So if the models are so hopelessly riddled with errors and uncertainty that an anthropogenic radiative forcing signal cannot be distinguished from noise, or if the total magnitude of the warming attributed to humans is one-tenth to one-hundredth of the error or uncertainty ranges, why are those who dare question the degree to which humans affect the Earth’s climate branded as “deniers” of science?

Kenneth Richard,

Saturday, 21 January 2012

Picture for the Climate Classroom Wall: the apparent impotence of airborne CO2 as a driver of warming

The C3 website has used the latest data published by NOAA's National Climatic Data Center to produce the above chart.

Two adjacent 50 year periods are compared side by side, for overall global temperature rise, and overall ambient CO2 rise:

1912 to 1961:   the temperature increase is 0.52C, the CO2 increase, 18ppm.
1962 to 2011:   the temperature increase is 0.41C, the CO2 increase, 74ppm. 

Whatever the overall effect of the CO2 increase is on global temperature, it is clearly not a dominating factor causing warming.  The atmosphere is behaving as if the extra CO2 does not really matter very much at all since the temperature jumps are similar, whilst the CO2 jumps are clearly not.

Steven Goddard at Real Science describes a similar result, using the periods 1975 to 2008, and 1915 to 1944.  These periods also are believed to show a modest warming of similar size, but the former period had a far larger increase in CO2 attributed to it (54ppm compared to 9ppm).  These periods are of interest because they appear in Email 2234 of the Climategate set– as highlighted by Tom Nelson

(Edited 22 Jan 2012 to delete last two sentences in the original Note for being inessential)