UPDATE: The "certificate" only isn't entirely "fake", due to it actually coming from the IPCC, not actually coming from the Nobel Institute.
Though, the court document claim by Mann that he was Awarded the Nobel Peace Prize is still 100% false.
https://www.youtube.com/watch?v=mKbDfP5DitAMichael Mann is one of the primary favorites of Climate Change claimants, and is where a large majority of the climate change/global warming fraud originates.
This video shows how Michael Mann has no problem "faking" his own Nobel Prize, when it was only issued to the agency he worked for, not him, and no personal certificate was issued to any individual as the below information shows from the Director of the Nobel Institute.
Thus, it's not a stretch that he's willing to lie about the "science" which I also show below, how he removes the Medieval Warm Period, and downgrades the Little Ice Age in order to create his fake "Hockey Stick" showing extreme last 100 years warming, which is actually considerably LESS Warm than the Medieval Warm Period.
Further, one other thing the video shows is that climate scientists were actually working together and trying to get the Medieval Warm Period removed in order to make their Global Warming claims, which as the below shows, Michael Mann was all to willing to do.
So, these are two examples of clear and intentional FRAUD in life and in science that one of the biggest global warming proponents are willing to engage in.
And YOU all willfully believe it, doing ZERO study to know what's actually the truth or not on this subject. You just appeal to authority because it fits your ideology.
Nobel Institute Director's response to Michael Manns FAKE Nobel Prize Certificate.

The IPCC's chart indicating the basic Temperature record for the last 1,000 years.

Michael Mann's manipulation of the data of the same period, contradicting the IPCC chart above. Mann's chart is the one most global warming Activists and even most leftist scientists use today, ignoring their actual peer-reviewed temperature data that the above chart shows.
Comparing these two charts, you see how Michael Mann eliminated the Medieval Warm Period in order to make the claim that modern C02 levels are causing extreme warming. This is clear and unequivocal FRAUD of the temperature record for political purposes... Mann is a radical Leftist.

And by the way, going further back in the Temperature record for 1,000's and 1,000's of years, you see even more clearly that today's warmth is not even close to "dangerous" or serious. We are actually at the tail end of the last Ice Age... We've been gradually getting COOLER for 1,000's of years.
This is another manipulation Leftists "scientists" and activists engage in, by cherry-picking small timelines to make their claims.