Study: cold-season temperature variability has significantly decreased over the mid- to high-latitude Northern Hemisphere in recent decades

This is one of the reasons severe weather has been on the decrease. Less variance means less mixing, and mixing of extreme temperature differential air masses is what contributes to volatile weather events like tornado outbreaks.

EF3-EF5

Source: http://www1.ncdc.noaa.gov/pub/data/cmb/images/tornado/clim/EF3-EF5.png

Here is the paper:

Arctic amplification decreases temperature variance in northern mid- to high-latitudes  

James A. Screen  Nature Climate Change (2014) doi:10.1038/nclimate2268

Changes in climate variability are arguably more important for society and ecosystems than changes in mean climate, especially if they translate into altered extremes1, 2, 3. There is a common perception and growing concern that human-induced climate change will lead to more volatile and extreme weather4. Certain types of extreme weather have increased in frequency and/or severity5, 6, 7, in part because of a shift in mean climate but also because of changing variability1, 2, 3, 8, 9, 10. In spite of mean climate warming, an ostensibly large number of high-impact cold extremes have occurred in the Northern Hemisphere mid-latitudes over the past decade11.

One explanation is that Arctic amplification—the greater warming of the Arctic compared with lower latitudes12 associated with diminishing sea ice and snow cover—is altering the polar jet stream and increasing temperature variability13, 14, 15, 16. This study shows, however, that subseasonal cold-season temperature variability has significantly decreased over the mid- to high-latitude Northern Hemisphere in recent decades. This is partly because northerly winds and associated cold days are warming more rapidly than southerly winds and warm days, and so Arctic amplification acts to reduce subseasonal temperature variance.

Previous hypotheses linking Arctic amplification to increased weather extremes invoke dynamical changes in atmospheric circulation11, 13, 14, 15, 16, which are hard to detect in present observations17, 18 and highly uncertain in the future19, 20. In contrast, decreases in subseasonal cold-season temperature variability, in accordance with the mechanism proposed here, are detectable in the observational record and are highly robust in twenty-first-century climate model simulations.

Source: http://ht.ly/2IgDV9

A non-paywalled presentation of the results is here: http://www.cesm.ucar.edu/working_groups/Polar/presentations/2014/screen.pdf

Zeke Hausfather notes:

Part of a growing consensus that a warmer world would, on balance, have less variance in temperature, particulary high-latitude areas. I wrote a bit about it here: http://www.yaleclimatemediaforum.org/2014/06/more-temperature-variability-in-a-warming-world-not-so/

33 thoughts on “Study: cold-season temperature variability has significantly decreased over the mid- to high-latitude Northern Hemisphere in recent decades

  1. anyone else ever notice…that about the time they get something published

    …the weather changes again

  2. To be fair, there is only really evidence of decreasing variability in fall/winter months. Summer variability has been largely unchanged (though there is little evidence that its increasing globally). Most of the declining variability has also been north of 55 latitude.

  3. Rather than decreasing, the graph seems to show a “regime change” at around 1975.
    Any chance that something about the collection of this data changed at around that time?

  4. Dr. Richard Lindzen of MIT has been advocating for decades that reduced latitudinal temperature differentials from slightly increasing global temperatures should lead to LESS severe weather incidence/severity; not more as advocated by CAGW acolytes.

    Even the IPCC finally admitted in their AR5 report released last year that global trends in severe weather incidences/severity of: hurricanes, typhoons, cyclones, tropical storms, tornadoes, flooding, drought, thunderstorms, hail, etc. have not shown any statistically significant increases for the past 50~100 years…

    And yet despite ALLLLL the empirical evidence to the contrary, political hacks, public school teachers/university professors, and leftists MSM entities still pound the CAGW propaganda into the minds of “useful idiots” that severe weather is increasing at “unprecedented rates” (TM)….

    The only things that are occurring at “unprecedented rates” are government: spending, lies, deceit, obfuscation, budget deficits, debt and money printing… The CAGW scam is merely a manifestation of all these truly unprecedented acts by governments.

  5. Indeed Nick Stokes, the last WUWT post regarding this author showed how this mathematician was discovering weather and climate… It was painful. This paper definitely confirmes this guy is clueless about atmospheric circulation -recycles the usual stuff, regardless of synoptic reality- and how it responds to climatic changes through weather.
    And to boot, I’d be very careful to link tornado occurrences to global climate.

  6. That bar graph seems like a step change at about 1975. If you cover the graph with your hand to the left of 1975, it seems rather flat, overall, in trend to me.

  7. unbelievable!!!!!!!!!!!!!!!!!!

    24 June: NYT: Justin Gillis: Bipartisan Report Tallies High Toll on Economy From Global Warming
    More than a million homes and businesses along the nation’s coasts could flood repeatedly before ultimately being destroyed. Entire states in the Southeast and the Corn Belt may lose much of their agriculture as farming shifts northward in a warming world. Heat and humidity will probably grow so intense that spending time outside will become physically dangerous, throwing industries like construction and tourism into turmoil.
    That is the picture of what may happen to the United States economy in a world of unchecked global warming, according to a major new report being put forward Tuesday by a coalition of senior political and economic figures from the left, right and center, including three Treasury secretaries stretching back to the Nixon administration….
    “The big ice sheets are melting; something’s happening,” George P. Shultz, who was Treasury secretary under President Richard M. Nixon and secretary of state under President Ronald Reagan, said in an interview. He noted that he had grown concerned enough about global warming to put solar panels on his own California roof and to buy an electric car. “I say we should take out an insurance policy.”
    The former Treasury secretaries — including Henry M. Paulson Jr., a Republican who served under President George W. Bush, and Robert E. Rubin, a Democrat in the Clinton administration — promised to help sound the alarm. All endorse putting a price on greenhouse gases, most likely by taxing emissions….
    “Here we have this existential threat that I really do think has the possibility of being catastrophic, and I don’t think people have any sense of that,” Mr. Rubin said…
    The campaign behind the new report, called Risky Business, is funded largely by three wealthy financiers who are strong advocates of action on global warming: Mr. Paulson, who with his wife, Wendy, has helped finance conservation efforts for decades; Thomas F. Steyer, a billionaire former hedge fund executive and Democrat who is pushing to make global warming a central issue in political races around the country; and Michael R. Bloomberg, the former mayor of New York, who now urges cities to confront the threat of climate change.
    They commissioned an economic modeling firm that often does work for the oil and gas industry, the Rhodium Group, to assemble a team of experts who carried out the risk analysis. Trevor Houser, a Rhodium partner who led the study, sought to insulate the findings from the political opinions of the sponsors, in part by setting up a committee of leading climate scientists and environmental economists who reviewed the work…
    ***Still, it is unclear whether the new report, or the voices of the former Treasury secretaries, will have an effect on companies or investors, given that many decisions on Wall Street are driven by short-term considerations of profit and loss…

    http://www.nytimes.com/2014/06/24/science/report-tallies-toll-on-economy-from-global-warming.html?_r=0

  8. re the Rhodium/Risky Business report:

    24 June: Rhodium Group: American Climate Prospectus: Economic Risks in the United States
    Report will be available at 7:00am EST, June 24, 2014.

    http://rhg.com/reports/climate-prospectus

    Rhodium Group: Trevor Houser
    He is also a visiting fellow at the Peterson Institute for International Economics in Washington, DC, where he writes on energy, commodity and environmental market and policy issues. Trevor is an adjunct lecturer at the City College of New York, and a visiting fellow at the school’s Colin Powell Center for Policy Studies. He is a member of the Council on Foreign Relations and the National Committee on US-China Relations and serves on the Advisory Board of Asia Society’s Center on US-China Relations…
    During 2009, Trevor left RHG temporarily to serve as senior advisor to the US State Department, where he worked on a broad range of international energy, natural resource and environmental policy issues. While in government, Trevor negotiated seven bilateral US-China energy agreements, including the US-China Shale Gas Initiative and the establishment of the US-China Clean Energy Research Center. Trevor also served as a US climate change negotiator through the Copenhagen conference in 2009…

    http://rhg.com/people/trevor-houser

    really trustworthy? LOL.

  9. Moscow’s “divide & rule strategy”? can’t stop laughing. go Eurosceptics!

    23 June: Reuters: EU sets energy security as priority for next 5 years of policy-making
    By Francesco Guarascio and Barbara Lewis
    Eurosceptics likely to oppose closer integration
    Europe’s best chance of standing up to the supply insecurity caused by the Russia-Ukraine conflict is a close-knit energy union to thwart Moscow’s divide and rule strategy, a draft document laying out the next five years of EU energy policy says…
    “Geopolitical events, the worldwide energy competition and the impact of climate change are triggering a rethink of our energy and climate strategy,” a draft document on the “strategic agenda” for the next five years.
    “We must avoid Europe relying to such a high extent on fuel and gas imports. To ensure our energy future is under full control, we want to build an Energy Union aiming at affordable, secure and green energy.”.
    The document is expected to be published after a meeting of EU heads of state and government on Thursday and Friday…
    Ahead of next year’s 2015 climate conference in Paris, which is meant to agree a new binding agreement on climate change, the draft also says Europe needs to continue to lead the fight against global warming.
    It will be signed by the next Commission president, possibly Luxembourg’s Jean-Claude Juncker, although Britain is opposing his candidacy…

    http://af.reuters.com/article/commoditiesNews/idAFL6N0P438V20140623

  10. Ritholtz doesn’t feel the need to mention Paulson’s connections to Risky Business & Bloomberg, but he’s big on the insults:

    23 June: Bloomberg: Barry Ritholtz: The Losing Bet on Climate Change
    The first, from former Treasury Secretary and Goldman Sachs Chief Executive Officer Hank Paulson, was headlined “The Coming Climate Crash.” …
    That posture comes from the rational wing of the Republican Party, an ever-decreasing niche. Despite the best efforts of the extremists, there are still some Republicans who believe in science. Many of these folks (regardless of their faith) do not think that the Bible was the literal word of God, and that humans were given a brain for a reason, namely, to think, to reason, to make judgments based on scientific evidence…
    Global warming and climate change are misnomers. What we are witnessing is rising global weather volatility. As I suggested a decade ago, “Global Weather Volatility was a Strong Buy…
    But what we really need is a Volatility Index for Climate (VXG is my idea for the symbol)…
    Regardless, this isn’t going to be a political discussion. I am not remotely a “green,” and you won’t hear me lecturing people to drive a Prius or recycle or any other such environmental admonitions. My own household fleet of cars ands boats numbers many more than the number of people in our home, with no vehicle having any less than 300 horsepower.
    This isn’t about politics, this is about investing…
    That is something that the 2,000-plus people who commented on our first such discussion missed. In “Global Warming Battle Is Over Market Share, Not Science,” we looked at the market competition driven by climate change. The science is settled, with the debate left to the trolls, conspiracy theorists, and corporate shills who much prefer to repeat thoroughly discredited memes than to discuss market share or investment-related issues. As I am fond of pointing out, someone has to be on the money-losing side of the trade, and it might as well be the anti-science crowd. Call it Darwin’s revenge: Ignorance as an evolutionary adaptive failure…
    I have but two goals: The ability to bet on global weather volatility, and a way to express the trade I like to call “short unscience.” As soon as I figure out how to do this, I am going to make a killing.

    http://www.bloombergview.com/articles/2014-06-23/the-losing-bet-on-climate-change

  11. Friday Funny! think progress/grist already picking this up – maybe the $$$ might turn them?

    The College Fix: Physicist Promises $10K to Anyone Who Disproves Man-Made Global Warming
    by Andrew Desiderio – George Washington University on June 22, 2014
    Dr. Christopher Keating posted “The $10,000 Global Warming Skeptic Challenge!” on his blog earlier this month, and confirmed in an email to The College Fix on Friday that the contest is 100 percent legit.
    Keating, an ardent believer in man-made global warming, said he’s not worried that he’ll be out ten grand, because he doesn’t believe anyone can disprove humans are not the cause of global warming.
    “Deniers actively claim that science is on their side and there is no proof of man-made climate change,” he told The College Fix in his email. But he called the science proving his beliefs “overwhelming.”
    “You would think that if it was really as easy as the deniers claim that someone, somewhere would do it,” he said, adding there’s nothing so far because “it can’t be done.”…
    Keating, a physicist who has taught at the University of South Dakota and the U.S. Naval Academy, is no fan of people who do not believe climate change is caused by humans. He compares them to tobacco executives of the past who denied a link between lung cancer and smoking…
    As for his contest, no entry fee is required, and entrants must be 18 or older to enter. In terms of disproving man-made global warming, he said he’ll take just about any scrap of evidence someone wants to provide.
    “They are even free to find proof on the Internet and cut and paste it,” he said, adding “you don’t have to be a scientist and you don’t have to submit an original proof.”…
    Comments on his blog so far are cynical about the contest.
    “You can’t prove a negative,” stated one…

    http://www.thecollegefix.com/post/18076/

  12. Everything goes in cycles, the ancients knew this, we just have very short records and even shorter memory. Unfortunately whatever the state of play humans (especially in their 20s and 30s) have a tendency to think that the time they are living in is the best for everything. Only with age comes the enlightenment, and not always then.

  13. Selected area, selected period, selected seasons, combined with the fact that for estimating variance with a certain precision about ten times as much observations are needed than for the mean, and combined with the fact that it is about a change of variance, makes the claim of a ‘significant’ change here very suspect.

  14. harry says:
    June 23, 2014 at 8:00 pm
    —-
    1975 is right about the time when the PDO was shifting from cool to warm.

  15. pat says:
    June 23, 2014 at 10:56 pm
    “being put forward Tuesday by a coalition of senior political and economic figures”

    That sentence alone should tell you all you need to know about this report.

    BTW, for some reason, the author of the article seems to equate “Republican” with conservative.

  16. I think about 2 decades ago or so, this was projected by the AGW proponents. It does make sense in that warming at the high latitudes would result in reduced baroclinicty between the poles and the equator. This reduction, over-all would reduce the number of large synoptic scale outbreaks of severe thunderstorms.

    And looking at the graph, there seems to be a step change after 1975 (The Great Pacific Climate Change of 1976?). However, the Alarmists for the last decade have argued the opposite. Their claim is that in a warming world there is more water vapor. And this increase in water vapor will lead to more “extreme weather”. This is a rather shallow argument, for in the tropic oceans, where there is an abundance of water vapor, there can still be droughts if the wind patterns are correct.

    If I had to pick a side, I would pick James Sheen’s. And his data does point to a correct result of a warming globe. However, I wonder if there is a 60-75 year cycle that mirrors periods where El Ninos dominate our weather followed by periods where La Ninas dominate global weather?

  17. MarkW says:
    June 24, 2014 at 5:28 am

    pat says:
    June 23, 2014 at 10:56 pm
    “being put forward Tuesday by a coalition of senior political and economic figures”
    —-
    That sentence alone should tell you all you need to know about this report.

    BTW, for some reason, the author of the article seems to equate “Republican” with conservative.
    ——————————-
    Amen to both of your points.

  18. This is all just more of the same. Everything that happens weather-wise is consistent with the manmade climate change meme. The only thing that isn’t, and scares the bejesus out of them is the near-18 year halt in the warming. Weather is their last refuge, their Last Hurrah. More violent weather? Manmade climate. Less violent? Manmade climate. Same weather? Manmade climate.

  19. The presentation is devoid of statistical significance rigor (IE no error bars and not a trace of statistical significance calculations) and serious attempts to factor in all other plausible causes of weather stability (natural AO oscillations, etc). Researchers these days simply refuse to investigate or consider the null hypothesis anymore. Rose colored glasses everywhere and an atmosphere of “I must be on the right track because I keep getting funded” is the new method of determining significance of any new idea, the null hypothesis be damned.

    Idiots.

  20. Looking at the tornado graph, it’s almost as if there was a great climate shift of 1976.

  21. Less temperature variability in NH climate is a prelude to another 90,000 year glaciation episode. Earth will merely sink to its normal default status during this current Ice Age, which has been going on for the last 3 million years.

  22. Earle Williams says:
    June 24, 2014 at 8:24 am
    Looking at the tornado graph, it’s almost as if there was a great climate shift of 1976.

    Yep. And when the climate swings back the other way, Al Gore’s hair will catch fire and his arms will begin waiving and he will say “SEE! I TOLD YOU CO2 would cause extreme weather!”

  23. Here is the other side of the coin, so to speak.

    Great storms of the Little Ice Age.

    Abstract
    Elyse Scileppi et. al.
    Sedimentary evidence of hurricane strikes in western Long Island, New York

    [1] Evidence of historical landfalling hurricanes and prehistoric storms has been recovered from backbarrier environments in the New York City area. Overwash deposits correlate with landfalls of the most intense documented hurricanes in the area, including the hurricanes of 1893, 1821, 1788, and 1693 A.D. There is little evidence of intense hurricane landfalls in the region for several hundred years prior to the late 17th century A.D. The apparent increase in intense hurricane landfalls around 300 years ago occurs during the latter half of the Little Ice Age, a time of lower tropical sea surface temperatures….
    doi: 10.1029/2006GC001463
    ———————-

    Abstract
    Laurent Dezileau et. al. – 2011
    Intense storm activity during the Little Ice Age on the French Mediterranean coast
    …The apparent increase of the superstorm activity during the latter half of the Little Ice Age was probably due to the thermal gradient increase leading to enhanced lower tropospheric baroclinicity over a large Central Atlantic/European domain and leading to a modification of the occurrence of extreme wind events along the French Mediterranean coast….
    doi: dx.doi.org/10.1016/j.palaeo.2010.11.009
    ———————-

    Abstract
    Hubert H. Lamb – 1984
    [Climatic Changes on a Yearly to Millennial Basis 1984, pp 309-329]
    Some Studies of the Little Ice Age of Recent Centuries and its Great Storms
    …And so the series gives us our most reliable estimate of the magnitude of the temperature depression in England and neighbouring countries. In northern Scotland, southern Norway and Iceland there are indications of a significantly greater depression of the prevailing temperatures…..The enhanced thermal gradient between latitudes about 50° and 60–65°N in this part of the world is thought to have provided a basis for the development of some greater wind storms in these latitudes than have occurred in most of the last 100 years…
    doi: 10.1007/978-94-015-7692-5_34
    ———————-

    Abstract
    Zhang, Jiacheng et. al. –
    Journal of Climate, vol. 2, Issue 8, pp.833-849
    Historical Climate Records in China and Reconstruction of Past Climates
    … 1) There were significant historical climate fluctuations in China, with a range of about 1.0°-1.5°C in recent centuries. 2) Significant decadal-scale warm fluctuations occurred during a cool interval broadly correlative with the Little Ice Age. 3) There was an increased frequency of both droughts and floods in some pans of China during the Little Ice Age. Increased frequencies of dust storms accompanied the dry phases of the cool periods….
    doi: 10.1175/1520-0442(1989)0022.0.CO;2
    ———————-

    Abstract
    Dr. Paul Reiter – 2000
    From Shakespeare to Defoe: Malaria in England in the Little Ice Age
    …Crop practices throughout Europe had to be altered to adapt to the shortened, less reliable growing season, and there were many years of dearth and famine. Violent storms caused massive flooding and loss of life. Some of these resulted in permanent losses of large tracts of land from the Danish, German, and Dutch coasts….
    doi: 10.3201/eid0601.000101
    ———————-

    Abstract
    L. Dezileaua et. al. – 2011
    Intense storm activity during the Little Ice Age on the French Mediterranean coast
    …The apparent increase in intense storms around 250 years ago occurs during the latter half of the Little Ice Age, a time of lower continental surface temperatures….
    ———————-

    Abstract – 2004
    Kam-biu Liu et. al.
    A 1,000-Year History of Typhoon Landfalls in Guangdong, Southern China, Reconstructed from Chinese Historical Documentary Records
    Remarkably, the two periods of most frequent typhoon strikes in Guangdong (AD 1660–1680, 1850–1880) coincide with two of the coldest and driest periods in northern and central China during the Little Ice Age.
    ———————-

    Abstract – 1997
    K. J. Kreutz et al
    Bipolar changes in atmospheric circulation during the Little Ice Age
    meridional atmospheric circulation intensity increased in the polar South Pacific and North Atlantic at the beginning (-1400 A.D.) of the most recent Holocene rapid climate change event, the Little Ice Age (LIA). As deduced from chemical concentrations at these core sites, the LIA was characterized by substantial meridional circulation strength variability,…
    DOI: 10.1126/science.277.5330.1294
    ———————-

    Abstract
    The Little Climatic Optimum, with its persistent trade winds, clear skies, limited storminess, and consistent Walker Circulation may have been an ideal setting for migration. The Little Ice Age with its increased variability in trade winds, erratic Walker Circulation, increased storminess, and increased dust from volcanism may have helped [prevent migration. Such changes in climate would influence the migration pattern through physical perception and decision making by the Polynesians, rather than having a direct impact.
    Doi: dx.doi.org/10.1016/0031-0182(83)90087-1
    ———————-

    Letter to Nature
    Jeffrey P. Donnelly
    Intense hurricane activity over the past 5,000 years controlled by El Niño and the West African monsoon
    …..It has been proposed that an increase in sea surface temperatures caused by anthropogenic climate change has led to an increase in the frequency of intense tropical cyclones2, 3, but this proposal has been challenged….sea surface temperatures as high as at present are not necessary to support intervals of frequent intense hurricanes….
    doi:10.1038/nature05834

    And then there’s this.

    Abstract
    Philippe Sorrel et. al. – 2012
    Persistent non-solar forcing of Holocene storm dynamics in coastal sedimentary archives
    …Here we present a reappraisal of high-energy estuarine and coastal sedimentary records from the southern coast of the English Channel, and report evidence for five distinct periods during the Holocene when storminess was enhanced during the past 6,500 years. We find that high storm activity occurred periodically with a frequency of about 1,500 years, closely related to cold and windy periods diagnosed earlier…..
    doi:10.1038/ngeo1619

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