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Convenient Untruths

Filed under: — group @ 15 October 2007 - (Svenska) (Español)

Gavin Schmidt and Michael Mann

Update 10/18/07: We are very disappointed that the Washington Post has declined to run an op-ed placing the alleged 9 ‘errors’ in a proper scientific context, despite having run an extremely misleading news article last week entitled “UK Judge Rules Gore’s Climate Film Has 9 Errors”.

Last week, a UK High Court judge rejected a call to restrict the showing of Al Gore’s An Inconvenient Truth (AIT) in British schools. The judge, Justice Burton found that “Al Gore’s presentation of the causes and likely effects of climate change in the film was broadly accurate” (which accords with our original assessment). There has been a lot of comment and controversy over this decision because of the judges commentary on 9 alleged “errors” (note the quotation marks!) in the movie’s description of the science. The judge referred to these as ‘errors’ in quotations precisely to emphasize that, while these were points that could be contested, it was not clear that they were actually errors (see Deltoid for more on that).

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The “Have you stopped beating your wife yet (yes/no)” questionnaire

Filed under: — david @ 15 October 2007

I got an email Climate Expert Survey today from DemandDebate.com, a creation of Steve Milloy. Milloy has practiced to deceive before in the climate arena, and his junkscience.com, claiming to debunk the junk science of others, is actually a terrific source of specious deception in its own right. This survey looks like another such initiative. (Note added later: If you get a copy of this, post a comment or send us an email. We’d like to keep track.)

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CO2 equivalents

Filed under: — gavin @ 11 October 2007

There was a minor kerfuffle in recent days over claims by Tim Flannery (author of “The Weather Makers”) that new information from the upcoming IPCC synthesis report will show that we have reached 455 ppmv CO2_equivalent 10 years ahead of schedule, with predictable implications. This is confused and incorrect, but the definitions of CO2_e, why one would use it and what the relevant level is, are all highly uncertain in many peoples’ minds. So here is a quick rundown.

Definition: The CO2_equivalent level is the amount of CO2 that would be required to give the same global mean radiative forcing as the sum of a basket of other forcings. This is a way to include the effects of CH4 and N2O etc. in a simple way, particularly for people doing future impacts or cost-benefit analysis. The equivalent amount is calculated using the IPCC formula for CO2 forcing:

Total Forcing = 5.35 log(CO2_e/CO2_orig)

where CO2_orig is the 1750 concentration (278 ppmv).

Usage: There are two main ways it is used. Firstly, it is often used to group together all the forcings from the Kyoto greenhouse gases (CO2, CH4, N2O and CFCs), and secondly to group together all forcings (including ozone, sulphate aerosols, black carbon etc.). The first is simply a convenience, but the second is what matters to the planet. Many stabilisation scenarios, such as are being discussed in UNFCCC negotiations are based on stabilising total CO2_e at 450, 550 or 750 ppmv.

Magnitude The values of CO2_e (Kyoto) and CO2_e (Total) can be calculated from Figure 2.21 and Table 2.12 in the IPCC WG1 Chapter 2. The forcing for CO2, CH4 (including indirect effects), N2O and CFCs is 1.66+0.48+0.07+0.16+0.34=2.71 W/m2 (with around 0.3 W/m2 uncertainty). Using the formula above, that gives CO2_e (Kyoto) = 460 ppmv. However, including all the forcings (some of which are negative), you get a net forcing of around 1.6 W/m2, and a CO2_e (Total) of 375 ppmv with quite a wide error bar. This is, coincidently, close to the actual CO2 level.

Implications The important number is CO2_e (Total) which is around 375 ppmv. Stabilisation scenarios of 450 ppmv or 550 ppmv are therefore still within reach. Claims that we have passed the first target are simply incorrect, however, that is not to say they are easily achievable. It is even more of a stretch to state that we have all of a sudden gone past the ‘dangerous’ level. It is still not clear what that level is, but if you take a conventional 450 ppmv CO2_e value (which will lead to a net equilibrium warming of ~ 2 deg C above pre-industrial levels), we are still a number of years from that, and we have (probably) not yet committed ourselves to reaching it.

Finally, the IPCC synthesis report is simply a concise summary of the three separate reports that have already come out. It therefore can’t be significantly different from what is already available. But this is another example where people are quoting from draft reports that they have neither properly read nor understood and for which better informed opinion is not immediately available. I wish journalists and editors would resist the temptation to jump on leaks like this (though I know it’s hard). The situation is confusing enough without adding to it unintentionally.

Oregon Institute of Science and Malarkey

Filed under: — group @ 10 October 2007

A large number of US scientists (to our direct knowledge: engineers, biologists, computer scientists and geologists) received a package in the mail this week. The package consists of a colour preprint of a ‘new’ article by Robinson, Robinson and Soon and an exhortation to sign a petition demanding that the US not sign the Kyoto Protocol. If you get a feeling of deja vu, it is because this comes from our old friends, the Oregon Institute of Science and Medicine and is an attempt to re-invigorate the highly criticised 1999 “Oregon Petition“.

The article itself is just an update of the original article, minus an author (Baliunas), with a switch of Robinson children (Zachary’s out, Noah is in), but with a large number of similar errors and language. As in previous case, this paper too, is not peer reviewed.

Since this is a rehash of the previous paper plus a few more cherry-picked statistics of dubious relevance, instead of tediously going through the whole thing ourselves, we are going to try something new – an open source debunking.
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Sustainability: A Nobel Cause

Filed under: — stefan @ 9 October 2007

I would like to share with you some impressions from a remarkable event taking place today and tomorrow in Potsdam: 15 Nobel laureates are meeting with top climate and energy experts and politicians to discuss global sustainability. You can follow the event with its presentations here, with a couple of hours of delay. More »


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