Carbon Dioxide: Global emissions dip 0.4% as Iran war disrupts oil supply

Global carbon dioxide emissions from fossil fuels fell by 0.4% in 2026, marking a decrease to 42.2 billion tons. The drop was primarily driven by the energy shock caused by the Iran war, not by sustained progress in the transition to clean energy, according to a new study published in the journal Earth System Science Data Discussions.

The Global Carbon Project, a team of more than 140 scientists, presented the estimates at the U.N. climate negotiations in Antalya, Turkey. The researchers noted that the closure of the Strait of Hormuz, a critical route for petroleum shipments, pushed up global oil prices and reduced consumption. Oil emissions specifically dropped by nearly 2%, while natural gas emissions fell by 0.3%. Coal emissions, however, increased by 0.6%.

Glen Peters, a scientist at the CICERO Center for International Climate Research in Norway and a co-author of the study, explained that the timing and nature of the drop point to the war. He stated that if the decline were due to renewable energy growth, oil emissions would have peaked and then declined slowly. Instead, oil emissions rose before falling sharply. Peters described the situation as a bit of good news, but for the wrong reasons.

This is the third time in the 21st century that global carbon pollution has declined. The previous drops occurred during the 2009 global recession and the 2020 pandemic. Peters observed that after those shocks, global emissions returned to previous levels. The current data shows that while the world is still adding more than 1,335 tons of carbon dioxide to the atmosphere every second, the rate of addition has slowed slightly from the previous year.

Reactions from outside experts were mixed. Niklas Höhne, co-founder of Germany’s NewClimate Institute, expressed hope that the global peak in carbon emissions is near. He cited the rapid adoption of electric cars and trucks, particularly in Asia, as evidence of permanent shifts. Conversely, Malte Mienshausen, a climate science and policy expert at the University of Melbourne, warned that oil-producing nations not affected by the Strait of Hormuz blockade earned windfall gains. He predicted that these nations will seek new oil sources, potentially offsetting the short-term emission reductions.

National data showed varied trends. China, the United States, Europe, and Japan all saw emissions drop by approximately 1%. Peters attributed these declines to the oil price shock. In contrast, India’s fossil fuel pollution increased by 4.4%. The drop in Chinese emissions generated particular interest, as experts have long awaited a decline in the nation's growing output.

Mohamed Adow, director of the environmental group Power Shift Africa, said China is providing reasons for optimism that its emissions may have peaked. He noted that the country is investing in solar power, wind energy, and electric vehicles at an extraordinary scale. Adow emphasized that this represents a fundamental transformation of the economy rather than a temporary response to a crisis.

Jonathan Overpeck, dean of the environment at the University of Michigan, acknowledged that while the phase-out of fossil fuels is not happening fast enough, some progress is better than none. The study also found that overall global carbon dioxide emissions, including those from land use changes like deforestation, increased by 1% despite the drop in fossil fuel burning.

The next step in the process involves monitoring how the world responds to the energy costs of the conflict. The scientific team will continue to track data to determine if the emission dip persists or if the economy reverts to previous consumption patterns in the coming months.