GISS ‘Hottest Year’ Claims On Dodgy Ground

As has been suspected for a few months now, GISS have announced that 2014 was the “hottest year on record”.

Nowhere does their press release tell us that it only beat the previous record by a tiny, effectively unmeasurable 0.02C. Nor do they mention that the error bars are many times greater, or even tell us what they are.

This is all very strange because in their report on 2010 Global Temperatures, they said:

Global surface temperatures in 2010 tied 2005 as the warmest on record, according to an analysis released Wednesday by researchers at NASA’s Goddard Institute for Space Studies (GISS) in New York. The two years differed by less than 0.018 degrees Fahrenheit. The difference is smaller than the uncertainty in comparing the temperatures of recent years, putting them into a statistical tie.

Although GISS do not tell us what their error bars, or as they call them estimates of uncertainty, are, NOAA, with their similar analysis give a figure of +/- 0.09C.

http://www.ncdc.noaa.gov/sotc/global/2014/13

http://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt

Allowing for these estimates of uncertainty, all they can honestly claim is that 2014 was in a statistical tie with 13 other years. Only 1999 and 2000 can statistically be said to be cooler.

The press release also makes other statements which need comment:

1) However, 2014’s record warmth occurred during an El Niño-neutral year.

This is categorically not the case.

The MEI index clearly shows moderate El Nino conditions for most of 2014, on a par with those in 2005.

http://www.esrl.noaa.gov/psd/enso/mei/

2) NOAA scientists used much of the same raw temperature data, but a different baseline period. They also employ their own methods to estimate global temperatures.

This refers to the NCDC dataset. What is interesting is their reference to “estimating global temperatures”. This is a clear admission that measuring global temperatures is not the exact art sometimes inferred, but largely guesswork.

Full post