In a significant setback for climate efforts, the United States saw its greenhouse gas emissions rise in 2025, breaking a years-long trend of reductions. According to a major new study, the increase was fuelled by soaring electricity demand from data centres and cryptocurrency mining, coupled with a colder winter.
Key Drivers Behind the Emissions Surge
Research from the independent firm Rhodium Group, published on Tuesday, calculated that heat-trapping emissions from burning fossil fuels grew by 2.4% in 2025 compared to 2024. This equates to an additional 139 million tons of carbon dioxide equivalent released into the atmosphere, bringing the yearly total to approximately 5.9 billion tons.
Ben King, a director at Rhodium and co-author of the study, identified several interconnected factors. A notably cool winter across the US led to increased heating in buildings, often powered by natural gas and fuel oil. Simultaneously, a sharp rise in electricity demand, largely attributed to the explosive growth of data centres and cryptocurrency mining operations, required more power generation.
This surge in demand, combined with higher natural gas prices, triggered a notable shift: coal power generation increased by 13% in 2025. This marked a reversal for a fuel source whose use had shrunk by nearly two-thirds since its 2007 peak.
Policy Impact and the Clean Energy Paradox
The report notes that environmental policy rollbacks initiated by the administration of President Donald Trump were not a significant factor in the 2025 increase, as most were only enacted later. However, their future influence is a major concern.
Despite the overall rise in emissions, the clean energy sector showed robust growth. Solar power generation jumped by an impressive 34%, surpassing hydroelectric to become a more prominent renewable source. Zero-carbon sources, including renewables and nuclear, now supply 42% of US electricity.
King emphasised that the fundamental economics still favour renewables. "The economic case for adding renewables is quite strong still," he stated, suggesting that attempts to alter this trajectory may struggle against market forces.
A Warning Sign for Climate Targets
The 2025 data represents an ominous shift. For years, the US had managed to decouple economic growth from carbon pollution, with emissions dropping 20% from 2005 to 2024. Last year, however, pollution grew faster than economic activity.
Rhodium's projections have darkened as a result. Prior estimates suggested US emissions could fall 38-56% below 2005 levels by 2035. The firm now expects the reduction to be about one-third less than that.
Experts reacted with alarm. Jonathan Overpeck, Dean of the School for Environment and Sustainability at the University of Michigan, called the increase "a harbinger of what’s to come" and a "huge unforced economic error" in favour of legacy fossil fuels. Veteran climate campaigner Bill McKibben offered a blunter assessment: "It’s so incredibly stupid that the US is going backwards on this stuff."
The study underscores the fragile nature of emissions progress and highlights how rapid technological growth and energy market fluctuations can swiftly undermine climate gains. All eyes will now be on 2026 data to see if this reversal becomes a sustained trend.
