Bill McKibben Makes a Bad Mistake

Bill McKibben repeats a bad mistake in Rolling Stone -- the same one that was corrected by Tamino in a recent post.

McKibben writes:

...June broke or tied 3,215 high-temperature records across the United States. That followed the warmest May on record for the Northern Hemisphere – the 327th consecutive month in which the temperature of the entire globe exceeded the 20th-century average, the odds of which occurring by simple chance were 3.7 x 10-99, a number considerably larger than the number of stars in the universe.

His number comes from assuming the chance of a month being warmer than average is 1/2; then

(1/2)³²⁷ = 3.7 ×10^-99 

But as Tamino pointed out recently, that is a bad assumption, because monthly temperatures are autocorrelated -- if this month is warm, chances are greater that next month will be warm too. There is a lot of inertia in the climate system, such as ENSO.

Making basic mistakes about climate is not a good way to make your point about climate change.