In November 2009, hackers gained access to a server used by the CRU and stole a large quantity of data, anonymously posting online more than 1,000 emails and more than 2,000 other documents.[24][25] Some climate change sceptics including bloggers asserted that a number of the leaked e-mails contain evidence supporting their global warming conspiracy theory that scientists had allegedly conspired to manipulate data[26][27] and to keep scientists who have contrary views out of peer-review literature.[28][29] This controversy was dubbed "Climategate".[30][31]
A series of independent public investigations of the allegations found no evidence of fraud or scientific misconduct.[32] The Muir Russell report exonerated the scientists, but found "a consistent pattern of failing to display the proper degree of openness, both on the part of CRU scientists and on the part of the UEA".[33][34] The scientific consensus that global warming is occurring as a result of human activity remained unchanged.[35]
In 2011, a new analysis of temperature data by the independent Berkeley Earth Surface Temperature group, many of whom had stated publicly that they thought it was possible that the CRU had manipulated data, concluded that "these studies were done carefully and that potential biases identified by climate change sceptics did not seriously affect their conclusions".[36]
