Gavin Schmidt and Michael Mann
Today we witnessed a rather curious event in the US Senate. Possibly for the first time ever, a chair of a Senate committee, one Senator James Inhofe (R-Oklahoma), invited a science fiction writer to advise the committee (Environment and Public Works), on science facts–in this case, the facts behind climate change. The author in question? None other than our old friend, Michael Crichton whom we’ve had reason to mention before (see here and here). The committee’s ranking member, Senator James Jeffords (I) of Vermont, was clearly not impressed. Joining Crichton on climate change issues was William Gray of hurricane forecasting fame, Richard Benedick (a negotiator on the Montreal Protocol on ozone-depleting chemicals), and David Sandalow (Brookings Institution). As might be expected, we paid a fair bit of attention to the scientific (and not-so-scientific) points made.
Many of the ‘usual suspects’ of half-truths and red herrings were put forth variously by Crichton, Gray, and Inhofe over the course of the hearing:
- the claim that scientists were proclaiming an imminent ice age in the 1970s (no, they weren’t),
- the claim that the 1940s to 1970s cooling in the northern hemisphere disproves global warming (no, it doesn’t),
- the claim that important pieces of the science have not been independently reproduced (yes, they have),
- the claim that global climate models can’t reproduce past climate change (yes, they can)
- the claim that climate can’t be predicted because weather is chaotic (wrong…)
and so on.
We won’t dwell on the testimony that involved us personally since the underlying issues have been discussed and dealt with here before, though we will note that comments from both of us pointing out errors in the testimony were entered into the Senate record by Sen. Barbara Boxer (D-California). Instead, we will focus on the bigger picture.
First, let’s be clear where there is agreement. Climate science doesn’t deal in certainties – it deals in probablities and the balance of evidence. We agree with Crichton’s statement that ‘Prediction is not fact’. That certainly doesn’t mean, however, that projections of possible future climate changes are not meaningful or useful, as Crichton claims.
Crichton seemed to imply that “prediction” (such as that provided by weather or climate models) is useless in the decision making process. (As an aside, we wonder how Gray, who is largely known for prediction of hurricane behavior based on (statistical) modeling, felt about this?). We fundamentally disagree. All science is about observation, understanding and prediction. When those predictions work, you make new predictions. When they don’t, you revisit the observations, attempt to improve your understanding of the underlying processes, and make a new prediction. And so on. In the case of climate models, this is complicated by the fact that the time scales involved need to be long enough to average out the short-term noise, i.e. the chaotic sequences of ‘weather’ events. Luckily, we have past climate changes to test the models against. Even more to the point, successful climate predictions have actually been made in past Senate hearings. The figure at the end of this comment by Jim Hansen demonstrates that projections of global mean climate presented in a 1988 senate hearing (17 years ago) have actually been right on the money
Others panelists attempted to combat the onslaught of disinformation. Sandalow sensibly suggested that the National Academy of Sciences be used to inform the Senate on where the consensus of the science is, and Benedick made some excellent points about how legislation can be successful in the face of scientific controversy and uncertain predictions. However, none of that provided as good theater as the other witnesses.
A highlight of the session was Gray making one particular statement that he may be asked to defend (at least financially): “I’ll take on any scientist in this field …. I predict that in 5 to 8 years the globe will begin to cool” (1:10:00 on the video). This would appear to be a direct call to those “global warmers” (see also here, here and here) who are trying to get contrarians to put their money where their mouths are (with very limited success). We eagerly await developments!
Inhofe ended the hearing by declaring his desire to ‘sit back and look at [this] in a non-scientific way’. We think he already has.