Svensmark hypothesized that cosmic rays flux affects cloud formation which, in turn, affects climate change.
Astrobiology Web reports:
The problem of the contribution of cosmic rays to climate change is a continuing one and one of importance. In principle, at least, the recent results from the CLOUD project at CERN provide information about the role of ionizing particles in ‘sensitizing’ atmospheric aerosols which might, later, give rise to cloud droplets.
Our analysis shows that, although important in cloud physics the results do not lead to the conclusion that cosmic rays affect atmospheric clouds significantly, at least if H2SO4 is the dominant source of aerosols in the atmosphere. An analysis of the very recent studies of stratospheric aerosol changes following a giant solar energetic particles event shows a similar negligible effect. Recent measurements of the cosmic ray intensity show that a former decrease with time has been reversed. Thus, even if cosmic rays enhanced cloud production, there will be a small global cooling, not warming.
Affect not effect
Thus, even if cosmic rays enhanced cloud production, there will be a small global cooling, not warming.
A very strange statement, since it implies that someone somewhere thinks that cosmic rays cause warming.
Of course GCR’s cause cooling. That is what the proposed Svensmark mechanism is. I am very suspicious given that phrasing that these people are not kosher.
Now all they have to do is explain why the cooling is ‘small’. That is the IPCC position, and is not supported by the data nor simple experience of anyone who has noticed temperature is not just slightly cooler on a cloudy day.
And anyway the correlation of previous solar cycle length and temperature the following decade corresponds to half the temperature rise last century. The GCR hypothesis is the hypothesised mechanism to explain this correlation. If GCR’s are not the reason, this does not change the fact that the solar dynamo was responsible for much of the rise in temperature. And the current slight fall in global temperature as the new solar grand minimum kicks in.
It is a good study, but it does not refute Svensmark directly. It only casts doubts on Kirkby’s assertion that “sulfuric acid vapour is the primary vapour responsible for atmospheric nucleation”.
With such a lot of stuff aloft in the atmosphere, I would wonder wether any experiment with just one or two types of aerosols is really representative.
Looking at the particles already formed for clues about the causes of their formation seems to be a worthwhile effort:
http://hmt.noaa.gov/news/2013/022813.html
although the above publication makes a misstatement about the uniqueness of their observation of spores and pollen as significant factors in cloud formation. There is an earlier work to the same effect:
http://www.scienceagogo.com/news/20090417224545data_trunc_sys.shtml
which is also wrong in claiming priority. I heard it from my grandfather that even in 1930s, people knew it was virtually impossible to find a snow particle that wouldn’t have a spore or something of that nature near its centre.