Friday, April 04, 2008

No Solar Link

All sorts of blogging on this story, re. the apparent refutation of Henrik Svensmark's theory linking solar activity to Global Warming. I can't add much to them, other than noting that the actual paper behind all the fuss is here , if anyone wants to get down and sciency.

In short, Svensmark's theory says that increases in solar activity (measured by sunspot numbers) drives an increase in the force/velocity of the solar wind, which in turn sweeps away Cosmic Ray particles that might otherwise reach Earth's atmosphere. Cosmic radiation in Earth's atmosphere drives ionization, which drives low cloud cover (LCC). Thus, high levels of solar activity mean low levels of sunlight-reflective LCC, from which follows an increase in global mean surface air temperatures (Global Warming).

So states the theory.

What U.K. physicists T. Sloan and A.W. Wolfendale did was to locate short term increases/decreases in CR intensity in existing data sets (Forbush decreases, for example), and look around for corresponding changes in LCC indexes. They didn't find any.

Note that this does not necessarily refute the notion of a correlation (or, more accurately, anti-correlation) between sunspot numbers and LCC. It simply shows that this cannot be caused by atmospheric ionization, as postulated in Svensmark's theory.


Sean Pelette said...

The CLOUD experiments being run at CERN are designed to test that hypothesis. I suggest you wait until they are done in 2010 before declaring there is no solar link.

EliRabett said...

CLOUD is irrelevant. The base question is not if there are enough ions, but what limits the growth of aerosols. The whole cosmic ray thing assumes that the number of CCNs formed is proportional to the number of ions. It ain;t necessarily so

sexy said...