Comments on: M&M at the NAS Panel

By: Steve Sadlov

Steve Sadlov — Thu, 16 Mar 2006 23:51:16 +0000

RE: #33. Why the smear? You try to imply that there are no scientists or other technically trained people participating here? Why does the idea that scientists, technically trained people, as well as others who have an interest, are not in accordance with the orthodoxy? That is your real issues, isn’t it? Oh, we must be on the take from Exxon, that’s it / sarc. The fact is, from my perspective, most skeptics tend to be more traditional in our approach – strict following of the scientific method, respect for noise, awareness of the limitations of measurement systems and the even greater uncertainties inherent in the use of so called proxy data. As usual, those who politicize science to promote the Radical Green agenda conveniently ignore what we all supposedly learned as Freshmen!

By: Rod

Rod — Thu, 16 Mar 2006 16:32:03 +0000

Steve – you should have an email from me!

By: Steve McIntyre

Steve McIntyre — Thu, 16 Mar 2006 14:35:50 +0000

Rod, can you email me the article?

By: John Davis

John Davis — Thu, 16 Mar 2006 14:31:44 +0000

Re #40
Presumably that will be the assertion that high variability in the past can only mean dangerously high sensitivity to CO2 change, since we know that solar variability for the past 1000 years has been negligible.
I’ve commented before that the past influence of solar variability seems to me to have been discounted in the last ten years, I do sometimes wonder whether this has actually been due to the status of the Hockey Stick.

By: Rod

Rod — Thu, 16 Mar 2006 11:33:33 +0000

There’s an article about the Hockey Stick debate in this weeks New Scientist: “Grudge Match: The crucial evidence for global warming is fatally flawed – or so we are told”

The article is written by Fred Pearce and it ends with the usual twist (i.e. it means it’s going to get worst than even we thought:-) ) , with a quote from Briffa – ” ‘Greater past climate variations imply greater future climate change,’ he says. From this perspective, it would be most worrying if all the hockey sticks really are wrong.”

I’m not sure whether the last bit of the quote is from Briffa or Pearce as the bit in quotes ends with a comma?

By: Pat Frank

Pat Frank — Tue, 14 Mar 2006 21:06:59 +0000

#38 Indeed, your point is right Bruce, and I’ve made it elsewhere on Steve’s blog several times. The critique is the same. The GCMs are not adequate to support a claim that rising CO2 has caused the apparent 0.6 C rise in global mean temperature. In science, data only take their meaning within the context of an unambiguous and falsifiable theory. The GCMs do not meet that standard and, if anything, the theoretical understanding of tree ring width seems poorer than that of climate.

To be more specific, atmospheric CO2 has a positive thermal effect, but the energy fluxes and feedbacks of Earth climate are too poorly constrained to know whether the effect of, e.g., doubling CO2 from the 1900 value, will produce a discernable effect on atmospheric temperature.

In Bart’s example, the logic most starkly is this: ‘Assume these tree rings reflect temperature. Therefore, these tree rings reflect temperature.’ Not only that, but the assumption that certain trees are following current temperature is then projected back into the centennial past to include previous temperatures. It’s circularity redux.

By: bruce

bruce — Tue, 14 Mar 2006 20:45:29 +0000

Re #37: To pound your point Pat, doesn’t that reasoning also apply to the relationship between rising CO2 levels and (supposedly) rising temperatures (supposedly until the temperature series can be disclosed, checked and confirmed) until a causal relationship is proven?

By: Pat Frank

Pat Frank — Tue, 14 Mar 2006 20:23:42 +0000

#36 – Bart you miss the point. If one doesn’t know why tree rings happen to diverge from temperature here, one also does not know why they happen to trend with temperature there. The underlying mechanisms determining tree ring width remain undetermined. One cannot choose out data that happen to trend with temperature, when it is not known whether it is temperature that is inducing the trend. You’re assuming causality where one can only defend association.

By: bart s

bart s — Tue, 14 Mar 2006 19:16:59 +0000

re 35. To repeat, only the high lat. series of Cook et al. show divergency in last 50 years, hence a number do not, and show a good fit to temperature. The divergence is between mid and high lats. In MWP this divergence was not there. Good paper to read for insight, if that is what one is after.

By: Pat Frank

Pat Frank — Tue, 14 Mar 2006 18:26:18 +0000

#33 Bart, if one doesn’t know why tree rings diverge in the present, one doesn’t know why they did not in Medieval times. The result is that with uncontrolled variables affecting the data throughout, the use of tree rings to model temperature is rendered entirely unreliable. This is basic experimental science. You must be able to extract the variable of interest from your data, with no hidden and confounding variables. Blinding oneself to accidental but accomodating correspondences is a sure way to disaster.