Although still very busy with other work, I keep looking out for results from the CLOUD experiment at CERN in Geneva, which is testing Henrik Svensmark’s hypothesis that cosmic rays help to make clouds. They are due for publication this summer. All I have just now is a startling remark by Rolf-Dieter Heuer, Director General of CERN, in an interview by Welt Online a few days ago.
Here is a tidied-up Google Translate version of the relevant exchange.
The results of the so-called CLOUD experiment, exploring the formation of clouds, are awaited with great excitement. Could these results still be important for understanding global climate change?
This is indeed a matter of understanding better the formation of clouds. In nature there are many parameters at work – including temperature, humidity, impurities and also cosmic radiation. In the experiment, CLOUD investigates the influence of cosmic rays on cloud formation, using radiation [meaning particles] coming from the accelerator. And in an experimental chamber one can study, under controlled conditions, how the formation of droplets depends on the radiation and particulate matter. The results will be published shortly. I have asked the colleagues to present the results clearly, but not to interpret them. That would go immediately into the highly political arena of the climate change debate. One has to make clear that cosmic radiation is only one of many parameters.