Oh no, not again

RP Sr's one-man kamikaze attack against the IPCC continues. RPs point appears to be that the IPCCs forcing-since-1750 of +1.6 W/m2 is not compatible with a current imbalance of about 0.85 W/m2. Sadly RPs link to the Hansen paper concerned is currently broken so I'm somewhat guessing what this figure is; I think its probably the earths current radiative imbalance. RP calls it the "the total observed radiative forcing and feedback" but I think he's got this wrong. If it was, it would need to have a start date on it; and since its based on deep ocean temps it would be tricky to start from 1750.

As far as I can tell, RPs calcs are all wrong: you need to add WV etc feedbacks to the +1.6; then subtract the increase in OLR from the ~0.8 oC temperature rise, to end up with a small (+ve) imbalance.

I'm pretty sure RP has said this before, and Gavin corrected him before , but can't find a ref to that. Can anyone point it out?

Oh, and one of RPs refs is his earlier post, which features the rather unfortunate "Assuming the Lyman et al data is accurate..." which of course it wasn't. RP really ought to correct the earlier post.

[Update: Hank found a and b(!) -W]

[Update: RP Sr replies here. At some point I'll reply to the reply... -W]

More like this

> said ... and corrected

Maybe ...


http://www.climateaudit.org/?p=1202 (comment 146)
"... I agree with Gavin Schmidt that Prof Pielke Sr has made an error. ..."

[Hank - I expected better of you... don't you know you're not allowed to link to CA, let alone read it :-)? -W]


By Hank Roberts (not verified) on 30 Nov 2007 #permalink

As I read this, the argument is rather the same as diagnosing climate sensitivity from climate heat content. Gavins argument in this respect seem to be that ocean data should not yet be used as it would be to premature - let's first see if the data is robust. Pielkes argument is that data indicates that climate sensitivity is somewhat smaller than most models (and, especially those that the IPCC use) give. In analog, if positive feedbacks dominate then climate sensitivity is high, and vice versa if negative feedbacks dominate.

In essence this boils down to: if climate is near equilibrum, then current radiative forcings will be small, and small or no increases in ocean heat content should be measured, unless of course we keep on adding new forcings. If so, past temperatures can be used to diagnose the climate sensitivity. If climate is not near equilibrum then changes in ocean heat content should be able to predict the ratio between positive and negative feedbacks.

I would appreciate an attempt to perform those calculation on your own, to se what you come up with.

(And a personal request: I don't know what you mean with "kamikaze" but I think such language will be detrimental to debate. Please consider...)

[K, in this context, means a combination of doomed to failure and injurious to the person making the attempt. RP has just forgotten some of the terms, which is why he gets the wrong answer -W]

What's more interesting is how carbon dioxide, methane and nitrous oxide all moved together in SPM.1 However, on the subject of .85 vs 1.6, it appears to me that Hansen is saying .85 for 2005 (.75 for the decade) and the IPCC 1.6 +/- 1 for 2005. I am unsure about what the argument is here; these don't appear to be numbers based on the exact same information. And Hansen's guess of .85 is in the range of the IPCC's guess, so what is the issue?

[You, like RP, are forgetting the feedbacks and T^4. But you're not a profssional climatologist so have an excuse -W]

Paragraph explaining forcing/feedback graph:

The understanding of anthropogenic warming and cooling influences on climate has improved since the TAR, leading to very high confidence that the global average net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6 [+0.6 to +2.4] W m-2 (see Figure SPM.2).

Footnote defining forcing:

Radiative forcing is a measure of the influence that a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system and is an index of the importance of the factor as a potential climate change mechanism. Positive forcing tends to warm the surface while negative forcing tends to cool it. In this report, radiative forcing values are for 2005 relative to pre-industrial conditions defined at 1750 and are expressed in watts per square metre (W m-2). See Glossary and Section 2.2 for further details.

Graph paragraph title

Figure SPM.2. Global average radiative forcing (RF) estimates and ranges in 2005 for anthropogenic carbon dioxide (CO2 ), methane (CH4 ), nitrous oxide (N2O) and other important agents and mechanisms, together with the typical geographical extent (spatial scale) of the forcing and the assessed level of scientific understanding (LOSU). The net anthropogenic radiative forcing and its range are also shown. These require summing asymmetric uncertainty estimates from the component terms, and cannot be obtained by simple addition. Additional forcing factors not included here are considered to have a very low LOSU. Volcanic aerosols contribute an additional natural forcing but are not included in this figure due to their episodic nature. The range for linear contrails does not include other possible effects of aviation on cloudiness.


The decadal mean planetary energy imbalance, 0.75 W/m2, includes heat storage in the deeper ocean and energy used to melt ice and warm the air and land. 0.85 W/m2 is the imbalance at the end of the decade

By Jason Harold (not verified) on 17 Dec 2007 #permalink

Roger Pielke has a new article at Climate Science, repeating the argument that if data is correct then the relative importance of different climate drivers needs to be reassesed. Comments?

[Not really sure which one you mean. That there are more important drivers than CO2 is a constant theme of his -W]