Do clouds disappear? 3


Falsification tests of climate hypotheses

Cosmic rays and clouds at various latitudes

An exchange with Prof. Terry Sloan of Lancaster University

I’m promoting to the start of a new post a comment on an earlier post that came from Terry Sloan, together with my reply and his comment on my reply. I’ve included a graph that he sent in an e-mail because it wouldn’t upload into the Comments section.

After that, the discussion continues here with further remarks from me.

Sloan is one of the severest critics of the Svensmark hypothesis that cosmic rays influence the Earth’s low clouds. The earlier post, entitled “Do clouds disappear when cosmic rays get weaker?”, was concerned chiefly with whether or not sudden changes called Forbush decreases have observable effects on cloud cover. You can see that post in full here:

But the present interaction with Sloan mainly concerns a different question, about the influence of the Earth’s magnetic field. To help readers to get quickly up to speed, here’s the most relevant extract from my original post:

Read the rest of this entry »



The Svensmark hypothesis

Sequence of discoveries

The connection between cosmic rays and the cloud cover observed by satellites was announced at a space science meeting in 1996 and published in the following year (Henrik Svensmark & Eigil Friis-Christensen 1997). The report’s title called the discovery the “missing link” because it solved a big puzzle for climate researchers, as to how the Sun could exert an impact on climate that empirically exceeded by a wide margin the effect of variations in solar brightness measured by satellites. Read the rest of this entry »