COPENHAGEN — A scandal involving leaked e-mails from American and British scientists involved in the official body advising the U.N. cast a shadow over Monday's opening of the major climate conference in Copenhagen, with U.N. delegates concerned it will adversely affect negotiations to forge a new protocol.

Last month, hundreds of private e-mails and other documents were hacked from a computer server at the University of East Anglia in the United Kingdom.

Some of the messages from scientists involved with the Intergovernmental Panel on Climate Change, an advisory body of 2,500 climate experts worldwide, showed irritation with climate change skeptics and shared tips on how to refute their claims.