Global Warming, Getting Colder?


David Legates, the director of the Center for Climatic Research at the University of Delaware, in an article published by the libertarian-leaning policy group National Center for Policy Analysis, casts doubt on one of the favorite proofs of human-induced global warming. Excerpts from the press release:

At issue is what is commonly referred to as the "hockey stick"—a widely circulated image that depicts a 700-year period where temperatures remained relatively constant followed by the last 100-plus years where temperatures have shot upwards. The "hockey stick," created by researchers Michael Mann of the University of Virginia and Phil Jones of the University of East Anglia, is used by the IPCC [United Nations' Intergovernmental Panel on Climate Change ]and environmental activists as proof of human-induced global warming.

The NCPA report cites findings from five independent research groups that have uncovered serious problems with Mann and Jones' methodology and calculations, which call into question any of its conclusions. For example:

— Several researchers found Mann and Jones made errors in the collection and use of varying data from multiple sources, used obsolete data, made incorrect calculations, associated data sets with incorrect geographical locations, inappropriately eliminated specific proxy records that they felt were inaccurate and employed statistical methods that removed long time period trends, such as the widely recognized Medieval Warm Period (about A.D. 800 to 1400) and the Little Ice Age (A.D. 1600 to 1850).

— Mann published a retraction in the June 2004 issue of Geophysical Research, in which he admits underestimating the temperature variations indicated by the proxy data by more than one-third since 1400, which accounts for why he missed the Little Ice Age. Strangely, Mann still argues this considerable error doesn't impact his conclusions.

— Further, Legates found the "blade" (or sudden rise in temperature) of Mann's hockey stick could not be reproduced using common statistical techniques, or even employing the same techniques as Mann and Jones.

Legates' complete essay here.

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  1. “typo” corrected, to correct the correction.

  2. lol.

    Honestly, it’s too bad there aren’t more policy groups that are libertarian learning.

  3. Good with the boxed look. Bad with the small font.

  4. I don’t know, I liked the old look and font better. I definately liked having a seperate window. Having to go ‘Back’ two pages after posting (or even one page after reading) is a bit of a pain.

  5. I like the little box being gone but the new type face is difficult to read. Microscopic, that is.

  6. How can the “blade” represent the “sudden rise in temperature”? The blade is the flat part at the bottom of the hockey stick, and so should represent that idyllic period when it was 70 degrees every day. If a global warmer wants to demonstrate a sudden rise in temperatures, you should give him the “shaft.”

    Matteau!! Matteau!! Matteau!!

  7. I like layout of the comments with the purple to the left. The font and size should be the same as before or the same as the post, IMHO.

  8. You can increase the size of the text on the page. In Mozilla/Firefox, use CTRL-+ to increase it. In Internet Explorer, you can use View > Text Size > and pick a larger one than is currently indicated. I’ve had to do this with Reason pages for a long time, since the articles and H&R always seem to have different font sizes.

  9. Wex, rotate the stick:


  10. So, if you get caught using an illegal stick, it’s two minutes in the sin bin, eh?


  11. Take that stick and shove it where it`s dark and warm,say 98.6 deg. F.

  12. The debate over global warming, causes, etc. is valid.

    What I’m running up against in the Pacific Northwest is this debate getting confused with the overall facts about climate warming on a local scale.

    We certainly have observed climate warming for the West for the past 100 years. 1.5 F mean annual temperature increase over that time period. This warming trend, if continues, will affect the supply of the most important and scarce resource: water.

    You can debate global warming all you want but if the climate trend in the West continues there will probably be a lot less inhabitable territory out here. Either that or the Bureau of Reclamation will be the favorite of every Western senator, again.

  13. trainwreck,

    A valid concern, perhaps, but suppose human intervention has nothing to do with that particular local change? You’d still be stuck with dealing with a fully natural climate change.

    According to the chart on the above link, we’re currently in one of the cooler climate eras in history. Odds are that up is the way the climate will be going, with or without human action.

    I’m all for responsible amelioration of human action on the environment, but we’re going to have to separate that from normal climatic changes.

  14. We all want to believe the world is going to Hell somehow (global warming, crime, gay marriage, Fox TV cancelling “Firefly”–OK that last one is just me). It’s a survival trait; for the sake of our worldview and our psyches we will jump at any percieved harm even when there is no evidence that any harm will occur at all.

    It would be nice to get back to some sort of reasoned debate regarding the environment (Is global warming happening? How much? What will be the effects?) and to find solutions to pollution that don’t involve throwing away our industrial/information based economy. However, as long those who have a political ax to grind get to frame the debate, we’re going ot have to combat scaremongering and apocolyptic scenarios.

  15. trainwreck, your name matches your math.

    And the reduction of water has more to do with human usage of it (more people, more farms) than climactic evaporation taking it away. In the West, conserving water means using up as much as possible rather than just letting it flow. That’s a policy issue, not the interaction of technology and nature.

  16. In a related development, David Appell is “feeling under the weather and taking a few days off” Hey, it’s statistically significant.

  17. We all want to believe the world is going to Hell somehow (global warming, crime, gay marriage, Fox TV cancelling “Firefly”–OK that last one is just me).

    No, it’s not just you. *mourns silently a moment for Firefly ? may the movie be just a new beginning!*

  18. 1. If this summer is an indicator, it’s definitely not getting hotter. This weather is crap. I might as well move to Canada.

    2. Is it a libertarian-learning policy group or a libertarian-leaning policy group. The first has piqued my curiousity.

  19. Brian: I have attended probably a dozen or so conferences at which the Mann data is cited. Just yesterday I was at a conference on “Integrity in Science” put on by the Center for Science in the Public Interest in which an NYU physics professor used the Mann “hockey stick” to prove to the audience that catastrophic man-made global warming was in the works. As computer programmers used to say “GIGO.”

  20. Iconoclast: “leaning,” yes. Type corrected, thanks.

  21. I must be getting old. Is the “comments” font size excessively small to anyone else?

  22. You know, maybe this post is 100% legit, and Ron Bailey is making a valuable contribution to society’s understanding of global warming issues.

    But even a political junkie like me only has so much time and energy to put into researching commentators’ ideas, and after three years, I’ve concluded that the odds of something he highlights being worthwhile are far too low to warrant the investment.

    If you want to change minds, you need to tend to your credibility.

  23. “And the reduction of water has more to do with human usage of it (more people, more farms) than climactic evaporation taking it away.”

    Actually, the biggest drought-related impacts of warming/climate change are likely to be changes in precipitation patterns.

  24. JC: don’t talk about my math until you see it in person!

    More farms? There probably hasn’t been any new farmland devloped in the West since the end of the great water projects in the 1960’s. All the dammed water is appropriated in nearly every river and piss-trickle creek from the Colorado to the Columbia.

    The climate warming in the West is factual, corroborated by many different types of sources. The impacts to the snow pack, the origin of all the water around here, are well documented.

    Yes it’s possible to make do with less, and water policy in the West for 150 years has directly discouraged conservation.

    If this trend holds steady, it’s gonna be tough to sustain what’s already built, and accomodating growth will be a series of hard choices.

  25. Strangely, Mann still argues this considerable error doesn’t impact his conclusions.

    It’s called weaseling. Mann makes this argument in a very less quantitative way. Bye bye, real science. Hello, eco law advocacy.

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