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Global Warming - How to Lie with Statistics

I usually try to avoid getting involved in debates about global warming these days - it tends to suck up huge amounts of my research time when I try to get things right while the other "debaters" just slap together a few random links they got from Google within half a minute. However, sometimes I just cannot resist, and the following examination is the latest result.

It started out with this debate. I was given a link to this article by one Christopher Monckton as evidence that global temperatures in the last decade had not in fact increased, but decreased. So I took a look at the provided graph and was fascinated - by the sheer amount of blatant manipulation I encountered:



Fortunately, the author provided a source for his data - the HadCRUT3 data set. So I sat out to recreate the graph, and managed to do so.:



First of all, while the used data did show a cooling trend, my linear fit (done with GNUPlot) produced a cooling of

-0.00156427 °C/month.

Extrapolated for an entire decade, like the author has done, this would translate into:

-0.00156427*12*10 °C/decade = -0.1877124 °C/decade

This is not even half as much as the 0.4 °C/decade the author claimed. But wait, it gets better!


It seems that the author of the article, has deliberately started using the 2001-2008 HadCRUT3 data set with one of the hottest months in this period - which happens to be January 2002 (so he didn't use any 2001 data after all, despite the caption of the graph) - and then ended using the data with the very coldest month in this period, which was the abnormally cold January 2008:



With such a self-selected data set to confirm his bias, is it any wonder that he got a significant cooling trend?

And what's with using only six years and one month to extrapolate a "cooling per decade" value - especially when the same data set goes back for far more than a decade and a real value could be easily calculated?

No wonder that this guy apparently doesn't have any peer-reviewed papers to his name - with such blatant attempts at cooking the data, the reviewers would laugh him out of town.

So what would temperature trends over the last decade actually look like?

Well, I've used the same data set for the period from April 1998 to March 2008 (the last entry), and the following graph is the result:



The linear fit produced a warming of 0.0349044 °C for the entire decade - not much, but as this long-term graph generated from the same data set shows, 1998 was an abnormally warm year while the last winter was particularly harsh:



To sum it up, global temperatures have indeed increased during the last decade, if not as strongly as in the time before that. We will have to continue to watch the long-term trends of global temperatures - and be wary of anyone who attempts to cook the data for his own agenda.

Comments

jimboboz
Apr. 17th, 2008 12:49 am (UTC)
Monckton recently presented a paper making somewhat different claims; that there was warming, but not as much, as reported here. As the article described it,

"When they applied their revised factor to the effect of greenhouse gases, the temperature rise was about a third of that predicted by the IPCC."

So in the paper Jurgen quotes, Monckton claims there's global cooling happening; in a more recent paper, he claims there's warming but only a third as much as stated.

That's the problem with the denialists, they can't even keep their stories straight.
"There's cooling!"
"There's warming, but not much!"
"There's warming, but it's nothing to do with us!"
"There's warming, it's to do with us, but it'll be good for us!"

Regarding the recent paper, I recently had to write something,

The paper mentioned is by three blokes. All the information below is in the public domain, easily found by half an hour of googling and using your common sense. sourcewatch is a good site for that.

Viscount Christopher Monckton is a "retired business analyst", degree in Classics and diploma in journalism. He used to work for Thatcher. He was a bit brassed off some years back when they reformed the House of Lords, and all but some 100 I think had to be elected, he didn't get in so he's decided he doesn't like the new system. He once said that everyone with AIDS should be locked up. On climate change he babbles about the fucking hockey stick, claims it's solar forcing that does most global warming (which is funny since solar irradiance has declined over the past few decades) but the world isn't warming anyway, and even if it is it'll be good for us, and also he talks about this blackbody radiation equation which he reckons they didn't apply right. Yes, he is a bit muddled about what he believes.

Monckton's a member of the "Science and Public Policy Institute", run by this loon Robert Ferguson, ExxonMobil gives Ferguson $50,000 a year to run it.

Dr Vincent Gray is this old old kiwi bloke, at least he has a degree in Physical Chemistry. He's one of the founders of the NZ Climate Science Coalition (AGW deniers). They're buddies with that old fraud and friend of tobacco Dr Fred Singer, and the Lavoisier Group. I'm not sure who they're funded by.

Dr David Evans is a member of the Lavoisier Group, which was founded by Ray Evans an exec from Western Mining Corp. Like Fred Singer, Evans is a PhD in electrical engineering, though he did his MSc in maths. Evans used to work for the Australian Greenhouse Office, of all places. He worked on modelling carbon uptake in forests. It was his model which told the Aussie PM that Australia could meet its Kyoto obligations just by stopping Queensland landclearing. He says he quit "for personal reasons unrelated to my views on global warming." I think he's on a couple of mining company boards, but on a casual websearch it's hard to tell as it's not exactly an uncommon name.

Also mentioned in the article is Roy Spencer, a guy who works on microwave satellites. He's a member of the Heartland Institute, which is funded by Phillip Morris to help them in showing the world how safe cigarettes are. They've had the better part of a million bucks from Exxon-Mobil. He's also a member of the George C. Marshall Institute, which receives funding from Exxon-Mobil and defence contractors.

So with this paper challenging the level of climate change, we're seeing four different denier groups get together, which is both interesting and scary.
(Anonymous)
Dec. 22nd, 2009 05:56 am (UTC)
Climategate emails
First, there is no scientific consensus. Over 30,000 scientists in the U.S. alone signed a petitition. The man-made global warming movement has little credibility due to the lies and manipulation of data being found over and over again. The nail in the coffin was the climategate email scam. Lies lies and more lies. The media is biased. It is a political movement with a dark history. Study history and politics and you will be surprised at what you learn. Maurice Strong, Henry Kissinger, Obama et al aren't actually nice people. All the best.

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