Sunday, July 29, 2012

Where BEST Should Have Stopped

It seems BEST is getting into trouble with their claims of attribution instead of their reconstruction of the temperature data. What they've done sounds like -- well, like what a bunch of physicists would do, not what climate science needs (and what climate scientists do).

Andrew Revkin quotes Judith Curry (who declined to be a co-author on the BEST results being announced today):
Their latest paper on the 250-year record concludes that the best explanation for the observed warming is greenhouse gas emissions. Their analysis is way oversimplistic and not at all convincing in my opinion.

There is broad agreement that greenhouse gas emissions have contributed to the warming in the latter half of the 20th century; the big question is how much of this warming can we attribute to greenhouse gas emissions. I don’t think this question can be answered by the simple curve fitting used in this paper, and I don’t see that their paper adds anything to our understanding of the causes of the recent warming. That said, I think there are two interesting results in this paper, regarding their analysis of 19th century volcanoes and the impact on climate, and also the changes to the diurnal temperature range.
Physicists tend to see the world as made up of simple physical systems (particles and fields), and when the physical systems get too complicated (atoms beyond Helium, molecules, galaxies), they hand them off to the chemists and astronomers for analysis. Heisenberg et al found the laws of quantum mechanics; but then they didn't get much beyond calculating the spectra of He2+ before saying, yeesh, that's hard, enough of that! So they turned to the structure of the nucleus and the laws of quantum electrodynamics and partied it up there.

What does x-ray crystallography say about the structure of DNA? Don't ask a physicist! Pure physicists don't do that kind of stuff. Sure, they could if they really wanted to. But by and large they really don't want to, and it's not what they're good at.

Attributing climate is more like figuring out the structure of DNA than it is like figuring out the laws of quantum mechanics -- simple curve-fitting ("exponentials, polynomials") doesn't cut it. In fact, it makes you look kind of foolish. If it were that simple climatologists would have done it in the 19th century (and, of course, they've all tried curve-fitting on the second week of their research, then hid those papers in a bottom drawer.) That's exactly why they scratch around for all the clues they can get, and why they ruin their youth build climate models. (Sure, CO2 is one of the big factors, which is already enough to be worried about our large emissions; but there is usually a lot going on.)

BEST did a great job reconstructing the temperature history of the planet (assuming their work passes peer review, at least). Perhaps they should have stopped there.


Mike Mangan said...

What caused the warming from 1750 until whenever co2 took over? Why was the rate of warming, when it did warm, the same under natural circumstances as human emission induced? What percentage of modern warming is human induced? If co2 is primarily responsible for modern warming how do we know that natural forcings stopped? Does it mean that earth's temps would have steadily cooled if Man had died out before the Industrial Revolution?
This is a prima facie argument against CAGW, Dave. When you look at the whole thing you just can't see a big difference between natural warming and supposed co2 warming. Combine that with a satellite record showing a 15 year plateau in temps and you can see why it's so easy to be skeptical. Your thoughts?

David Appell said...

I have no idea what the "C" in "CAGW" means -- it's not a scientific term.

And there are no known natural factors that could have caused the long-term warming calculated by BEST. No one said natural forcings have "stopped," but that they do not explain most of the warming.

Unknown said...

David: The 'C' in "CAGW" signifies the word "Catostrophic". Mike Mangan is attempting to bring something into the argument that was never studied. the only thing that was studied was past temperature changes and their relation to carbon dioxide. There was no study about how hurricanes will react to a warming atmosphere or how rainfall will increase in a warming atmosphere in some parts of the world while in others there will be longer and drier droughts.

And Mike, as David stated the natural factors have not stopped. Natural factors have actually been causing cooling which in turn has masked some of the warming attributable to the rise in greenhouse gases. According to Milankovitch theory we should have been in a cooling trend for 6000 years now. The Sun has been declining in output for 50 years now. We have been in the negative or neutral phase of the PDO since 1998. Those must be combined with the heat retention of greenhouse gases for the overall picture.

Dano said...

And Mike, as David stated the natural factors have not stopped. Natural factors have actually been causing cooling which in turn has masked [etc]

Poor Mike has FUD to spread to make a living. He can't be bothered with explanations.



Unknown said...

It is hard to imagine what it would take to convince Judith. Manhattan under water, I suppose.