NOAA: Another ‘AGW caused heat wave’ is actually just natural variation

You may remember headlines like these last summer:

2012_heatwave_grauniad

  1. With Blow-Out March Heat Wave, Meteorologist Masters Says ‘This is not the atmosphere I grew up with’
  2. The 2012 Heat Wave: “Almost Like Science Fiction” | Popular Science
  3. Record Heat Wave Pushes U.S. Belief in Climate Change to 70%
  4. US heatwave may have been made more likely by global warming 
  5. Global Warming May Have Fueled March Heat Wave Odds

A new paper by a team of NOAA scientists published in the Bulletin of the American Meteorological Society finds that the US extreme heat wave of March 2012 was due to natural variability, not AGW. According to the authors, “Several lines of evidence strongly implicate natural variations as the primary cause for the extreme event,” and “We conclude that the extreme warmth over the central and eastern U.S. in March 2012 resulted primarily from natural climate and weather variability, a substantial fraction of which was predictable.”

They go on to show how synoptic scale weather forecasting models like GFS predicted the event, indicating it was a “weather, not climate” event. Now that the analysis says ‘natural variability”, will there be followup headlines? Doubtful. News of “normalcy” doesn’t sell, hype and sensationalism does.  However, I’m going to take this opportunity to call out Climate Central’s Andrew Freedman, who is one of the more reasonable people who sensationalized the event, to post a follow up to his collection of stories on it here.

The full paper is below. 

The Making of An Extreme Event: Putting the Pieces Together

Randall Dole 1, Martin Hoerling 1, Arun Kumar 2, Jon Eischeid 1,3, Judith Perlwitz 1,3, Xiao-Wei Quan 1,3,George Kiladis 1, Robert Webb 1, Donald Murray 1,3, Mingyue Chen 2, Klaus Wolter 1,3, and Tao Zhang 1,3

1 NOAA Earth System Research Laboratory, Boulder, Colorado 2 NOAA Climate Prediction Center, Camp Springs, MD 3 University of Colorado, Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado

Abstract

We examine how physical factors spanning climate and weather contributed to record warmth over the central and eastern U.S. in March 2012, when daily temperature anomalies at many locations exceeded 20°C. Over this region, approximately 1° C warming in March temperatures has occurred since 1901. This long-term regional warming is an order-of-magnitude [10 times] smaller than temperature anomalies observed during the event, indicating the most of the extreme warmth must be explained by other factors. Several lines of evidence strongly implicate natural variations as the primary cause for the extreme event.

The 2012 temperature anomalies had a close analogue in an exceptionally warm U.S. March occurring over 100 years earlier, providing observational evidence that an extreme event similar to March 2012 could be produced through natural variability alone. Coupled model forecasts and simulations forced by observed sea surface temperatures (SSTs) show that forcing from anomalous SSTs increased the probability of extreme warm temperatures in March 2012 above that anticipated from the long-term warming trend.

In addition, forcing associated with a strong Madden-Julian Oscillation further increased the probability for extreme U.S. warmth and provided important additional predictive information on the timing and spatial pattern of temperature anomalies. The results indicate that the superposition of a strong natural variation similar to March 1910 on long-term warming of the magnitude observed would be sufficient to account for the record warm March 2012 U.S. temperatures.

We conclude that the extreme warmth over the central and eastern U.S. in March 2012 resulted primarily from natural climate and weather variability, a substantial fraction of which was predictable.

================================================================

Full paper (draft revision submitted) is available here:

http://www.esrl.noaa.gov/psd/csi/pubs/docs/Making_Extreme_Event_revised_04_12_13.pdf

h/t to The Hockey Schtick

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35 Responses to NOAA: Another ‘AGW caused heat wave’ is actually just natural variation

  1. Bill_W says:

    Anthony,

    Can you add links at bottom of this story to the 2 – 4 other stories over the last few years where the same thing happened? That is, a weather event was hyped as the new normal, and then the next year a paper or two is released with no fanfare saying, no, it’s just weather?

    I’m thinking of Greenland last year, the Russian heatwave from a few years ago, and was it Europe last year?

    THanks.

  2. Dr. Lurtz says:

    “US heatwave may have been made more likely by Global Warming”. Is this the result of scientific research and analysis? Are these the new words that scientific PhDs use to describe physical reality? What happen to the word “law” like in the “Law of Gravity”?

    “May have been”, “more likely”, this is an insult to science!

  3. Chuck L says:

    I wouldn’t hold my breath waiting for Freedman to respond…

  4. “…resulted primarily from natural climate and weather variability, a substantial fraction of which was predictable.”

    I keep seeing the word “predictable” associated with natural variability. Does this imply the CO2- caused climate and weather variability is inherently unpredictable?

  5. JimS says:

    Perhaps it is easier to take such a route for NOAA since weather is not supposed to be climate? Otherwise, what would be the explanation for the Negative Arctic Oscillation experienced by the Midwest States this year in the month of May. There are not many believers in AGW in Minnesota this year, so I hear.

  6. johnmarshall says:

    Every weather event is now caused by climate change. They claim, no, weather is caused by a chaotic system driven by solar heat so every high or low will fall within the natural changes hat occur. Within the long term weather climate will trend one way or another naturally.

    It is the height of conceit to think we, mere humans, can change events driven by a star.

  7. So, it’s official now? Global warming = AGW?

    Whether it’s weather or climate, the conclusion that it “was due to natural variability, not AGW” is not news. It fits everywhere because to the extent that AGW exists, it is not measurable. What would be news is the first bit of evidence of the existence of AGW.

  8. John W. Garrett says:

    Thanks to the Second Amendment, the fourth estate is never held to account.

    Just like Wall Street, the blabbermouths and professional gossips of the media cause enormous damage with their usually inaccurate forecasts.

    You’d think the crystal ball and tea leaf readers would eventually suffer pangs of conscience. After years of observation, I finally came to agree with the wisdom of the admonition: Never appeal to a man’s conscience; he might not have one.

  9. numerobis says:

    They’re arguing against a strawman. The case for saying global warming caused a weather event is more subtle: given natural variability around a mean, you can get a week of temperatures 10F above normal, which is unusual, or a week at 9F above normal, still unusual but a bit more common. Let’s say the norm is 80F, for round numbers.

    Increase the norm by 1F to 80F and a heat wave of 90F temperatures is now about as common as the heat wave of 89F used to be, even if you have the same natural variability.

    So if in a summer you used to have one 90F heat wave and two 89F ones, and now you get three 90F heat waves, the argument is you should count that as having two of them being caused by global warming.

    The authors are arguing against the ridiculous claim that nobody made: that global warming increased the temperature by 10F.

  10. Coke says:

    I just visited Climate Central and read an article written by Andrew Freedman.

    My visit was bizarre, to say the least.

    He claimed that “Arctic Warming Could Cost Upwards of $60 Trillion” in just one decade (2015-2025). The article gave absolutely no examples whatsoever regarding how or why the arctic warming would cost the world so much, and referenced a “report” as the source of the article contents.

    So, being a denier in the employ of Big Oil, I did exactly what the warmists claim we don’t do… I clicked the link to take a look at the “evidence” for myself.

    It wasn’t a “report”. It was a two-page screed devoid of any science at all. Maybe the links at the end of the “report” contained enough science to justify the claim that “Arctic Warming Could Cost Upwards of $60 Trillion”. But, if the original article was devoid of supporting scientific evidence, and the “report” that the article was based on was also devoid of supporting scientific evidence… then I am skeptical that the links at the bottom of the “report” contain the supporting scientific evidence.

    But! Had they done so, I’m sure Andrew Freedman would have been more than delighted to include it in his pathetic opinion piece.

    I guess he couldn’t find any supporting scientific evidence in the “report” either.

    So, now I’m back at my favourite blog (WUWT FTW!), slightly at a loss for words as to the utter claptrap I just witnessed (it’s just as well that I’m typing and not talking!)

    Oh, and the “report” that Andrew’s opinion piece took its lead from also states “For this study, the researchers relied on methane-release estimates produced from a separate study” but does not specifically cite the study or its authors. It could be any one of the sources, possibly even none of them. I’m not a scientist so I will just stop here instead of tracking down each (alleged) source to find the origin of the $60 trillion figure.

    If you were a scientist, trying to replicate the (alleged) work done in conjuring this $60 trillion figure… well, all I can really say to that is, I hope your search for the science was more fruitful than mine.

    But you don’t have to replicate the work done to know if the article was just plain scare-mongering.

    You can just read it instead.

  11. Bob Tisdale says:

    Thanks, Anthony.

  12. Patrick says:

    I wonder when the recent Spanish train crash, sad though it is, will be attributed to the heat wave (Buckled rails etc)? So far it’s driver error and speed.

  13. highflight56433 says:

    Incredible waste of time, money, and associated resources…what other science receives such hogs to trough funding? What ever happened to NASA and real space exploration with real space travelers…the final frontier is on perpetual hold.

  14. Réaumur says:

    For those of us outside the US, did the March heat wave actually “shatter” records?

  15. steveta_uk says:

    “Several lines of evidence strongly implicate natural variations as the primary cause for the extreme event,”

    Maybe so, but it’s still possible that the temperatures reached about 0.8C higher that they would have done 100 years ago when exactly the same set of causes was present.

    Or maybe not. Who knows?

  16. wws says:

    This game is so old – announce “HEATING PROBABLY CAUSED BY GLOBAL WARMING!!!” on Page 1 of every major paper, then a year later say “okay, it wasn’t.” on the back pages of some journal that no one except a handful of people will ever see.

    When you realize that this is the PLAN from the start, every time this happens, the reason these things keep happening become much more clear.

    Do you really think that this will ever stop? Everyone who writes and prints this stuff knows that this is the script from day 1.

  17. Mumble McGuirk says:

    John W. Garrett says:
    July 26, 2013 at 6:58 am
    Thanks to the Second Amendment, the fourth estate is never held to account.
    ————————————————————————————————————–
    Did you mean to say “Thanks to the First Amendment” or are you saying because reporters can carry around firearms, no one can tell them what to say? Frankly, I am amused by the mental image of the the palisades of the NYT being patrolled by reporters in fedoras sporting Uzis. Maybe in Venezuela this would be a good idea. ;)

  18. beng says:

    Some summers have warm spells, some won’t.
    Almond Joy’s got nuts an’, Mounds don’t.

  19. DesertYote says:

    Mumble McGuirk says:
    July 26, 2013 at 8:23 am

    John W. Garrett says:
    July 26, 2013 at 6:58 am
    Thanks to the Second Amendment, the fourth estate is never held to account.
    ————————————————————————————————————–
    Did you mean to say “Thanks to the First Amendment” or are you saying because reporters can carry around firearms, no one can tell them what to say? Frankly, I am amused by the mental image of the the palisades of the NYT being patrolled by reporters in fedoras sporting Uzis. Maybe in Venezuela this would be a good idea. ;)
    ###

    A dishwasher at a restaurant I was working at, was a reporter from Mexico City. He had to go everywhere armed. After a particular series of stories, he needed to have body guards when out in public. Eventually, things got too hot for him which is why he was working as a dish washer.

    I learned more Mexican History and Politics in the six months I worked with him then I did American History and Politics in four years of High School.

  20. Peter Stroud says:

    It seems no time at all when all respectable climate authorities, the Met Office, NASA and NOAA, rushed to deny any relationship between global warming and extraordinary weather. What has changed? Other than the global temperature hiatus, of course.

  21. dbstealey says:

    Réaumur says:

    “For those of us outside the US, did the March heat wave actually ‘shatter’ records?”

    Answer: No.

    GISS altered the temperature record to fabricate warming in recent years.

    This deceptive alteration is done to justify requests for increased annual funding. GISS is not the only government agency that does this, but they are one of the more blatant ones.

    The 1930′s were by far the warmest decade recorded in the U.S. and globally. Since CO2 was much lower seven decades ago, these agencies have a choice:

    a) Honestly report the past temperature record, or

    b) Sell their souls

  22. gary gulrud says:

    I realize central MN gets 270 days of partial or full cloud cover per year. Yet despite its anecdotal character, tomorrow, a shade past the ‘dog days of Summer’, our high will only be in the 50′s. Today is rainy and cool. We’ve had 3 or 4 days touch 90 degrees but barely.

    Our handy 3000 acre lake is 4 degrees cooler than last, a comparatively warm dry summer. Yet in ’83 we had a July with all but one day in the 90s and 3 days in the 100s. Not a global measurement, but it was the Northern Hemisphere.

  23. Bill Illis says:

    Now here is some record temps for North America in April of this year – except they are cold ones this time as low as -12.0C (for the entire month). Same satellite composite source as at the top of this post.

    http://s23.postimg.org/eycmn2th7/North_America_April_2013.png

  24. RobRoy says:

    Every time one reads the word “may” or “could” it could (or could not) as easily have had the word “not” after each “may” and “could”. I guess it depends on what one hopes for.

  25. Ph.D. Guy says:

    Sheesh! “may have been made more likely.” What a mouthful. “May have” and “more likely” in one little sentence. Talk about exaggerating to make a point.

  26. Nick Stokes says:

    Andrew Freedman’s Guardian article actually quoted Randall Dole, who is the lead author of the new study:
    As to whether global warming might be contributing to the recent hot wave, Randall M. Dole, a deputy director of research at NOAA’s Earth System Research Laboratory (ESRL) in Boulder, Colo., said, “Absolutely. The planet as a whole is warming, the continents on average are warming faster than the oceans, so there is a great body of scientific evidence that would support such an interpretation. The question is how much.”

    ” . . . It’s hard to attribute more than a modest fraction of the event magnitude to [manmade climate change] itself. It could well have made a truly extreme event even warmer,” Dole said.’

    That’s pretty much what the new paper says.
    “Overall, our results indicate that the extreme magnitude of the March 2012 temperature anomalies can be largely explained by natural variability, with an additional contribution from a long-term warming trend of approximately 1°C that is likely due mostly to human influences.”

    Freedman presented Dr Dole’s view as in line with his article, and I think it is. It’s just saying that the meteorological causes were superimposed on a 1° rise. This is a small part of the heat wave excess, but not nothing. That’s the standard scientific view of the effect of AGW on extreme events. Heat waves aren’t different, just apt to be a bit hotter.

  27. Carrick says:

    Nick Stokes:

    Freedman presented Dr Dole’s view as in line with his article, and I think it is. It’s just saying that the meteorological causes were superimposed on a 1° rise. This is a small part of the heat wave excess, but not nothing.

    Since we’re discussing the US, actually the SE US has actually been cooling since the start of the 20th century. See this.

    In particular, the Chicago region has had near neutral temperatures over that period, so AGW could not have played a role in their local temperature extremes.

    You also need to look at trends in daytime high temperatures, rather than mean temperatures, since that is what is relevant for “tagging AGW onto high temperature extremes”.

  28. Nick Stokes says:

    Carrick,
    ” SE US has actually been cooling since the start of the 20th century. See this.”

    You’ve shown a map of June trends. But this was a March heatwave. The March trend map shows a rise pretty much in line with the paper’s 1&deg’C.

  29. Carrick says:

    Good catch. I was thinking summertime weather..

    Here’s March.

    I don’t see Chicago at 1°C there either. You have to go outside of the affected region to find a 1°C increase. And again, this is (tmax + tmin)/2, and I’d expect the trend in maximum temperature to be smaller than what’s shown here.

    I’d rate this as a case where AGW contributions aren’t very important, if present at all, in the observed extreme weather.

  30. barry says:

    NOAA: Another ‘AGW caused heat wave’ is actually just natural variation

    Not according to the paper cited.

    Overall, our results indicate that the extreme magnitude of the March 2012 temperature anomalies can be largely explained by natural variability, with an additional contribution from a long-term warming trend of approximately 1C that is likely due mostly to human influences.

    That would seem to be in line with the mainstream view. Heatwaves will still happen, but the underlying long-term warming will make them hotter. The articles from last year don’t diverge from this view either. Quoting some of them (The Pop Science link is wrong),

    While natural factors are contributing to this warm spell, given the nature of it and its context with other extreme weather events and patterns in recent years there is a high probability that global warming is having an influence upon its extremity.

    “Having an influence”

    …scientific researchers who specialize in studying the role climate change plays in influencing individual extreme events… said global warming may have made March’s soaring temperatures more likely to occur, although they add that natural variability has played a key role as well.

    “Natural variability… key role”

    What is the controversy here?

  31. dbstealey says:

    barry,

    As Jeff Glassman points out above:

    “…to the extent that AGW exists, it is not measurable. What would be news is the first bit of evidence of the existence of AGW.”

    CO2 may cause some minor global warming. But at current concentrations it is too small to measure, so you are getting your knickers in a twist over something so minor that it can be completely disregarded as inconsequential.

    Don’t you have anything better to do?

    If you’re at a loss as to something constructive to do, may I suggest writing comments on various blogs attacking the anti-environment, anti-wildlife, bird-chopping windmills we see going up everywhere? That would certainly be a lot more productive than endlessly arguing about something that is too small to even measure.

    Also, the NOAA position you quoted is nothing but their opinion; their belief. There is NO verifiable, testable, measurable, quantified AGW occurring. NOAA is simply speculating, and they should label it as such.

  32. barry says:

    …the NOAA position you quoted is nothing but their opinion

    It comes from the same paper Anthony quoted to make his point in the article. All I’m showing is that it is consistent with last year’s views, contrary to the headline above.

  33. Tim Folkerts says:

    “NOAA: Another ‘AGW caused heat wave’ is actually just natural variation”

    Really, Anthony?

    Near as I can see, the scientists a year ago thought that the heat was was natural variation plus a bit of AGW (although they carefully stated that analysis needed to be done to confirm that). Well, now that the studies have been done, the scientists now think {{{ drum roll }}} that the heat was was natural variation plus a bit of AGW.

    It is one thing to argue the relative merits of AGW — there are lots of issues there that are clearly up for debate. It is another thing altogether to leave out one key point from the earlier reports and leave out the opposite key point from current reports, and then say the two have opposite conclusions.

  34. ghl says:

    If storm, hurricane, and heat wave frequency are within historical norms, how does “more likely” manifest?
    I think we have a new definition of likely.
    This is professional baffle-gab.

  35. Climatism says:

    Reblogged this on CACA and commented:
    NOAA found 2012 US drought not caused by global warming. Now Obama’s same Govt agency finds 2012 heat-wave not caused by anthropogenic climate change?!
    Phone line busy, both times when Obama dialled NOAA for updates or…?!

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