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 Abb73argued 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.