Judge's sanctions against Michael Mann revive battle over climate defamation case

A Washington, D.C., judge accused climate scientist Michael Mann and his legal team of misconduct during a defamation trial, reigniting a legal fight that has spanned over a decade.

DeSmog reports.


In short:

  • In 2024, Michael Mann won a $1 million jury verdict in a defamation case against two bloggers, but Judge Alfred Irving later reduced the award to $5,000 and imposed sanctions against Mann’s legal team.
  • The judge claimed Mann’s lawyers intentionally misled the court about research grant data, though the team insists the discrepancies were acknowledged and corrected before trial.
  • Mann’s lawyers are asking the court to reverse the misconduct ruling, while critics link the judge’s stance to a broader political trend undermining climate science.

Key quote:

“The current Trump administration is engaging in an aggressive effort to defund and marginalize climate science. In this atmosphere, attacks on climate science and scientists have increased.”

— Robert Brulle, professor of climate science and society at Brown University

Why this matters:

This case reflects the precarious position of climate scientists in the United States, where legal and political forces often shape public understanding of science. Lawsuits like this one have become a battleground over the legitimacy of climate research, especially when scientists challenge powerful industries or ideologies. When courts penalize researchers for procedural missteps — even ones acknowledged and corrected — it sends a signal that speaking out carries serious professional and financial risks. Judge Alfred Irving’s decision to slash damages and accuse Mann’s team of misconduct could embolden those who seek to discredit scientists through litigation rather than scientific debate. At a time when the Trump administration is scaling back climate programs and rolling back environmental rules, these rulings echo a broader push to marginalize and stifle climate expertise.

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