Sunday, July 14, 2013

Matt Ridley: Nobody ever calls the weather average

How come then that last week the World Meteorological Organisation produced a breathless report claiming that "the decadal rate of increase (of world temperature) between 1991-2000 and 2001-2010 was unprecedented"? It took professor Ed Hawkins of Reading University a short time to point out that this was no longer true if you compared 1993-2002 and 2003-2012 - ie, if you took the most up-to-date records. In that case, the latest decade showed a smaller increase over the preceding decade than either of the preceding decades did. In other words, the temperature standstill of the past 16 years has begun to show up in the decade-by-decade data.
And this is even before you take into account the exaggeration that seemed to contaminate the surface temperature records in the latter part of the 20th century - because of urbanisation, selective closure of weather stations and unexplained "adjustments". Two Greek scientists recently calculated that for 67 per cent of 181 globally distributed weather stations they examined, adjustments had raised the temperature trend, so they almost halved their estimate of the actual warming that happened in the later 20th century.
Anyway, by "unprecedented", the WMO meant since 1850, which is a micro-second of history to a paleo-climatologist like Carter. He takes a long-term perspective, pointing out that the world has been warming since 17,000 years ago, cooling since 8000 years ago, cooling since 2000 years ago, warming since 1850 and is little changed since 1997. Consequently, "the answer to the question 'is global warming occurring' depends fundamentally on the length of the piece of climate string that you wish to consider". He goes on: "Is today's temperature unusually warm? No - and no ifs or buts."
Viscount Matt Ridley, an acclaimed author and former Science and Technology Editor for the Economist blogs at

1 comment:

Anonymous said...

another explanation is that more energy in the atmosphere redistributes cold air etc.