What a difference a year makes. In February 2010, climate sceptics were crowing about apparent admissions from at the Climate Research Unit (CRU) in Norwich, UK, that warming trends over the period 1995 to 2009 were “not statistically significant”
Sceptics including far-right media pundit Glenn Beck , made in an , to support their contention that global warming is a mirage, and had effectively come to a halt.
This week, in a follow-up to last year’s announcement, Jones has said that simply adding the temperature data from 2010 to the data set has pushed the trend back into “significance”. That makes it above the 95 per cent confidence interval, meaning that there is only a 1 in 20 likelihood that the warming trend is occurring by chance.
By releasing the latest analysis, Jones is attempting to illustrate the perils of plucking long-term trends from relatively short periods, such as the 15-year stretch in question.
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“Next year, it could slip back into non-significance, but it shows the naivety of looking at short-term trends,” Jones told Â鶹´«Ã½. Trends over at least 30 years are more reliable, he adds.
Cherry-picking data
“The point Phil’s trying to make is that cherry-picking data to confound overall trends is not a legitimate approach,” says of the Grantham Institute at the London School of Economics, who is a fierce critic of climate sceptics.
Jones told Â鶹´«Ã½ that in the short time since his latest statement on the data’s “significance” had been aired in the media, some sceptics had already .
But Jones insists that his latest analysis is correct because it is a combination of land and marine temperatures. “It’s the combination that gives the true global picture,” he says.
In 2009, Jones was plunged into the “Climategate” row over public disclosure of emails from the CRU which sceptics said showed data had been manipulated to support global warming conclusions. Subsequent internal and external inquiries cleared him and the unit of wrongdoing.
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