Study finds a natural cause for early 20th century Arctic warming – but kowtows to CO2 in the present

From the universities of Kyoto & San Diego comes this old tired catchphrase, along with a polar bear picture to go with the press release.

Is a warmer Arctic a canary of global warming?

Kyoto University and UCSD uncover a cause for the warming in the Arctic in the early 20th century.
CREDIT Kyoto University

Since the 1970s the northern polar region has warmed faster than global averages by a factor or two or more, in a process of ‘Arctic amplification’ which is linked to a drastic reduction in sea ice.

But then how to explain a similar rapid warming that occurred during the early 20th century, when the effects of greenhouse gases were considerably weaker than today? And what can we prove about the period, given the scarcity of usable data and observations prior to the 1950s?

Now scientists from Kyoto University and UC San Diego have discovered that this phenomenon occurred when the warming phase — ‘interdecadal variability mode’ — of both the Pacific and Atlantic Oceans coincided. The team’s findings appeared recently in the journal PNAS.

“We found that early 20th century sea surface temperatures in the tropical Pacific and North Atlantic had warmed much more than previously thought,” explains lead author Hiroki Tokinaga of Kyoto.

“Using observations and model simulations, we’ve demonstrated that rising Pacific-Atlantic temperatures were the major driver of rapid Arctic warming in the early 20th century.”

Previous explanations for early Arctic warming have including decreased volcanic aerosols and increased solar radiation, but none of these have been able to simulate observed conditions from the period.

Tokinaga’s team found that when the interdecadal rise in sea surface temperatures was included in simulation calculations, the results properly reflected early Arctic conditions.

“Coupled ocean-atmosphere simulations also support the intensification of Arctic warming,” continues Shang-Ping Xie of UCSD, “which was caused by a concurrent, cold-to-warm phase shift of Pacific and Atlantic interdecadal modes.”

The researchers explain that these new findings can help constrain model climate projections over the Arctic region.

“It is likely that temperatures in the Arctic will continue to rise due to anthropogenic global warming,” concludes Tokinaga. “Our study does not deny this. We are rather suggesting that Arctic warming could accelerate or decelerate due to internal variability of the Pacific and the Atlantic.”

“It is a challenge to accurately predict when the next big swing of multidecadal variability will occur. Careful monitoring is essential, given the enormous impact on the Arctic climate.”

###

The paper “Early 20th-century Arctic warming intensified by Pacific and Atlantic multidecadal variability” appeared 30 May 2017 in the Proceedings of the National Academy of Sciences of the United States of America, with doi: 10.1073/pnas.1615880114

Pacific North American circulation pattern links external forcing and North American hydroclimatic change over the past millennium

Significance

We have developed a new reconstruction of changes in the wintertime atmospheric circulation over North America based on data distributed across the region. The record spans almost 1,000 years and shows how variation in ocean temperatures, solar energy, volcanic eruptions, and greenhouse gases has affected circulation over this period. We show that the circulation pattern is strongly correlated with fluctuating drought conditions in the western United States. Climate models do a poor job of simulating the reconstructed record of circulation change, and thus may have difficulty predicting future patterns of drought influenced by changing winter storm tracks across this region.

Abstract

Land and sea surface temperatures, precipitation, and storm tracks in North America and the North Pacific are controlled to a large degree by atmospheric variability associated with the Pacific North American (PNA) pattern. The modern instrumental record indicates a trend toward a positive PNA phase in recent decades, which has led to accelerated warming and snowpack decline in northwestern North America. The brevity of the instrumental record, however, limits our understanding of long-term PNA variability and its directional or cyclic patterns. Here we develop a 937-y-long reconstruction of the winter PNA based on a network of annually resolved tree-ring proxy records across North America. The reconstruction is consistent with previous regional records in suggesting that the recent persistent positive PNA pattern is unprecedented over the past millennium, but documents patterns of decadal-scale variability that contrast with previous reconstructions. Our reconstruction shows that PNA has been strongly and consistently correlated with sea surface temperature variation, solar irradiance, and volcanic forcing over the period of record, and played a significant role in translating these forcings into decadal-to-multidecadal hydroclimate variability over North America. Climate model ensembles show limited power to predict multidecadal variation in PNA over the period of our record, raising questions about their potential to project future hydroclimatic change modulated by this circulation pattern.


The paper is paywalled, so I can’t comment on the merits of it, but a couple of things come to mind from what is presented so far in the press release and abstract.

  1. Do you really need to use a polar bear photo? Won’t the science stand on it’s own merit without the need for something that tugs at peoples heartstrings?
  2. By the same token, why push the overused “canary in the coal mine” meme? Same argument.
  3. If the early 20th century Arctic warming was caused by ” this phenomenon occurred when the warming phase — ‘interdecadal variability mode’ — of both the Pacific and Atlantic Oceans coincided” but in the present you claim “It is likely that temperatures in the Arctic will continue to rise due to anthropogenic global warming,” concludes Tokinaga. “Our study does not deny this. We are rather suggesting that Arctic warming could accelerate or decelerate due to internal variability of the Pacific and the Atlantic.”, is this just throwing a bone to the financing gods? Why couldn’t “‘interdecadal variability mode’ — of both the Pacific and Atlantic Oceans” be the cause now?
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106 thoughts on “Study finds a natural cause for early 20th century Arctic warming – but kowtows to CO2 in the present

      • “It is a challenge to accurately predict when the next big swing of multidecadal variability will occur. Careful monitoring is essential, given the enormous impact on the Arctic climate.””

        “It is a huge investment to accurately predict when the next big swing of multidecadal variability will occur. Careful monitoring is essential by a large well paid (by the tax payer) staff, given the enormous impact on the Arctic climate.”

        Cheers

        Roger

        http://www.rogerfromnewzealand.wordpress.com

    • But, did they just tweak their models to prove the null hypothesis?…yet still proclaim CO2 to be evil
      Enough with the genuflecting!

    • “Climate model ensembles show limited power to predict multidecadal variation in PNA over the period of our record, raising questions about their potential to project future hydroclimatic change modulated by this circulation pattern.”

      How many times, and in how many ways, must everyone from Dr. Curry on down state the obvious: IPCC climate models are bunk.

    • “It is likely that temperatures in the Arctic will continue to rise due to anthropogenic global warming,” concludes Tokinaga. “Our study does not deny this. We are rather suggesting that Arctic warming could accelerate or decelerate due to internal variability of the Pacific and the Atlantic.”

      “Our study does not deny this.” is the ultimate in weasel wording. How about: “Arctic warming could accelerate or decelerate due to internal variability of the Pacific and the Atlantic.” Acceleration is a lot different than deceleration, at least in the normal, non-climate science world.

      If we could take the authors’ at their word, anything could happen. Warm? Cold? No change?

      • Dave:
        “Warm? Cold? No change?”
        Warm? Cold? No change? No idea!
        Does that help you see where UCSD’s understanding of the science is?

        Auto

    • Not all models are bad. Rejecting all models just because the GDMs are abused is as anti-scientific as anything the warmunists are doing.

  1. Are they using tree rings to estimate precipitation or temperature? Or both? The abstract notes their reconstruction disagrees with other estimates of paleoclimate. Which? Mann’s?

    • Their main observational input is HADISST2, a larger collection of sea surface temperatures than before. They then match that up with the phases of the PDO and AMO. Then run quite a few models (which had been unsuccessful before due perhaps to fewer observations) and get better agreement with obs.

    • They continue to ignore actual air temperature observations from weather stations around the Arctic circle. A recent study of those records concluded:

      “The Arctic has warmed at the same rate as Europe over the past two centuries. Heretofore, it has been supposed that any global warming would be amplified in the Arctic. This may still be true if urban heat island effects are responsible for part of the observed temperature increase at European stations. However, European and Arctic temperatures have remained closely synchronized for over 200 years during the rapid growth of urban centres.”

      https://rclutz.wordpress.com/2016/05/06/arctic-warming-unalarming/

      • And wither the Antarctic? Polar amplification? Colder? Warmer? More land ice? More sea ice? More BS?

        The dogma is running off the rails. The more the in-crowd try to explain away the contradictions, the more they just sound like the silly prevaricators they are.

      • An interesting paper, and well worth a read.

        It is probably worth pointing out that it shows that when there were more stations, ie., the period 1930 to 1985, there was if anything cooling, and when the stations dropped out and became less, there was slight warming ie., during the period 1985 to 2010.

        This begs the question whether the slight warming post 1985 is a factor of station drop out, rather than due to actual and real change.

        See generally (red line 5 year smoothing, blue line, the number of stations returning observational data).

      • ..
        They did not predict either event…..and go on to predict another
        ….and go on further to reference lack of snowpack in the NW right after a record snowpack

      • >>
        . . . lack of snowpack in the NW right after a record snowpack
        <<

        Using warmists’ logic, more or less snow means global warming (Or is that climate change? Disruption? Something-or-other?).

        Jim

      • Hey Jim!…most likely it was Murphy

        The day they sent the paper in…it started snowing :)

    • Lead author is Hiroki Tokinaga of Kyoto (!).

      “Early 20th-century Arctic warming intensified by Pacific and Atlantic multidecadal variability”, PNAS, DOI: 10.1073/pnas.1615880114

    • In a sense they do rule out CO2 effects. The 37-year-long UAH temperature series (from satellites) shows no warming in the Antarctic, almost no warming in the souther extra-tropics, slight warming in the tropics, slightly more warming in the norther extra-troipcs and by far the most warming in the Arctic. If most of the warming in the north is due to ocean oscillations (as I have long held), then the CO2 warming that is left over is triflingly small. Climate sensitivity would be somewhere between essentially zero and one degree C.

      If Arctic warming is caused by CO2 having more effect there due to very low levels of water vapor (because it’s very cold) then why no Antarctic warming?

      • Good question. The polar deserts are the only regions in which CO2 and H2O are at similar low levels.

      • Bingo, Thomas! Let the CO2 crowd explain that.

        Oh, wait a minute! Skeptics must posit and prove scientific alternative theories in scholastic journals, not just ask questions about alarmists’ pseudo-scientific inconsistencies.

  2. It’s good to know their office building will not be shot at and they won’t be fired as heretics. This must have been the reality during the Dark Ages. So it’s a reenactment of historical social norms.

  3. It was a Thursday. 1950. Neither winter nor summer, a day much like any other. Gia, Mother Nature was there. Anthro, owner of the magic molecule was there. “Anthro, so glad you could make it. For the last 10,801 years I have been fighting the ice and I am tired.” “Gia, yes dear Earth mother. I see the ice getting stronger. I can help. I have this nature trick. I can take it from here. Henceforth all warming will be man’s and not yours.”

  4. “It is likely that temperatures in the Arctic will continue to rise due to anthropogenic global warming,” concludes Tokinaga.

    Conclusion based on………what?

  5. Air temps are a function of ocean temps. Who would’a thought??

    So looking at the Sun and Ocean Cycles vs Temps graph this morning, which peaked 10 yrs or so ago and has a +-60 year period, looks like the PDO+AMO and lower Sun activity is pointing us toward a lot of Arctic ice sometime in the next 20-30 years. Hope I’m around to enjoy it.

    • I’m too, it looks great, the last time when it appeared in the press it looked terrible

      sarc/

      • That is one emaciated bear!

        I don’t give a shit about your politics, but give the bear a seal.

      • That just reminded me of the joke about Kermit applying for a loan using a ceramic elephant as collateral. When the loan officer, Mr. Paddiwack went to get approval, his superior said: “It’s a knick knack, Paddiwack, give the frog a loan.”

  6. “Our study does not deny this. We are rather suggesting that Arctic warming could accelerate or decelerate due to internal variability of the Pacific and the Atlantic.”

    Translation: Please allow us to publish our paper. See? We are playing by your rules.

  7. “If the early 20th century Arctic warming was caused by ”

    Except the argument is contribution… not the singular and only cause. About 1/3 of early warming is down to GHGs.

    • Mr. Mosher, where in your Weed Patch Wanderings was it revealed to you that 1/3 of early 20th Century warming was caused by GHGs? Models? Divination?

      We are also told that over 100% of post-1950 warming was human-caused. Models again?

    • “About 1/3 of early warming is down to GHGs.”

      Absolute unprovable twaddle, Mosh

      That’s a used car with no darn engine or wheels.!

    • About 1/3 of early warming is down to GHGs

      But during the early part of the 20th century, there were extremely modest increases in the level of CO2..

      Your assertion begs the question, why was there cooling post 1940 just when CO2 starting to rise significantly?

      At this stage, if CO2 has any significant driving effect on temperatures, how come was there so much cooling during the period 1940 to mid 1970s (The Northern hemisphere cooled some 0.5 degC during this period)?

    • I guess I’ll add my two cents worth.

      >>
      About 1/3 of early warming is down to GHGs.
      <<

      Based on what? Based on models that have no demonstrated skill? There is no GHG signature in the atmosphere. The atmosphere has to warm slightly faster than the surface to indicate a GHG signature. This adjusting the surface temperatures to show warming without adjusting the atmospheric temperatures shows basic ignorance of the physics. (Notice I didn’t say the atmosphere had to be warmer than the surface.)

      Jim

  8. Abstract concludes with:

    “Climate model ensembles show limited power to predict multidecadal variation in PNA over the period of our record, raising questions about their potential to project future hydroclimatic change modulated by this circulation pattern.”

    But in presser the author says this:

    “The researchers explain that these new findings can help constrain model climate projections over the Arctic region.”

    They showed the climate models can’t project internal variability, so how are they going to be constrained?

    Again, the chaotic, non-linear beast raises its head and defeats human attempts to project it’s behavior into the future.

    That presser would have been more honest to say, “these new findings add further evidence that the model projections to future Arctic climate are hopelessly flawed.”

    • Maybe they hope that the new regime will read between the lines and keep funding their research, if the US does grants for Kyoto.

      The younger researchers can also claim in future to have been brave pioneers, when Arctic sea ice rebounds despite continued accumulation of plant food in the air.

      It looks as if early next month Arctic sea ice will be in the normal range, despite starting out from a low winter maximum, due to slower than usual melting, thanks to colder than average SSTs in the Arctic Ocean and adjacent seas, from heat loss to space from open water during the winter.

      http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

  9. It’s about time someone published something this obvious. Those of us pushing the ocean cycles as the main driver of climate will now have a paper to reference.

    But what is really needed is to understand the drivers of these cycles. It is completely possible they are also the drivers of the various warm periods and cool periods over the past 4,000 years.

    • It’s about time someone published something this obvious.

      Yep. It cements the early 20th century arctic warming as fact.

      We very often see comments with a logbook entry or newspaper clipping showing much reduced arctic ice in the early 20th century. While I was looking for one of those, I found this. It’s a survey of old Russian papers showing reduced ice between 1920 and 1940.

      Every such bit of evidence chips away at the CO2 narrative. It’s a good thing.

  10. We are rather suggesting that Arctic warming could accelerate or decelerate due to internal variability of the Pacific and the Atlantic.

    That narrows it down then! Nobel prizes all round, guys…..

  11. Given that the rise in the early 20th century was natural, reset the 1.5 degree to that temp and take our time. NOT A CATASTROPHE!

  12. This amounts to academic positioning to be the cited paper when the AMO declines further and the hunt for excuses heats up. It is imperative for the climate cabal to have a backup excuse plan to explain the continued dangerous threat of global warming when it becomes more obvious in the main metrics that there isn’t any. Call it the dark energy of global warming–You can’t see it or measure it, but it’s there all right and you better think it’s there or be sent to the ideological wilderness.

  13. Unfortunately the only way to get published these days is to repeat the company line of “CO2 caused it”. But at least part of the paper is real science.

    • I don’t know about the paper being “real science.” Just one of its statements would engender caution: “We are rather suggesting that Arctic warming could accelerate or decelerate …”

      Bet the farm on global warming?

  14. I am also heartily sick of the ” canary in the coal mine” meme.
    As an Australian, and with the recent South Australian blackouts in mind, I much prefer the expression ” canary in the wind turbine blades”.

    • I like it. Here in Wyoming, the coal mines were closing down, but the billionaire from Colorado is installing a thousand eagle-killing energy from weather turbines to make up for it. The energy goes to California and the income to Colorado (except a paltry increase in property tax revenue, maybe), so I’m not sure how that works out. Anyway, at the rate we are going, it will be the “canary in the wind turbines blades” soon.

  15. “Arctic warming could accelerate or decelerate due to internal variability of the Pacific and the Atlantic.”

    ….And whatever it does we’ve got it nailed. If observations don’t support it, no problem, the science has a lot experience fixing ornery data. For example, we used to argue that reports on reduced sea ice in the 20s was wrong and our adjusted temps, BEST and Hadcrut showed much more cooling than originally thought after their adjustments. We are simply adjusting it back to what is was before, because we found this warmy PDO ADO thingy.By the way, now we have cold Pacific AND Atlantic right now, so this warming is different. Its logic Jim, just not as we know it…

  16. And the Antarctic? Oops, forgot about that pole and fact it isn’t behaving as the ALARMISTs would hope.

  17. “We are not CAGW deniers” is such an obligatory catch-phrase you’d think by now they could just include an acronym at the start of each paper – WANCAGWD – whenever there might be even the slightest chance that the truth would not support the catechism of global warming and thus be denounced as heresy…

  18. It got past the Sierra Club censors with an “R” rating for restricted audiences only because of words like multidecadal variability and warming in the early 20th century.

  19. Notickszone recently drew attention to 15 recent papers attributing some of the arctic climatic changes to natural effects such as the influence of PDO and solar forcing
    http://notrickszone.com/2017/05/15/15-new-papers-scientists-abandoning-claims-of-dominant-man-made-influence-on-arctic-climate/
    The papers come from reasonably respected sources such as “Nature Climate Change” and the European Geosciences Union and lend some support to the comments above .

    • Trump appears on the scene and illegal immigration from Mexico drops 70% before inauguration and besieged non-team climate scientists are coming out of bunkers and are trashing the climastrophists creed. There’s a president that should but won’t receive the Nobel Prize.

  20. lts noticeable at the moment that there is a cold blob in the North Atlantic west of the Azores.
    The cause of that blob has in a large part been due to the weather. Over the last month or so there has been a interesting trend of area of low pressure sitting in and around the Azores area of the Atlantic.
    Which has decreased amount of Azores highs from forming. So there been decrease of warm air over this area where the cold blob has formed and a increase in colder air been drawn down from eastern Canada/Greenland. Which shows the weather can and does effect the Oceans/Climate rather then just only the other way round. This is important to understand when it comes to climate change.

  21. Can someone give me an email address to send “stay out of paris” req to the WH or Pres. Trump?

  22. Anthony, there are two separate papers mentioned in the Article. I don’t think you meant to copy the abstract of the 2nd paper which is itself an interesting paper.

    “Early 20th-century Arctic warming intensified by Pacific and Atlantic multidecadal variability”

    “Pacific North American circulation pattern links external forcing and North American hydroclimatic change over the past millennium”

  23. “similar rapid warming that occurred during the early 20th century”
    Similar? Nothing like it.

    • That graph appears to be a prime example of lying with numbers, something you warmunists are both good at, and comfortable doing. Congratulations.

    • Tony, I believe this graph is a little more accurate/comprehensive

      Puts a different point of view on it, eh.

    • TM, you have three problems with your fake news graphic. 1. What month? 2. Has NEVER been as low as depicted even 3rd week September per DMI and NSIDC (red). 3. IPCC projectiions (blue) had zero as soon as 2015 (Wadhams). Never going to happen.
      Children in kindergarten can color as they wish with crayons. As you have here. Meaningless.

      • Wadham’s “ice free” wasn’t zero ice, it was 1,000,000 square kilometres. Minor point, and doesn’t change the thrust of your comment.

      • On track for a major melt-out this summer with thin, fragile ice over the whole basin except for a tiny bit of multi-year ice north of Greenland and CAA.

        1. Graph is labelled September

        2. 2012 had 3.2 million q km

        3 Volume is the better indicator:

      • 1 Month is labelled on the graph – September minimum.
        2. Certainly has been under 4million km

        3 Volume give a better view of the state of the ice – thin and fragile. The chance of a melt out of all but the thicker bits north of Greenland and the CAA are high.

      • tony mcleod

        And so what? Under today’s conditions, less sea ice = MORE cooling and MORE heat LOSS from the newly-exposed arctic ocean 7 months of the year. And, what heat is gained during those few weeks of April-August, is made up by the increased losses the remaining months of the year.

        By the time Arctic sea ice minimums are reached in mid September, there are less than 20 watts/m^2 (average) of solar energy hitting the Arctic surface of that “ice-free arctic” you so greatly fear!

        Yet, on that same day, because the sun so low in the sky, there are only 200 watt-hours absorbed difference after 24 hours exposure of an ice-covered sea and an open ocean.

        (Specifically, on a clear day at the edge of the sea ice at 78 degrees north, 414 watts-hours of direct radiation from sunlight would hit the surface over the entire day. 208 would be absorbed by the open ocean and 79 would be reflected. If that same solar energy hit sea ice on that same day-of-year, 71 watt-hours would be absorbed bu the sea ice, and 344 would be reflected. The difference is 208 watt-hours. Over the entire day.

        But just increased longwave losses radiating into space from a 2 degree C sea surface, rather than from a -20 degree ice surface, are more than 150 watts. Every hour of the 24 hours that same day.

        Less sea ice? More cooling.

      • Hey McClod,

        MASIE has 2017 extent above that of 2006, 2007, 2008, 2009, 2010, 2011, 2015, 2016

        NSIDC has 29017 extent above that of 2006, 2010, 2011, 2015, 2016.

        Both MASIE and NSIDC have the SLOWEST May melt this century.

        Facts, always the enema of the AGW clown cultist.

      • Temperatures in Iceland, McClod.

        No wonder the Arctic sea ice scam starts in 1979

        And you do know that late 1970’s was a time of EXTREME Arctic sea ice, up there with the extremes of the LIA.

        And look what happens when we add the early sat data from 1973 to the DOE chart

    • Hey Tony, how’s it going,

      From the graph, 1980: why is “projection” at 1,000,000 square kilometers (about 10%) above “actual”?

      Couldn’t they at least calibrate the model to resemble reality at some point in time? Do you think this specific model, that you reference, is a good indication of the type/caliber of work product that the IPPC has compiled?

      Looks like a pretty shoddy model to me.

    • So how did we have so much sea ice when temperatures were just as warm 80 years ago?

    • Uh, Tony. Why aren’t we seeing data through September 2016? Why does your graph end at 2007?

      It is my understanding that the 2007 values you present at the end of your graph set a floor at which we remain ten years later.

      Tell me it ain’t so. Tell me that ice has dropped below 2007 values.

      Prove to me you have any credibility, Tony.

      Oh, by the way; the IPCC climate models obviously cannot predict (project) annual ice extent, can they? If they are so far off on a fundamental climate parameter as Arctic ice extent, why would I believe their predictions (projections) of temperature, humidity, floods, drought, hurricanes, etc.?

      • “If they are so far off”
        …as in way too conervative?

        Not sure where you’re getting 2007 from. The first one goes to 2012. Does this answer your question?

        This is one of the causes of the current thin, fragile, mobile ice:

      • Tony,
        You have labelled the graph “as much as 30C warmer” yet the data on the graph indicates the artic temperature anomaly is, on average, +4.8C. Using your logic, couldn’t we also proclaim “catastrophic global cooling” by pointing out that much of the northern hemisphere experienced “as much as 10C cooling”??

  24. This is “me too” science. The relationship between Arctic sea ice and AMO was established by:

    A signal of persistent Atlantic multidecadal variability in Arctic sea ice
    M.W. Miles et al. 2014. Geophys. Res. Lett., 41, 463–469.
    http://folk.uib.no/ngftf/CV/PDF_Furevik/miles_et_al_grl_2014.pdf
    “We establish a signal of pervasive and persistent multidecadal (~60–90 year) fluctuations… Covariability between sea ice and Atlantic multidecadal variability as represented by the Atlantic Multidecadal Oscillation (AMO) index is evident during the instrumental record. This observational evidence supports recent modeling studies that have suggested that Arctic sea ice is intrinsically linked to Atlantic multidecadal variability.
    Given the demonstrated covariability between sea ice and the AMO, it follows that a change to a negative AMO phase in the coming decade(s) could —to some degree— temporarily ameliorate the strongly negative recent sea-ice trends.”

  25. They tune the CO2-driven models to match the late 20thC warming, so the models’ only possible conclusion is that the late 20thC warming was caused by CO2. It’s standard circular logic. The models then fail to match the earlier warming, because there was less CO2 growth then.

    The modellers, to protect their models, then need to find an excuse for the earlier warming. The “culprit” they chose was the combination of AMO and PDO, neither of which is represented in the climate models. They used “a network of annually resolved tree-ring proxy records across North America”. Well, here is how North American temperatures stack up against the AMO and PDO:

    [full article: https://wattsupwiththat.com/2010/09/30/amopdo-temperature-variation-one-graph-says-it-all/%5D

    No CO2 is needed!

    • This is a very telling graph and be the key to why we see the ~1000 year cycles. Note the PDO+AMO shows warming influence for about 2/3 of the 60+ year cycle and a cooling influence for only 1/3 of the cycle. It is possible the PDO and AMO are on slightly different cycles.

      If they’re cycles only differ by 3-5 years then over 1000 years they might go through some periods where they were in sync, some periods out of sync and some periods with some overlap.

  26. Are these two different papers? The first part of the article seems to refer to this paper by Tokinaga, is http://www.pnas.org/content/early/2017/05/23/1615880114.short?rss=1 titled Early 20th-century Arctic warming intensified by Pacific and Atlantic multidecadal variability

    However, the link is to a paper written by Zhongfang Liu, et al http://www.pnas.org/content/114/13/3340.abstract Th is is the paper titled, Pacific North American circulation pattern links external forcing and North American hydroclimatic change over the past millennium

    In other words, the article which is discussed in the first have of the post is not related to the PNAS report which is cited in the 2nd half of the post. If you are interested in reading the second one in its entirety, it is available in Researchgate for free (no paywall). You merely have to have an account on researchgate.

    https://www.researchgate.net/publication/314434770_Pacific_North_American_circulation_pattern_links_external_forcing_and_North_American_hydroclimatic_change_over_the_past_millennium

  27. Preferred patterns of atmospheric circulation. That’s all we’re looking at. And all we veteran Meteorologist have know it for a long time. The “climate change” hoax!

  28. It is interesting to look at Icelandic temperatures and the adjustments made to them.

    Here is GISS data, RAW and ADJUSTED. Look at the 1940 adjustment.

    More starkly, the adjustments made are:

    Why do they wish to rewrite the 1940 temps by so much?

  29. What did glaciers do during this time? If they were receding, what kind of additional atmospheric temperature change would that latent heat translate to had there been no ice to melt? What caused all that forcing?!

  30. Arctic sea ice on 31 May 2017 was in the middle of the past 12 years for this date:

    2013: 12.478 M sq km
    2009: 12.447
    2012: 12.437
    2008: 12.311
    2007: 12.263
    2014: 12.219
    2017: 12.108
    2011: 12.054
    2010: 12.041
    2006: 11.966
    2015: 11.795
    2016: 11.203

    http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

    The importance of late season weather on summer low ice extent is obvious from the relatively high ranking for 2012 and 2007, both record low years due to August cyclones, which also struck in the already lower than average years of 2015 and 2016.

    This year would also probably have been higher than 2004, but ice essentially quit melting then for a few days at the end of May.

    At its present low rate of melt, thanks to colder than usual SSTs, Arctic sea ice extent should soon enter the normal range for the 30-year reference interval, 1981-2010.

    So, unless a storm or two hits the Arctic in August or September this year, piling up the floes and so distributing them that less area meets the 15% minimum to be counted as icy, Griff will lose his bet that this was “sure” to be a record low year, due to its slightly lower than last year’s winter maximum.

    • The summer and winter lows of 2015 and 2016 and the winter low of 2017 were all thanks to the super El Nino now past.

    • Next week is when the melt rate often accelerates. We’ll soon see whether this year’s extent will be above even more years in mid-melt.

    • Griff’s bet as I recall was that it would be possible to sail to the N pole through open water. Extent is higher than last year mainly because the ice is more fragmented (and thinner), as a result it is likely to melt faster so I expect a record minimum year this year.

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