Jody Freeman and Carrie Jenks

Jody Freeman and Carrie Jenks


Jody Freeman, the Archibald Cox Professor of Law, is founding director of the Environmental and Energy Law Program at Harvard Law School and a leading expert on administrative law and environmental law. Jody served as counselor for Energy and Climate Change in the Obama White House from 2009-2010 and worked with the Biden transition team on its climate action plan.

Carrie Jenks is executive director of the Environmental & Energy Law Program, leading the EELP team in identifying legally durable strategies to support climate and environmental policies and advance clean energy deployment. Before joining EELP, Carrie was an executive vice president at M.J. Bradley & Associates where she directed power company coalitions that played a critical role in supporting — and defending in court — air pollution and climate regulations.

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The president targets EPA’s authority to address climate change – will he succeed?

It would be an uphill battle to convince federal judges in 2025, even conservative ones, that the scientific record on climate change is wrong.
Jan 28, 2025
By Jody Freeman and Carrie Jenks

On his first day in office last week, President Trump began to redirect American energy and environmental policy with a series of executive orders that could have long-term effects on both the climate and American businesses.

One of these January 20 orders – Unleashing American Energy takes aim at the Environmental Protection Agency’s ability to regulate climate-warming greenhouse gases. It directs the EPA to submit recommendations on the “legality and applicability” of the agency’s 2009 endangerment finding – the science-based determination, made under the Clean Air Act, that greenhouse gases endanger the public health and welfare. The endangerment finding underpins the EPA’s climate regulations.

The obscurely worded directive appears to suggest that the EPA should consider rescinding the endangerment finding, which the first Trump administration contemplated but ultimately declined to do. Rescinding the finding now would require the agency to rebut a voluminous scientific record attesting to the serious harms to public health already occurring and likely to worsen with rising temperatures. That record has only grown stronger since 2009 when the Obama administration first made the endangerment finding in the aftermath of the Supreme Court’s Massachusetts v. EPA decision, when the Court ruled that greenhouse gases are pollutants under the Clean Air Act and that the George W. Bush EPA had erred in refusing to decide, based on the science, whether these gases posed an endangerment.

But it would be an uphill battle to convince federal judges in 2025, even conservative ones, that the scientific record on climate change is wrong.

Instead of taking this legal risk, the Trump administration may opt for a different strategy – one it tried late in the president’s first term, which was never legally tested. In January 2021, just before Trump left office, the EPA adopted a threshold test for whether it would regulate a sector’s greenhouse gas emissions, based on a calculation of how much that sector emits on an absolute basis and the sector’s emissions as a share of global emissions. Only power plants crossed the chosen threshold for regulation, and the standards the EPA ultimately adopted to control power plant emissions were extremely weak*. The Trump administration might try this approach again to avoid having to regulate emissions from the transportation sector and the oil and natural gas industries.

Another option would be for the EPA to leave the endangerment finding alone and simply weaken climate rules across the board. This is the least legally risky approach but also takes the longest, since rescinding and replacing rules for each sector will take considerable agency resources and several years. The final rules inevitably will be challenged by states, industries, and environmental groups if they rely on contestable legal interpretations or dubious technological and economic analyses.

A final option was alluded to by incoming EPA Administrator Lee Zeldin, who signaled in his confirmation hearing that he might favor a maximalist approach to the EPA’s discretion. In his testimony, Zeldin argued that the Supreme Court does not require the EPA to regulate greenhouse gases but rather authorizes the EPA to regulate. This reasoning tracks Justice Scalia’s dissent in Massachusetts v. EPA, which Chief Justice Roberts and Justices Thomas and Alito joined. Scalia argued that there may be reasons not to regulate greenhouse gas emissions beyond scientific uncertainty, and that the Clean Air Act authorizes the EPA to determine whether to regulate. Perhaps Zeldin thinks that it is worth taking another swing at this argument now that Court’s composition has changed. Notably, none of the justices from the Massachusetts majority remain on the Court. He might also believe that the Justices would tolerate a lengthy period during which EPA simply reconsiders the endangerment finding in light of many developments since 2009, which would buy the agency time and significantly delay any climate rules. 

From a policy perspective, rescinding the endangerment finding, setting a significant contribution threshold, gutting climate rules or delaying them could prove to be bad for business and U.S. competitiveness. Many companies in a wide range of industries have made strategic business decisions and investments in anticipation of an ongoing transition to a cleaner global energy economy; regulatory churn only adds cost and creates uncertainty, undermining incentives for innovation. Think of the U.S. auto industry trying to compete with Chinese EV makers for global market share, or the power sector trying to shore up the resilience and robustness of our electricity supply, while planning for intensifying fire risks. As the legal battle over the endangerment finding plays out, and the Trump administration’s deregulatory strategy unfolds, it will be important to watch both how Congress and these private sector players react. 

The EPA has until February 19, 2025, to offer its recommendations on the endangerment finding, so we will know more soon about how the administration plans to proceed. At a minimum, the administration will seek to weaken Biden administration standards; at a maximum, it will try to block the EPA from regulating greenhouse gases under the Clean Air Act in perpetuity. Either way, legal battles will ensue.

* The D.C. Circuit struck these EPA standards down and President Biden replaced them, but an appeal resulted in a Supreme Court decision in West Virginia limiting how the EPA may regulate these sources.

All perspectives expressed in the Harvard Climate Blog are those of the authors and not of Harvard University or the Salata Institute for Climate and Sustainability. Any errors are the authors’ own. The Harvard Climate Blog is edited by an interdisciplinary team of Harvard faculty.