The Met-Office has issued a ‘decadal’ climate forecast which runs from 2018 to 2023. Maybe it should be called a ‘semi-decadal forecast’ instead, but we’ll let it pass, as that’s not the most amusing aspect of it by a long chalk.
I thought it would be fun to see how it’s doing after 10 months, so I plotted the latest annually averaged HadCRUt 4 global data using Wood For Trees in red and overlaid it on the Met-O prediction plot:
It’s quite amusing to see that the global average temperature is already dipping below the blue prediction envelope, but when I pointed this out to the Met-O’s Professor of climate impacts, Richard Betts, he told me that it was:
Too early to say yet – you’ll notice the blue plume hasn’t started yet! It’s annual means, not individual months.
This made me look a little more closely at the data. You can see that although I started my overlay plot at the same 1960 date, I’ve had to offset it to the middle of 1959 to get it to line up with the Met-O plot of the same HadCRUt data.
I used annually averaged data! Your data is also annually averaged, and running around 6 months early. Come to the talkshop next spring when we shall taunt you a second time. :-))
— Rog Tallbloke (@RogTallbloke) October 10, 2018
Now since it’s annually averaged data, that will put the end point of the plot another six months back from the “start of the blue plume”. Taken with the offset already noted, this means the annually averaged data won’t reach the ‘start of the blue plume’ until the end of December 2018.
However, the Met-O ‘Deadal Forecast’ page tells us:
Forecast issued in January 2018. The forecast will next be updated in January 2019.
So the Met-O will be updating the forecast in January 2019, when, without a doubt, the “start of the blue plume” will be ‘adjusted’ to take account the previous year’s data, which will only just have reached it!
Ladies and Gentlemen, I present you with the Met Office’s unfalsifiable and infallible ‘Decadal’ climate forecast.
via Tallbloke’s Talkshop
October 11, 2018 at 07:33AM