The planet is no longer warming. The brief warming episode of the late 20th century completed its course in the mid 1990s, and is now extinct. These are now uncontroversial statements.
They are based on hard data which has been available for many years on the websites of many official agencies. But somehow those agencies found ways to interpret the data differently, and to continually sidestep the elephant in the room.
The IPCC report of 2007 came and went, failing to detect – or at least failing to acknowledge – that global warming was no more. On the contrary, “it’s worse than we thought” was the rallying cry throughout the lead-up to the COP15 at Copenhagen.
But the prevarication couldn’t last forever. Three years ago, CRU’s Phil Jones admitted to the BBC that there had been no statistically significant warming since 1995.
The pace picked up when the UK Met Office models surreptitiously projected a 20-year standstill on Christmas Eve 2012; and then James Hansen – oft described as the father of global warming – confirmed “a pause” of a decade or more. Now the whole house of cards finally tumbled, with Rajendra Pachauri, official spokesman for the IPCC, confirming in Melbourne that global temperatures had plateaued for 17 years.
Will global warming ever start again? Nobody knows.
The long flat trend will of course be replaced by a new trend at some future point, but its eventual sign and slope are inscrutable. The as-yet-unidentified combination of forces driving the current standstill might break in any direction.
Some diehards contend that a 16-17 year plateau is too short a period to comprise a flat trend. But actions speak louder than words, and much shorter trends have been seen as decisive in the past.
The 1992 Rio Conference founded a major international treaty on a warming trend that was 12 years old. Hansen’s 1988 launch of the DAGW campaign was little more than a decade after scientists had feared the beginning of a new ice age.
It is widely acknowledged that 15+ years is ample to determine a trend:
• In 2008, the NOAA reported that 15 years of zero trends would invalidate the expected warming rate.
• On May 7, 2009, a leading climate modeler emailed colleagues: “the ‘no upward trend’ needs to continue for 15 years before we get worried”.
• In 2011, Dr Ben Santer averred that a ‘hiatus period’ of 17 years would be required to negate the ‘human fingerprint’ shown in climate models.
• Gavin Schmidt on RealClimate.com: “you can’t use short term (15 years or less) trends to prove that global warming has or hasn’t stopped”.
Let us turn to the best practice manual for climatology, the “Guide to Climatologogical Practices” (3rd Edition) published by the World Meteorological Organisation in 2011. At 4.8.1 under the heading “Period of Calculation”:
“A number of studies have found that 30 years is not generally the optimal averaging period for normals used for prediction. The optimal period for temperatures is often substantially shorter than 30 years, but the optimal period for precipitation is often substantially greater than 30 years….. In general the most recent 5- to -10 year period of record has as much predictive value as a 30-year record.”
Following Dr Pachauri’s admission, we can expect a spin barrage built on words like “hiatus”, “remission”, “lull”, “time-out”, “stalled” and “paused”.
The use of a term like “pause” is a blatant misuse of language. It relies upon an evidence-free prophesy that the deceased trend will some day be resurrected. It is no more than Freudian wish-fulfillment.
There have been three distinct warming episodes since the instrumental record began – 1860-80,1912-40 and 1978-96 – but nobody suggests that any of them were linked by a “pause”. Some historians argue that the two World Wars were a single event with a 21-year ‘intermission’, but few find this convincing.
The statistical fact is that the late 20th century warming trend is history. It is over. It is so yeterday. As Monty Python’s immortal “Dead Parrot” sketch illustrates so vividly, there is a vast gulf between “resting” and “dead”.
Hon Barry Brill OBE is a New Zealand barrister and solicitor. He is a former Minister of Science & Technology, and Minister of Energy, and is currently chairman of the New Zealand Climate Science Coalition