Comments on: Hansen Simplified

By: David Lewis

David Lewis — Fri, 11 Jul 2008 19:06:36 +0000

Do any of you think it is wise to continue on changing the composition of the atmosphere as civilization is doing?

By: Steve McIntyre

Steve McIntyre — Fri, 29 Dec 2006 01:10:16 +0000

#23. I apologize about the figures. When we changed servers, most of the figures took a walk. I’m trying to track John A down to locate them.

By: McCall

McCall — Thu, 28 Dec 2006 23:24:56 +0000

re: 12 “… Sargasso Sea cores …”
Dr Keigwin’s study included forams, as well.

By: DAV

DAV — Thu, 28 Dec 2006 21:31:58 +0000

FWIW: I don’t know about anyone else but I can’t see any of the figures on this page or any of the Hansen posts. When I tried accessing them directly, I get a “Forbidden Access” message. Without the figures, it’s hard to follow some of the text.

By: Steve McIntyre

Steve McIntyre — Wed, 04 Oct 2006 05:17:44 +0000

In Warm Pool terms 0.3 deg C is the total amount of Warm Pool warming in the last century according to just-published D’Arrigo et al, Paleoceanography, 2006:

Monthly gridded SST data were extracted from the Kaplan et al. [1998] data set for the warm pool region in the vicinity of Indonesia and averaged over the area bounded by the coordinates 15S–5N; 110–160E (i.e., an average of 40 grids, Figure 1). This area was selected because it encompasses much of the warm pool region associated with the Indonesian Low (a center of action of the ENSO system), while also optimizing the signal between the SST and proxy data. …Warming is evident over the past century in both the instrumental and reconstructed warm pool series (Figure 3a, both series increase by 0.2 deg C/100 years over the 1856–1992 period). Similarly, warming has been observed for Indonesia [Harger, 1995] and over the tropics (30S–30N) as a whole [Wilson et al., 2006] (Figure 3c), although over the same period, the rate of increase of mean tropical annual SSTs is marginally greater at 0.3 deg C/100 year

By: Nicholas

Nicholas — Wed, 04 Oct 2006 05:09:08 +0000

Plus 0.3 degrees may be a small number but that’s something like 50% of the warming we’ve experienced over the last 100 years. So it certainly does not seem insigificant to me, esp. if you’re going to compare it to said globally averaged instrumental temperature series.

Of course they probably didn’t have that in mind when they did their study, but it just goes to show you how careful you have to be when citing other people’s studies and using them for purposes such as this comparison.

By: Jeff Weffer

Jeff Weffer — Wed, 04 Oct 2006 03:17:03 +0000

Looks like a “hockey stick”, another hockey stick that is.

By: John S

John S — Tue, 03 Oct 2006 20:36:47 +0000

“…only serves to change the absolute SST value.”

Which is precisely the thing Hansen was using it for. Sheesh!

By: Steve McIntyre

Steve McIntyre — Tue, 03 Oct 2006 18:21:00 +0000

David Lea writes:

Hi Steve: the adjustment based on the Dekens 2002 equation is quite small at
the location and depth of Hole 806b (~0.3 deg in SST), and, in the absence
of time-varying dissolution corrections, only serves to change the absolute
SST value. For that reason we chose to maintain the earlier calibration to
be consistent with the published data in the 2000 study.

Sincerely, David

By: James Erlandson

James Erlandson — Tue, 03 Oct 2006 17:55:51 +0000

The relationship between Mg/Ca and water temp where the plankton live is still under study.
Further calibration of the Planktonic Foraminiferal Mg/Ca Paleothermometer: Sediment Trap Results from the Cariaco and Guaymas Basins

Our preliminary results indicate the Mg/Ca ratio in G. ruber accurately records the observed seasonal temperature cycle … with the estimated temperatures typically being within 1.25 degrees C of the observed values.

http://www.agu.org/meetings/fm02/fm02-pdf/fm02_PP51A.pdf#search=%22%22shell%20chemistry%22%20mg%2Fca%20%22shell%20formation%22%22

From the Ocean and Climate Change Institute

We are setting up a laboratory culturing system that will let us grow deep-sea benthic foraminifera under controlled physical and chemical conditions. We will then use this system to carry out the first culture-based calibration of the benthic foraminiferal magnesium/calcium (Mg/Ca) thermometer.