IT is a tragic sign of the times that, given the flagrant military assaults and leadership decapitation campaigns by the US on Iran and earlier on Venezuela, and hyper-aggressive assertion of US hegemony all around the world, the Trump administration’s repeal of the earlier “endangerment finding” in the US regarding the adverse effect of greenhouse gas (GHG) emissions on human health, has not received the attention it deserves, especially outside the US.

THE “ENDANGERMENT FINDING”            

In 2007, the US Supreme Court ruled that GHG emissions were pollutants under the US Clean Air Act and called upon the US regulator, the Environment Protection Agency (EPA), to determine whether they caused harm to human health. After extensive studies and consultations with scientific agencies and experts, the EPA found in 2009 that 6 major GHGs including carbon dioxide (CO2) did indeed endanger “the public health and welfare of current and future generations,” thus triggering an obligation to regulate them. This “endangerment finding” as it is known in environment circles, led to a slew of US federal regulations aimed at reducing GHG emissions in the US, notably on fuel-efficiency and pollution standards in automobiles, coal and oil-fired power stations and other industries, and also led to policies promoting renewable energy. These domestic regulations through executive rules and judicial pronouncements enabled measures which could not be legislated in the US. In a serious indictment of the US political establishment across both Democrat and Republican Parties, both more concerned about special interests in the energy and automobile industries, the necessary two-thirds majority in the US Congress never appeared possible then, and still remains a distant dream.

This legislative gridlock drove the US to first drop out of the UN Kyoto Protocol governing global emissions control in 2001, and forced even relatively climate-friendly subsequent US administrations to seek non-legislative means for the purpose. The Obama administration made binding emission reduction commitments under the Paris Agreement at the 2015 climate summit, albeit only moderate ones compared with what the science called for and also compared to what other leading developed countries or blocs such as the EU were making. However, Trump in his first term in office withdrew the US from the Paris Agreement in 2017. After US President Biden re-joined in 2021, Trump in his second term promptly announced US withdrawal again in January 2025, denying climate change and declaring it to be a “hoax.” Through all this turmoil in the US approach to the global emissions control regime, domestic US regulations enabled by the “endangerment finding” had placed at least some checks on US emissions, even if ostensibly with a domestic health rationale rather than a global one of tackling climate change.

IMPACT ON US GHG EMISSIONS                

Now the climate-denier Trump administration, by one stroke of the pen, has revoked the “endangerment finding,” which will lead to unraveling of all federal domestic regulations relating to GHGs, particularly in the automobile, power generation and industrial sectors, undoing 9 years of regulatory efforts and emissions curbs. Since the same atmospheric GHGs also contribute to global warming, this will also further increase US emissions and add to the dangerously mounting climate crisis.

Some estimates are that tighter vehicle tailpipe pollution and fuel efficiency standards alone would have removed 8 billion tons of CO2 over the next three decades, which may now reduce substantially. US transport sector emissions are equal to that of the entire Russian economy, and would hold the fifth rank in the world if it were a country. Other estimates suggest that covering all sectors, an additional 7.5-18 bn tons of GHGs would be added to the atmosphere in the same period, about 3 times the current annual GHG emission of the US at around 6.4bn tons. These are significant and dangerous increases to global emission levels. At a time when climate change is galloping, bringing unprecedented heat waves, forest fires, extreme rainfall and floods, melting polar ice caps and glaciers, sea-level rise, ocean acidification, bio-diversity loss and many other grave impacts, this deplorable decision by the US under Trump, callously adding to global emissions, deserves the most severe condemnation. It flies in the face of science and will bring untold misery to people around the world, including in the US. Unfortunately, as has happened with other Trumpian roughshod approach to international policies, global and regional powers have mostly preferred to keep silent rather than oppose the Trump administration.  

At the same time, it may be noted that even though the US has been a reluctant participant in international emission control efforts, US emissions have been on a declining trajectory since 2005, having reduced by about 17 per cent since that year. This is far below the commitment by the Biden administration to reduce emissions by 61-66 per cent of 2025 levels by 2035. Even this is much less than the UK’s commitment to cut emissions by 81 per cent below 1990 levels and the EU’s commitment of 69 per cent with the same baseline and target year. (It may be noted that the US baseline of 2005, rather than 1990 as adopted by most developed countries, further reduces the US commitment to 44-49 per cent by 2035)

However, environmental groups and think tanks in the US believe that federal regulations are responsible for only a part of GHG emissions from the US. State and local regulations, responding to public pressure, also drive emission reductions, as do falling costs of renewable energy, electric mobility and pollution abatement technologies. Some estimates suggest that even after de-regulation brought about by revocation of the “endangerment finding,” US emissions would decline by 26-35 per cent below 2005 levels by 2035, whereas the decline would have been 32-44 per cent if de-regulation had not taken place. Given the generally poor emissions reduction performance by the US, there is at least a very thin silver lining to that cloud.

TECHNO-ECONOMIC REALITIES    

Changing techno-economics and lower costs have also driven an increase in solar, wind and natural gas power generation in the US, while adoption of electric cars has increased substantially, although aided by but not totally dependent of regulatory policies.

Coal-fired power generation has become increasingly uneconomical in the US compared to renewable and gas. Despite the rhetoric, the Trump presidency has seen the largest reduction in coal-based power capacity compared to any other administration. Further, despite an overtly hostile policy environment, wind and solar continue to be more competitive than gas-fired power. An overwhelming majority of new power plants in the US, amounting to more than 90, have been solar, wind and storage, with the remainder all gas.

Electric vehicles (EV) broadly continue their growing popularity in the US despite a substantial and sudden drop in sales volumes in the last quarter of 2025 due to the withdrawal of the sizeable Biden-era subsidies. However, given the record EV sales in 2024 of 1.3 million units, the drop in Q4 sales only resulted in an overall drop of sales volumes from the 8.1 per cent of total passenger vehicle sales in 2024 to 7.8 per cent in 2025. Automobile industry analysts assess that upfront prices, the main point emphasized by the Trump administration, is only one aspect of consumer choice. Lower running costs of EVs, at around $5 per mile compared to $13 for petrol vehicles, and introduction of new models by different manufacturers at different price points, are all influencing trends favouring EVs.

US automakers, already declining in global sales of internal combustion passenger vehicles due to technological innovation by competitors in Europe, Japan and South Korea, now risk falling behind in EVs too. EVs are registering close to 20 per cent year on year sales growth, with China establishing itself as the clear market leader. The recent de-regulation reduces the incentive for US car makers to innovate and shift to EVs. Together with the reversals in renewable energy, the US economy is staring at the sunset in a wide range of sunrise industries. However, there is some blowback in the US.

COUNTER CURRENTS     

The revocation of the “endangerment finding” is facing legal challenges from a host of environmental groups, science and health organizations, and think tanks, such as the American Public Health Association, Alliance of Nurses for a Healthy Environment, Physicians for Social Responsibility, Environmental Defense Fund and the Natural Resources Defense Council. Legal experts also foresee many local tort suits for causing damage to health, air pollution and what are known as public “nuisance.”

19 States in the US are committed to next-zero targets by 2050 and other Paris Agreement-like goals, while numerous counties and cities too have adopted tight emission reduction targets.

The last word may yet not have been heard on the “endangerment finding.”