The Cloud Mystery

The theory of the sun, cosmic rays and clouds effecting Earth's climate. In 2007, Henrik Svensmark and Nigel Calder published a book The Chilling Stars: A New Theory of Climate Change which introduces the theory that cosmic rays "have more effect on the climate than manmade CO2": During the last 100 years cosmic rays became scarcer because unusually vigorous action by the Sun batted away many of them. Fewer cosmic rays meant fewer clouds--and a warmer world.

A documentary film on Henrik Svensmarks theory, 'The Cloud Mystery', was presented by MortensenFilm.dk early in 2008.

Part I


Part II


Part III


Part IV


Part V


Part VI


UPDATE: At Jennifer Marohasey's blog Paul explains the theory in more detail and the attempts to silence and censor the science.

A brief summary of the evidence for a cosmic ray climate link:

Svensmark (1998) finds that there is a clear correlation between cosmic rays and cloud cover. Since the time he first discovered it, the correlation continued as it should (Svensmark, 2007). Here is all the other evidence which demonstrates that the observed solar/cloud cover correlation is based upon a real physical link.

1) Empirical Solar / CRF / Cloud Cover correlation: In principle, correlations between CRF variations and climate does not necessarily prove causality. However, the correlations include telltale signatures of the CRF-climate link, thus pointing to a causal link. In particular, the cloud cover variations exhibit the same 22-year asymmetry that the CRF has, but no other solar activity proxy (Fichtner et al., 2006 and refs. therein). Second, the cloud cover variations have the same latitudinal dependence as the CRF variations (Usoskin et al. 2004). Third, daily variations in the CRF, and which are mostly independent of the large scale activity in the sun appear to correlated with cloud variations as well (Harrison and Stephenson, 2006).

2) CRF variations unrelated to solar activity: In addition to solar induced modulations, the CRF also has solar-independent sources of variability. In particular, Shaviv (2002, 2003a) has shown that long term CRF variations arising from passages through the galactic spiral arms correlate with the almost periodic appearance of ice-age epochs on Earth. On longer time scales, the star formation rate in the Milky Way appears to correlate with glacial activity on Earth (Shaviv, 2003a), while on shorter time scale, there is some correlation between Earth magnetic field variations (which too modulate the CRF) and climate variability (Christl et al. 2004).

3) Experimental Results: Different experimental results (Harrison and Aplin, 2001, Eichkorn et al., 2003, Svensmark et al. 2007) demonstrate that the increase of atmospheric charge increases the formation of small condensation nuclei, thus indicating that atmospheric charge can play an important role (and bottleneck) in the formation of new cloud condensation nuclei.

4) Additional Evidence: Two additional results reveal consistency with the link. Yu (2002), carried out a theoretical analysis and demonstrated that the largest effect is expected on the low altitude clouds (as is observed). Shaviv (2005) empirically derived Earth's climate sensitivity through comparison between the radiative forcing and the actual temperature variations. It was found that if the CRF/cloud cover forcing is included, the half dozen different time scales which otherwise give inconsistent climate sensitivities, suddenly all align with the same relatively low climate sensitivity, of 0.35±0.09°K/(W/m2).

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A cautionary note, when reading things about global warming, ignore the alarmist obligatory reference to a consensus there is no consensus, it exists only in the minds of alarmists. Consensus is not science, testing and proving your hypothesis is. Computer models are not science. And unproven, untested computer models are just exercises in mathematics with absolutely no meaning in the real world. Wikipedia is ripe with these non-sense "consensus declarations" ...