With the release of the 2014 HadCRUT4 data by the UK Met Office, and the previous release of global temperature data by Berkeley Earth, Nasa and Noaa, the main conclusion to be drawn from the data is that 2014 was a warm year, but not statistically distinguishable from most of the years of the past decade or so meaning that the “pause” in global annual average surface temperatures continues.
The Met Office said:
“The HadCRUT4 dataset (compiled by the Met Office and the University of East Anglia’s Climatic Research Unit) shows last year was 0.56C (±0.1C) above the long-term (1961-1990) average. Nominally this ranks 2014 as the joint warmest year in the record, tied with 2010, but the uncertainty ranges mean it’s not possible to definitively say which of several recent years was the warmest.”
HadCRUT4. Click on image to enlarge.
Quoting the temperature to one hundredth of a degree and the error on that measurement to a tenth of a degree is not normal scientific practice. It is against normal scientific practice to have an error of the measurement larger than the precision of that measurement. This means that most scientists would have rounded the data so that it was 0.6 +/- 0.1 °C. If this is done to the HadCRUT4 dataset it is even more obvious that there has been a warming “pause” for the past 18 years.
Looking in detail at why 2014 was a warm year shows that it was down to unusually warm temperatures for a few months in the northeast Pacific. It is also obvious that had December not been such a warm month 2014 would have been much cooler. The Met Office says in its press release:
“Phil Jones, of the University of East Anglia, said: 2014 was an exceptionally warm year which saw warm tropical pacific temperatures, despite not being officially regarded as an El Niño.”
Unusually warm Pacific temperatures in the region they were observed indicates that what made 2014 interesting was not down to any predicted manifestation of “global warming.”
However, the Met Office considers that the temperature attained in 2014, and therefore all of the years of the past decade or so, would not have been achieved without human influence. In a press release put out in December (when HadCRUT4 data was available to October), when it was still possible that 2014 would have set a “record” and could have been treated as a separate event, they said that new research techniques developed by them allow for rapid assessment of how human influence might have affected the chances of breaking temperature records. They said:
“This technique, known as an attribution study, uses climate models and observations to see how likely an event would be in the real world and in a world without human greenhouse gas emissions – enabling assessment of how human influence has altered the chances of an event.”
Peter Stott, Head of Climate Attribution at the Met Office, said: “Our research shows current global average temperatures are highly unlikely in a world without human influence on the climate.” Such attribution research is highly speculative and should have been flagged as such in a press release whose aim was the get the media to print a story suggesting that 2014 would be a ‘record’ year, and give them an explanation for it. As it turned out November’s and December’s HadCRUT4 data whittled away the chances of 2014 being a “record.”
In general the Met Office and before them the Berkerley Earth project were reasonable about the data in pointing out that a new record was not established unequivocally because of the large error bars that encompass 2014 and many other recent years. This is in contrast to the stance taken by NASA who proclaimed without doubt, and without even quoting the temperature and any error information, that 2014 was the warmest year ever.
2014 fits in perfectly with the suggestion that for the past 18 years HadCRUT4 is best represented by a constant temperature.