?

        You seem more worried about the livelyhoods of the dealers than whether the product is worth paying for.

        If you’re willing to pay for forecasts that are easily derived from publicly-funded and available data, then you’re welcome to sit at my table.

      • It’s not the size of the magician’s wand that brings the private forecast rabbit out of the public records hat, rather the skill of the magician.

      • No, in fact I’m not willing to accept publicly available forecasts. I’ve been a private subscriber for many years. If these forecasts were available for free, that would be nice. I doubt the guys who make a living providing these would like it however.

    • cnp – “easily derived”?

      I’m totally with pg on this one.

  41. andrew adams

    I found the following interesting – it’s a transcript of evidence given to the Environmental Audit Committee of the UK Parliament by Tim Lenton, Peter Wadhams and John Nissen (names which I guess may be familiar to Dr Curry).

    It’s quite a long document but gives an interesting summary of what is going on in the arctic at the moment.

  42. Is open Arctic in the autumn impacting atmospheric CIRCULATION and the observation of such an effect is winter snowfall? The models were employed to vary circulation? Are you saying the open Arctic impacts the Arctic Oscillation and when AO is negative/positive then open Arctic will amplify/detract from AO influence on winter weather in regions of Northern Hemisphere?

  43. Is this the paper that backs up the rationale for that fabled headline “Global Warming is the reason why you’re freezing your butt off?”

    Keep ’em coming Doc. You just gorra lurv it.


  44. Studying the Arctic past may indeed help to understand present climate movements. There are good and reliable data from Reykjavik Stykkisholmur observatory (just outside the Arctic circle 64.5 N), going back to more than 150 years. What is found now in the Equator ( is approximately reverse of the Reykjavik data some 60 years earlier.
    This may be a coincidence, illusion or even data aberration, but if real than it could be a one small step forward in the understanding of our planet.

  45. tempterrain

    ” We conclude that the recent decline of Arctic sea ice has played a critical role in recent cold and snowy winters.”

    Is it just me, or does Judith Curry really say one thing in her scientific papers and another, altogether different, thing in this blog?

    Correct me if I’m wrong, but aren’t “recent cold and snowy winters” used as evidence by Judith’s climate change denier friends, sorry sceptics, that AGW isn’t really happening after all?

    Don’t they ridicule the idea that AGW can actually, in some circumstances, make winters colder?

    Can anyone explain?

    • steven mosher

      is it acceptable to lie in furtherance of the AGW cause?

    • No, hotter doesn’t make “winter colder”. That’s impossible.

      Dr. Curry’s paper is showing the “where” of the winter cold regions are changing in response to the nature of sea ice in the Autumn.

    • ceteris non paribus

      Don’t they ridicule the idea that AGW can actually, in some circumstances, make winters colder?

      Oh – it’s even worse than that, Temp.

      As you may know, the HADCRUT global surface temperature dataset, often preferred by climate ‘skeptics’, got increased Arctic coverage in ver 4.

      As with other datasets, the inclusion of Arctic climate data puts HADCRUT4 2010 as the hottest year on record – over the top of previous record holders 1998 and 2005.

      The ‘global cooling’ we’re always hearing about now starts in 2011.

      • hadcrut3 has enjoyed peace with climate deniers because they like to cite hadcrut3 for their no warming claims.

        hadcrut4 won’t enjoy such peace. I expect they’ll come out throwing mud at hadcrut4, just as they threw mud at BEST when they didn’t like the results there.

        They’ll try to cling onto hadcrut3 for as long as possible, still reporting claims based on it long after hadcrut4 is published, but ultimately they’ll find the ridicule too much. It’s just too obvious to laypeople that citing old data is misleading.

        So inevitably they’ll switch to satellites-only mode. Full abandonment of the surface record (except of course they need them for their 60-year cycles – but that’s not something that concerns them even now..)

        Then wait for all attacks on hadcrut in general to start coming out of the woodwork:
        “it’s a Climate Research Unit record!”,
        “Phil Jones made it!”
        Claims that have so far been suppressed by their desire to use hadcrut3. We’ll find they never accepted hadcrut3 all along!

        Lets see if I am right.

  46. It does not matter if AGW caused some of the warming or if AGW caused a lot of the warming or if AGW did not cause any of the warming.

    Warmer oceans and open arctic do cause the more snow which already has or soon will stop the warming.

    Open arctic and more snow explains the 15 year lack of warming travesty that the alarmist tell us about.

  47. Harold H Doiron, PhD

    Dr. Curry,

    Thank you and your colleagues for this paper. Hopefully it will open a new, modern area of research that can prove the important negative feedback mechanism hinted at in this paper, help to improve the accuracy and usefulness of climate models and help to tone down alarmists. I credit Tom Wysmuller, (formerly of NASA GISS), for first introducing Donn and Ewing’s research to me and a number of my aerospace colleagues (including Alex Pope who has been urging you in this direction for months on these pages) several years ago in his talk to a dinner meeting of our Chapter of the Johnson Space Center NASA Alumni League. I was pleased to learn of your familiarity and high regard for Donn and Ewing’s work several months ago in a private email exchange with you. I would have slept better in the intervening months if I had known you and your colleagues were working on this paper. Climate Change is complex, and as an objective, outside observer, I feel that waaaay too much emphasis has been placed on CO2 in recent years, at the expense of other important factors that need more attention. I think this will be an exciting new direction of research that will bear fruit.

    An interesting related piece of data at Tom Wysmuller’s website is associated with his “Toucan Equations” where he tracks the decreasing frequency at which Leap Seconds are added to our calendar. (see Question 11 at This offers supporting evidence that the earth’s spin rate is currently increasing, in agreement with Laws of Conservation of Angular Momentum due to a reduction in the earth’s spin axis Moment of Inertia, that in turn suggests there is a mechanism in the current part of the Donn and Ewing climate cycle that is transferring equatorial ocean water to ice in polar regions…..more evidence for the climate phenomena you discuss in your paper.

    • Length of Day (LOD) and the global temperature

    • ceteris non paribus

      This offers supporting evidence that the earth’s spin rate is currently increasing, in agreement with Laws of Conservation of Angular Momentum due to a reduction in the earth’s spin axis Moment of Inertia, that in turn suggests there is a mechanism in the current part of the Donn and Ewing climate cycle that is transferring equatorial ocean water to ice in polar regions…..more evidence for the climate phenomena you discuss in your paper.

      Not really. The earth’s ‘spin rate’ is actually decreasing.

      And the secular increase in the earth’s rotation period can be easily explained by the transference of angular momentum to the moon.

      • Harold H Doiron, PhD

        Yes, I understand long term effects (millions of years) of tidal friction from earth-moon dynamics will will gradually slow the spin rate of the earth, as I learned in my undergrad Astronomy course in the early 1960’s. However, what about shorter term trends? Why in the plot you provided at:

        did the slope of the red curve that shows the dates at which Leap Seconds were added to our calendar, abruptly change and flatten noticeably at the year 1999? If Leap Seconds were added at less frequent intervals since 1999, this implies to me that the rate at which the spin rate of the earth is slowing due to earth-moon tidal friction effects has decreased since 1999, which means there was an opposing effect that started at 1999 due to a temporary (how temporary?) and gradual decrease in the spin axis Moment of Inertia of the earth that could be associated with a climate mechanism that transfers equatorial ocean water to the polar regions in a new trend of polar ice build-up. Interestingly, 1998-99 was about the time that the rapid global warming trend of the 1980’s and 90’s seems to have been put on hold.

        If we start having to subtract Leap Seconds in June 2025, as Wysmuller predicts from his curve fit of present trends, what would that mean? To me, it would mean that the spin rate of the earth is actually increasing and temporarily reversing its long term trend of slowing, while we are in the polar ice build-up phase of this climate cycle.

        The importance of this seemingly unrelated Leap Second data which Wysmuller recognized some time ago using his knowledge of Donn and Ewing’s research in the 1950’s and 60’s, would tend to corroborate water transfer and precipitation trends discussed in the subject Liu, Curry, et. al. paper.

    • Harold H Doiron, PhD

      CORRECTION: The Leap Second data are discussed and plotted at Question 16 Wysmuller’s “Toucan Equations” at Question 11 with a similar shaped curve deal with sea level rise trends.

    • Earth is certainly transferring angular momentum to the moon and there’s also some transfer of angular momentum to the orbital motion of the Earth around the sun as the sun influenced the tides as well.

      In spite of this effect that must ultimately slow down the rotation of the Earth, it is true that the short term change of the rate of rotation has been in the opposite direction, i.e. the moment of inertia has decreased more rapidly than the angular momentum. The length of day had its maximum in 1972 and it’s now about 2 ms shorter than then, but close to what it was in 1962, which is the earliest year in the graph shown on the Wikipedia page on Earth’s rotation and listed in the available data of the International Earth Rotation and Reference Systems Service.

      • ceteris non paribus

        The length of day had its maximum in 1972 and it’s now about 2 ms shorter than then, but close to what it was in 1962…

        You are mistaken.

        The maximum you see at 1972 is the daily anomaly.

        Note that the green line (moving 365-day mean of the anomaly) is all above zero – and that the red line (cumulative) is monotonically increasing.

      • ceteris non paribus

        What happened in 1972 is that the rate of increase in the length of the day was at a maximum – That’s why the slope of the red line is the greatest at that time.

      • And what is the daily anomaly?

        It is the difference of the length of day compared to 24 hours based on the standard second.

        It is really a measure of the length of day.

        The red line is the cumulative deviation that is now growing at lesser speed that it did in 1972, when the day was longest.

      • cnp,

        You are taking one derivative too much.

        The correct interpretation is seen also from the fact that leap seconds have been added less often than earlier.

      • ceteris non paribus

        You are taking one derivative too much.

        Not at all.

        The earth’s rotation period has increased by between 0 and 4 ms per year since 1974.

      • ceteris non paribus

        The correct interpretation is seen also from the fact that leap seconds have been added less often than earlier.

        The fact that leap seconds have to be added at all should tell you something.

      • I looked at the picture. Pekka is right.

        CNP – I think the confusion about the adding of leap seconds could be the “adding” is referring to added to the standard day.

        I guess they don’t roll over like anytime minutes.

        So in 2004-05, the fewest leap seconds would have been added, for example.,

      • and cumulative deviation could be interpreted as subtracting “where we would be if none of this had happened” from “where we are now”.

      • CNP,

        Think at the Earth as a giant watch. It goes a little slow. Thus you must adjust the time every now ant then, more often, when it goes more badly slow and less often when watch is less slow. As long as it’s slow the deviation grows, the deviation would turn to decreasing only, if the watch would go fast.

        The Earth rotates a little slow over the whole period from 1962, but less slow now than in 1972.

        You may look also at the units – and you may read the caption.

      • ceteris non paribus

        Someone is confused. :-)


        Since the first leap second in 1972, all leap seconds have been positive and there were 23 leap seconds in the 34 years to January, 2006. This pattern reflects the general slowing trend of the Earth due to tidal braking.


        …the net acceleration (actually a deceleration) of the rotation of the Earth, or the change in the length of the mean solar day (LOD), is +1.7 ms/day/cy. This is indeed the average rate as observed over the past 27 centuries.


        …from historical records over the past 2700 years the following average value is found:
        +1.70 ± 0.05 ms/cy

        The corresponding cumulative value is a parabola having a coefficient of T² (time in centuries squared) of:
        ΔT = +31 s/cy²

        See also:

        The earth’s rotation does occasionally ‘speed up’ over short periods – such as during the 2004 Indian Ocean earthquake. But the long-term secular change is generally an increase in the rotational period.

        The LOD did not have a maximum in 1972.

      • CNP,

        You are confused. From your first link:

        “Confusion sometimes arises over the misconception that the regular insertion of leap seconds every few years indicates that the Earth should stop rotating within a few millennia. The confusion arises because some mistake leap seconds for a measure of the rate at which the Earth is slowing. The 1 second increments are, however, indications of the accumulated difference in time between the two systems. (Also, it is important to note that the current difference in the length of day from 86,400 seconds is the accumulation over nearly two centuries, not just the previous year.) As an example, the situation is similar to what would happen if a person owned a watch that lost 2 seconds per day. If it were set to a perfect clock today, the watch would be found to be slow by 2 seconds tomorrow. At the end of a month, the watch will be roughly a minute in error (30 days of 2 second error accumulated each day). The person would then find it convenient to reset the watch by one minute to have the correct time again.

        This scenario is analogous to that encountered with the leap second. The difference is that instead of setting the clock that is running slow, we choose to set the clock that is keeping a uniform, precise time. The reason for this is that we can change the time on an atomic clock, while it is not possible to alter the Earth’s rotational speed to match the atomic clocks! Currently the Earth runs slow at roughly 2 milliseconds per day. After 500 days, the difference between the Earth rotation time and the atomic time would be 1 second. Instead of allowing this to happen, a leap second is inserted to bring the two times closer together.”

        Key is the 2nd and 3rd sentence of the first paragraph, IOW, what Pekka said.


      • ceteris non paribus
      • yeah. and we’re in one of the tiny downdips in the most detailed curve on that huge graph. nothing different than what Pekka and I were saying.

      • ceteris non paribus

        You and Pekka are right. Although the long-term trend is increasing the rotational period, it has decreased since the 1970s.
        I stand corrected.

      • Harold H Doiron, PhD


        Thanks for all of your reasoned and patient comments, especially to my posts when I stray from precision in my statements. Through all of the discussion of the earth’s spin rate from my comment above on the Leap Second curve to other links that you and others have provided in this discussion, down to cnp’s final agreement below, as well as more similar debates with my colleages since March 6, I have found a lot of good data to make my point more clearly than the LEAP Second data trends I was aware of. I found a plot of Length of Day (LOD) going back to 1954 when atomic time was first instituted at this link:
        That plot shows an 18 year general rise in LOD from 1954 to the 1972 maximum.

        I also found at the following link:

        an ability to access, plot and analyze much of the available data on the earth’s spin axis and LOD behavior. In particular, at that link, there is a data series from JPL that has a yearly average of LOD going back to 1846 that I was able to get a plot for, but I don’t know how to paste it in here. That plot clearly shows the longer term trend increase in LOD, as well as, the general decreasing trend since 1972…. and some interesting periodic trends in the data. There is a period of about 6000 days (16.5 years) in the data since 1972 of about +/- 1 ms amplitude superimposed on the general LOD decreasing trend. I read in one report at
        that experts think the decadal length periodicity in LOD is related to interaction of the earth’s molten core and mantle, (the orbital period of Jupiter is 11.86 years and may be related IMO.) I will be looking for climate changes that may be related to LOD changes and evidence of water transfer to and from ice at the poles. That report concludes that seasonal changes in LOD are due to interaction of the earth’s atmosphere and mantle.

  48. Just wanted to say, congrats on publishing the paper, Dr. Curry!

    It’s very interesting, and fun seeing the shifting patterns moving about. Kinda reminds me of sound wave ripples in a cup of water changing in response to frequency changes; how the waves bounce around, interfere with each other destructively and constructively, and make completely new patterns. Looks like the behavior and shape of the arctic ice acts to change that resonation.

  49. Climate change is bumpy. There are short term bumps and long term bumps.
    Long Term, warm follows cool, cool follow warm, and so on.
    Short Term, warm follows cool, cool follow warm, and so on.
    You can superimpose these and you know what climate has done and will do.

  50. Captain Kangaroo


    Nice result. As we stand in awe of the complexity of climate – it is just such work that brings glimmers of understanding of the tremendous energies cascading through powerful mechanisms.

    Best regards
    Robert I Ellison

  51. We could as easily conclude that snow cover, winter temperature and the frequency of cold air outbreaks in northern mid-latitudes is consistent with observational data indicating thickening ice sheets of Greenland, and Antarctica, cooler ocean temperatures, solar variation and burning books for warmth by the elderly in the UK, tra-la.

  52. I lost the plot of this paper on Figure S1. Only four (4) years of data and the vast majority of Russia, Canada, and Greenland show zero (0%) snow cover anomaly — which is self-evident because these parts of the world are always covered by snow in the winter.

    I’d want to see the amount of snow for these regions. Is there a valid reason for excluding 1/2 the land mass of the NH other than the data wasn’t readily available?

    The Canadian snow cover anomalies are in the places known to have the most variability (amount of snow, periods of snow or no-snow) so four years of data is not proving anything (to me). Why is this data set only covering the last 4 years?

    • Captain Kangaroo


      Face it – you lost the plot a long time ago. You should just enjoy.

      Best regards
      Captain Kangaroo

      • OK Robert why don’t you answer the questions.

        What is so significant about snow cover (the Rutgers data)? As someone who lives in a place (Ottawa) that is snow covered 2-3 months of the year — it is a pretty vague metric.

        Why only 4 years of data? The areas of Canada with the significant +ve anomaly are notorious for boom-bust periods — they have had 4 years of excellent spring skiing but what about the years where the snow cover has been -ve?

  53. Dr Curry,

    Agnostic, look at figure 1 from the paper. There is nothing there to infer anything quantitatively about NH total snow cover, which is what Willis analyzed.

    I’m sorry but this does not seem correct, and for the moment Willis’s objections are reasonable. That is because figure 1 says:

    Spatial distribution of snow cover anomalies (%) for the winter (my bold).

    I happen to be familiar with Rutger data set quoted as a reference in the paper and it is for snow extent NOT total fall.

    Figure 7 says something about differences in total fall, and that might argue toward a change in snowfall at different locations but it doesn’t point to an increase in actual snow fall.

    This is not merely a semantic difference. An important CAGW concern is that total extent diminshes with global warming and is a positive feedback because of reduced albedo. Extent is the important thing for albedo – the snow cover can be quite light – it merely needs to cover a large area.

    Is there any other supplementary material not mentioned in the paper that discusses actual snow fall as volume?

  54. Michael Larkin

    Just wanted to say that I have been appreciating this thread – for the most part, the trolls have been keeping out of it. I really and truly do not miss Joshua one bit! :-)

  55. Beth Cooper

    Thx, Juidith. Tony et al, so if’n it aint snowin’ here, it’s snowin’ there. Slidin’ to the left, slidin’ to the right. Powerful cascades. Guess the science jest aint settled. )

    • Peter Davies

      Beth you sound a lot like Kim. Love it!

      If there are indeed two of you then I very much look forward to my daily dose of sharp wit and wisdom!

  56. Beth Cooper

    Apologies, for mis-type, “Judith.”

  57. Beth Cooper

    Peter D, Kim is non pareil,but thx )

  58. I just spotted a new article that seems to support the idea of evaporation from open water in the arctic increasing precip over land.

    • James Hansen:
      Arctic sea ice insulates the atmosphere from the ocean, allowing the atmosphere to become very cold, as much as tens of degrees below freezing. If warming yields thinner sea ice and areas of open water, these changes allow heat to escape from the ocean more readily. Thus surface air can warm substantially as the sea ice cover thins, even though the ocean (water) temperature changes little. It is the surface air temperature that is most relevant to humans and it is the surface air temperature change that is presented in most global climate model simulations. Exchange of continental and marine air masses in the Arctic implies that coastal meteorological stations should provide a better estimate of surface air temperature change than would measurements of ocean temperature. Satellite infrared observations, as discussed by Hansen et al. (2010), support our conclusion that the GISS analysis does not exaggerate Arctic temperature anomalies, indeed, the anomalies seem to be conservative.

      • Hansen says, “Satellite infrared observations, as discussed by Hansen et al. (2010), support our conclusion that the GISS analysis does not exaggerate Arctic temperature anomalies, indeed, the anomalies seem to be conservative.” I agree, but the Antarctic temperatures are exaggerated by the same logic. With Antarctic ice increasing, the temperature should be decreasing as indicated by the satellite data as opposed to the increase shown in the surface station data.

        Once that data is corrected, we can start getting somewhere.

    • John from CA

      You may be able to loop a longer time span from the NOAA Arctic water vapor animations but the principal ice loss is from the Barents and Greenland sea ice areas. The late formation of ice from the Beaufort, Chukchi, East Siberian, and Bering Seas should be visible in the NOAA animations.

    • Judith

      Within your link is another that goes to ‘results.’ But these are surely not the complete results of the study as it is very brief.

      I am left wondering over what geographic area the open water will have an effect. Immediately adjacent to the open water concerned? If the winds/pressure systems are blowing in the right direction as far as the UK?

      Many more questions than answers


  59. I have a question (maybe it was addressed, I don’t know):
    Ice melting and open water in the Arctic ocean occur in the end of summer and early autumn, say – maximum until October-November.
    Heavy snows fell this year mostly in February.
    Is such a delay physically plausible? Does hot and humid air linger in the athmosphere for two months before it impacts the weather ?

    • Blanchard-Wrigglesworth et al. (2011) analyze the lagged correlation of the Arctic sea ice in observations and a GCM ensemble. They showed a persistence of total sea ice area anomalies for the 1-5 month time scale, longer in winter and summer months and shorter in spring and fall months. Sea ice anomalies could be persistent from autumn to winter (see Fig. 4A.B in our paper).

    • Is that plausible? Judah Cohen has some papers that cover that very well.

  60. I see the Arctic ice has reached it’s maximum extent. Here we go, this year may well be significant one way or the other.

  61. Jennifer Francis (arctic climate scientist at Rutgers Univ) has a blog article at Yale 360: Linking Weird Weather to Rapid Warming of the Arctic

    This article is relevant to our recent PNAS paper, and well worth reading

    • Dr. Curry,
      Interesting article.
      Since what the author is calling ‘weird’ is actually not unprecedented weather, does this not imply that similar arcitic conditions have existed before?

    • Judith

      The report says;

      ‘Does it seem as though your weather has become increasingly “stuck” lately? Day after day of cold, rain, heat, or blue skies may not be a figment of your imagination. ‘

      Interesting, because several months ago I very nearly suggested an article to you based on this topic as looking at tens of thousands of testimonials of the weather (for ‘the Long Slow Thaw?) through the LIA (Hot and cold periods!) I was contnually struck by the fact that weather patterns appeared to have become stuck and -in the case of the UK-a week of cold weather turned into 4 or 6 weeks and fundamentally affected the temperature record..

      I have come increasingly come to believe (a putative theory?) that we need look no further than the weather becoming ‘stuck’ to explain such events as the LIA (not continually cold) or the MWP (not continually warm)

      We don’t need to look at orbits or any other explanations but that the Jet stream seems to have become fastended in one position or other and then if you add in all the other sub factors such as EL Ninos etc etc our weather will assume the character of the resultant patterns-lots of easterlies for cold lots of westerlies for warmth (in the UK)

      ,The ‘weather became stuck’ theory is well worth investigating further as it seems more plausible to me than many other theories, but stickiness is not reserved for the modern era..

      • Judith my 11.46

        I note that I actually refer to this stickiness in the notes within the supplemntary information to the ‘Long slow thaw?’ as follows;

        “13) Due to its geographical location British weather is often quite mobile and periods of hot, cold, dry or wet weather tend to be relatively short lived. If such events are longer lasting than normal, or interrupted and resumed, that can easily shape the character of a month or a season. Reading the numerous references there is clear evidence of ‘blocking patterns,’ perhaps as the jet stream shifts, or a high pressure takes up residence, feeding in winds from a certain direction which generally shape British weather.”

        So the stickiness observation you refer to has its precedents.

  62. Ah, it is nice to know & see, that ice is just beautiful…

    once again. There is hope yet for all.

  63. Dave in Canmore

    Isn’t Europe and Russia’s snow fall the result of moist Atlantic Maritime air?

    Not sure what the process is for Arctic air (which is very dry and low humidity even with open water due to it’s coldness) to affect the source air for Europe’s snowfalls?

    I see an interesting correlation without viable process, or am I missing something?