Carbon Pollution Drops, but Scientists Say Iran War—Not Clean Energy—Is the Reason

Global carbon pollution edged lower this year, but scientists say the decline had less to do with climate action than with oil-market disruptions caused by the war in Iran.

The world produced 42.2 billion tons (38.2 billion metric tons) of carbon dioxide from burning fossil fuels, including coal, oil and natural gas, in 2026. That was 0.4% below last year’s total, according to researchers with the Global Carbon Project. Their estimate was published in the journal Earth System Science Data Discussions.

“It’s downwards, which sounds good, but this is largely driven by the war in Iran and what’s happened in the Strait of Hormuz,” said Glen Peters, a study co-author and scientist at Norway’s CICERO Center for International Climate Research. “So in a way, a little bit of good news, but for the wrong reasons.”

The conflict has effectively shut the Strait of Hormuz, a crucial route for global petroleum shipments, sending gasoline and oil prices higher worldwide.

The researchers calculated that oil-related emissions fell by nearly 2%, while emissions from natural gas declined 0.3%. Coal emissions, however, increased 0.6%.

More than 140 scientists from around the world contributed to the annual estimate, which includes projections for the final months of the year. The findings will be presented at the United Nations climate negotiations in Antalya, Turkey. Peters said the timing and pattern of the decline strongly indicate that the war-driven energy shock was responsible.

If the decrease had resulted solely from expanding renewable energy and a sustained reduction in fossil-fuel use, oil emissions would have gradually peaked before slowly falling, Peters said. Instead, “what we see this year is oil emissions are going up and then suddenly BANG, down 2%.”

Previous carbon pollution drops

This marks only the third global decline in carbon pollution during the 21st century. The previous drops came during the worldwide recession in 2009 and the COVID-19 pandemic in 2020.

After both crises, there was hope that the eventual economic rebound would accelerate the shift to clean energy. “But at the end of the day, we seem to go back to where we were before,” Peters said.

Outside researchers responded to the figures with cautious optimism, while questioning whether the decline can continue.

Niklas Höhne, co-founder of Germany’s NewClimate Institute, said “permanent shifts are happening,” particularly as electric cars and trucks gain momentum across Asia. He believes global carbon emissions may be approaching, or may already have reached, their peak.

Malte Meinshausen, a climate science and policy expert at the University of Melbourne, offered a more cautious assessment. Oil-producing countries and companies unaffected by the Strait of Hormuz disruption have enjoyed “tremendous windfall gains,” he said, giving them greater incentive to search for new supplies outside the Middle East. That could weaken the war’s short-term impact on emissions, he added.

NEXT UP: Trump Says Iran War Is ‘Effectively Over’ as Status Quo Holds

More than 1,000 tons per second of pollution

The 42 billion tons of carbon dioxide released this year equates to roughly 1,335 tons (1,211 metric tons) of the transparent, heat-trapping gas entering the atmosphere every second.

“We shouldn’t lose sight of the bigger picture. The world is still pumping more than a thousand (metric tons) of carbon dioxide into the atmosphere every second,” Mohamed Adow, director of the environmental group Power Shift Africa, said in an email.

“It’s very abstract to think about the magnitude of stuff we throw in the atmosphere every year, but it’s a ginormous number,” Peters said. “If it was black and not transparent, the sky would be dark.”

Despite the slight decline in fossil-fuel emissions, total global carbon dioxide emissions rose 1%. The increase was driven by land-use changes, including deforestation and human-caused peat fires, which grew more rapidly than fossil-fuel emissions declined, the study found.

China’s emissions drop raises eyebrows and hope

China, the United States, Europe and Japan—the world’s largest carbon polluters—each recorded an emissions decline of about 1%. Peters said those reductions were also largely linked to the oil shock. India moved in the opposite direction, with fossil-fuel emissions rising 4.4% this year.

China’s decline has drawn particular attention because experts have been waiting for the country’s long-running emissions growth to turn downward.

“China is giving us real reasons to be optimistic that its emissions may have peaked,” Adow said. “It’s building the world’s first major electrostate, investing at extraordinary speed and scale in solar power, wind energy, electric vehicles and the infrastructure to support them. This isn’t a temporary response to an oil crisis. It’s a fundamental transformation of China’s economy that is steadily reducing its dependence on fossil fuels.”

Jonathan Overpeck, dean of the University of Michigan’s environment school, said the world is still not moving quickly enough to eliminate fossil fuels. “We’re not phasing out fossil fuels fast enough, but some progress is better than no progress.”

___

The Associated Press’ climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP’s standards for working with philanthropies, a list of supporters and funded coverage areas at AP.org.