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Monday, May 30, 2011

“People underestimate the power of models. Observational evidence is not very useful.”

Nasa Cosmic Rays

Andrew Orlowski at the UK Register has an anecdotal account of Downing College’s skeptics-vs-believers mash-up. Ace of Spades pulled the juiciest bit:

In short, the day lined up Phil Jones, oceanographer Andrew Watson, and physicist Mike Lockwood, the latter to argue that the sun couldn’t possibly have caused recent warming. He was followed by the most impressive presentation from Henrik Svensmark, whose presentation stood out head and shoulders above anyone else. Why? For two reasons. The correlations he shows are remarkable, and don’t need curve fitting, or funky statistical tricks. And he has advanced a mechanism, using empirical science [image above], to explain them.

At the other end of the scale, by way of contrast, the Met’s principle research scientist John Mitchell told us: “People underestimate the power of models. Observational evidence is not very useful,” adding, “Our approach is not entirely empirical.”

Yes, you could say that.

Ken Haapala on the history of models vs. empirical evidence

He notes that the opponents of Galileo held the attractiveness of a model to be a kind of evidence that could outweigh against the empirical evidence that Galileo amassed. Worth reading.

Lockwood’s failed argument against a solar explanation

Orlowski on Lockwood:

The strongest argument, according to Lockwood, for the sun not being a driver in recent climatic activity is that “it has been going in the wrong direction for 30 years.”

Hmmm. So as soon as solar magnetic activity passed its peak, when it was still at some of the highest levels ever recorded, these very high levels of solar activity could no longer have caused warming?

As I have noted a number of times, this argument depends on an unstated assumption that, by 30 years ago (by 1980 or so), ocean temperatures had equilibrated to whatever forcing effect the 20th century’s high level of solar activity might be having. Otherwise the continued high level of forcing would continue to create warming until equilibrium was reached, regardless of whether solar activity had peaked yet. (The actual peak seems to have been solar cycle 22, from 1986-96, not 1980, as Lockwood claims.)

When I pressed Lockwood on his implicit equilibrium assumption he justified it by citing evidence that the planet's surface temperature response to solar activity peters out (as measured by decorrelation) within a few years:

Almost all estimates have been in the 1-10 year range.

But decorrelation between surface temperatures and solar activity is very different from equilibrium. All decorrelation is measuring is the rapid temperature response of the upper ocean layer when solar activity rises or falls. That rapid response indicates that the sun is indeed a powerful driver of global temperature, but it says next to nothing about how long it takes for heat to carry into and out of deeper ocean layers.

This was brought out by AGW believers like Gavin Schmidt who are concerned about the energy balance implications of equilibration-speed. In a simple energy balance model, rapid equilibration implies (other things equal) that climate sensitivity must be low. Since belief depends on high climate sensitivity, the rapid equilibration claim cited by Lockwood had to be shot down, which was managed quite successfully (ibid).

In sum, Lockwood’s rapid equilibrium assumption is dead and buried, leaving him no grounds for dismissing a solar explanation for post 70′s warming. I’ll keep an eye out for video of Lockwood’s presentation, but I doubt he mentioned the rapid equilibrium assumption upon which his argument depends.

More punk students

Remember these graduate student “climate scientists,” going all Clockwork Orange for the planet or something:

Sounds like they made an appearance at Downing College too:

The audience had been good enough to heed Howard’s opening advice that “if anybody mentions Climategate, they’ll be evicted”. Nobody ambushed the CRU crew all day – it was all very polite. I noted that the skeptics made a point of listening politely to the warmists, and applauding them all. A group of students and a few others, simply giggled and mocked the skeptics, however from start to finish. One of their tutors (I presume) was in hysterics all day.

Give ‘em an A. They learned their “observational evidence is not very useful” lesson well.

(Posted a couple weeks ago at WUWT. I'm being kind of lackadaisical about updating things here.)

I have to say that I am one of those skeptics that do not believe in those theories about the end of the world by a collision of an asteroid
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