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Are Greenhouse Gases No Longer a Threat? Potential Impact of EPA’s Proposed Repeal on Human Health

August 8, 2025

This July the U.S. Environmental Protection Agency (EPA) proposed rescinding its 2009 Endangerment Finding. The original scientific finding concluded that six greenhouse gases, including carbon dioxide and methane, endanger public health and welfare and established a legal basis for the EPA to regulate them as air pollutants under the Clean Air Act.

A landmark scientific and legal determination, the original declaration led to vehicle fuel-efficiency standards, power plant emissions rules, identification of methane producers and more.

If finalized, this repeal would remove the scientific and legal foundation for regulating greenhouse gases, undercutting decades of progress on climate and air quality protection. These include clean-car standards, power plant rules, and other greenhouse gas regulatory programs as well as significantly undermining efforts to curb emissions in the transportation, energy and industrial sectors.

The science linking greenhouse gas–driven climate change to human health harms is clear and settled. According to EPA’s earlier analysis, rising temperatures lead to:

  • More frequent and intense heat waves, increasing heat-related deaths and hospitalizations. Because of the greenhouse effect where rising levels of greenhouse gases trap heat in the atmosphere it leads to a warming planet and more extreme weather events, including heat waves. With a warmer planet, the frequency, duration, and intensity of heat waves are increasing. This means that not only will there be more days of extreme heat, but the heat will also be more intense and last for longer periods.
  • Poorer air quality, especially elevated ground‑level ozone, exacerbating asthma and other respiratory illnesses. Climate change also increases people’s exposure to allergens like pollen due to lengthened growing seasons that increase pollen production, potentially worsening respiratory conditions.
  • Worsened extreme weatherfloods, wildfires, storms—that cause injuries, mental stress, and displacement. Warmer oceans mean more energy for storms, leading to stronger hurricanes, cyclones, and typhoons. This can lead to rising sea levels and more intense rainfall contributing to more frequent and severe flooding, causing displacement and property damage leading to further social and economic disruption.
  • Greater water- and insect-borne infectious diseases. Warmer temperatures and changing precipitation patterns can expand the geographic ranges of vectors like mosquitoes and ticks, increase their reproduction rates and lifespan, and create conditions that allow pathogens to thrive. Additionally, extreme weather events associated with climate change can lead to increased contamination of water sources and disrupt natural ecosystems, further contributing to disease outbreaks.

Unfortunately, these adverse conditions often predominantly affect vulnerable populations, including children, the elderly, low‑income communities, indigenous groups, and low-lying populations due to limited resources, pre-existing health conditions, and because they do not have the capacity to adapt to or recover from environmental hazards as quickly. Public health experts already warn that repealing the finding would dismantle protections and likely lead to more heat-related deaths, higher asthma rates, and greater spread of infectious diseases.

Repealing the original finding removes the regulatory tools EPA uses to mitigate these effects, thereby heightening human health risks — at a time when we’re witnessing more and more catastrophic events like the recent flooding in Texas.

While findings aren’t laws themselves, they are critical scientific determinations that form the legal foundation for regulatory action. Removing such a finding can have legal, scientific, regulatory, and public trust consequences. Here’s how:

1. Undermining Science-Based Policymaking

The 2009 Endangerment Finding was grounded in peer-reviewed science from authoritative sources like the Intergovernmental Panel on Climate Change (IPCC) and the recently dismantled U.S. Global Change Research Program. Repealing it:

  • Signals a rejection of established climate science by a federal agency tasked with protecting public health.
  • Erodes the norm that policy decisions should follow scientific evidence rather than political pressure or ideological preferences.
  • Sets a precedent that scientific conclusions can be reversed without new evidence, damaging the role of science in governance.

This kind of move may chill scientific independence within agencies, discouraging researchers from presenting inconvenient facts. This is not only a theoretical threat but a real one today. We’ve already seen real repercussions as it relates to the recent firing of Erika McEntarfer, the commissioner of the Bureau of Labor Statistics, after the bureau released monthly jobs data showing surprisingly weak hiring in July and large downward revisions to job growth in the previous two months.

2. Weakening the Legal Basis for Regulation

In U.S. environmental law, a scientific finding like the Endangerment Finding is a legal prerequisite for regulation. Specifically:

  • Without the Endangerment Finding, EPA loses its authority to regulate greenhouse gases as air pollutants under the Clean Air Act.
  • Courts have upheld that such findings are necessary to justify emission limits for vehicles, power plants, and other sources.
  • A repeal could invite a cascade of lawsuits challenging existing or future climate-related rules.

So, while not a regulation itself, the Endangerment Finding is the cornerstone of many legally binding standards.

3. Disrupting Regulatory Stability

Repealing a finding like this sends a message that science-driven policy can change with political leadership, regardless of the evidence. This creates:

  • Regulatory uncertainty for industries, state governments, and international partners.
  • Risk of delays or paralysis in crafting climate solutions — since rules based on the finding (vehicle standards, methane rules, etc.) may be suspended or thrown out.
  • A chilling effect on investment in clean technologies that depend on stable climate policy.

4. Prioritizing economic concerns over environmental and health risks

In proposing the repeal, concerns have been raised about the economic costs associated with climate regulations.

  • Critics argue that focusing solely on economic concerns neglects the significant health and environmental benefits of reducing greenhouse gas emissions.

While economic growth is important, it is a solely near-term issue that should not come at the expense of the environment and public health. A sustainable approach that integrates environmental and health considerations into economic decision-making is crucial for long-term prosperity and well-being.

5. Eroding Public Trust in Agencies and Science

EPA findings carry weight because they reflect neutral, peer-reviewed evidence. A politically motivated repeal may:

  • Deepen public skepticism of federal science agencies.
  • Undermine confidence in public health and environmental protections.
  • Discourage collaboration with academia, health organizations, and international institutions that rely on consistent scientific standards.

This is especially dangerous during times when public trust is essential for health communication, such as during climate-driven disasters or disease outbreaks. We’ve seen this play out in real time as misinformation about COVID-19 vaccines has led to increased vaccine hesitancy and a decline in vaccination rates leaving our most vulnerable populations at risk of infection from preventable diseases.

More Than a Policy Change

The EPA’s proposal to repeal the 2009 Endangerment Finding is not just an administrative move — it’s a foundational shift that could:

  • Strip away protections that millions depend on for clean air and stable climate.
  • Erase the scientific basis for regulating the pollutants driving global warming.
  • Expose vulnerable populations to increasing, avoidable health risks.

As scientific communicators, it’s our job to ensure that scientific findings are not political toys. We need to ensure that both lawmakers and the public understand that scientific findings are built on rigorous evidence and serve as the bedrock for policies that save lives.

Repealing a scientific finding dismantles the infrastructure that allows governments to act on science to protect the public. Without a clear federal mandate to regulate greenhouse gas emissions, the U.S. risks unchecked warming, degraded air quality, more severe weather, and increased disease burdens. The consequences are not hypothetical; they are grounded in decades of peer-reviewed science and real-world monitoring.

It not only puts lives — but our shared future — at risk.

POSTED BY: Meredith Sosulski

Meredith Sosulski