Serial Nobel Peace Prize hoaxer Michael Mann is maintaining his fake claim to have won the prestigious award in a new HBO documentary — four years after he was exposed for lying to a Washington, D.C. court.

The Penn State professor and leading global warming activist is featured prominently in a new Josh Fox directed HBO documentary How to Let Go of the World and Love All the Things Climate Can’t Change, where he is clearly and dramatically described as a co-winner of the 2007 Nobel Peace Prize.

However, Mann has had to withdraw this inaccurate claim on numerous occasions since 2007 — most dramatically, in 2012, he was forced to admit that a sworn affidavit he submitted to a D.C. court contained the lie about being a Nobel Peace Prize winner.

Four years later, the claim is again repeated in the HBO documentary which has just had a theatrical release in New York. The fake prize claim is given particular prominence because in a break with documentary convention the caption has its own stand-alone card. Normally in documentaries, a descriptive caption appears in the lower corner of a screen whilst the subject is talking. However, Mann’s caption in the How to Let Go documentary is a stand-alone card with large, dramatic, white writing against a black background and which describes him as a CO-WINNER 2007 NOBEL PEACE PRIZE.

We have reached out to HBO and Michael Mann for comment. It’s possible this was an HBO error; however, standard procedure for captions in documentaries is that the interviewee submits the information to the production team.. This is particularly true for academics who may be professors or visiting professors at a number of institutions, and may have won numerous prizes in their career. The academics would know which prize or position is more prestigious or relevant and would generally be allowed and trusted to write their own caption.

Mann’s repeated exaggeration of his qualifications is significant: He stands accused of exaggerating and manipulating data in his academic work. Mann was the author of the famous “hockey stick” graph which purported to show that world temperatures had been stable and flat until a violent upswing caused by industrialization.

The”hockey stick” was taken to be proof that man has influenced climate, and global warming is real. However, the “hockey stick” has since been criticized by other scientists amid allegations that Mann manipulated data and used unscientific methods to bolster his claim.

These claims prompted Mann’s 2012 legal complaint against the Washington-based think-tank, the Competitive Enterprise Institute and author Mark Steyn.

In a sworn affidavit, Mann described himself as a Nobel Prize Winner, and said the fact that he was the recipient of such a prestigious prize compounded the libel.

“It is one thing to engage in discussion about debatable topics. It is quite another to attempt to discredit consistently validated scientific research through the professional and personal defamation of a Nobel prize recipient,” the affidavit stated.

However, the Nobel Prize committee said that Mann was not a winner of the prize, and that working part-time for the IPCC which won the prize does not entitle people to claim they are a winner. In a statement to National Review, a committee spokesperson stated emphatically: “Mann has never won the Nobel Prize.”

Mann was forced to resubmit his sworn statement removing the Peace Prize claim, and he had to scrub the claim from numerous university and professional websites. The re-occurance of his fake claim to be a Nobel laureate is likely to weaken his legal case against the CEI and Steyn given that they are basing their defense on allegations that he has fabricated scientific findings and statistics.

HBO, Michael Mann and Josh Fox did not respond to requests for a comment.