The Times reports that many weather stations have recorded rising temperatures due to urban heat islands rather than a natural rise in temperatures.
“The temperature records cannot be relied on as indicators of global change,” said John Christy, professor of atmospheric science at the University of Alabama in Huntsville, a former lead author on the IPCC.
The doubts of Christy and a number of other researchers focus on the thousands of weather stations around the world, which have been used to collect temperature data over the past 150 years.
These stations, they believe, have been seriously compromised by factors such as urbanisation, changes in land use and, in many cases, being moved from site to site.
Christy has published research papers looking at these effects in three different regions: east Africa, and the American states of California and Alabama.
“The story is the same for each one,” he said. “The popular data sets show a lot of warming but the apparent temperature rise was actually caused by local factors affecting the weather stations, such as land development.”
The IPCC faces similar criticisms from Ross McKitrick, professor of economics at the University of Guelph, Canada, who was invited by the panel to review its last report.
The experience turned him into a strong critic and he has since published a research paper questioning its methods.
“We concluded, with overwhelming statistical significance, that the IPCC’s climate data are contaminated with surface effects from industrialisation and data quality problems. These add up to a large warming bias,” he said.
Such warnings are supported by a study of US weather stations co-written by Anthony Watts, an American meteorologist and climate change sceptic.
His study, which has not been peer reviewed, is illustrated with photographs of weather stations in locations where their readings are distorted by heat-generating equipment.
Some are next to air- conditioning units or are on waste treatment plants. One of the most infamous shows a weather station next to a waste incinerator.
Watts has also found examples overseas, such as the weather station at Rome airport, which catches the hot exhaust fumes emitted by taxiing jets.
In Britain, a weather station at Manchester airport was built when the surrounding land was mainly fields but is now surrounded by heat-generating buildings.
Here is a picture of the weather station at Rome airport right behind a runway for planes taking off (Source: Watts Up With That?):
Meanwhile, Phil Jones, one of the scientists at the center of the Climategate scandal, made some startling admissions in an interview with the BBC. The Daily Mail reports:
Professor Jones told the BBC yesterday there was truth in the observations of colleagues that he lacked organisational skills, that his office was swamped with piles of paper and that his record keeping is ‘not as good as it should be’.
The data is crucial to the famous ‘hockey stick graph’ used by climate change advocates to support the theory.
Professor Jones also conceded the possibility that the world was warmer in medieval times than now – suggesting global warming may not be a man-made phenomenon.
And he said that for the past 15 years there has been no ‘statistically significant’ warming.
Read about other recent revelation of bogus claims: