An alternative theory for climate change based on the influence of cosmic radiation lead to prominent predictions of an imminent cooling of global temperatures. Three years after the book by Fritz Vahrenholt and Sebastian Lüning was a bestseller in Germany and translated into English, its predictions – popular with climate sceptics also in the US –  have been shown to be false. Instead of a rapid cooling since the publication of the book, the world has experienced new temperature records.

In 2012, I reviewed a best-selling book by two German scientists critical of the greenhouse effect as a theory  explaining recent temperature rise. These scientists claimed that it was  cosmic radiation, instead. Part of public attraction of the book was  the prominence of the first author, Fritz Vahrenholt, a former  environmental activist, chemist-turned-politician and later corporate  big-wig at Germany’s largest electric utility, another part was the  scientific appearance of the argument, with a book full of figures and  references, but written in accessible language. Wishful thinking for the  dire predictions of future doom tobe ill-founded may also have played a  role. For me, finding a consistently


argued  contrarian case was welcome, as it allowed me to understand and probe  the intellectual content of that position. I had been faced with various  contrarian arguments often contradicting each other and no alternative  theory to explain the phenomenon of global warming or other climatic  developments. Probing the book, I identified inconsistencies of the  presented arguments, e.g. about feedback mechanisms, contradiction  between observations in the scientific literature and those reported in  the book, a very selective representation of the available evidence, and  gross misrepresentations of a few of the cited articles.

Sure of their alternative theory, the authors predicted that given  the expected development of cosmic radiation in response the sun’s  regular cycles, temperatures would decline. In fact, they predicted a  measurable decline to levels seen in the 1990s already by 2015. I am  afraid the picture I took at the time of the figure in question was not  the sharpest, but you can get a good impression. What has happened was  exactly the opposite. After 2014 already setting a new temperature  record, 2015 is now the warmest year on record by a good margin. This  new evidence clearly contradicts the predictions made by the sceptics.  They were very sure of themselves. I wonder what they say now.