Bill McKibben, who wrote the first book on global warming aimed at a general audience in 1989, notes that at the time even the Wall Street Journal and then president Bush (Senior) both generally agreed that there was a problem. Way back then, there were only a few dozen scientific studies that supported man-made global warming.

But now, two decades later, there are thousands of rigorous studies that confirm global warming, not to mention little things like the fact that the 15 warmest years on record have occurred during that time. And yet, the number of Americans who believe that global warming is man-made is decreasing.

McKibben makes an interesting analogy to the OJ Simpson trial. At the start of the trial everyone knew Simpson was guilty of murder, but the dream team of lawyers Simpson hired did everything to create doubt, any doubt, by examining any crack in the evidence, or anything done wrong by the police. And the more evidence there is, the easier it is to find cracks or mistakes.

And that’s the whole point. Because there are so many studies on global warming, it is easier to find one or two studies where some small scientific mistake was made, or at least some shortcut taken. As he says, the larger the haystack, the more likely it is to contain a needle or two.