The good old "1970's cooling" stuff comes up again, this time over at Slate about an article by Chris Mooney. CM blogs about this with "Here We Go Again Over in the "Fray" at Slate, they're having a pointless argument over global "cooling" in response to my recent piece. Will the misinformation ever end?". But in fact, things aren't that bad at all...
Because the comments end up with the right answer: which is to refer to the RealClimate post on the same subject. Excellent.
But re-reading that, and my page http://www.wmconnolley.org.uk/sci/iceage/ I find that one thing is missing, or there only by implication, which is to answer "OK then, so why was there a cooling trend from the 40's to the 70's, if CO2 was increasing?". Which is a fair question. The right answer above answers it about right:
Firstly, the cooling was fairly small, and if it wasn't in the middle of warming periods it probably wouldn't even have been called cooling. The cooling was stronger in the NH (which fits the aerosol explanation), and even there it isn't (in retrospect) nearly as large as some of the datasets of the time seem to have implied.
Secondly, its quite explicable within the standard theory: as usual, its all in the IPCC TAR, specifically SPM and figure 4 and fig 12.7 . Which is to say, its mostly the sulphate aerosols. Those figures can be over interpreted though: as it says elsewhere " These results show that the forcings included are sufficient to explain the observed changes, but do not exclude the possibility that other forcings may also have contributed". Which is to say... that modelling will get better, we may well tighten up these results, and may even discover something unexpected: but its certainly wrong to say the cooling is inexplicable.