Wednesday, 21 January 2015

Cairns Post Letters from the Wingnuts #28: NASA temperature probabilities get wingnuts in stereo

After a change in employer I don't get to see the Cairns Post's Letters to the Editor page very often, but I had a quick glance today. A pair of brief rants caught my eye, in part because they essentially repeated the one point. I'll give one a glance, and decline to give any oxygen to the other on this day.
Re: Hottest year ever. Wayne Brandon fails to mention that the "new record" was less than 0.02C (well within the margin of error) and that within hours of the statement being released, one of NASA's chief scientists admitted there was only a 38 per cent chance it was the hottest year, geez! How's that peer review working out?
Andy, Gordonvale
It's true that it's hard to say if 2014 was definitely hotter than 2010. There is no single thermometer that we can check - the temperature is estimated using many different measurements, and the results have some degree of error.

Imagine a game in which I drew a coloured ball out of a hat, There are 100 balls and 5 colours, and in order to win the game you just need to guess the colour. If I have an equal number of each colour, it's a toss up as to which colour you should choose - 20 of the balls are each colour.

But imagine if you knew that the balls weren't 20 of each colour. Imagine that you knew that 38 of the balls are red, 23 are blue, 18 are yellow, 17 are green, and 4 are black. What colour would you choose? I think anyone with half a brain would go for red.

Place your bets...
This is what NASA were describing. The probability that 2014 is the hottest year is indeed 38% (the red balls). The probability that 2010 was the hottest year is 23% (blue).  The 17 green balls represent the probability that 2005 is the hottest year. The 5 black balls represent the climate change denier's favourite year, 1998. The 18 yellow balls represent the probability that any of the many other years was the hottest.

2014 is thus more than 8 times more likely to be the hottest year than 1998. the year that deniers like to claim marked the end of warming.

Our two wingnuts are apparently betting on black.

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