For the first time in three years, greenhouse gas emissions in the United States rose last year, reversing a downward trend and raising fresh concerns among climate experts about the pace of progress in cutting planet-warming pollution. New preliminary estimates indicate that emissions of carbon dioxide and other heat-trapping gases increased by approximately 2.4 per cent in 2025 compared with the previous year, marking a notable shift after two consecutive years of declines.
The increase was driven largely by a combination of unusually cold winter weather early in the year and rapidly growing electricity demand from data centres and other high-load facilities powering artificial intelligence applications. According to analysts, these factors pushed up energy consumption and led to greater reliance on fossil fuels, especially coal, in key sectors such as buildings and power generation.
Data from the independent research firm Rhodium Group show that emissions in the buildings sector climbed by nearly 7 per cent as households and commercial spaces burned more natural gas and fuel oil to stay warm during the colder months. Meanwhile, emissions from the power sector rose by roughly 3.8 per cent, partly because utilities increased coal-fired electricity generation to meet surging demand.
The rebound in coal use was notable; utilities in several regions, including parts of the Midwest and Texas, turned to the “dirtiest” fossil fuel as higher natural gas prices made it more expensive to generate electricity from cleaner sources. As a result, coal-fired generation jumped by about 13 per cent compared with 2024, analysts said.
Experts also point to the growing energy footprint of data centres and cryptocurrency mining operations, which require vast amounts of continuous electricity to power servers, cooling systems and computational infrastructure. The expansion of artificial intelligence technologies and digital services accelerated electricity consumption in the commercial and industrial sectors, contributing to higher overall emissions.
Despite the rise in greenhouse gas output, some sectors showed resilience. Transportation emissions, historically the largest single source of emissions in the US, remained relatively stable year-on-year, in part because of increased use of hybrid and electric vehicles. Additionally, growth in renewable energy sources such as solar continued to offset some fossil fuel use. Last year saw a significant increase in solar generation, with capacity rising sharply and helping to expand the share of zero-emission energy on the grid.
Still, the overall uptick in emissions means that the United States, which remains one of the world’s largest sources of greenhouse gases, has stumbled in its efforts to cut pollution at the pace needed to meet long-term climate goals. While emissions are still lower than they were before the COVID-19 pandemic and have declined significantly from 2005 levels, the reversal underscores how variable factors like weather and technological growth can influence national emission trajectories.
Climate analysts say that without stronger policies and investments to accelerate the transition to cleaner energy and improve energy efficiency, emissions could continue to grow as economic activity expands and digital infrastructure demands increase. The findings highlight the complex challenges policymakers face in balancing economic growth, energy reliability and climate commitments amid evolving technological and environmental conditions.
