Is there any statistical evidence that global temperatures have changed since 1997 ?
Guest post by Clive Best
‘The linear trend from August 1997 (in the middle of an exceptionally strong El Nino) to August 2012 (coming at the tail end of a double-dip La Nina) is about 0.03°C/decade, amounting to a temperature increase of 0.05°C over that period.’
Several of us have been requesting statistical evidence via their blog that this trend is actually indistinguishable from flat.
Dave Brittan has done a sterling job in replying on behalf of the Met Office, but he eventually crafted a complex answer as to whether the above statement made statistical sense.
“The first is measurement uncertainty associated with basic measurement error and uncertain biases in the observations. These are included in the HadCRUT4 ensemble, and when computing linear trends in global temperatures from August 1997 to August 2012 these give a trend of 0.034 ± 0.011 °C per decade (95% confidence interval) for the observed portion of the earth.”
I questioned this statement because I think their quoted error is actually about a factor 10 less than it should be. After waiting 36 hours with my post still in moderation, and with no other posts being accepted I am now presuming that this is their last word on the matter.
Frustrated by the lack of response, I decided instead to do the analysis myself. – see post here: