Complex sentence: Discussion between scientists regarding the paper were leaked in the 2009 Climatic Research Unit e-mail hacking incident, one email sent by Michael Mann stated I think we have to stop considering "Climate Research" as a legitimate peer-reviewed journal.
Split into simpler sentences: Discussion between scientists regarding the paper were leaked in the 2009 Climatic Research Unit e-mail hacking incident. One email sent by Michael Mann stated I think we have to stop considering "Climate Research" as a legitimate peer-reviewed journal.