About six years ago I posted an article about CLOUD, an experiment to better understand the correlation between intensity of cosmic rays which varies with the sunspot cycle (solar activity), and cloud formation. In summary the findings to date indicate that the effect of cosmic rays on cloud formation is small compared to the large variations in natural biogenic aerosol emissions.
A paper by Hamish Gordon, Jasper Kirkby and thirty others titled “Causes and importance of new particle formation in the present-day and pre-industrial atmospheres”.
[doi: 10.1002/2017JD026844]
The abstract states: [my bold]
New particle formation has been estimated to produce around half of cloud-forming particles in the present-day atmosphere, via gas-to-particle conversion. Here we assess the importance of new particle formation (NPF) for both present-day and pre-industrial atmospheres. …
Concerning causes, we find that the importance of biogenic volatile organic compounds (BVOCs) in NPF and CCN formation is greater than previously thought. …
Our model suggests that the effect of changes in cosmic ray intensity on CCN is small and unlikely to be comparable to the large variations in natural primary aerosol emissions. …
I presume you have now seen the latest Svensmark paper?
https://wattsupwiththat.com/2017/12/19/new-svensmark-paper-the-missing-link-between-cosmic-rays-clouds-and-climate-on-earth/
The debate continues, with people like Svalgaard ready to dismiss it.
Thanks. Yes I have seen several articles about the paper and have started to read it. I will put a short post here about it after I have read the paper. As you say, the debate continues.