Lee Zeldin became the first Environmental Protection Agency Administrator in history to deliver a keynote address at a climate denial conference, telling attendees at the Heartland Institute gathering that "today is a moment to celebrate" following the agency's repeal of foundational climate regulations.
The appearance marks an extraordinary reversal for an agency established in 1970 to protect human health and the environment. Zeldin told the audience of climate skeptics: "It is a day to celebrate vindication," framing the EPA's elimination of the 2009 endangerment finding as liberation from what he characterized as "radical ideology."
The endangerment finding, established during the Obama administration, served as the legal foundation for federal climate regulations on emissions from vehicles, power plants, and industrial facilities for 16 years. The determination, based on comprehensive assessment of climate science, concluded that greenhouse gases endanger public health and welfare—a finding that enabled EPA regulation under the Clean Air Act.
Its elimination removes the legal basis for vehicle emissions standards, power plant regulations, and numerous other climate-related rules, with potentially far-reaching consequences for U.S. and global climate policy.
The Heartland Institute, which hosted the conference, has spent decades challenging climate science and promoting fossil fuel interests. The organization has received funding from energy companies and conservative foundations, publishing materials that dispute the scientific consensus on anthropogenic climate change—a consensus shared by every major scientific body worldwide.
"This is unprecedented," said Joe Bonfiglio, senior director at the Environmental Defense Fund. "The head of the EPA is rallying climate deniers and promoting disinformation. This is not about scientific debate—the Heartland Institute is a disinformation factory, not a legitimate scientific organization."
The repeal arrives amid mounting evidence of accelerating climate impacts, including record-breaking temperatures, intensifying extreme weather events, and, as documented in research published this week, heatwaves that are breaching human survivability limits in populous regions.
An EPA spokesperson defended the Administrator's appearance, stating that the agency "has ended serving as a vehicle for radical ideology" and now focuses on statutory obligations "backed by gold standard science." The spokesperson did not address questions about which scientific evidence the agency relied upon in repealing the endangerment finding, nor explain how mainstream climate science—endorsed by institutions including NASA, NOAA, and the National Academy of Sciences—constitutes "radical ideology."
In climate policy, as across environmental challenges, urgency must meet solutions—science demands action, but despair achieves nothing. The EPA's trajectory represents a policy choice that contradicts the scientific evidence the agency was established to heed.
The endangerment finding was grounded in comprehensive assessment of peer-reviewed research, following rigorous scientific and legal processes. Its 2009 establishment came after the Supreme Court ruled in Massachusetts v. EPA that greenhouse gases qualify as air pollutants under the Clean Air Act, requiring EPA to determine whether they endanger public health.
That determination found that elevated greenhouse gas concentrations "threaten the public health and welfare of current and future generations," based on evidence including rising global temperatures, ocean acidification, sea level rise, and increased frequency of extreme weather events. The scientific evidence supporting these conclusions has only strengthened in the subsequent 17 years.
Nearly two dozen states and numerous environmental organizations have filed legal challenges to the repeal, arguing it violates the Clean Air Act and administrative law requirements. California Attorney General Rob Bonta called the action "legally indefensible and scientifically bankrupt," pledging to pursue litigation "to the highest court if necessary."
The international implications are significant. The United States, historically the world's largest cumulative greenhouse gas emitter, had committed to reducing emissions 50-52% below 2005 levels by 2030 under the Paris Agreement. The endangerment finding's elimination makes achieving this target vastly more difficult, potentially undermining global climate cooperation.
European Union climate officials expressed concern but emphasized their commitment to climate action regardless of U.S. policy. "The climate crisis does not pause for political changes in any single country," said Wopke Hoekstra, EU Climate Commissioner. "Europe will continue accelerating our transition to clean energy."
China, now the world's largest renewable energy investor, offered no official comment but continues massive deployment of solar and wind capacity. The country installed more renewable energy in 2025 than the rest of the world combined, suggesting that global climate action may increasingly proceed with or without U.S. federal participation.
Domestically, the repeal's impact may be limited by market forces and state-level action. California, which sets vehicle emissions standards followed by numerous other states representing more than 40% of the U.S. auto market, has pledged to maintain its regulations. Renewable energy costs have declined so dramatically that clean energy deployment continues on economic grounds even without federal mandates.
Yet the symbolic significance of an EPA Administrator celebrating the abandonment of climate science at a denial conference cannot be overstated. The agency's mission statement commits it to protecting human health and the environment "based on the best available science." Zeldin's Heartland Institute appearance represents a departure from that founding principle with implications extending far beyond any single regulation.
"This is about more than policy," said Bonfiglio. "It's about whether science and evidence guide decisions that affect every person on the planet. That principle is now in question at the federal level."
