The late Andrew Breitbart once stated outright that the United States should put to death a climate scientist. The loudmouth of the right-wing tweeted: “Capital punishment for Dr. James Hansen. Climategate is high treason.”

Shortly after, Dr. Michael Mann, renowned climate researcher and author of the new book, The Hockey Stick and the Climate Wars, received this death threat in his Penn State University email inbox:

“You and your colleagues who have promoted this [climategate] scandal ought to be shot, quartered and fed to the pigs along with your whole damn families.”