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These Stairs Aren’t Climbing — They’re Flat!

The views expressed are those of the author and are not necessarily those of Scientific American.


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There’s been quite a bit of reaction to the article published by the Economist, dated March 30, suggesting that there may be evidence that climate change has been overestimated. The data that concern those cheering the Economist writers is an apparent lack of warming since 1998 or so. Here’s a video package the Economist put together about the piece. Now first it’s worth pointing out that the Economist writers are far from cheery, to a one noting that climate change is happening, it’s clearly related to human activity, and it requires action. But those cheering the Economist cherry pick their data, focusing only on one piece that quotes NASA Goddard Institute for Space Studies head James Hansen noting “the five-year mean global temperature has been flat for a decade.” Fortunately the nice thing about these webs is that as soon as people start making claims based on such quotations, responses emerge including clarifying data and context. This one, by Weather Underground cofounder Jeff Masters, does a masterful job of explaining how the data show the climate warming in something like a series of steps, as clearly presented by the site Skeptical Science.

Each cherry-picked step looks flat

Masters goes into thorough detail, showing how volcanic eruptions, El Nino, La Nina, and other variations create short-term temperature trends that flatten or shift the graph for a while. But then the long-term trend reasserts itself and it’s up one more step. Skeptics are basically acting like North Carolina legislators and the sea level, measuring what they like and leaving the rest out. “I’ve measured from the lip to the back of the tread, and for more than a foot, this supposed ‘stairway’ is completely flat, not rising at all! Explain that away, stair alarmists!” Such a flat spot began in about 1998 with a strong El Nino heating things up, which was followed by many years of La Nina, keeping things comparatively cool. Despite the spate of hottest-years-on-record since then, the graph has remained flattish. This video explains the whole thing

But if you do a moment’s thinking you’ll recognize that if we’re having the hottest years on record during the weather patterns that keep us cool, uh-oh. And if you want to see what real science looks like, this update presents updated data that render the video as produced slightly inaccurate. It includes a new graph that very slightly weakens the force of the video, though not in a statistically significant way. But the creators wanted to make sure the best possible data was out there. Which is what scientists do.

Anyhow. Whenever, as the Economist did, a usually reasonably reliable publication produces work that makes me question a core scientific belief, I like to check it out to make sure new evidence hasn’t suddenly emerged to change that belief. So it hasn’t, and so I don’t need to change my belief. Skeptical Science, by the way, remains a great site to go to when the turkeys have got you down. Between them and Weather Underground, it’s pretty hard not to get the kind of data-based explanation for anything climate-based that’s worrying you.

Scott Huler About the Author: A writer who commonly explores science, culture, and the relationship between the two. Follow on Twitter @huler.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. curmudgeon 12:32 pm 04/5/2013

    Hah! Sci-Am questioning the scientific accuracy and wont for speculation of another publication? Pot, kettle!

    Link to this
  2. 2. Leroy 12:44 pm 04/5/2013

    I’m curious how ocean temps are considered (or not considered) in these kind of analysis. When we say “global temperature mean” … that’s just talking about atmospheric temps, correct? Seems to me that if the heat content of the ocean is steadily rising, the lack of rising atmospheric temps is fool’s gold. The ocean is the thermostat, and it’s getting slowly turned up… opening the windows (el nino, increased rainfall, soot, etc) might cool things down for a bit, but the elephant in the room is the ocean temps.

    That said, it’s still a reason for optimism… if the ocean is capable of sequestering heat more rapidly than we’ve been modeling… it might buy us a little more time. Time to transition to cleaner energy. Time to relocate our agricultural areas. Time for species to adapt, etc.

    Link to this
  3. 3. RSchmidt 12:48 pm 04/5/2013

    @curmudgeon, did you read the article?

    Link to this
  4. 4. RSchmidt 1:05 pm 04/5/2013

    @Leroy, ocean temps are part of the equation and they have been increasing even at great depths. Ultimately atmospheric temps affect ocean temps and vice versa so you can’t have a situation where only one is affected. That doesn’t mean they move in lock step but the trends will be similar.

    The point of the article is to illustrate the denier tactic of cherry picking. They select the samples that support their claims and deny everything else. Deliberate misinformation campaigns reveal the underlying goal which is to delay action. They want to buy themselves more time but not to prepare for environmental change rather to consolidate wealth and transition power. These people would gladly sacrifice the planet to line their wallets and thanks to a scientifically illiterate population they are succeeding.

    Link to this
  5. 5. Leroy 2:20 pm 04/5/2013

    @RSchmidt Guess I could’ve read that Economist article. : )

    “What is going on below that—particularly at depths of 2km or more—is obscure. A study in Geophysical Research Letters by Kevin Trenberth of America’s National Centre for Atmospheric Research and others found that 30% of the ocean warming in the past decade has occurred in the deep ocean (below 700 metres).” (from the Economist)

    That’s kinda what I was pondering. If the deep ocean is warming faster than expected then it’s pulling more heat that would otherwise end up at the surface. As far as I can tell this “flat decade” is only considering surface temps. I believe this chart includes total ocean warming…

    This chart might clarify: http://tinyurl.com/d4seu2s

    From that perspective the surface temps of the last 10 years don’t seem all that surprising… but the overall trend is clear.

    Link to this
  6. 6. Charles Hollahan 2:53 pm 04/5/2013

    The video is excellent, for those who are unable to read a graph it does it for you…

    Link to this
  7. 7. SAReadersince67 4:13 pm 04/5/2013

    Thank you, Mr. Huler for this report. When I read/viewed the Economist feature, I wondered if the factors you have ellucidated where considered. Furthermore, when we see a departure from trend in a dynamic system wherein the causative factors are largely persistent, surely a scientific minded person would ask if there may be a multiplicity of variables complicating the data. Also, there is the possibility that responses to factors are lagged in some systematic way. Taking out the effects of known causes of climate variability seems to lay bare the trend to anthropomorphic global temperature increase, but there may yet be discovered some “back damming” of the effects on green house gases, which may lead to future periods of accelerated warming.

    Anyway, the whole phenomenon of human induced atmospheric warming by burning of fossil fuels seemed at least theoretically determined many decades ago. If we were to see some departure from trend on the down side, it would call in to question the fundamentals of chemistry, which seems far less likely than that global warming caused by rising CO2 and other green house gases is a reality.

    Link to this
  8. 8. alan6302 4:49 pm 04/5/2013

    Scientific America is ignoring the other planets in the solar system.

    Link to this
  9. 9. Carlyle 2:37 am 04/6/2013

    There is a trove of data stretching back thirty years from over three thousand Argos buoys that bob up & down from the surface to three thousand feet. they simply do not show warming at depth. of course if you tweak the data, anything is possible. For more unreliable data you can not beat sceptical science:
    Lewandowsky, Cook claim 78,000 skeptics could see conspiracy survey at Cooks site where there is no link
    http://joannenova.com.au/
    March 30th, 2013

    Link to this
  10. 10. SAReadersince67 3:47 pm 04/6/2013

    OK, so in my previous post, I meant “anthropogenic”.
    Tnks

    Link to this
  11. 11. sault 1:41 am 04/7/2013

    Carlyle, if there is a “treasure trove” of data, then why don’t you link to it? Don’t try to sucker people towards some denier website without even TRYING to sound legitimate first!

    Link to this
  12. 12. Carlyle 3:05 am 04/9/2013

    I had not revisited this site & just found your comment. for one who claims to be so knowledgeable I can not believe you were unaware of the Argo data. Here it is: https://www.bodc.ac.uk/data/online_delivery/argo/

    Link to this

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