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.

Related:

Pregnant woman in white lace sleeveless dress standing beside brown wooden crib.

Climate change is shrinking children’s height — and humidity is making things worse

Researchers have warned of the unexpected consequences of extremely hot, humid conditions during pregnancy.
person holding white and black striped shirt on a clothing store rack.

The case for giving garments a passport

As part of the forthcoming Ecodesign for Sustainable Products Regulation, which is set to take effect in 2027, every garment sold in European Union member states will be required to carry a digital product passport: a scannable record that traces an item’s full lifecycle.

aerial photography of tanker ship.

Oil, gold and rare earth elements: the backdrop to US political tension with Venezuela

The country’s enormous energy and mineral resources are consolidating as a key factor in the geopolitical dispute and in Venezuela’s institutional collapse.

Sea otter floats on its back.

Zombie urchins & the Blob: California sea otters face new threats & ecosystem shifts

Southern sea otters living along California’s coast are struggling in warmer seas, with new threats and changing food sources. They, like the other two sea otter subspecies, are classified as endangered.

Little girl sitting on green grass in an apple orchard holding green apple during daytime.

Trump’s EPA focus: Delay, rescind, dismantle environmental and health protections

For the first time in the agency’s 55-year history, Congress has ceded its responsibility to oversee the EPA to a single politician who sanctioned its “wholesale demolition,” former staff charge.

A group of climate protesters holding a sign that says our house is on fire.

One word sums up climate politics in 2025: Greenlash

In a year shaped by Trump's return to the White House, the new administration touted "energy dominance" and protesters threw eggs at "swasticars."

From our Newsroom
Multiple Houston-area oil and gas facilities that have violated pollution laws are seeking permit renewals

Multiple Houston-area oil and gas facilities that have violated pollution laws are seeking permit renewals

One facility has emitted cancer-causing chemicals into waterways at levels up to 520% higher than legal limits.

Regulators are underestimating health impacts from air pollution: Study

Regulators are underestimating health impacts from air pollution: Study

"The reality is, we are not exposed to one chemical at a time.”

Pennsylvania governor Josh Shapiro speaks with the state flag and American flag behind him.

Two years into his term, has Gov. Shapiro kept his promises to regulate Pennsylvania’s fracking industry?

A new report assesses the administration’s progress and makes new recommendations

silhouette of people holding hands by a lake at sunset

An open letter from EPA staff to the American public

“We cannot stand by and allow this to happen. We need to hold this administration accountable.”

wildfire retardants being sprayed by plane

New evidence links heavy metal pollution with wildfire retardants

“The chemical black box” that blankets wildfire-impacted areas is increasingly under scrutiny.

Stay informed: sign up for The Daily Climate newsletter
Top news on climate impacts, solutions, politics, drivers. Delivered to your inbox week days.