CERN Studies Connection Between Cosmic Rays and Climate Change

Layzej writes with this quote from Nature: "For a century, scientists have known that charged particles from space constantly bombard Earth. Known as cosmic rays, the particles are mostly protons blasted out of supernovae. As the protons crash through the planet's atmosphere, they can ionize volatile compounds, causing them to condense into airborne droplets, or aerosols. It is hypothesized that clouds might then build up around the droplets — possibly affecting the Earth's climate. To find out, [Jasper] Kirkby and his team are bringing the atmosphere down to Earth in an experiment called Cosmics Leaving Outdoor Droplets (CLOUD). ... Early results seem to indicate that cosmic rays do cause a change (abstract). The high-energy protons seemed to enhance the production of nanometer-sized particles from the gaseous atmosphere by more than a factor of ten. But, Kirkby adds, those particles are far too small to serve as seeds for clouds."

Re:No doubt

[Rei]

Obligatory graph [photobucket.com]. That shows the different climate forcings, their medians, and their error bars. What the current study is working on is cloud formation. You'll notice that cloud formation has a pretty huge error bar; we're not very good at modelling it, and there's a lot of research to try to improve that. But note that even if you assume the best-case cooling effect from clouds, rather than the median (or the worst, for that matter), you're still not cancelling out the other forcings. Note the error bars on the net result at the bottom.

Re:Lack of

[Layzej]

I would think the crucial information would be if there had been a significant change in the cosmic ray flux over the last century and how that correlates with a change in cloud coverage or density.

Studies in that area have been inconclusive. The IPCC AR4 summarizes:

There appears to be a small but statistically significant positive correlation between cloud over the UK and galactic cosmic ray flux during 1951 to 2000 (Harrison and Stephenson, 2006). Contrarily, cloud cover anomalies from 1900 to 1987 over the USA do have a signal at 11 years that is anti-phased with the galactic cosmic ray flux (Udelhofen and Cess, 2001)

Here are some more recent studies which also have been unable to show a definitive link:

Calogovic, J., et al. (2010): Sudden cosmic ray decreases: No change of global cloud cover. Geophysical Research Letters, 37, L03802, doi:10.1029/2009GL041327.

Erlykin, A.D., et al (2009a): On the correlation between cosmic ray intensity and cloud cover. Journal of Atmospheric and Solar-Terrestrial Physics, 71, 17-18, 1794-1806, doi:10.1016/j.jastp.2009.06.012.

Kulmala, M., et al. (2010): Atmospheric data over a solar cycle: no connection between galactic cosmic rays and new particle formation. Atmospheric Chemistry and Physics, 10, 1885-1898, doi:10.5194/acp-10-1885-2010.

Pierce, J.R., and P.J. Adams (2009): Can cosmic rays affect cloud condensation nuclei by altering new particle formation rates? Geophysical Research Letters, 36, L09820, doi:10.1029/2009GL037946.

Sloan, T., and A.W. Wolfendale (2008): Testing the proposed causal link between cosmic rays and cloud cover. Environmental Research Letters, 3, 024001, doi:10.1088/1748-9326/3/2/024001.

Re:More Anti-AGW Commenters

[ScentCone]

So, to be clear, it's your position that one of the things that Bush said in the context of that particular discussion, makes all of the other facts - and everything else said about them at the time - suddenly no longer true?

My guess is that you're so deep into partisan US politics to ever be able to understand how the rest of the world looks at your actions.

My guess is that you're so pleased to let other people pay in blood and money to deal with many of the world's bad guys that the only way you can make yourself feel better about it is to pretend you resent them for it. It's craven of you, but I get it.