Global fossil-fuel carbon dioxide emissions fell 0.4% amid Iran war

Land-use increases drove total global carbon dioxide up 1%

Global fossil-fuel carbon dioxide emissions fell 0.4% from their 2025 level to an estimated 42.2 billion tons (38.2 billion metric tons) in 2026, according to scientists from the Global Carbon Project. The decline in heat-trapping carbon dioxide released by burning coal, oil and gas contrasted with a 1% increase in overall global carbon dioxide emissions. The study said land-use changes, including deforestation and human-caused peat fires, increased faster than fossil-fuel burning decreased.

Study co-author Glen Peters, a scientist at the CICERO Center for International Climate Research in Norway, said the decline was largely driven by oil shocks reverberating from the Iran war rather than by actions the world has taken to fight climate change. “It’s downwards which sounds good, but this is largely driven by the war in Iran, what’s happened in the Strait of Hormuz,” Peters said. “So in a way, a little bit of good news, but for the wrong reasons.”

The Iran war has effectively closed the Strait of Hormuz, a vital shipping artery for petroleum products, pushing up global gasoline and oil prices. Peters said the researchers were certain the decline was connected to war-triggered energy shocks because of both the timing and the type of fuel-emission drops.

The Global Carbon Project found oil emissions dropped nearly 2% and natural gas emissions fell 0.3%, while coal emissions rose 0.6%. If the overall carbon dioxide emission drop were due solely to a rise in renewables and a systemic drop in fossil fuel use, oil emissions “would slowly come up to a peak and then slowly decline afterward, whereas what we see this year is oil emissions are going up and then suddenly BANG, down 2%,” Peters said.

Most of the world’s biggest carbon-polluting nations — China, the United States, Europe and Japan — showed about a 1% drop in emissions in 2026, which Peters attributed to the oil shock. India’s fossil-fuel pollution went up 4.4%, the study found.

The 2026 result was the third time global carbon pollution dropped in the 21st century. The other two drops came because of the global recession in 2009 and the COVID-19 pandemic in 2020. In those past two crises, people hoped the recovery from the shocks would emphasize clean energy, Peters said, “but at the end of the day, we seem to go back to where we were before.”

Outside experts greeted the figures with both hope and skepticism about whether the decline would last. Niklas Höhne, co-founder of Germany’s NewClimate Institute, said “permanent shifts are happening,” especially with skyrocketing switches to electric cars and trucks, especially in Asia. He said he thinks the global peak of carbon emissions is near or has already arrived.

Malte Mienshausen, a climate science and policy expert at the University of Melbourne in Australia, said oil-producing nations and companies not affected by the blockage of the Strait of Hormuz reaped “tremendous windfall gains.” Those gains boost their efforts to look for oil outside the Middle East, he said, which will dampen any short-term effects of reduced carbon emissions from the war.

The 42 billion tons of carbon dioxide emitted in 2026 amounts to about 1,335 tons (1,211 metric tons) of the transparent, heat-trapping gas entering the air every second, more than 1,000 tons per second. Mohamed Adow, director of the environmental group Power Shift Africa, said in an email, “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.” Peters said, “It’s very abstract to think about the magnitude of stuff we throw in the atmosphere every year, but it’s a ginormous number.” He added, “If it was black and not transparent, the sky would be dark.”

China’s emission drop raised eyebrows and hope for some experts, who had been waiting for the country’s ever-growing emissions to start dropping. Adow said, “China is giving us real reasons to be optimistic that its emissions may have peaked.” He 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.” University of Michigan environment dean Jonathan Overpeck said, “We’re not phasing out fossil fuels fast enough, but some progress is better than no progress.”

The Global Carbon Project’s international team of more than 140 scientists uses data from around the world to calculate each year’s carbon dioxide emissions estimate, with estimates for the final months of the year, and presents the figures at U.N. climate negotiations in Antalya, Turkey. The Global Carbon Project publishes its estimates in the journal Earth System Science Data Discussions.

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