90%.
By tagging subjective judgments with percent values, the climatologists erode the long-standing distinction between chance and raison de croire. As we read the report, we’re likely to assume that a number represents a degree of statistical certainty, rather than an expert’s confidence in his or her opinion. We’re misled by our traditional understanding of percentages and their scientific meaning.
The uncertainty cops argue that in the face of global warming—and the spin campaign to discredit it—we must do whatever it takes to boost the credibility of the experts. If the public is more inclined to believe in percentages, then the experts should give them percentages. It’s a reasonable argument and one that could help us to address the precipitous rise in greenhouse-gas emissions. But we have to acknowledge that the new headline-grabbing rhetoric of climate change has elements of propaganda. However valid its conclusions, the report toys with our intuitions about science—that a number is more precise than a word, that a statistic is more accurate than a belief.
Don’t worry, the climate scientists themselves are just as confused about what these probabilities mean
Glad that you confirm that Daniel Engber has an interesting point, worth of reading (at the very least).