Claim: More persistent weather patterns in US linked to Arctic warming

Rutgers-led study suggests extreme weather will become more common

Persistent weather conditions, including dry and wet spells, generally have increased in the United States, perhaps due to rapid Arctic warming, according to a Rutgers-led study.

Persistent weather conditions can lead to weather extremes such as drought, heat waves, prolonged cold and storms that can cost millions of dollars in damage and disrupt societies and ecosystems, the study says.

Scientists at Rutgers University-New Brunswick and the University of Wisconsin-Madison examined daily precipitation data at 17 stations across the U.S., along with large upper-level circulation patterns over the eastern Pacific Ocean and North America.

Overall, dry and wet spells lasting four or more days occurred more frequently in recent decades, according to the study published online today in Geophysical Research Letters. The frequency of persistent large-scale circulation patterns over North America also increased when the Arctic was abnormally warm.

These are land surface temperatures from December 26, 2017 to January 2, 2018, compared with the 2001 to 2010 average for the same eight-day period. The persistent warm West and cold East pattern that was so prevalent last winter caused a western drought that led to summer fires, a prolonged cold spell in much of the East and a parade of nor’easters along the East Coast. CREDIT NASA Earth Observatory

In recent decades, the Arctic has been warming at least twice as fast as the global average temperature, the study notes. The persistence of warm Arctic patterns has also increased, suggesting that long-duration weather conditions will occur more often as rapid Arctic warming continues, said lead author Jennifer Francis, a research professor in Rutgers’ Department of Marine and Coastal Sciences.

“While we cannot say for sure that Arctic warming is the cause, we found that large-scale patterns with Arctic warming are becoming more frequent, and the frequency of long-duration weather conditions increases most for those patterns,” said Francis, who works in the School of Environmental and Biological Sciences.

The results suggest that as the Arctic continues to warm and melt, it’s likely that long-duration events will continue to occur more often, meaning that weather patterns – heat waves, droughts, cold spells and stormy conditions – will likely become more persistent, she said.

“When these conditions last a long time, they can become extreme events, as we’ve seen so often in recent years,” she said. “Knowing which types of events will occur more often in which regions and under what background conditions – such as certain ocean temperature patterns – will help decision-makers plan for the future in terms of infrastructure improvements, agricultural practices, emergency preparedness and managed retreat from hazardous areas.”

Future research will expand the analysis to other regions of the Northern Hemisphere, develop new metrics to find causal connections, and analyze projections to assess future risks from extreme weather events linked to persistent patterns, she said.

###

The paper: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL080252

North American weather regimes are becoming more persistent: Is Arctic amplification a factor?
Jennifer A. Francis,  Natasa Skific,  Stephen J. Vavrus

Abstract
Rapid Arctic warming is hypothesized to favor an increased persistence of regional weather patterns in the northern hemisphere [Francis and Vavrus 2012]. Persistent conditions can lead to drought, heatwaves, prolonged cold spells, and storminess that can cost millions of dollars in damage and disrupt societal and ecosystem norms. This study defines a new metric called long‐duration events (LDEs) ‐‐ conditions that endure at least 4 consecutive days ‐‐ and takes two independent approaches to assessing seasonal changes in weather‐pattern persistence over North America. One applies precipitation measurements at weather stations across the United States; the other is based on a cluster analysis of large‐scale, upper‐level atmospheric patterns. Both methods indicate an overall increase in LDEs. We also find that large‐scale patterns consistent with a warm Arctic exhibit an increased frequency of LDEs, suggesting that further Arctic warming may favor persistent weather patterns that can lead to weather extremes.

Plain Language Summary
Rapid Arctic warming and sea‐ice loss are expected to affect weather patterns around the northern hemisphere. An increased persistent of weather regimes is one hypothesized impact. Long‐lasting weather conditions can lead to destructive extreme events, such as droughts, prolonged cold spells, heatwaves, and flooding. This study uses daily precipitation measurements across the United States, as well as daily large‐scale atmospheric patterns over the eastern Pacific and North America, to assess changes in weather‐regime persistence, and whether any changes are associated with a rapidly warming Arctic. We find an increased frequency in long‐lived patterns in recent decades, especially those with abnormally warm high latitudes, suggesting that further Arctic warming may favor an increase in extreme events caused by prolonged weather conditions.

The paper is paywalled, but the SI is here: grl58052-sup-0001-2018gl080252_s01 (PDF)


I’m not very impressed by this paper for several reasons.

  1. There’s a question mark in the title abstract, suggesting the paper is mostly speculation.
  2. They don’t seem very cognizant of long-term natural patterns as being the driver, instead assuming climate change/AGW is the driver from the get-go.
  3. They apparently only use data back to 1950, even though older data is available. This completely eliminates the dust bowl years of the 1930’s for no apparent good reason except it might not produce the results they want.
  4. 17 stations across the U.S. isn’t a very representative sample. How did they choose those stations? Sounds like a recipe for cherry picking to me.
  5. Lead author is Jennifer Francis, who in my opinion is just as openly biased as Dr. Michael Mann, which makes me doubt the veracity of her work.

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78 thoughts on “Claim: More persistent weather patterns in US linked to Arctic warming

  1. Mother Nature does not cooperate with an increased hurricane frequency “prediction”. So let’s just predict more “persistent weather patterns”. That claim is so beautifully unspecific that it will be almost impossible to disprove.

  2. “the Arctic has been warming at least twice as fast as the global average temperature,”….

    uh no…..the arctic is part of the global average temperature…so it’s figured in that

    • I checked.
      UAH data set, latest and greatest.
      Global = +0.128 deg./decade
      NoPol = +0.251 deg./decade

      Trends for the entire record.
      Close enough.

        • The actual value is +0.25062.
          Your reported value of +0.25098 is way too high and is totally indefensible.
          You will find out quickly that around here, pushing alarmist exaggerations and propaganda gets you called out for your dishonesty.

          Side note:
          Did you notice that the last three digits of your number are the first three digits of the constant Pi? (314)

    • Back in about 2009 – 2010, there was a batch of articles here on WUWT that reported different areas of the world were heating at higher rates than the rest of the world. That year, the areas included Africa, Asia, Australia, Europe, North America, South America, Central America, the Arctic Circle, Antarctica, the Pacific Ocean, The Atlantic Ocean, The Gulf of Mexico, and various other bodies of water.
      Since then, I’ve had a rather jaundiced eye when I hear one area or another is warming faster than the average.

  3. Then, as per usual, correlations are presented as bare facts , with no detailed explanation as to why the correleation should exist. “Persistant weather patterns” doesn’t strike me as something that has been the subject of extensive study.

  4. Funny how it only makes bad weather patterns more persistent, but doesn’t make any good weather more persistent.

    • If their weather pattern projections are correct, then the U.S. will certainly have fewer outbreaks of F3+ tornadoes.

      I guarantee that all of the people living in the Plains States will consider that a huge benefit of CAGW.

  5. Their map shows a large data-free area in southern Texas. There are 3 Climate Reference Network facilities in this area. While the Reference network only covers the past 13 years, it is the best after all. Did they not check their results for the past 13 years against Reference network info? Did they use Reference network info at all?

    • It’s an odd map indeed. They have data for uninhabited islands in the Arctic but not for San Antonio or Corpus Christi….

      • The uninhabited islands do not have anybody to contradict the numbers they make up. They cannot get away with lying like that where there are people.

  6. Data from just 17 stations is not representative of the entire North American continent. It is perhaps representative of persistently deliberate ‘cherry picking’ though?

  7. Persistent weather patterns seems like weather as usual. A more descriptive name for this phenomenon might be seasonal weather patterns. It’s persistently warm in the summer and persistently cold in the winter.

    The obsession over climate change turns mountains out of mole hills. Just the suggestion that it’s warming is enough to get the scientifically illiterate masses to believe it is, even though the few tenths of a degree warming we’ve apparently observed over the last few decades is imperceptible to human senses.

    When you repeat the same lies over and over, people begin to think that they are true. This is how political truth is established and given how politics has subverted climate science since the inception of the IPCC, this is how the scientific ‘truth’ about the climate is being established. This claim by Francis is just another example of how to coerce the gullible into believing in something that the laws of physics precludes.

  8. Now, stats are not my strongest point, so this:
    the Arctic has been warming at least twice as fast as the global average temperature,
    is giving me real serious brain-ache.

    Because how I read it as that the Rest of The World is not warming at all
    … and…
    if the Arctic is warming *more* than twice as much as than ‘everywhere’ as implied by the “at least” is ‘everywhere else’ not then cooling?

    Its like the thing when politicians make great speeches about how, with them in charge, *everyone* will in future get ‘above average’ school exam results

    am I thinking garbage or are they talking it……

    • Here’s how it works. ‘Warming’ is linear in power, not temperature, so an increase in 1 W/m^2 will be different, depending on the starting temperature.

      For an average temperature of -20C (253K, -4F), the emissions are 232 W/m^2. Add 1 W/m^2 to this and convert back into a temperature results in a 0.27 C increase.

      Starting from an average temperature of 20C (293K, 68F), the emissions are 418 W/m^2. Add 1 W/m^2 to this, convert back and the resulting temperature increase is only 0.18C higher.

    • From a purely statistical point of view it is entirely possible for a small part of the earth to warm at twice the average rate. The Arctic is approximately 4% of the Earth, so the warming rate there has only a small effect on the average; it just takes a significant part of the other 96% to be below average. If some other 4% does not warm that would compensate for a double rate in the Arctic. Alternatively 8% having half the average warming rate would compensate.

      Leaving pure mathematics and moving to the real world, two times zero is zero.

    • Jimmy Carter, (yet another stellar president) actually did say he wanted all Americans to have an above average income.
      I guess he merely forgot to specify average of what group?
      World average, already above.
      American average…well he’s got some innumeracy to fix.

  9. This just in from the Arctic, holly crap its cold as hell!

    How much of our tax money was wasted on this”study”? And can nothing productive and useful be found for these people to do? I’m sure there is some litter to be picked up, or some poison ivy to be pulled.

  10. Weather patterns generally are persistent until they aren’t.

    There are all kinds of factors but probably the biggest is ocean water temperatures. The warm and cooler waters typically cause large highs and lows to form over them in the winter, which in turn cause the jets to ride along the edges.

    Depending on where these warmer and colder pools are determines where these persistent highs/lows set up and the directions of the jets… and where the air comes from and goes to. If a high is over the Gulf of Alaska, the jet rides over top of it and constantly feeds arctic air into the eastern US. If low forms over the GOA, the western US gets cold and the eastern US is warm as the jet goes under the low and the persistent flow over the eastern US is from the southwest.

    The ocean waters typically don’t give up their heat that fast so the patterns persist until they change. Hence the AMO, PDO, El Niños and La Niñas influencing continental temperatures over years in the Northern Hemisphere.

    We have cycles and things will change. It just takes a while.

  11. It’s amazing what a combination of cherry picking, confirmation bias, hivemind, and need for continued funding can do.

  12. Global Cooling, Global Warming, then Global Climate Change. Are we about to pivot to Global Climate Persistence? That sounds so scary.

    • I thought that persistent global climate is what they were attempting to legislate? Isn’t that the beef, the climate won’t remain constant?

  13. That is probably the worst abstract I have ever read. While the plain language summary can be for the non-expert layperson, the abstract in scientific papers are written for experts and scientists in the field or closely related fields to get a quick sense of what this study used in the language of the field.

    For example: In a science abstract say on solar physics, one could use the term “Maunder minimum” without wasting the words for a further explanation. It would be assumed that the expert reader would be knowledgeable of what that term means. But the use of “Maunder minimum” in a plain language summery would need to specify that as “an approximate 60 year long period of very low or no observed sunspot activity, and thus low magnetic activity, on the sun.”

    A science abstract should:
    – tell the reader what was studied,
    – and briefly how it was studied,
    – the main findings,
    – and (maybe) a conclusion, if one can be drawn.

    In this abstract, they offer no periods of time from which they access historical data, and no identity of the records used. Are they using paleo-records? Are they using US historical climate network records? Newspaper clippings? Drought records from state agriculture bureaus? What exact time periods studied is essential for the context of an abstract like this.

    Some other bad parts of the abstract:
    “Persistent conditions can lead to drought, heatwaves, prolonged cold spells, and storminess that can cost millions of dollars in damage and disrupt societal and ecosystem norms.”

    This statement is a tautology. It is self-evident. But a ‘heatwave’ is indeterminate, and can easily be 4 days or more, but a ‘drought’ certainly is months long. 2 or 3 weeks of no rain in any area in no way does not make drought… unless you are a carnival barker alarmist. And ‘persistent storminess’? WTF is that?

    And this abstract sentence likely is intentionally vague:
    “One applies precipitation measurements at weather stations across the United States;…”
    They are obviously hiding how many, as Anthony pointed out. If they had put the real number used in the abstract (17), to the expert reader, this would have immediately set off “cherry picking alert” alarm bells. The expert would have immediately thought “why just 17??!!” There are hundreds of high quality precipitation measurements across the U.S and Canada for the last 100 years.

    Then there is this howler.
    “Both methods indicate an overall increase in LDEs. “

    Methods! methods? Sorry, but methods don’t indicate jack shit. Results come from methods and data. Data goes into methods. That wording right there tells you either their wording is being sloppy (best case) or that they designed methods to give them what they wanted (likely case) and so they know their conclusions are based on their chosen methods, not the results. In other words, their conclusions are likely not to robust to other methods, only to their chosen methods

    Then there is their ‘Conclusion’ statement in the Abstract:
    We also find that large‐scale patterns consistent with a warm Arctic exhibit…”

    So they start out telling us they used methods to study long-duration events (which they hide their chery picking limited coverage), then in their conclusion they bring up “large-scale patterns”….and consistent with warm Arctic? So now are they telling us they studied large mesoscale continental-wide patterns too, and they studied Arctic warming patterns? And again, no mention of the data sets used, the time frames studied.

    This is an absolute worst kind of junk science, and that’s just from the Abstract, that is just one more indicator how broken peer-review is in science.

  14. This new “old” comment system really bites “The Big Phallota.”
    Longer comments with lots of formatting are going off into the ether and never seen again.

    • Yes, just happened to me too. I think if you spend too much time composing your comment in the comment box and try and post it, that is when it disappears. Usually in the past, I would copy my comment, and refresh the page and then paste the copy fresh, it will go thru. Or it used too. But now I have two of these just disappear. Frustrating. Or maybe I am blocked cause I already used up my allotment of comments for the day. Disqus seems to work for very well…testing 123

      • Yep, a long post seems to vanish upon hitting the post comment tab. In the past I got in the habit of always copying a comment first on wordpress.

  15. Or, more persistent weather patterns tend to direct warmer air up to the Arctic……., if there is even any real trend in ‘persistence’!

  16. “More persistent weather patterns in US linked to Arctic warming”

    Really?

    The winter of 1978-1979 was the coldest winter on record for the contiguous United States. The coldest winter on record was also one of the wettest. Precipitation was well above normal across most of the country during January 1979.

    This winter occurred during the highest Arctic sea ice recorded during the satellite era. The other six American winters that became the stuff of legend being 1940, 1922, 1888, 1886, 1857 and 1816.

    Obviously the coldest persistent seasons all had even more Arctic warming back in the past. (sarc/off)

    England also have similar findings where the coldest winters have no links with Arctic warming, but more related to low solar activity with a weak jet stream leading to a meridional behaviour. High pressure blocks occurred frequently causing persistent dry or wet, hot and cold periods during Summer and Winter respectively. Europe recently had a hot Summer and no coincidence that occurred during low solar activity.

    Most of Americans hottest Summers also occurred around low solar activity and/or when ENSO was weak. Reason being a strong ENSO favours a zonal jet stream with infrequent short term lasting blocking highs. With the jet stream being always much weaker in Summer this leads to less variation and prone to mixed signals.

    Extremely biased by the author that has no supportive evidence.

  17. These “claims” have much in common with the “RAPIST!” claims being made by the left against Brett Kavanaugh; no one seriously thinks they are true, not even those on the left, but the point is just to make so many ridiculous claims that (they hope) their opponents will get sick of fighting them forever and just give up.

    • Or the goal is to give the Democrats arguing points for the upcoming electsion, and to delay any vote in the full Senate until January, when the new Senate is seated. They are hoping that the Senate will be majority Democrat by then. Elections have consequences.

  18. Paper is OPEN ACCESS

    Francis keeps plucking her 1 string banjo The results of her papers depend on her choice of start date and “ignoring” the elephant in the room ….. PDO

    CLIMATEGOV How much do climate patterns influence predictability across the United States?
    Pacific Decadal Oscillation (PDO)
    The effects of the PDO on U.S. climate occur mainly during winter and spring, when the positive phase is associated with above average rainfall in the southwestern U.S., and negative phase with below average rains there (Dai 2013). Consistent with this, a recent study (Lyon et al. 2013) has implicated a PDO-like pattern in the recent persistent drought in the Southwest U.S., at least during spring. The PDO was in positive phase during 1924-1945, negative phase during 1946-1976, positive 1977-1998, and negative since 1999

    GRL The Pacific Decadal Oscillation, air-sea interaction and central north Pacific winter atmospheric regimes

    Abstract. Prominent and persistent anomalies in the at- mospheric flow (troughs and ridges) occur sporadically over the central North Pacific, and can have profound conse- quences for the weather of North America. We have exam- ined how these events are associated with large scale cen- tral North Pacific sea surface temperature (SST) anomalies, using an index for the Pacific Decadal Oscillation (PDO). The anomalies in turbulent air-sea heat fluxes and low-level baroclinity associated with the P DO are manifested differ- ently during troughs than during ridges in their effects on the transient eddies (storms). These effects may help ex- plain why prominent troughs (ridges) occur about 3 (2.5) times more frequently during periods when the PDO is sig- nificantly positive (negative) than of opposite sign. Our re- sults suggest that the state of the mid-latitude Pacific Ocean more fundamentally affects the atmosphere than has been thought.

  19. Nice glaciation climate map of the good ole’ exceptional.
    Otherwise BS.
    Arctic ice turned on Sept 23.
    SH SST very cold especially around Antarctica – but they always are.
    New upwelling off Peru.
    El Nino for Christmas – not so much.

  20. THE MOST IMPORTANT DOCUMENT IN THE HISTORY OF MANKIND
    ************************************************************************
    I am Canadian and cannot do a FOI request to the American government. Thus I appeal to my fellow American skeptics to do one. See below.

    The person who beat Hansen to the alarmist podium was the Swedish scientist Bert Bolin. However Bolin himself didnt have any experimental proof of CO2 raising temperature. He basically took Hansen’s numbers which as I said came from the 8 US air force researchers in a study done in 1973. How they came up with the forcing temperature numbers from a doubling I dont know; because I cant find that study and since I am not an American I cannot access their Freedom of information requests. The names of those 8 Air Force researchers are 1)R.A. McClatchey 2) W.S. Benedict 3) S.A. Clough 4) D.E. Burch 5) R.F. Calfee 6) K. Fox 7) I.S. Rothman 8)J.S. Garing

    The only reference to the study is AirForce Camb, Res. Lab. Rep. AFCRI-TR-73-0096 (1973)

    That has to be the most important document in the history of mankind, seeing that the CO2 scam is the most costly scam in human history.

    • Hey,

      your full citation is McClatchey, R. A., and Benedict, W. S. (Univ. of Md.), Clough, S. A., and Burch, D. E. (PhilcoCorp.), Calfee, R. F., Fox, K. (Univ of Tenn.), Rothman, L. S., and Garing, J. S. AFCRL Atmospheric Absorption Line Parameters Compilation AFCRL-TR-73-0096

      I got that from the AFCRL Report on Research For the Period July 1972 – June 1974 http://www.dtic.mil/dtic/tr/fulltext/u2/a027358.pdf

      Ok, I found your full report at http://www.dtic.mil/dtic/tr/fulltext/u2/762904.pdf

      • Most unclassified research on basic science from the Air Force Labs is freely available through the dtic web site. You just have to figure out how to tickle it out.

        The classified stuff is a little harder because first you have to know of its existence, then you have to specify a rationale for declassification, and they still may answer you “what report is that again?” Then the FBI guys start following you to figure out why you know classified information all the while trying to pretend that you didn’t specify anything real. Not that I would know anything about that or anything…..

  21. The claims that a warming world is responsible for all bad weather now is nonsense, since bad weather has always been with us. Probably much worse weather in a colder world than we have now in a warmer world. Our (human) problem is that it is subjective, because it flooded my beach front house or my community was flooded in a river flood plain. Well, maybe we shouldn’t build in a flood plain if we can’t handle the water periodically. It is only perceived as bad because it messes up our lives, usually because we didn’t take heed and build in a suitable location, or with proper materials, or didn’t follow a proper building code. Haiti comes to mind regarding building code, or Calgary on a flood plain from a river upstream aptly named High River. The first clue should have been the name of the river. And it rained on a high elevation snow pack in mid June after a long cold spring had a heavy rain and big melt water all come at once. Or Tropical Storm Sandy hit New York conveniently at a King Tide. Or New Orleans when hit by Katrina as a Cat 3, and breached key levees, including the 17th Street and London Avenue canals in the heart of the city, failed with water well below levels they were designed to withstand. There are dozens of other examples I could give, but these are man made disasters, not proof of some nefarious dangerous happenings of climate change. If we lived a nomadic life, we would just pull up our tent and barely even get our feet wet.

    The planet Venus is very warm, in fact hot, but it doesn’t have any significant winds at the surface. That is because there is no major temperature gradient differential to cause mass movement of air masses at ground level. Different story higher up in the Venusian atmosphere where the heat is escaping to space. In the ice age, I think it safe to assume that the hurricanes were much more intense and moving much, much faster because of the greater temperature gradient towards the poles. Probably less rain but with the hurricane tracking very fast and added to the wind speed within the hurricane itself, then a very destructive combination.

    But if the Arctic really does significantly warm up, then that logically says that the storm intensity movement should become slower. Perhaps in a warmer world the atmosphere will hold more water vapor, causing more rain in some areas where the storm tracks are and in a slower moving storm, means it may rain longer in one spot such as when Hurricane Harvey in Houston stalled out and caused major flooding. But then Houston is pretty much paved over in a flood plain, and the flooding damage that was caused to humans which was what made it so terrible. And Harvey just ran into another higher pressure weather event that slowed it down so nothing really unusual about that. If Houston had hills, and most everyone lived on the hillsides, the flooding damage would have been that much less and nowhere near the tens of billions in damages. Same for the Cat 2 Hurricane Florence that just hit South Carolina. Lots of rain for a fairly long time, but the flooding damage was because of the large population density in the river valleys over a very large area. The same storm 100 years ago, would have had 10% of the damage to humans. So, we have to differentiate between the damage caused because of so many people living in the way, instead of blaming all this on CAGW. Therein be the crux of the problems, in my opinion. But like the peoples of ancient times, we will need to blame it on something, and for now, it appears to be at the Alter of ‘Carbon’ and CACC and CAGW. Bonus, they can tax it too. But now, they are starting to sacrifice people to this religion, and this must be stopped, or we just repeat history all over again.

    • Earthling2- I don’t think the gradient has an effect on hurricanes.

      Will people move from the dangerous areas because of AGW?

  22. I would say the weather patterns are less persistent, at least over the central United States. Back in the very warm 1930’s, high pressure systems pesisted for months at a time over the central plains, and the entire decade of the 1930’s was like this.

    There is no comparison between the 1930’s and today. Today, the only thing persistent is good, mild weather.

  23. “This study defines a new metric called long‐duration events (LDEs) ‐‐ conditions that endure at least 4 consecutive days…”

    Why four days? It seems rather subjective. Do they get the same results with three days or five days, and/or did they just mine the data to find any pattern they could? I would have thought that there out to be some more rigorous statistical technique available to measure the “clumping” of any particular metric.

    And if they lived in the Arctic I bet they would turn it around and blame recent warming on persistent North American weather patterns.

  24. Hmmm, so arctic warming causes longer lasting weather spells.

    Doesn’t that then say that a warmer arctic causes more stable weather?

    Go for it i would think, these changes in weather always cause me the most grief.
    Especially with the wardrob selection and i’m not at my best in the morning anyway 😉
    Makes planning a lot easier as well,

    Have a good one,
    Willem

    • Maybe the presently warm oceans cause both Arctic warming and persistent weather conditions.
      That makes the most sense to me.

    • Willem – The planetary waves grow larger and have more inertia with Arctic warming. Embedded waves in these waves give us weather changes at the surface.

  25. Because the earth absorbs most infrared energy nearest the equator with much larger areas and much of that energy is moved through to the poles with smaller areas through atmospheric and oceanic currents, it is actually natural for the polar regions, especially the Arctic for geographic reasons, to warm faster as part of the process of removing heat through the atmosphere. This happens with normal warming and is born out by long term records of Arctic warming. When the temperature differential between the poles and the equator is less, it allows the jet stream to meander with more north and south movement rather that a tighter more latitude consistent path. This is called meridional circulation. When troughs go further south and ridges go further north, then we have increased likely hood of unusually high or low temperatures. And these patterns of ridges and troughs can lock in place for extended periods of time. Since this happens with natural, not anthropogenic forcing, it’s occurence is only evidence of warming. It does not provide attribution to the cause of warming. Referring to “Arctic Amplification” misses the idea this happens naturally. We are currently at a point where warming from the late 1970’s to about 1998, largely stalled post 2000. We are also seeing reduced solar activity which can mean that the incoming radiation at the equators is reduced and the warming there is likely slowing. A slowing of warming near the equators at the same time previous warming in the Arctic, delayed from equatorial input, is still persistent can produce less temperature differential that when the entire planet is warming. This is a better situation for meridional circulation. So these results are not surprising and can happen with naturally driven warming.

    • I said in my previous post that “Since this {meridional circulation] happens with natural, not anthropogenic forcing, it’s occurrence is only evidence of warming.” I should clarify that anthropogenic forcing can produce a similar, though not identical result. However, differentiation between the two causes, natural and anthropogenic is frequently not addressed and not easily addressed. Using models to claim what portion of warming is natural are highly dependent on assumptions and data and continue to see a large range of sensitivities to anthropogenic forcing.

      • mike – which effect has more influence over the wave pattern? Maybe it’s cyclical short term.

  26. ‘Arctic warming linked to more persistent weather patterns in US, and elsewhere.’

    Fixed. It’s called poleward heat transport, Arctic humidity events, and warm AMO anomalies.

  27. Why do they think that we have any control over extreme weather events at all? They can’t even tell one kind of warming or not anyway – and….. “…We are still going to see extreme weather events whether or not humans are influencing the climate.” – Judith Curry
    It’s what weather and climate do. We just experience a summer with Kilauea creating its own weather system and the East coast is still recovering from a hurricane we could do nothing to stop – and they still maintain that lowering our contribution to CO2 would stop these things? That is delusional thinking.
    https://www.facebook.com/fourtimesayear/photos/a.427072877441780/547074252108308/?type=3&theater

    • “They can’t even tell one kind of warming or not anyway” should be “They can’t even tell one kind of warming from another” – the perils of editing one’s comments by moving texts around, lol

  28. In Finland the climate has not warmed at all for about 80 years. It is easy to check at our FMI, Finnish Meteorological Institute pages. The corruption of the institute has not yet reached all the way through, so pages in Finnish are still truthful, but pages in English are completely different. Try googling Ilmatieteen Laitos (FMI), there “ilmasto” (climate), “vuositilastot” (annual statistics), and the graph of Sodankylä and Helsinki Kaisaniemi (Lapland at Arctic Circle, and southernmost Finland inside biggest city with UHI). If choosing the same page in English, there is just the normal liturgia of global warming.

  29. This is excellent news – for Governor Cuomo. He had earlier stated that people were leaving New York for Florida – not because of high taxes – but because they seek warmer weather. I thought he had forgotten the Global Warming meme, but this article gives him cover: New York is getting colder because the Arctic is getting warmer.

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