By Richard Black, Environment correspondent, BBC News
20 October 2011
The Earth's surface really is getting warmer, a new analysis by a US scientific group set up in the wake of the "Climategate" affair has concluded.
The Berkeley Earth Project has used new methods and some new data, but finds the same warming trend seen by groups such as the UK Met Office and NASA.
The project received funds from sources that back organisations lobbying against action on climate change.
"Climategate", in 2009, involved claims global warming had been exaggerated.
Emails of University of East Anglia (UEA) climate scientists were hacked, posted online and used by critics to allege manipulation of climate change data.
The Berkeley group says it has also found evidence that changing sea temperatures in the north Atlantic may be a major reason why the Earth's average temperature varies globally from year to year.
The project was established by University of California physics professor Richard Muller, who was concerned by claims that established teams of climate researchers had not been entirely open with their data.
He gathered a team of 10 scientists, mostly physicists, including such luminaries as Saul Perlmutter, winner of this year's Nobel Physics Prize for research showing the Universe's expansion is accelerating.
Funding came from a number of sources, including charitable foundations maintained by the Koch brothers, the billionaire US industrialists, who have also donated large sums to organisations lobbying against acceptance of man-made global warming.
"Science is best done when the problems with the analysis are candidly shared."
The group's work also examined claims from "sceptical" bloggers that temperature data from weather stations did not show a true global warming trend.
The claim was that many stations have registered warming because they are located in or near cities, and those cities have been growing - the urban heat island effect.
The Berkeley group found about 40,000 weather stations around the world whose output has been recorded and stored in digital form.
It developed a new way of analysing the data to plot the global temperature trend over land since 1800.
What came out was a graph remarkably similar to those produced by the world's three most important and established groups, whose work had been decried as unreliable and shoddy in climate sceptic circles.
Two of those three records are maintained in the US, by the National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA).
The third is a collaboration between the UK Met Office and UEA's Climatic Research Unit (CRU), from which the e-mails that formed the basis of the "Climategate" furore were hacked two years ago.
"Our biggest surprise was that the new results agreed so closely with the warming values published previously by other teams in the US and the UK," said Prof Muller.
"This confirms that these studies were done carefully and that potential biases identified by climate change sceptics did not seriously affect their conclusions." […]
Bob Ward, policy and communications director for the Grantham Research Institute for Climate Change and the Environment in London, said the warming of the Earth's surface was unequivocal.
"So-called 'sceptics' should now drop their thoroughly discredited claims that the increase in global average temperature could be attributed to the impact of growing cities," he said.
"More broadly, this study also proves once again how false it was for 'sceptics' to allege that the e-mails hacked from UEA proved that the CRU land temperature record had been doctored.
"It is now time for an apology from all those, including US presidential hopeful Rick Perry, who have made false claims that the evidence for global warming has been faked by climate scientists." […]