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New Decadal Forecast From The Met Office

January 11, 2013

By Paul Homewood


There has been much controversy concerning the UK Met Office’s new decadal forecast of global temperatures recently issued. Leaving aside the controversial aspects (!), I thought it would be a good idea to see how the forecast fits in with recent temperatures.



Two things to note.

  1. The new “decadal” forecast only runs for 5 years, 2013-17. (Don’t ask me why!)
  2. The forecast is shown as anomalies from 1971-2000, whereas HADCRUT numbers are based on 1961-1990, so we need to convert these.

The new forecast predicts that:-

Global average temperature is expected to remain between 0.28 °C and 0.59 °C (90% confidence range) above the long-term (1971-2000) average during the period 2013-2017, with values most likely to be about 0.43 °C higher than average.

Since the 1971-2000 baseline is 0.10C higher than the 1961-90 version, we can convert the 0.43C figure to 0.53C, so it is comparable with the HADCRUT4 actuals. When we do , we get the following graph.




It does not appear as if temperatures will significantly exceed 1998, 2005 or 2010, though the forecast does represent an increase over the last two years.

I have not shown the previous forecast, made in December 2011, but this predicted anomalies of 0.64C for 2012-16, and 0.86C for the following 5 years.


It is also instructive to take a look at the 10 year averages, for both the last 10 years actuals and the actuals for 2008-12 together with the 2013-17 forecast.


2002-11 0.47C
2008-17 0.49C


So there is a probably statistically insignificant increase of 0.02C over 6 years, that would translate to 0.33C per century.

Even this is likely to disappear when the AMO enters the cold phase, probably sometime in the next 10 years or so.

One Comment
  1. Andy DC permalink
    January 12, 2013 4:24 pm

    The Met Office’s credibility is zero with respect to their track record with long range forecasts.

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