Good auditing – and a good result.

Maybe she didn’t notice that Mann08 had proxies showing an MWP in China and Latin America. She seems to be trying to validate Mann’s previous hand-wave, that of the EWP, but he’s already moved on to a new idea – that of the smallish, worldwide MWP.

It seems extraordinary that the current skeptical theories of Roy Spencer, Bill Gray, A. Tsonis and others, viz. that current warming is shown to be related to phases of the PDO/AMO/etc/intersections-thereof, are brushed aside by the Team without comment, and the next thing we hear is that, “ooh, let’s say the entire MWP was caused by the NAO!”

My understanding of the IPCC2007 report is that they were able to marginalise the atmospheric heating from ocean oscillations by arguing that the current positive phases of the ocean oscillations (AMO, PDO, NAO, …) could only have been caused or amplified by human-caused global warming.

Can anyone tell me what is different about the MWP? If the ocean oscillations aren’t strong enough in principle to cause this awfully massive 0.3 C temperature increase (or whatever the actual number is) since 1976 how can it be considered as the several hundred year cause of the MWP?

Also does anyone know what the standard rebuttal to Spencer’s PDO, Tsonis’s superposition theory (or whatever it’s called), and similar theories?

I’ve also replotted the figures and e-mailed Valerie, and we agree that in Figure S1 the detrended data was incorrectly used. This figure is the only place where this occurs; the NAO reconstruction uses the non detrended data of Proctor et al (2002) as in my earlier correspondance. I hadn’t spotted the mistake in Figure S1 at that time. Apologies for any confusion that has caused.

At present, I haven’t been able to figure out exactly what sequence of smoothing and re-scaling is used to yield their NAO reconstruction and am not in a position to comment one way or another on this statement.

I’m a little bit annoyed at the haphazardness – all too typical – but I’m more appreciative of Baker at least taking the trouble to acknowledge that there was an error. I hope that they issue an erratum.

For further analysis, I’ll use the non-detrended data which Baker to his credit archived and took the trouble to annotate the archive after the above discussion.

Given what I have been reading on this website for the past few years, that strikes me as a perfect analogy.

Now, I have not proven that personally, its just what I have frequently read. All things considered, it seems physically reasonable to me.

For the record, I am an AGW skeptic. But, I would certainly welcome an additional 2C in Ohio USA (this month its a couple C colder than normal).