On Tue, 18 Feb 2014 07:44:50 -0800 (PST)
matt_sykes wrote:

On Tuesday, 18 February 2014 15:03:27 UTC+1, Graham P Davis wrote:
On Mon, 17 Feb 2014 02:17:28 -0800 (PST)

matt_sykes wrote:



As you all probably know the direct warming effect of doubling CO2

from preindustrial times can be calculated at 1.2 C. This is well

known, there is plenty of data on line on this and there is not

argument about it, it is basic physics.



We do? I don't. But then I supposed it's all changed since I were a
lad.



". . . changes of mean atmospheric temperature due to CO2 [as

calculated by Manabe (1971) on the assumption of constant relative

humidity and fixed cloudiness] are about 0.3C per 10 percent change
of

CO2 and appear capable of accounting for only a fraction of the

observed warming of the earth [sic] between 1880 and 1940. They
could,

however, conceivably aggregate to a further warming of about 0.5C

between now and the end of the century."



That's from "Understanding Climate Change - A Program for Action"

published in 1975 (March).



As for the forecast of a 0.5C rise in temperature by the end of the

century, it was actually 0.48C (using 11-year smoothing). Pretty
damn

close, I'd say.



Taking the longer view, a 3C rise for a doubling of CO2 would
account

for a 1.03C rise in temperature from 1866 to 2007 (mid-points of

11-year means). The actual rise was 0.87C.


Nearer 0.6 C
http://www.woodfortrees.org/plot/had...m:1866/to:2007


Following anomalies are based on 1951-80 normal (or 1901-2000, same
thing).

11-year mean centred on 1866 is -0.28.
11-year mean centred on 2007 is +0.59

Care to do the sums on that and tell me whether your answer is nearer
0.6C or 0.87C?



--
Graham P Davis, Bracknell, Berks. Mail: 'newsman' not 'newsboy'.
"Welcome to the year of the whores. People around the globe celebrate."
- BBC News subtitle