Iran war helps fuel global drop in fossil fuel emissions — but there’s a catch

The world's carbon emissions from oil, gas and coal are projected to decrease by 0.4% this year, driven partly by the expansion of solar and wind power capacity and the price increases caused by the Iran conflict, according to a new report.

The 2026 Global Carbon Budget report was published in the journal Earth System Science Data Nov. 10 and is due to be presented at the U.N. Climate Change Conference's COP31 meeting in Antalya, Turkey, this week.

It is the first time annual carbon dioxide (CO₂) emissions from fossil fuels have fallen since the coronavirus pandemic in 2020. But the overall emissions picture suggests the world is still likely to miss key climate goals.

"It is an encouraging sign that the growth of emissions is slowing and decarbonisation efforts are starting to make a difference," said Joeri Rogelj, a climate scientist at the Centre for Environmental Policy at Imperial College London who wasn't involved in the research. "However, at 0.4%, the projected decline is very small," Rogelj told Live Science in an email.

The report projects 38.2 billion metric tons (42.1 billion U.S. tons) of emissions of the climate-warming greenhouse gas CO₂ from fossil fuel sources this year. Greenhouse gases trap heat by absorbing the sun's radiation, and as their concentrations in the atmosphere increase, so do global average temperatures, leading to altered weather patterns and higher sea levels, as well as other major impacts.

Part of the 0.4% reduction in CO₂ emissions is attributable to 40 countries that have cut emissions over the past decade while growing their economies. These include the U.S., Australia, New Zealand, South Korea, the United Kingdom, Japan and about 30 countries in the European Union, the researchers reported.

When it comes to some of the biggest emitters, annual CO₂ emissions are projected to decrease by 0.9% in China, 1.3% in the U.S., 1.5% in the European Union and 1% in Japan, but India's annual CO₂ emissions are projected to grow by 4.4%.

Fossil-fuel-linked CO₂ emissions from the rest of the world are projected to decrease by 0.7%, driven mainly by a 1.9% drop in oil emissions. The report authors suggested that this is a short-term response to the global supply constraints and increased prices triggered by the Iran conflict.

"The war with Iran has resulted in restricted fuel availability and high prices, with a corresponding reduction in demand," Rogelj said.

While fossil fuel emissions and demand for oil are declining globally, overall demand for energy is actually increasing.

"Based only on the demand for energy, which has grown, we would have expected an increase in fossil CO₂ emissions by about 0.8 gigatonnes," said study co-author Judith Hauck, a biogeoscientist at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Germany.

About two-thirds of that increase in demand is being met by solar and wind power and electric vehicles, showing that clean technologies are making a real difference in reducing global emissions, Hauck said. However, the hike in energy prices that resulted from the Iran conflict also decreased demand by 0.4%, she said.

"So only together with the energy crisis did we bring the change in emissions down to negative," Hauck told Live Science, adding that she expects CO₂ emissions to rebound if the conflict ends, as they did after the temporary emissions drop caused by the lockdowns during the COVID-19 pandemic.

Nearing the peak?

The exceptional circumstances that energy markets experienced this year make it clear that the small projected emissions decline is no reason to declare that emissions are now reducing, but there are hopeful signs, Rogelj said.

"Despite my muted enthusiasm about whether these lower emissions for 2026 represent the start of a long-term decline, the analysis shows encouraging signs of deeper long-term structural changes," he said. "But this shift must accelerate to ensure it is not outpaced by energy demand growth."

The report found that clean energy growth isn't yet fast enough to drive a steady decline in global CO₂ emissions attributable to fossil fuels. The study authors expect that to happen in the next few years, Hauck said, as long as there is a continued push to deploy solar and wind power, batteries and electric vehicles.

CO₂ emissions from fossil fuels are just part of the picture, though. Because of increases in human-caused peat fires, deforestation and forest fires linked to dry El Niño conditions, total global CO₂ emissions from all sources this year are projected to increase slightly from 42.8 billion metric tons (47.2 billion U.S. tons) last year to reach a record 43.3 billion metric tons (47.7 billion U.S. tons) this year, according to the report.

This means that the total budget of CO₂ that can be emitted before global warming reaches 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels is now just 150 billion metric tons (165 billion U.S. tons) ‪—‬ equivalent to less than four years of emissions at the current rate.

Hauck, like many climate scientists, thinks we have already missed our chance to hit the 1.5 C target and could only get back to that level through extensive removal of CO₂ from the atmosphere.?

"I'm still hopeful for something between 1.5 and 2 C [3.6 F]," Hauck said. "But for 1.5 degrees, we would need to see such a drastic strong drop in emissions. Based on what we've seen in the past years, even with this strong increase in avoided emissions, I don't think we can make that."

To halt global warming from increasing ever further, the world needs to be more ambitious in its planned emissions cuts, said Rogeli. We need to bring annual emissions down to zero to protect future generations from a double whammy of “having to try to transform economies so that they produce less climate pollution, while dealing with the impacts and damages of an increasingly adverse climate system," he said.