Ask Onix
Global CO₂ emissions reach new peak in 2025, despite slower growth and renewable progress
The world's combustion of fossil fuels is projected to release a record 38.1 billion tonnes of carbon dioxide (CO₂) in 2025, marking a 1.1% increase over 2024, according to the Global Carbon Budget report published Thursday. The findings underscore the persistent gap between climate targets and reality as negotiators gather in Brazil for the UN COP30 climate summit.
While the rise in emissions continues, the growth rate has slowed dramatically over the past decade-averaging 0.3% annually compared to 1.9% per year in the prior decade-largely due to the rapid expansion of renewable energy, particularly in China. Total emissions from all human activities, including land-use changes like deforestation, are expected to dip slightly to 42.2 billion tonnes in 2025, down from 42.4 billion in 2024, the report notes.
Renewables curb power-sector emissions for first time since pandemic
A separate analysis by the clean energy think tank Ember reveals a critical shift: fossil fuel use in electricity generation has flatlined in 2025, defying the post-pandemic rebound trend. This stagnation occurred even as global electricity demand surged, with the gap filled by record growth in solar and wind power.
"We've spent centuries relying on fossil fuels to drive economic growth, but the last decade has rewritten that rule," said Nicolas Fulghum, senior data analyst at Ember. "Solar power is now expanding faster than any energy source in history-outpacing even the rise of coal in the Industrial Revolution."
"Whatever happens in the power sector ripples globally. It's the single largest emitter, and its trajectory will shape whether we meet climate goals."
Nicolas Fulghum, Ember
The International Energy Agency (IEA) echoed this optimism Wednesday, projecting that global energy-sector CO₂ emissions-encompassing electricity, transport, and industry-could peak within years under current policies. While the exact timing remains uncertain, such a peak would mark a historic turning point, though not an end to warming.
Mixed signals: Slowing growth vs. insufficient cuts
Despite the progress, scientists warn that emissions remain far above the reductions needed to limit global warming to 1.5°C above pre-industrial levels. The Climate Action Tracker (CAT) group, in a report released Thursday, found that current policies put the world on track for 2.6°C of warming by 2100-a figure virtually unchanged since 2020.
"We're at a crossroads," said Dr. Bill Hare, CAT's chief scientist. "The tools to avert catastrophe-scalable renewables, proven policies-are at our fingertips. Yet without urgent action at COP30, we risk locking in a future of 2.5°C or 3°C warming, with devastating consequences."
"As long as we emit CO₂, warming will continue. To stop it, we must reach net-zero emissions."
Prof. Pierre Friedlingstein, University of Exeter
The Global Carbon Budget report highlights a silver lining: 35 countries have slashed fossil fuel emissions while growing their economies over the past decade-nearly double the number from 2010-2020. Corinne Le Quéré, a climate scientist at the University of East Anglia, called the trend "a sign that decoupling growth from emissions is possible," though she cautioned, "We're not cutting fast enough."
COP30: A pivot point for climate action?
Delegates in Brazil face mounting pressure to accelerate transitions away from fossil fuels. The IEA and Ember reports suggest that structural shifts-like solar's dominance in new electricity capacity-could soon tip global emissions into decline. Yet CAT's analysis underscores the risk of backsliding if governments double down on gas and oil.
"The technology is there. The economics favor renewables. The question is political will," said Hare. "COP30 must be the moment we choose the 1.5°C path-or admit we've given up on it."
