WASHINGTON – Contrary to the previous trend of declining emissions, the United States saw a 2.4% increase in greenhouse gas emissions from fossil fuels in 2025 compared to the prior year, as reported by a study released Tuesday.

The uptick in emissions is linked to several factors, including a particularly chilly winter, the rapid expansion of data centers and cryptocurrency mining operations, and a surge in natural gas prices, according to findings by the independent research firm Rhodium Group. The study clarified that the rise was not significantly influenced by environmental policy changes under President Donald Trump, as those were only recently implemented. Scientists identify the burning of coal, oil, and natural gas as the primary contributors to the acceleration of global warming.

From 2005 to 2024, U.S. emissions of carbon dioxide and methane decreased by 20%, despite occasional short-term spikes. Historically, carbon emissions would climb in tandem with economic growth, but recent clean energy initiatives had managed to break this link, allowing emissions to fall even as the economy strengthened.

However, last year marked a shift, with emissions increasing at a pace exceeding economic growth, noted Ben King, a co-author of the study and director at Rhodium’s energy group. King estimated that in 2025, the U.S. emitted 5.9 billion tons (5.35 billion metric tons) of carbon dioxide equivalent, a rise of 139 million tons (126 million metric tons) from 2024.

The frigid winter in 2025 led to heightened heating demands, which predominantly rely on natural gas and fuel oil—major sources of greenhouse gases, King explained. Additionally, the burgeoning electricity requirements of data centers and cryptocurrency operations resulted in increased output from power plants, including those burning coal, a high carbon-emitting energy source.

Rising natural gas prices contributed to a 13% boost in coal-generated power, reversing some of the significant reductions seen since coal’s peak usage in 2007, King reported.

“It’s not like this is a huge rebound,” King said. “We’re not sitting here claiming that coal is back and going to dominate the sector or anything like that. But we did see this increase and that was a large part of why emissions went up in the power sector.”

It will take time for data to reflect Trump policies

King said the list of more than two dozen proposed rollbacks of American environmental policies by the Trump administration hadn’t been in place long enough to have an effect in 2025, but may be more noticeable in future years.

“It’s one year of data so far,” King said. “So we need to see the extent to which this trend sustains.”

Solar power generation jumped 34%, pushing it past hydroelectric power, with zero-carbon emitting energy sources now supplying 42% of American power, Rhodium found. It will be interesting to see what happens as the Trump administration ends solar and wind subsidies and discourages their use, King said.

“The economic case for adding renewables is quite strong still,” King said. “This stuff is cost-competitive in a lot of places. Try as they might, this administration can’t alter the fundamental economics of this stuff.”

Before the Trump administration took office, the Rhodium team projected that in 2035 U.S. greenhouse gas emissions would have fallen between 38% and 56% compared to 2005 levels, King said. Now, the projected pollution drop is expected to be about one-third less, he calculated.

Experts say pollution increase is an ominous sign

Others who were not involved in the Rhodium report said last year’s increase in emissions is an ominous sign.

“Unfortunately, the 2025 U.S. emission increase is likely a harbinger of what’s to come as the U.S. federal leadership continues to make what amounts to a huge unforced economic error by favoring legacy fossil fuels when the rest of the world is going all in on mobility and power generation using low-carbon technology, primarily based on renewables and batteries,” said University of Michigan environment dean Jonathan Overpeck.

Overpeck said that favoring fossil fuels will harm both the U.S. economy and air quality.

Longtime climate change activist Bill McKibben said bluntly: “It’s so incredibly stupid that the U.S. is going backwards on this stuff.”

The Environmental Protection Agency said in a statement it wasn’t familiar with the Rhodium Group report and is “carrying out our core mission of protecting human health.”

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