The bad news is that this is not only going to muddy the waters a heck of a lot, but may also set back prospects of meaningful action to address global warming any time soon. The good news is that global warming may not actually be real.

Because this time it’s not just so-called scientists who have prostituted themselves to the oil companies who are questioning the scientific consensus on global warming. It’s respected scientists, respected by none other than the UN’s Nobel-prize-winning global warming panel, the Intergovernmental Panel on Climate Change (IPCC).

The United Nations climate panel faces a new challenge with scientists casting doubt on its claim that global temperatures are rising inexorably because of human pollution.

In its last assessment the Intergovernmental Panel on Climate Change (IPCC) said the evidence that the world was warming was “unequivocal”.

It warned that greenhouse gases had already heated the world by 0.7C and that there could be 5C-6C more warming by 2100, with devastating impacts on humanity and wildlife. However, new research, including work by British scientists, is casting doubt on such claims. Some even suggest the world may not be warming much at all.

“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.
[...]
Terry Mills, professor of applied statistics and econometrics at Loughborough University, looked at the same data as the IPCC. He found that the warming trend it reported over the past 30 years or so was just as likely to be due to random fluctuations as to the impacts of greenhouse gases. Mills’s findings are to be published in Climatic Change, an environmental journal.

“The earth has gone through warming spells like these at least twice before in the last 1,000 years,” he said.

I don’t see how anyone can dismiss the likes of John Christy and Ross McKitrick and Terry Mills as kooks or prostitutes.

Wisely, the IPCC is not challenging their credibility or motives. Instead, it is resorting to the spin method of damage-control:

Kevin Trenberth, a lead author of the chapter of the IPCC report that deals with the observed temperature changes, said he accepted there were problems with the global thermometer record but these had been accounted for in the final report.

Which may not be so wise. Because, like the article said, “In its last assessment the Intergovernmental Panel on Climate Change (IPCC) said the evidence that the world was warming was “unequivocal”.

Words like that will come back and bite you if they’re not warranted.