Shocking, fascinating, entirely unsurprising: the leaked documents, if authentic, confirm what we suspected but could not prove. The Heartland Institute, which has helped lead the war against climate science in the United States, is funded among others by tobacco firms, fossil fuel companies and one of the billionaire Koch brothers.

It appears to have followed the script written by a consultant to the Republican party, Frank Luntz, in 2002. “Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly. Therefore, you need to continue to make the lack of scientific certainty a primary issue in the debate.”