And an investigative panel at Pennsylvania State University has cleared a scientist linked to the so-called “Climategate” controversy last year. The scientist, Dr. Michael Mann, was among the authors of emails stolen from the computer system of the Climatic Research Unit at the University of East Anglia in Britain. Deniers of global warming had claimed the stolen emails provided evidence of an effort to silence academics who have questioned or downplayed human-driven climate change. In its probe, Penn State said it found no evidence Mann manipulated scientific findings on global warming.