- Energy
- Climate
Evaluating the EPA’s claim on U.S. power plant emissions
Key takeaway
Scientists agree that electricity generation is a major contributor to climate change worldwide. The vast majority of this can be attributed to power plants that burn fossil fuels like coal or gas, which directly produce CO2 and other greenhouse gas emissions. This accounts for about a quarter of U.S. emissions.
Reviewed content
Verdict:
Claim:
Models continue to show that GHG emissions from power plants have no material impact on global climate change.
Verdict detail
Factually inaccurate:
The power plant sector is one of the largest contributors to greenhouse gas emissions both in the U.S. and worldwide.
Flawed reasoning:
Climate scientists say the EPA’s method comparing the emissions from one sector in one country to the emissions of the entire world can mislead by making emissions look less significant than they are.
Full Claim
Models continue to show that GHG emissions from power plants have no material impact on global climate change. In fact, if all carbon dioxides were eliminated tomorrow, there would be no meaningful climate impact.
Review
On 14 September, the U.S. Environmental Protection Agency (EPA) – the body of the federal government that’s responsible for controlling pollution – announced it planned to end limits on the greenhouse gases that power plants in the U.S. can emit.
The EPA said it would immediately repeal certain regulations set before 2025, during Joe Biden’s presidency. Furthermore, the EPA indicated plans to eliminate all remaining rules on the greenhouse gases from power plants. If successful, observers believe, these repeals could permanently stop the U.S. federal government from controlling these greenhouse gases.
How does the EPA justify these repeals? In its announcement, the EPA claims that ‘models’ show the greenhouse gases from power plants “have no material impact on global climate change”.
To be precise, in a supporting information sheet published the same day, the EPA claims it ran models and found, amongst other things, that U.S. power plants are only responsible for 2–6% of global CO2 emissions, global warming, and sea level rise across the rest of the 21st century. The EPA tries to argue this percentage is too small an impact to legally justify regulation.
We do not give a legal opinion. But from a climate science perspective, the claim that power plants “have no material impact on global climate change” does not hold up, as we show in this review. Climate scientists point out that the EPA’s use of this percentage is misleading.
The EPA misleads on percentages
Simply put, the power plants clearly have an impact on the climate. Around the world, about one-third of all our greenhouse gas emissions come from generating electricity or heat[1] (Figure 1):
But that is the entire world – what about power plants in the U.S. alone? This is what the EPA does in its supplementary information sheet. They claim they use climate models (FaIR and BRICK) to calculate this.
When we reached out to the EPA for comment, an EPA spokesperson reiterated what was in the EPA’s statement and added “EPA is using the same models that the Biden administration used”.
According to the EPA’s claim, U.S. power plants will contribute 0.035 °C of warming between 2026 and 2100, in a scenario where global temperatures rise 1.30 °C for a total of 2.66 °C above pre-industrial levels – that’s about 3% of global warming.
The EPA also suggests that U.S. power plants will contribute 6% of the increase in atmospheric CO2 between 2026 and 2100 and 2% of global sea level rise in that time period. The EPA uses these numbers to argue that power plants don’t emit enough greenhouse gas to legally justify regulating this under U.S. law.
We cannot comment on the legal implications of this. However, from the perspective of climate science, this argument doesn’t make much sense even if we take the EPA’s numbers at face value. If ‘2 to 3% of global warming’ or ‘6% of CO2 emissions’ seems small, then consider that the entire U.S. accounted for 13% of the world’s CO2 emissions in 2024.
Comparing a fraction of a single country’s emissions to the entire world will almost always make that fraction look relatively insignificant, but tiny fractions like these add up.
Put differently, the UK, France, and Germany put together account for about 3% of global CO2 emissions. If we used similar logic to ignore the emissions from every country responsible for less than 2% of global emissions, we’d ignore 37% of the world’s emissions – hardly insignificant.
Joanna Haigh
Emeritus Professor, Imperial College London
That human activity is causing the climate crisis through emission of greenhouse gases is indisputable. The US provides the largest source after China. If the US were to justify lack of climate action by the fact that “only 3%” of global emissions come from its power sector then nearly every other country/sector in the world could likewise claim exemption.
Don Grant
Professor, University of Colorado Boulder
The EPA’s claim that U.S. power plants account for only about 2% of the increase in global surface temperature through 2050 and 3% through 2100 may be technically compatible with emissions data while still giving a misleading impression of the importance of U.S. power-plant emissions.
Grant’s group has previously calculated that the U.S. power sector is responsible for about 17% of the world’s electricity-sector emissions – which is roughly in line with the EPA figures. However, even if that’s true, Grant told Science Feedback that comparing the two figures is misleading:
Don Grant
Professor, University of Colorado Boulder
A source responsible for a large fraction of global electricity-sector emissions can appear quite small when its effect is compared with total global warming caused by emissions from all countries, sectors, and greenhouse gases.
Putting the numbers in perspective
Many power plants generate electricity by burning fossil fuels like coal, gas, or fuel oil, or biofuels like wood chips. These power plants invariably produce greenhouse gases like CO2 in the process.
We have no reason to treat these “GHG emissions from power plants” differently from other types of emissions. All greenhouse gas emissions act in the same way. They all trap heat in the atmosphere and help warm the planet. (You can read more about how that process works, here.)
According to the EPA’s own data (collected during the Biden presidency), “electric power” accounted for 25% of U.S. greenhouse gas emissions in 2022 (Figure 2). By comparison, transport – like cars, trucks, and planes burning fuel – accounted for 28%, and industry – like the emissions from factories – accounted for 23%.
We know that U.S. power plant emissions have decreased since the 2000s, but this trend did not happen in a vacuum. The portion of low-carbon electricity in the U.S. has risen from about 28% to 43% in the past two decades. This is largely because the U.S. has built out low-carbon renewables like solar and wind.
Nor is this trend guaranteed to continue. Today, U.S. electricity demand is surging largely due to an expansion of data centers – some early estimates suggest this caused U.S. power emissions to rise in 2025, since coal power plants were turned on more often to meet this new demand. For the same reason, the U.S. is building a surge of new gas power capacity, which some researchers believe could increase U.S. power emissions for years to come.
Scientists’ models have actually established quite well that fossil fuel plants contribute to climate change. They’ve studied how much fossil fuel power plants contribute to global warming[2,3] and the net climate impacts of coal power plants[4]. They’ve also studied how much CO2 comes from individual power plants[5] and how emissions standards can reduce their impacts[6].
Conclusion
There is no doubt that CO2 is a greenhouse gas that warms the climate[7], even though the EPA’s statement also falsely claims that nothing would happen “if all carbon dioxides [sic] were eliminated tomorrow”.
But this sort of confusion is not out of character for the U.S. federal government since Donald Trump re-entered the presidency in 2025. Trump has repeatedly made misleading or false statements denying climate change or attacking renewables.
The loosening of rules on power plants is just the latest such move under Trump’s tenure – earlier this year, the EPA used similar logic to weaken regulations on road vehicle emissions.
Furthermore, the EPA repealed the Endangerment Finding, a 2009 decision ruling that greenhouse gases are a danger to human health and welfare. This decision gave the Obama-era EPA legal reason to regulate greenhouse gases. Repealing it would give the Trump-era EPA legal reason to end all restrictions.
(Some environmentalist groups and opposition politicians are fighting the EPA’s repeal in court, so this is probably not the last we’ll hear about the Endangerment Finding.)
Last year, a different U.S. government body – the Department of Energy – published a report authored by five well-known climate contrarians. The report misrepresented much other published science to understate the effects of climate change, misleadingly and at odds with the climate science consensus.
In similar fashion, the EPA again repeats an argument that climate contrarians have made in the past. The argument that a certain climate policy would not have meaningful effects on a global scale, and therefore is not worth pursuing, is a common one from opponents of climate action.
Reviewer feedback
Don Grant
Professor, University of Colorado Boulder
The EPA’s claim that U.S. power plants account for only about 2% of the increase in global surface temperature through 2050 and 3% through 2100 may be technically compatible with emissions data while still giving a misleading impression of the importance of U.S. power-plant emissions.
Our research using global plant-level data indicates that U.S. fossil-fueled power plants account for roughly 17% of worldwide electricity-sector CO₂ emissions. The 17% and 2–3% figures measure very different things. The first measures the U.S. share of emissions from a major global emitting sector; the second estimates how much global temperature would change if emissions from one national source category were removed while emissions from other sectors and countries continued.
Consequently, our findings do not necessarily show that EPA’s modeled temperature estimates are incorrect. Rather, they raise questions about the inference drawn from those estimates—that the contribution of U.S. power plants is too small to be considered significant.
There are several reasons this distinction matters:
- The denominator matters. A source responsible for a large fraction of global electricity-sector emissions can appear quite small when its effect is compared with total global warming caused by emissions from all countries, sectors, and greenhouse gases.
- The reasoning creates an aggregation problem. Climate change results from the cumulative emissions of many countries and sources. If each national source category is evaluated according to whether eliminating it alone substantially changes global temperature, even some of the world’s largest emitters could appear individually insignificant.
- EPA’s own modeling illustrates the sensitivity to the chosen metric. EPA estimates a smaller percentage contribution when expressed in terms of global temperature change than when expressed in terms of the increase in atmospheric CO₂ concentration. Thus, the conclusion about “significance” depends partly on which measure is emphasized.
- The relevant scientific question is therefore not simply whether EPA’s 2–3% calculation is numerically correct. It is also whether the individual-source/global-temperature comparison provides an appropriate basis for characterizing the contribution of a major emissions source to climate change.
A useful independent assessment would therefore examine both EPA’s climate-model calculation and the framing surrounding it. In particular, it could ask what share of global electricity-sector CO₂ emissions comes from U.S. power plants, where the United States ranks among national power sectors, and what would happen if the same “individual contribution to global temperature” reasoning were applied consistently to other major emitting countries.
The central point is that “a relatively small percentage of total global temperature change” is not equivalent to “a relatively small source of CO₂ emissions.” Both statements can be quantitatively true at the same time, but they answer different scientific questions.
References:
1 – Qin et al. (2022) Global and Regional Drivers of Power Plant CO2 Emissions Over the Last Three Decades Revealed From Unit-Based Database. Earth’s Future.
2 – Zhang & Caldeira (2015) Time scales and ratios of climate forcing due to thermal versus carbon dioxide emissions from fossil fuels. Geophysical Research Letters.
3 – Ekwurzel et al. (2017) The rise in global atmospheric CO2, surface temperature, and sea level from emissions traced to major carbon producers. Climate Change.
4 – Shindell & Faluvegi (2010) The net climate impact of coal-fired power plant emissions. Atmospheric Chemistry and Physics.
5 – Brunner et al. (2023) Evaluation of simulated CO2 power plant plumes from six high-resolution atmospheric transport models. Atmospheric Chemistry and Physics.
6 – Tong et al. (2018) Current Emissions and Future Mitigation Pathways of Coal-Fired Power Plants in China from 2010 to 2030. Environmental Science & Technology.
7 – IPCC (2023) Climate Change 2023: Synthesis Report. Sixth Assessment Report of the Intergovernmental Panel on Climate Change.
