Gerry North will be back in Boulder on Nov 2, 2007 delivering a lecture at CIRES at 4 pm on climate over the past 1000 years. The announcement says
A variety of evidence points to a gradual cooling of the planet from about 1000 AD to a few hundred years ago when it bottomed out. Over the last one hundred and fifty years the planet has been warming at an unusual if not unprecedented rate. The published evidence caused a groundswell of activity among climate change skeptics culminating in congressional hearings featuring battling assessments. A cadre of skeptics continues to joust at the consensus of scientific assessment that the climate is warming and that its cause is anthropogenic. Climate will continue its course of warming over this century modulated by our choices and the political will to curb greenhouse gases.
“Joust” seems to be the word de jour on the Island.
In addition to the NAS panel report itself, anyone interested in going to the lecture might be interested in a couple of presentations following up on the NAS panel report, discussed last year. Richard Monastersky of the Chronicle wrote an article on the report; he then had an interesting online “colloquy”, at which I asked a couple of questions (Gavin Schmidt also asked a question) – CA discussion
I asked the following question which seems quite prescient in light of our recent study of bristlecones at Almagre:
Question from Stephen McIntyre:
The NRC Panel stated that strip-bark tree forms, such as found in bristlecones and foxtails, should be avoided in temprature reconstructions and that these proxies were used by Mann et al. Did the Panel carry out any due diligence to determine whether these proxies were used in any of the other studies illustrated in the NRC spaghetti graph?
The answer, of course, is that the Panel carried out no such due diligence. In fact, all 4 studies used in their spaghetti graph used bristlecones – indeed 2 of the 4 even used Mann’s PC1. Here’s North’s answer:
There was much discussion of this matter during our deliberations. We did not dissect each and every study in the report to see which trees were used. The tree ring people are well aware of the problem you bring up. I feel certain that the most recent studies by Cook, d’arrigo and others do take this into account. The strip-bark forms in the bristlecones do seem to be influenced by the recent rise in CO2 and are therefore not suitable for use in the reconstructions over the last 150 years. One reason we place much more reliance on our conclusions about the last 400 years is that we have several other proxies besides tree rings in this period.
If an engineer held this position and then used strip bark forms in a bridge design, he’d lose his licence. But hey, this is climate science.
There is also an online seminar in which North discusses the NAS panel report and the events leading up to it. His comments about me are somewhat schizophrenic – in some places, he talks well of me, and, we’ve got along decently whenever we’ve met and in email; and in other places, he makes quite condescending remarks. He gets a lot of facts wrong – he refers to this blog saying that it was started because we couldn’t get published. Actually the blog started after our GRL and EE2005 articles were published and largely in response to the severe non-peer reviewed criticism being launched against us as a preemptive strike by Michael Mann. This seminar was discussed last year here. Listening to it again, there’s some interesting material that I didn’t note up last year. I described the remarks that really caught my attention as follows:
At minute 55 or so, he describes panel operating procedure by saying that they didnt do any research, that they just took a look at papers, that they got 12 people around the table and just kind of winged it. He said thats what you do in these sort of expert panels. Obviously I suspected as much, but its odd to hear him say it.
When you put that together with their failure to do any due diligence whatever on use of strip bark trees in multiproxy reconstructions, it’s pretty disconcerting. It would be worth asking my colloquy question about strip bark one more time, specifically inquiring about the use by the NAS panel in their spaghetti graph of 4 studies all using strip bark trees and 2 of which used Mann’s PC1, without assessing the impact of the strip bark trees on these reconstructions.