At first, Michael Mann, a Penn State professor and a central figure in the Climategate scandal, but best known for his discredited "hockey stick graph" didn't like being mocked in a YouTube video. Now Mann is alleging he's a victim of hate groups.

On ABC's May 23 "World News Sunday," a segment from anchor Dan Harris alleged that threatening e-mails Mann received were part of a "spike" in violence aimed at the global warming alarmist community.

"The ongoing oil spill crisis in the Gulf is keeping the debate over climate and energy very much in the headlines and that debate is becoming increasingly venomous with many prominent scientists now saying that they are being severely harassed," Harris said.