Fossil CO2 Emissions Fall in 2026, With a Big Assist From the Iran War

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It took a war to achieve what 30 climate conferences could not: Global CO2 emissions from coal, oil and gas are set to fall 0.4 percent this year, to 38.2 billion metric tons. That is the finding of the newly published Global Carbon Budget 2026, the work of more than 140 researchers from over 90 institutions. The second surprise follows right behind: Humanity is still emitting more CO2 overall than ever before.

Oil Down, Coal Up

Almost all of the decline comes from oil. Emissions from oil are falling 1.9 percent, one of the steepest drops on record, exceeded only in 2020, 2009 and 1992, according to Carbon Brief. The cause is the energy shock that followed the closure of the Strait of Hormuz during the Iran war, which also pushed European gas prices above €100. Gas is essentially flat at minus 0.3 percent, and coal is up 0.6 percent.

In China, oil use in particular is falling while renewables grow strongly. In the United States, coal use is dropping again after a jump last year. India is the big outlier: Its emissions are growing faster than the average of the past decade, driven by coal. The figures are projections, with a range of minus 1.5 to plus 0.6 percent, so a small increase cannot be ruled out.

The Five Surprises

Behind the headline number are several findings that stand out:

• A record despite the decline: Once land use is included, total CO2 emissions rise to a record 43.3 billion tons. The reasons are peat fires and forest destruction in Southeast Asia, made worse by the onset of El Niño. Emissions from land use jump to 5.1 billion tons from 4.4 billion.
• No oil shock, no decline: According to a companion study in Nature Climate Change, emissions would have kept rising without the energy shock. Solar, wind and electric vehicles are absorbing about 69 percent of the increase that growing energy demand would have caused. High prices and supply constraints did the rest.
• A.I. is a small item: The growth of data centers, driven largely by A.I., added about 0.03 billion tons of CO2 in 2025. That is roughly 2 percent of the demand-driven increase.
• Nature bounced back: Forests and soils absorbed more CO2 in 2025 than ever before, about 13.3 billion tons, half again as much as in the El Niño year of 2024. The new El Niño is expected to weaken that sink again in 2027.
• Growth without emissions: Forty countries, accounting for 26 percent of fossil emissions, cut their emissions over the past decade while their economies grew. In the decade before, there were 22.

The picture for carbon removal is sobering, by contrast: New technological methods currently offset less than 30 minutes of annual fossil emissions.

The Budget Keeps Shrinking

What matters for the climate is the total, and it is growing. The concentration of CO2 in the atmosphere is rising by 2.2 parts per million this year, to 427.7 p.p.m., which is 54 percent above preindustrial levels. Only recently, the World Meteorological Organization reported new record highs for greenhouse gases.

To have a 50 percent chance of limiting warming to 1.5 degrees Celsius, the world can emit another 150 billion tons of CO2. At the current pace, that budget will be used up in less than four years. For 1.7 degrees, about 12 years remain, and for 2 degrees, about 24 years. The United Nations also assumes in its latest report that the world will overshoot the 1.5-degree limit. The figures arrive as the COP31 climate conference opens in Antalya, Turkey.

Turning Point or Blip?

Even the study’s own authors differ on whether 2026 will go down as the year emissions peaked. Corinne Le Quéré of the University of East Anglia struck a confident note: Clean technologies are already making a real difference, she said, and a further acceleration could turn the tide on global emissions within a few years. According to the companion study, solar, wind and electric vehicles will absorb between 64 and 79 percent of the emissions growth from new demand through 2028.

Her colleagues sound considerably more skeptical. Pierre Friedlingstein of the University of Exeter, who led the study, called the decline encouraging but said a reduction driven by geopolitical shocks was no sustainable climate solution. Glen Peters of CICERO, a climate research institute in Oslo, stressed that a single year of falling emissions is no peak unless structural change is behind it. His colleague Robbie Andrew told Gizmodo the drop was a short-term blip: If the Strait of Hormuz reopens for good, the constraint disappears. And even in the companion study’s optimistic scenario, emissions in 2028 are higher than in 2025.