No (statistical) warming since 1995? Wrong

Yes, I’m still on vacation. But I couldn’t resist a quick response to this comment (and the subsequent debate):

BBC: Do you agree that from 1995 to the present there has been no statistically-significant global warming

Phil Jones: Yes, but only just.

Here is the global temperature data from 1995 to 2010, for NASA GISS and Hadley CRU. The plot comes from the Wood for Trees website. A linear trend is fitted to each series.

Both trends are clearly upwards.

Phil Jones was referring to the CRU data, so let’s start with that. If you fit a linear least-squares regression (or a generalised linear model with a gaussian distribution and identity link function, using maximum likelihood), you get the follow results (from Program R):

glm(formula = as.formula(mod.vec[2]), family =
                       gaussian(link = "identity"),
    data = dat.2009)

Deviance Residuals:
      Min         1Q     Median         3Q        Max
-0.175952  -0.040652   0.001190   0.051519   0.192276  

Coefficients:
              Estimate Std. Error t value Pr(>|t|)
(Intercept) -21.412933  11.079377  -1.933   0.0754 .
Year          0.010886   0.005534   1.967   0.0709 .
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

(Dispersion parameter for gaussian family taken to be 0.008575483)

    Null deviance: 0.14466  on 14  degrees of freedom
Residual deviance: 0.11148  on 13  degrees of freedom
AIC: -24.961

Two particularly relevant things to note here. First, the Year estimate is 0.010886. This means that the regression slope is +0.011 degrees C per year (or 0.11 C/decade or 1.1 C/century). The second is that the “Pr” or p-value is 0.0709, which, according to the codes, is “not significant” at Fisher’s alpha = 0.05.

What does this mean? Well, in essence it says that if there was NO trend in the data (and it met the other assumptions of this test), you would expect to observe a slope at least that large in 7.1% or replicated samples. That is, if you could replay the temperature series on Earth, or replicate Earths, say 1,000 times, you would, by chance, see that trend or larger in 71 of them. According to classical ‘frequentist’ statistical convention (which is rather silly, IMHO), that’s not significant. However, if you only observed this is 50 of 1,000 replicate Earths, that WOULD be significant.

Crazy stuff, eh? Yeah, many people agree.

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Open Thread 5

Open Thread 4 is about to spool off the BNC front page, after 700+ comments, so it’s time to kick off a new one.

The Open Thread is a general discussion forum, where you can talk about whatever you like — there is nothing ‘off topic’ here — within reason. So get up on your soap box! The standard commenting rules of courtesy apply, and at the very least your chat should relate to the broad theme of the blog (climate change, sustainability, energy, etc.). You can also find this thread by clicking on the Open Thread category on the left sidebar.

To add some grist to the new discussion mill, I provide three interesting extracts:

On scepticism, from Bertrand Russell, extracted from the ‘Introduction to his ‘Sceptical Essays’ (1928):

I wish to propose for the reader’s favorable consideration a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine is this: that it is undesirable to believe a proposition when there is no ground whatever for supposing it true.

First of all, I wish to guard myself against being thought to take up an extreme position. … [Pyrrho] maintained that we never know enough to be sure that one course of action is wiser than another. In his youth, … he saw his teacher with his head stuck in a ditch, unable to get out. After contemplating him for some time, he walked on, maintaining that there was no sufficient ground for thinking that he would do any good by pulling the old man out. … Now I do not advocate such heroic scepticism as that. I am prepared to admit the ordinary beliefs of common sense, in practice if not in theory. I am prepared to admit any well-established result of science, not as certainly true, but as sufficiently probable to afford a basis for rational action.

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The gentle art of interrogation

How do you dig down to the core of a person’s beliefs? Can you really hope to influence ‘the unpersuadables’ (a term recently coined by George Monbiot)? Is it worth arguing science and empirical evidence with ‘non-greenhouse theorists’ (you know, the really way-out-there kooks, who won’t even acknowledge that CO2 traps and re-emits infrared radiation)? Should we bother talking up nuclear engineering triumphs like ‘passive safety’ and ‘total actinide burning’ with anti-nuke zealots (you know, the ones who just know that atomic energy is bad)?

I’ve argued elsewhere that, in the greater (global) scheme of things, it doesn’t really matter that such ideologically straight-jacketed people exist. They always will. Rather, Hansen (and others on this blog) have argued that powerful vested interests — principally those with a major stake in fossil fuels forever — are far more dangerous. I’d have to agree, especially in the way they are so easily able to use the climate change/nuclear ‘antis’ as their pawns — usually, but not always, inadvertent — to slow the transition to real alternatives to coal, gas and oil (I rank them in that order of danger). But overcoming the influence of these powerful interests will need a lot of political currency, and that can only come by influencing enough sensible but weakly informed sections of society to advocate for the sort of pragmatic action that is in their own best, long-term interest.

Okay, so is there a way to get through to these people — or, perhaps more pertinently, to get others to see through them? Yes, I know of at least one method — I’ve tried it many times, and it works. I call it ‘the gentle art of interrogation’ (although I’m hardly the first to use this term).

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Do climate sceptics and anti-nukes matter? or: How I learned to stop worrying and love energy economics

This is a Discussion Thread, because I really want your feedback. But first, some context.

By late 2008, I was pretty stressed about climate change. Working on the science of climate (and other anthropogenic) impacts on natural systems, as I do, I could foresee potentially insurmountable problems for biodiversity and human civilisation this century. A time of consequences. Things looked grim, unless there was a massive change in attitudes towards energy supply and resource sustainability. This was exemplified by my post on the Olduvai Theory and Paul Gilding’s short essay on “The Great Disruption”. I got really annoyed by ‘climate change sceptics’ because I felt they were undermining our collective will (and political capital) to take effective action, using mostly recycled, pseudo-scientific distractions.

Then, I started to study the energy problem in detail. It was a Damascene conversion, as I came to realise, via the analysis of the real-world numbers rather than hype or spin: (a) the inadequacy of renewable energy as a complete (or even majority) solution to achieving low-carbon future (…and therefore avoiding the worst of climate change impacts), and (b) the comprehensive value of nuclear energy in solving the energy and climate challenges the world now faces, in the race to supplant our dependence on fossil fuels.

At this point, mid- to late-2009, I got really annoyed with anti-nuclear protesters, because I felt that, through their outdated ideology and inexcusable hypocrisy,  they were undermining the collective will (and political capital) needed to pursue a future in sustainable atomic energy. What galled me the most about this was that I felt I was now fighting a war on two simultaneous anti-science fronts — against trenchant ‘fossil fuels forever’ interests (who ironically understood the need for energy security and technological prosperity)  on one side, and hardline ‘nuclearphobes’ (who ironically understood the need for action to avoid serious climate change) on the other.

Now though, I’m much more relaxed about it all. In short, I’ve learned to stop worrying about ‘sceptics’ and ‘antis’ and love energy economics (the real-world outcome, not the academic discipline!). Let me explain briefly, prior to further elaboration in the comments section.

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Monckton vs Brook debate – the video

I’m in Melbourne today with Tom Blees, and tomorrow we’re heading to Sydney to visit ANSTO. Whilst there, Tom will give a talk; I’m delighted to see that some of the regular commenters on BNC will be there (look forward to meeting you John D. Morgan, Ewen Laver and perhaps some others). Details here.

Whilst in Adelaide, Tom Blees gave two talks. His Q&A session at the Royal Institution of Australia was a great success. Head over here to listen to the audio of his chat with Prof. Mike Young, and the subsequent question time. The 2nd event was the ‘nuclear debate’, when Tom and I went head-to-head with Mark Diesendorf (UNSW) and David Noonan (ACF). We (the Environment Institute) recorded this debate in audio format, and Slow TV videoed it (although disappointingly, they missed most of the Q&A, which was where the sparks flew). I’ll post back here when the Slow TV video is up (UPDATE: It’s here).

The nuclear debate was pretty entertaining, although the format really didn’t allow for many important issues to be thrashed out in convincing detail. As others have noted in comments on BNC, Diesendorf took to personally attacking my credentials, which I thought was unprofessional and totally uncalled for. I said as much on the night, but the crowd seemed to be predominantly anti-nuclear, so I guess they were willing to overlook this most dubious of debating ‘tactics’. Still, my opinion of Diesendorf has now hit rock bottom, and I want nothing more to do with him, professionally or otherwise. At least David Noonan stuck to the topic rather than playing the man, even if he basically ignored what Tom and I were saying on the matter of proliferation, availability of weapons-grade plutonium, etc. with IFRs, and instead hammered out his pre-prepared script. Read here for one independent write-up of the debate. If you find others, post links in the comments below.

Then there was the debate I had with Lord Monckton, in Brisbane on Friday 29 January. This was performed in front of 500 suits-and-ties at the Hilton Hotel; needless to say, I was up against a tough crowd! Ian Plimer was a panel member with Monckton, and Graham Readfearn (formerly of the Courier Mail) was my fellow panellist. I took the position of explaining how science deals with uncertainties, and why climate change was a serious risk management challenge (no, I wasn’t arguing for the precautionary principle, despite what Monckton concluded). Readfearn took the line of attacking the credentials of Monckton/Plimer, which was much the same tactic used by Diesendorf in the nuclear debate, and, quite rightly, it didn’t got down well.

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