The Agatha Christie approach to global warming

  • 14 Feb 2011, 09:51
  • Christian

David Archer in his book 'the Long Thaw' uses this analogy to explain the difficulties of arguing that recent climate change is merely the result of natural cycles in the Earth's climate:

"Think of it like a murder mystery. The butler (CO2) was caught with a smoking gun in his hand in the room with the dead guy. There is a lot of public interest in this case, so your boss is driving you nuts writing reports and such like; everything has to be pinned down on this one. Yes, the bullets came from the gun. Yes, the gun was purchased by the butler. Everything checks out."

"But now your partner Bob argues that it was really the chauffeur did it. Actually, you find out that the chauffeur was at his sister's wedding on the other side of town for the whole time and lots of people saw him.. But Bob says, maybe there is some way he did it but you're just not smart enough to figure it out. OK, you retort, but if Bob is going to convict the chauffeur, he has to think of a way to unconvict the butler. He would have to come up with an innocent explanation for the butler's smoking gun, and the bullets and all that."

Archer's point is this: If you want to argue that most recent climate change has not been caused by humans putting greenhouse gases into the atmosphere, but by something else, your theory has to explain not only the warming planet, but also explain away all of the evidence that suggests it's largely human-induced CO2 which is to blame.

This has been on my mind, because Skeptical Science has responded to a challenge thrown out by climate-sceptic scientist Roy Spencer, based at the University of Alabama. Spencer is described by Skeptical Science as "one of very few climate scientists who remain unconvinced that most of the recent global warming has been caused by humans". ( Real Climate has also discussed his role in the climate debate.)

Spencer recently wrote on his blog:

"Show me one peer-reviewed paper that has ruled out natural, internal climate cycles as the cause of most of the recent warming in the thermometer record."

Skeptical Science argues that:

"This challenge is problematic … the fact that research has not ruled out a hypothesis does not mean the hypothesis necessarily has any validity.  For example, there have been no peer-reviewed papers ruling out leprechauns as the cause of most of the recent global warming, either.  But perhaps more importantly, our understanding that humans are causing global warming is not based on just one scientific study, but rather a very wide range of scientific evidence."

They go on:

"Skeptics like Spencer and [fellow sceptic-scientist] Lindzen believe that the default assumption should be one which requires that a very large body of scientific evidence is wrong. The only alternative hypothesis they have put forth cannot explain the many empirically-observed "fingerprints" which are consistent with human-caused global warming.  Although Spencer's unspecified "natural internal cycle" hypothesis has not been explicitly disproved, there is a very low likelihood that it is correct.  For this reason, we should operate under the assumption that humans are causing dangerous global warming - an assumption which is supported by a very large body of evidence - until the skeptics can provide solid reason to believe that this scientific theory is wrong."

In other words, it was the butler. (Or as the IPCC would say, it's "very likely" the butler dunnit.)

The Skeptical Science piece is here.

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