> On the contray, k and A were determined by the best fit to the GTA > data, a standard method of estimating parameters. Then the parameter > k is reporteed as OGTR for 2xCO2 being equal to k*ln(2). I don't care > what IPCC AR4, etc., say, this is the observed global temperature > response from the GISTEMP data.> ...
So k (on the right hand side) is determined from the GISSTEMP record of global temperature anomalies? > The formula calculates changes in temperature based on CO2 > > concentrations. > Yes. You then calculate temperature anomolies and correlate the result with the GISSTEMP record? > The Arrhenius formulation is used by the IPCC to derived 'forcing' of > > trace atmospheric gases from empirical data. > > If so, I didn't see it; the big AOGCMs don't use this approximation > being too crude for careful work. Sorry - I was thinking of the TAR - s 6.3.5 - simplified expressions. 4AR endorses the simplified expressions as still being pretty good. Also with the net forcing - 4AR shows other forcings cancelling out as you say. > The US National Academy of Science disagrees - 'Modern climate records > > include abrupt changes that are smaller and briefer than in > > paleoclimate records but show that abrupt climate change is not > > restricted to the distant past.' > So it depends upon the definition of abrupt. Fine. Then I'll say > that the global temperature change since the 1960s is abrupt. It > certainly is already impacting society, irrespective of definitions. 'What defines a climate change as abrupt? Technically, an abrupt climate change occurs when the climate system is forced to cross some threshold, triggering a transition to a new state at a rate determined by the climate system itself and faster than the cause. Chaotic processes in the climate system may allow the cause of such an abrupt climate change to be undetectably small.' http://www.nap.edu/openbook.php?record_id=10136&page=14 > 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
