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.

Curiously Harris makes no mention of the real violence in the form of eco-terrorism that has come from the environmental left or Greenpeace repeatedly targeting the Competitive Enterprise Institute's Chris Horner, by stealing his garbage on a weekly basis, as his Web site points out. Instead, this "severe harassment" ABC warned about were e-mails from fringe Internet elements sent to Mann.

"The FBI tells ABC News it's looking into a spike in threatening e-mails to climate scientists like Penn State's Michael Mann," Harris said.

And Mann, who has a lawsuit against Minnesotans for Climate Change, a group that publicly mocked him for his discredited hockey stick graph, where he allegedly intentionally hid data to accentuate the argument of global warming alarmism, complained that the e-mailers are trying to trample his free speech rights.

"It's an attempt to chill the discourse and I think that's what most disconcerting," Mann said.

But despite overwhelming evidence that Mann's science has some flaws and that there are some bad characters among the global warming alarmists, Harris attempted to link radical fringe elements on the Internet to outspoken climate change alarmism skeptic Sen. James Inhofe, R-Okla.

"A white supremacist Web site recently posted Mann's picture alongside several other climate scientists, with the word 'Jew' next to each image," Harris said. "To many scientists, however, the most disturbing recent development was a report released by Republican Sen. James Inhofe, naming 17 climate scientists, some of whom Inhofe says have engaged in potentially illegal behavior."

According to Harris and NASA's Dr. Gavin Schmidt, Inhofe's efforts to highlight the evidence that scientists deliberately manipulated data to mislead the public is "McCarthy-ite."

Harris cited internal investigations at these scientists' respective institutions to assure viewers there was nothing wrong.

"Sen. Inhofe's report was referring to an incident late last year known as ClimateGate, where stolen e-mails gave the impression that climate scientists may have been trying to hide flaws in their research, although several subsequent investigations have exonerated the scientists," Harris said.

ABC News did air a few sentences from Marc Morano of ClimateDepot.com (A news aggregator site Harris called "aggressive.)

"Sen. Inhofe's former spokesman, Marc Morano, who now runs one of the most aggressive climate skeptic Web sites in the country, did agree to an interview, arguing that skeptics have been getting threats for years."

Morano explained that no one was promoting violence, but when so much on the line from a government policy perspective, the public should be engaged.

"No one is advocating violence," Morano said, "but it is refreshing to see these scientists hear from the public. When you go to a used-car salesman and you get conned ... you don't go back to the used-car dealer all happy and pleasant. You have a lot of anger, and that's what these scientists are appropriately feeling."

Nonetheless, at the end of Harris' segment, Schmidt dismissed any challenges on the theory of anthropogenic global warming and said scientists were too "hyper-competitive" to allow that to happen.