The Times of London delivers a separate blow to the AGW movement today in a report on scientific review of the data used to claim man-made warming of the planet over the last few decades.  Several researchers have found that the measurements of temperatures in the AGW record that showed temperature increases mainly came from land development and urbanization, not from actual temperature increases.  They have made their findings public through peer-reviewed studies that come at a very bad time for the IPCC and AGW advocates:

“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.

Watts’ study has not yet been peer reviewed, but it shows the questionable conditions of temperature measurements in many of the IPCC-cited weather stations.  One weather station is located next to an incinerator, while others have air-conditioning units in close proximity to the instruments.  Apparently more than one is adjacent to waste-treatment plants, which generate significant heat.

These revelations come on top of a series of embarrassing disclosures about the IPCC report.  Another research team at Loughborough University may expose even more.  Terry Wills will publish a paper in Climatic Change that will argue that the IPCC misread its data, and that the temperature fluctuations it saw are just as likely to be random weather than any systemic trend, whether caused by greenhouse gases or not.

The struts have begun to collapse under AGW hysteria.