Aerosols did not cause global cooling...

An interesting point to bring up on the climate change debate.

Those members of the Church of Climatology (TM) have one response to climate skeptics who point out that despite CO2 emissions increasing in the period of 1940 to 1970 globe temperatures cooled:

CO2 doesn't match the temperature record over the 20th C. True but not relevant, because it isn't supposed to. The programme spent a long time agonising over what they presented as a sharp temperature fall for 4 decades from 1940 to 1980 (incidentally their graph looks rather odd and may have been carefully selected; on a more usual (and sourced!) plot the "4 decades of cooling" is rather less evident). They presented this as a major flaw in the theory, which is deeply deceptive, because as they and their interviewees must know, the 40-70 cooling type period is readily explained, in that the GCMs are quite happy to reproduce it, as largely caused by sulphate aerosols.

The only problem is that if you look at the wikipedia entry linked by said poster, it shows the graph below.

If you notice on this graph, the effect of man made sulphate emissions has had cooling effect on the atmosphere increasing at a relatively constant rate since the year 1900. (See purple line)

There are no dramatic long term drops starting in the year 1978 when the EPA implemented a ban on CFC aerosols, or dramatic long term increases in the 1930's when CFC aerosols were first produced.

So, by simple logic, we are left again with the fact that CO2 emissions don't match the temperature record over the 20th century. By the very models referenced by this member of the Church of Climatology (TM) sulphate emissions have had an increasing cooling effect on global climate with no appreciable shifts related to CFC aerosol use.

Further evidence of constant increases in man made sulphate emissions is given here:

Much of the sulfate aerosol in the atmosphere derives from the oxidation of sulfur dioxide produced in the combustion of fossil fuels. Industrial activities are not the only source: Natural aerosols--mostly dust, sea salt, and other compounds of marine origin--do exist, but they have remained in nearly constant concentrations in the atmosphere for a long time. However, the man-made version has increased dramatically since about 1950.

Two points I need to make at this point:

1) if the global climate change poster above really believes that it is "not relevant" that the CO2 emissions record does not directly correlate with the temperature record over the 20th century, why does he feel the need to reaffirm that the discrepancy in the record can be readily explained?

2) By his own reference man made sulphate aerosols do not affect appreciably the global climate over the 1940 to 1970 period more than they do today. So the excuse of CFC aerosols is very much a lame one.

In the end it still means that from 1940 to 1970 the earth cooled yet CO2 emissions rose. This is still a valid point that members of The Church of Climatology (TM) cannot explain.