Tree ring dating reliability

22 Dec

‘I am certain that the science is rock solid.’ He admitted that his CRU colleagues had sometimes used ‘injudicious phrases’, but that was because they kept on being ‘diverted’ from their work by those who wished to scrutinise it.‘It’s understandable that sometimes people get frustrated,’ he said. Roger Pielke, Professor of Environmental Studies at the University of Colorado, could in no sense be described as a climate change sceptic, let alone a ‘denier’.Some tree-ring data eliminates the medieval warmth altogether, while others reflect it.In September 1999, Jones’s IPCC colleague Michael Mann of Penn State University in America - who is now also the subject of an official investigation --was working with Jones on the hockey stick.It was the chart displayed on the first page of the ‘Summary for Policymakers’ of the 2001 IPCC report - the famous ‘hockey stick’ graph that has been endlessly reproduced in everything from newspapers to primary-school textbooks ever since, showing centuries of level or declining temperatures until a dizzying, almost vertical rise in the late 20th Century.There could be no simpler or more dramatic representation of global warming, and if the origin of worldwide concern over climate change could be traced to a single image, it would be the hockey stick.In the course of an extraordinary BBC interview in which he called an American critic an ‘****hole’ live on air, Jones’s colleague Professor Andrew Watson insisted that the fuss was completely unjustified, because all Jones had been talking about was ‘tweaking a diagram’.

It is only now that their concerns have started to emerge from the thousands of pages of ‘Warmergate’ emails leaked last month from the CRU’s computers, along with references to performing a ‘trick’ to ‘hide’ temperature decline and instructions to resist all efforts by the CRU’s critics to use the Freedom of Information Act to check the unit’s data and conclusions. ‘In the long term, it will make very little difference to the scientific consensus, and to the way politicians respond to it,’ Professor Trevor Davies, the university’s Pro-Vice Chancellor and a former CRU director, told me.

Critics such as Mc Intyre had been ‘after the CRU station data for years.

If they ever hear there is a Freedom of Information Act now in the UK, I think I’ll delete the file rather than send to anyone’.

Gabriel Fahrenheit did not invent the mercury thermometer until 1724, so scientists who want to reconstruct earlier climate history have to use ‘proxy data’ - measurements derived from records such as ice cores, tree-rings and growing season dates.

For example, some suggest that the ‘medieval warm period’, the 350-year era that started around 1000, when red wine grapes flourished in southern England and the Vikings tilled now-frozen farms in Greenland, was considerably warmer than even 1998.