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.


So, that's increasing CO2 from 280 ppm to 560 ppm, we expect to get
1.2 C. We are currently at 400.

Nope. We expect a further rise of at least 1.75C from now to 2076 when
we reach 560ppm, assuming a constant rise (based on rate of increase of
last ten years) in CO2 from now on.

--
Graham P Davis, Bracknell, Berks. Mail: 'newsman' not 'newsboy'.
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