David, Sorry - meant to finish this rather then send.
The formula you use is unintelligible. In between the missing brackets, undefined terms and dimensionaly impossible mathematics (e.g. ln(PPM) - ln(PPM) - degrees K ?) - let's try to see how it works. You estimate the 'observed' (???) global temperature response to a doubling of CO2 (???) as 2.28 degrees K - so your formula is: delta global temperature (doubling of CO2) = 2.28 ln 2 = 1.58 degrees C. I see, not much of a problem at all and consistent with the low end of the models? So we get a temperature increase of 1.58 degrees (K or C whatever) for a doubling of CO2 - but where you have already 'estimated' it as 2.28. Not only circular reasoning but circular reasoning that arrives at an inconsistant answer. The Arrhenius formula is: delta global temperature = gamma X delta forcing = gamma X alpha X ln (CO2/CO1) - where alpha is estimated empirically at 5.35 in Arrhenius' calculation. An empirical result (from laboratory results) I believe and and not related at all to 'so-called' climate sensitivity to doubling of CO2. Calculating gamma is a different exercise. delta forcing = 5.35 ln(380/280) = 1.6 W/m2 - not remarkably the IPCC CO2 forcing for CO2 in the past 130 years. delta T = 0.7 degrees C (observed temperature increase) = gamma X 1.6 => gamma = 0.42 => gamma X alpha = 2.30 - a little different from your 2.28 but essentially the same except arrived at logically and without the leap into dimensional inconsistencies. I define the relationship in terms of temperature observations but wouldn't dream of then correlating to observation. You do see this fundamental problem I hope? I rather think you need to add also other forcings and feedbacks. If it were as simple as you suggest - there would not be a complex problem. And surely you should understand that the 120 year old science of Arrhenius needs to be understood in the light of 21st century physics? You blithely talk about 'well explained' (but undefined) 'internal variability' around 1910 and the mid 1940's - but claim on the basis of simple and misguided calculations that the abrupt 'Great Pacific Climate Shift' of 1976/1977 was driven by CO2. You need to get a wider perspective. I think you should define what you mean by 'internal variability' and then try to explain the underlying physics to yourself - and not simply by naming it as ENSO, the AMO or some other physical manifestation of an abrupt and nonlinear climate oscillation. Cheers Robert On Apr 19, 11:04 am, "David B. Benson" <[email protected]> wrote: > On Apr 16, 5:01 pm, Robert I Ellison <[email protected]> > wrote:> ... > > Major climate shifts around 1910, the mid 1940's, the late 1970's and, > > ... > > Fromhttp://www.realclimate.org/index.php/archives/2010/03/unforced-variat... > we can see that the so-called shifts around 1910s and 1940s are well > esplained as internal variabity while that of the 1970s is driven by > CO2. > > -- > You received this message because you are subscribed to the Google Groups > Global Change ("globalchange") newsgroup. Global Change is a public, > moderated venue for discussion of science, technology, economics and policy > dimensions of global environmental change. > > Posts will be admitted to the list if and only if any moderator finds the > submission to be constructive and/or interesting, on topic, and not > gratuitously rude. > > To post to this group, send email to [email protected] > > To unsubscribe from this group, send email to > [email protected] > > For more options, visit this group > athttp://groups.google.com/group/globalchange -- You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/globalchange
