The University of East Anglia says there is "no evidence of a recent breach of our systems." Associated Press

The British university whose leaked emails caused a global climate science controversy in 2009 says it has discovered a potentially much larger data breach.

University of East Anglia spokesman Simon Dunford said that while academics didn't have the chance yet to examine the roughly 5,000 emails apparently dumped into the public domain Tuesday, a small sample examined by the university "appears to be genuine."

The university said in a statement that the emails did not appear to be the result of a new hack or leak. Instead, the statement said that the emails appeared to have been stolen two years ago and held back until now "to cause maximum disruption" to the imminent U.N. climate talks next week in Durban, South Africa.

If that is confirmed, the timing and nature of the leak would follow the pattern set by the so-called "Climategate" emails, which caught prominent scientists stonewalling critics and discussing ways to keep opponents' research out of peer-reviewed journals.

Those hostile to mainstream climate science claimed the exchanges proved that the threat of global warming was being hyped, and their publication helped destabilize the failed U.N. climate talks in Copenhagen, Denmark, which followed several weeks later.

Although several reviews have since vindicated the researchers' science, some of their practices — in particular efforts to hide data from critics — have come under strong criticism.

The content of the new batch of emails couldn't be immediately verified — The Associated Press has not yet been able to secure a copy — but climate skeptic websites carried what they said were excerpts.

Although their context couldn't be determined, the excerpts appeared to show climate scientists talking in conspiratorial tones about ways to promote their agenda and freeze out those they disagree with. There are several mentions of "the cause" and discussions of ways to shield emails from freedom of information requests.

'Desperate climate change deniers' blamed

Penn State University Prof. Michael Mann — a prominent player in the earlier controversy whose name also appears in the latest leak — described the latest leak as "a truly pathetic episode," blaming agents of the fossil fuel industry for "smear, innuendo, criminal hacking of websites, and leaking out-of-context snippets of personal emails."

He said the real story in the emails was "an attempt to dig out two-year-old turkey from Thanksgiving '09. That's how desperate climate change deniers have become."

Bob Ward, with the London School of Economics' Grantham Research Institute on Climate Change, said in an email that he wasn't surprised by the leak.

"The selective presentation of old email messages is clearly designed to mislead the public and politicians about the strength of the evidence for man-made climate change," he said. "But the fact remains that there is very strong evidence that most of the indisputable warming of the Earth over the past half century is due to the burning of fossil fuels and other human activities."

The source of the latest leaked emails was unclear. The perpetrator of the original hack has yet to be unmasked, although British police have said their investigation is still active.