Scientists at the heart of the Climategate controversy face new allegations which cast further doubt about global warming. Analysis shows researchers had tried to suppress key details of their findings for twenty years.

New allegations swirl in Climategate, which began last November with an email leak at the University of East Anglia, suggesting that one of the world’s foremost centres for climate research had been manipulating data to prove the existence of man-made global warming.

Now, it turns out data manipulation has been going on since at least 1990.

The head of the university’s climate research unit, Professor Phil Jones, has come under fresh suspicion due to a paper he released 20 years ago, claiming urban warming wasn’t a factor in higher temperature readings he’d recorded. But he doesn’t seem to be able to show where his information came from.

“That research was paid for with public money so everyone should have access to it, and if we’re spending that kind of money to stop climate change then the fundamental data should be open to anyone who wants to check it,” International Climate Science Coalition executive director Tom Harris says.

That same paper was used as evidence in the latest report from the UN Intergovernmental Panel on Climate Change. The panel has also recently come under fire for falsely claiming in one of its own reports that all Himalayan glaciers could completely melt down by 2035.

The head of the panel has refused to apologise, calling the error “an isolated mistake”. However, global warming skeptics say such occurrences mean we essentially know nothing about the climate.

“It means that we do not have a measure of how temperatures have changed over the last 50-100 years, that we can say, well, one year is warmer than the other but the relative amounts, like 2002 compared with the 1930’s, was that it warmer or colder, but we do not actually know,” Piers Corbyn from Weatheraction says.

More worrying, another case suggests the whole system of scientists reviewing their colleagues’ work has been corrupted. Some of the leaked emails from the University of East Anglia’s Climate Research Unit refer to a paper that Professor Jones reviewed and deliberately suppressed.

What emerged was an analysis of data from weather stations around Russia’s Lake Baikal. It showed much less warming than Professor Jones’ own analysis using much the same data.

“The other things which they have been doing which are grossly unacceptable – is trying to prevent the publication of valid scientific opinion and research which goes against what they believe, and that is absolutely monstrous! So they not only suppress the scientific opinion they don’t like, but they actively avoid commissioning work which I’m certain would have appeared in print, but to the fact that they have a total grip and bias against anything they don’t agree with,” Corbyn adds.

The University of East Anglia continues to call its data “rock solid”.

These latest Climategate revelations show this scandal is far from over. And all through it, the voices of the skeptics are getting louder. They’re asking, if man-made climate change is such an unassailable fact, why does it have to be proven using manipulated data?