The British university at the center of a 2009 global climate science controversy says a second batch of stolen emails has surfaced.
Although University of East Anglia officials say they've not yet had an opportunity to examine the more than 5,000 missives, they say a small sample they've seen "appears to be genuine."
They added that latest group of emails are not new but part of the original batch that were never released.
In 2009, hackers dumped emails taken from the university. The messages showed researchers hid data that does not support the global warming theory.
The revelations damaged the reputation of the climatic research unit at East Anglia, a leading proponent of global warming.
"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," Bob Ward, with the London School of Economics' Grantham Research Institute on Climate Change, said.
"But the fact remains that there is very strong evidence that most the indisputable warming of the Earth over the past half century is due to the burning of fossil fuels and other human activities," he concluded.
The leak comes ahead of next week's conference on global warming at the United Nations.