Timothy Ball, a former climatology professor at the University of Winnipeg in Canada, has received five deaths threats by email since raising concerns about the degree to which man was affecting climate change.
One of the emails warned that, if he continued to speak out, he would not live to see further global warming.
"Western governments have pumped billions of dollars into careers and institutes and they feel threatened," said the professor.
"I can tolerate being called a sceptic because all scientists should be sceptics, but then they started calling us deniers, with all the connotations of the Holocaust. That is an obscenity. It has got really nasty and personal."
Last week, Professor Ball appeared in The Great Global Warming Swindle, a Channel 4 documentary in which several scientists claimed the theory of man-made global warming had become a "religion", forcing alternative explanations to be ignored.
Richard Lindzen, the professor of Atmospheric Science at Massachusetts Institute of Technology - who also appeared on the documentary - recently claimed: "Scientists who dissent from the alarmism have seen their funds disappear, their work derided, and themselves labelled as industry stooges.
"Consequently, lies about climate change gain credence even when they fly in the face of the science."
Dr Myles Allen, from Oxford University, agreed. He said: "The Green movement has hijacked the issue of climate change. It is ludicrous to suggest the only way to deal with the problem is to start micro managing everyone, which is what environmentalists seem to want to do."
Nigel Calder, a former editor of New Scientist, said: "Governments are trying to achieve unanimity by stifling any scientist who disagrees. Einstein could not have got funding under the present system."
In the long past, scientists were persecuted for saying Earth revolved around Sol. Scientists were banished, silenced, and some were executed. Hundreds of years later, have we returned to the old ways of settling science questions with torture and fire? Once again the lives of scientists are in danger. Al Gore, Prophet of Climate Doom, should be very proud of what he has wrought. All hail al-Gore. All praise be to Gaia.
The life of Indigo Red is full of adventure. Tune in next time for the Further Adventures of Indigo Red.