Can it really be two years since we last visited the “cosmic ray theory” of climate change? According to Power Line’s state-of-the-art search engine it has. Anyway, just weeks before the release of the next IPCC report, there’s a fresh study of the “Svensmark Hypothesis,” the controversial theory that changes in the level of cosmic particles bombarding the Earth’s atmosphere have significant effects on cloud formation, which is a much more important (though evanescent) variable in temperature than greenhouse gases.
WattsUpWithThat has a good plain-English summary of the latest publication on this hypothesis out of Europe. You can download the underlying paper here (PDF file), though it is very technical, as can be seen from the abstract:
In experiments where ultraviolet light produces aerosols from trace amounts of ozone, sulfur dioxide,and water vapor, the relative increase in aerosols produced by ionization by gamma sources is constant from nucleation to diameters larger than 50 nm, appropriate for cloud condensation nuclei. This result contradicts both ion-free control experiments and also theoretical models that predict a decline in the response at larger particle sizes. This unpredicted experimental finding points to a process not included in current theoretical models, possibly an ion-induced formation of sulfuric acid in small clusters.
Got that? I don’t either, but since, as our previous report on this two years ago showed, this has some traction in what might be called the “mainstream” climate science community at the CERN lab in Switzerland, it would seem fit for serious consideration by the climate establishment. So will the next IPCC report due in three weeks take account of the Svensmark Hypothesis, or ignore it?