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Does a Global Temperature Exist?

Filed under: — rasmus @ 25 March 2007 - (Português)

Does a global temperature exist? This is the question asked in a recently published article in Journal of Non-Equilibrium Thermodynamics by Christopher Essex, Ross McKitrick, and Bjarne Andresen. The paper argues that the global mean temperature is not physical, and that there may be many other ways of computing a mean which will give different trends.

The common arithmetic mean is just an estimate that provides a measure of the centre value of a batch of measurements (centre of a cloud of data points, and can be written more formally as the integral of x f(x) dx. The whole paper is irrelevant in the context of a climate change because it missed a very central point. CO2 affects all surface temperatures on Earth, and in order to improve the signal-to-noise ratio, an ordinary arithmetic mean will enhance the common signal in all the measurements and suppress the internal variations which are spatially incoherent (e.g. not caused by CO2 or other external forcings). Thus the choice may not need a physical justification, but is part of a scientific test which enables us to get a clearer ‘yes’ or ‘no’. One could choose to look at the global mean sea level instead, which does have a physical meaning because it represents an estimate for the volume of the water in the oceans, but the choice is not crucial as long as the indicator used really responds to the conditions under investigation. And the global mean temperature is indeed a function of the temperature over the whole planetary surface.

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Climate Reporting in Physics World

Filed under: — rasmus @ 23 February 2007 - (Português)

PhysicsWorld cover, Volume 20, no. 2, February 2007 The February 2007 issue of PhysicsWorld contains several articles relevant to climate research, with a main feature article on climate modelling written by Adam Scaife, Chris Folland, and John Mitchell, and a profile on Richard Lindzen as well as an article on geoengineering in the ‘News & Analyses’ section. The magazine also contains an article (‘Living in the greenhouse’) under ‘Lateral Thoughts’ that brings up a bunch of tentative analogies to a wide range of topics completely unrelated to the greenhouse effect in a technical sense, and an editorial comment ‘Hot topic‘, arguing that it would be wrong of PhysicsWorld to ignore those outside the mainstream. To be more precise, the editorial comment devotes a few lines justifying the profile on Lindzen and the report on geoengineering, with a reference to a Feynman quote: “There is no harm in doubt and scepticism, for it is through these that new discoveries are made”. Wise words! Nevertheless, I cannot resist making some reflections.

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Nigel Calder in the Times

Filed under: — group @ 12 February 2007

As a prelude to a new book, Nigel Calder (who was the editor of New Scientist for four years in the 1960s) has written an op-ed for the Times (UK) basically recapitulating the hype over the Svensmark cosmic ray/climate experiments we reported on a couple of month ago (see Taking Cosmic Rays for a spin). At the time we pointed out that while the experiments were potentially of interest, they are a long way from actually demonstrating an influence of cosmic rays on the real world climate, and in no way justify the hyperbole that Svensmark and colleagues put into their press releases and more ‘popular’ pieces. Even if the evidence for solar forcing were legitimate, any bizarre calculus that takes evidence for solar forcing of climate as evidence against greenhouse gases for current climate change is simply wrong. Whether cosmic rays are correlated with climate or not, they have been regularly measured by the neutron monitor at Climax Station (Colorado) since 1953 and show no long term trend. No trend = no explanation for current changes.

WSJ Editorial Board: Head Still Buried in the Sand

Filed under: — group @ 7 February 2007 - (Português)

While the rest of the world has basically accepted the conclusion of the latest IPCC report, one small village still holds out against the tide – the Wall Street Journal editorial board. This contrasts sharply with the news section of the paper which is actually pretty good. They had a front-page piece on business responses to global warming issues which not only pointed out that business was taking an interest in carbon reduction, but the article more or less took as a given that the problem was real. However, as we have pointed out before, the editorial pages operate in a universe all their own.

This would not be of much concern if the WSJ wasn’t such an influential paper in the US. However, the extent of its isolation on this issue is evident from the amusing reliance on the error-prone Christopher Monckton. They quote him saying that the sea level rise predictions were much smaller than in IPCC TAR (no they weren’t), that the human contribution to recent changes has been ‘cut by a third’ (no it hasn’t), and that the Summary for Policy Makers (SPM) was written by politicians (no it wasn’t – the clue is in the name).

Even more wrong is the claim that “the upcoming report is also missing any reference to the infamous ‘hockey stick’ “. Not only are the three original “hockey stick” reconstructions from the IPCC (2001) report shown in the (draft) paleoclimate chapter of the new report, but they are now joined by 9 others. Which is why the SPM comes to the even stronger conclusion that recent large-scale warmth is likely to be anomalous in the context of at least the past 1300 years, and not just the past 1000 years.

Thus on any index of wrongness, this WSJ editorial scores pretty high. What puzzles us is why their readership, who presumably want to know about issues that might affect their bottom line, tolerate this rather feeble denialism. While we enjoy pointing out their obvious absurdities, their readers would probably be better off if the WSJ accepted Jeffery Sachs’ challenge. For if they can’t be trusted to get even the basic checkable facts right on this issue, why should any of their opinions be taken seriously?

Quick pre-SPM round-up

Filed under: — group @ 1 February 2007

Tomorrow is the big day for all IPCC-watchers (and we’ll comment then) but in the meantime here are a few interesting tidbits floating around today.

First off, there are some curious patterns in the whitehouse.gov search engine. It turns out that it has been blocked from returning most results if the search phrase includes “global warming” – even if it’s from the President himself. For instance, searching for “issue of global” gives as top result the President’s Rose Garden speech in June 2001 on Global Climate Change, but searching for “issue of global warming” (which of course is the full phrase used) returns nothing. Hmmm…..

Secondly, Bill Nye (‘the underprepared science guy’) had a rather rough time of it up against Richard Lindzen on Larry King last night – an episode notable only for the regression back to the ‘false balance’ notion that most of the media has been moving away from (sigh…). However, tucked away at the end was a rather confused section, where it appears that Lindzen bet Nye that ice cores don’t have a resolution better than 2000 years. Now this is an odd claim, and an odder thing to bet on, since Greenland cores (GRIP, GISP2) and Antarctic cores (EPICA DML) have sub-annual resolution in many cases for the isotope (temperature) records, and at least decadal resolution (Law Dome, Siple Dome) for the greenhouse gases (CO2, CH4). It’s true that the very longest records (Vostok and Dome-C) have coarser resolution, but surely Lindzen doesn’t think they are the only ones that exist? So, to make up for Nye’s performance, he should at least get a quality bottle of scotch. Bill, let us know if Lindzen pays up!

Finally, there is an excellent article on the sausage making going on in Paris… more on that tomorrow.


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