Researchers credit two forces: the spread of solar and wind power, and an oil shock from the Iran war. They differ on the weighting. Robbie Andrew, a senior researcher at the CICERO climate research center in Norway, attributes the drop mainly to energy supply constraints from the war, which disrupted oil traffic through the Strait of Hormuz, a route that handles about 20 million barrels of petroleum a day. Glen Peters of CICERO, a co-author of the study, also put the decline primarily down to the war in Iran. He said a sudden, sharp fall in oil emissions looks different from the gradual declines expected from an energy transition. Other analysts of the data give more weight to the way higher oil and gas prices sped up the shift to electric vehicles and renewables. Renewables and electric vehicles now cover two-thirds of the growth in global energy demand.

Oil emissions are projected to fall about 1.9% and natural gas emissions 0.3%, while coal emissions rise 0.6%. The European Union is down 1.5%, the United States 1.3%, Japan 1% and China 0.9%, with the rest of the world down 0.7%. India is the exception at 4.4% growth, above its ten-year average of 3.5%. China produces 32% of global fossil fuel emissions and accounts for half of the emissions avoided worldwide through clean energy and electric vehicles. The US decline follows a spike in 2025, and the Trump administration has repealed emissions standards and invested in the coal industry.

Total emissions, which include land-use change, are projected to rise about 1.2% in 2026, from 42.8 billion tonnes to 43.3 billion. Deforestation drives much of that, along with peat fires and El Niño-driven wildfires in Southeast Asia and South America. Land-use emissions are projected to reach 5.1 billion metric tons. Atmospheric CO2 is set to rise 2.2 parts per million to 427.7, which is 54% above pre-industrial levels.

Most of the scientists quoted say the fall is not a turning point. Peters said current structural changes are not enough to lock in a global peak. Mike O'Sullivan, a senior lecturer at the University of Exeter, called it a "short term shock rather than a systemic peak." His Exeter colleague Pierre Friedlingstein called the fossil fuel decline encouraging but said a reduction driven by crisis is not a sustainable climate solution, and that clean energy technologies need to be deployed faster. Bill Hare of Climate Analytics described the 0.4% drop as "statistically indistinguishable from zero."

Others see more promise. Niklas Höhne of Germany's NewClimate Institute said the global peak may be near, citing the rapid adoption of electric vehicles in Asia. Mohamed Adow of Power Shift Africa said China's decline matters because it reflects a "fundamental transformation" of its economy toward renewables. He added that the world still releases more than 1,000 metric tons of CO2 every second. Malte Mienshausen of the University of Melbourne cautioned that "windfall gains" for oil producers outside the war zone could fund more exploration elsewhere, dampening the war's short-term climate benefit.

This is the third fall in global carbon pollution this century. The earlier two came with the 2009 recession and the 2020 COVID-19 pandemic. The report's authors say more than two dozen countries have grown their economies without increasing emissions, and they estimate that solar, wind and electric vehicles will offset 64% to 79% of the emissions from new energy demand through 2028.

More than 90 heads of state are at COP31, where analysts have noted a lack of decisive action to cut fossil fuel use. A UN report in September found global temperatures on track to overshoot the Paris Agreement's 1.5°C target within the next few years. The remaining carbon budget for holding warming to 1.5°C is estimated at between 150 and 165 billion tonnes of CO2, which is less than four years of emissions at current rates.