Phil Jones, director of the research program at the center of "climategate," temporarily stepped down from his post Tuesday. And last week, Pennsylvania State University said it would launch an inquiry into the conduct of Michael Mann, one of its professors and perhaps the world's most prominent paleoclimatologist.

Messrs. Jones and Mann have both been key contributors to the U.N.'s Intergovernmental Panel on Climate Change. The emails leaked from the University of East Anglia's Climatic Research Unit...