The 8008 1764

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In the reference above Prof. Jaworowski does not mention 13C depletion in the ice core data. Among other things, he takes issue with measurement difficulties with accurate dating of recent CO2 content of the Siple ice cores. The research he cites was performed prior to 1986. The problems he points out are well known, and have been addressed by various groups (Barnola et al, Tellus-B, 1991,1999;Battle et al, Nature, 1996; Johnsen et al, Tellus-B, 1995; Jouzel et al, JGR, 1997). Further, we now have many more ice core results from Greenland (GRIP, GISP, NGRIP) Antarctica (Vostok,EPICA) and others. All these support the earlier results.

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This reference states: "Whilst climatologists now think that the warming in the temperature record from some small urban areas is partly the result of the UHI, this is not evidence that Australia's climate has remained unchanged rather than warmed over the past 100 years."

This reference supports the results from Parker, Peterson and others who have found that there is no statistically significant difference in the temperature trend in the surface temperature data from urban as opposed to rural stations.

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Not so: Archer (JGR,2005) finds that there is a very long tail in the CO2 lifetime, that the mean lifetime is on the order of 30Kyr, with 7% of emitted CO2 remaining in the atmosphere as long as 100 KYr. The calculation indicates that it takes a few hundred years for the first 3-4 of emitted CO2 to be absorbed by dissolution in the oceans. However, since the oceans are getting more acidic, they may not oblige us for long, either.

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You are presumably referring to the Soon et al (Climate, 2003) paper. This paper seems to confuse regional, short-lived variation with global, long lived trends. For a detailed discussion, please see Mann et al, Eos,2003.

This reference is to the McIntyre and McKitrick paper challenging the Mann(1998) results. Mann has responded (in Eos, 2003, Nature,2004). Even setting aside the Mann(1998) results, a large body of research exists using borehole data, ground surface temperatures, isotopic measurement, and tree ring data (Briffa et al, JGR,106,2001; Esper et al, Science 2002; Gerber et al, Climate Dynamics, 2003; Gonzales-Rouco et al, GRL, 30, 2003; Jones et al, Rev. Geophys., 37,1999; Mann et al, JGR,2003) supporting the Mann(1998) temperature reconstruction.

550ppm is a huge number for the CO2 concentration in the 19th century. Please may i have a cite for this ? I seem to recall that CO2 concentrations then were around 200ppm.

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in some cases; current understanding is that in these cases, something else started the warming process, which were then intensified by CO2.

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I do not debate here your points regarding the futility of the Kyoto protocol. I merely point out that a) Soon et al and McKitrick et al have not convinced their colleagues b) A strong scientific case exists indicating anthropogenic causes of climate change in the twentieth century. (A weaker case has been made by Ruddiman in Climate Change, 61, 2003 and Quat. Sci. Rev., 24, 2005, for even earlier human influences on global climate.)

sidd