How can NASA physicist and climatologist James E. Hansen, writing in the New York Times today, “say with high confidence” that recent heat waves in Texas and Russia “were not natural events” but actually “caused by human-induced climate change”?

It wasn’t all that long ago that respected MIT atmospheric scientist Kerry Emanuel flatly refuted the notion that you can pinpoint global warming as the cause of an extreme weather event. “It’s statistical nonsense,” he told PBS.