[Cytech+] “Global fossil fuel CO₂ emissions expected to decline this year… Aftermath of the Iran war”

Although carbon dioxide emissions from fossil fuel use around the world are expected to decrease this year, research has shown that this cannot be seen as a turning point in responding to climate change due to the impact of rising oil prices following the Iran War.

On the 11th, Professor Corin Le Queret's team at the University of East Anglia in the UK announced in the scientific journal Nature Climate Change that as a result of estimating this year's CO₂ emissions by fossil fuel and the offsetting effect of clean technology, fossil fuel CO₂ emissions are expected to decrease by 0.4% compared to last year.

The research team said that although clean energy technology is already offsetting a significant portion of the increase in CO₂ emissions, it is not enough to sustainably reduce global fossil fuel CO₂ emissions, and that the deployment of clean technology must be further accelerated to reduce emissions.

Global fossil fuel emissions increased by an average of 0.8% per year from 2019 to 2025, and increased by 1.2% in 2025. Although the supply of clean energy also increased, carbon dioxide emissions continued to increase as energy demand increased over the same period.

The research team analyzed past fossil fuel CO₂ emissions and this year's emissions projections based on 2026 data from the Global Carbon Budget.

In addition, we estimated the annual emissions offset effect of solar and wind power generation and electric vehicles using data on electricity production and electric vehicle sales collected in most countries from January to September of this year.

In particular, we estimated the emissions reduced by electric vehicles replacing internal combustion engine vehicles and solar and wind power generation replacing coal and gas power generation, respectively, and compared this with the increase in emissions due to economic growth and changes in energy use.

As a result of the analysis, global fossil fuel CO₂ emissions this year are expected to decrease by 0.4% compared to last year. The cause was analyzed to be a decrease in oil CO₂ emissions due to rising oil prices and oil supply disruptions after the Iran War, rather than replacing fossil fuels with clean technology.

This year, oil CO₂ emissions are expected to decrease by 1.9% and natural gas CO₂ emissions by 0.3%, but coal CO₂ emissions are expected to increase by 0.6%.

The research team explained that the increase in the offset effect of electric vehicles' CO₂ emissions in 2026 is only about 20% of the projected decrease in oil emissions, and that most of this year's decrease in oil emissions is estimated to be due to high oil prices and supply constraints.

The CO₂ emissions offsetting effect of clean technologies continues to increase. As a result of the analysis, it was estimated that without clean technology, global fossil fuel emissions would have increased by an average of 1.9% per year between 2019 and 2025. This is more than twice the actual increase rate of 0.8%.

CO₂ emissions offset by solar and wind power generation increased from 280 million tons in 2010 to 4.1 billion tons in 2025, and are expected to reach 4.6 billion tons in 2026.

Of the CO₂ emissions offset in 2025, China accounted for about half (about 2.1 billion tons), the United States and the European Union (EU) each accounted for about 500 million tons, and India accounted for about 300 million tons.

CO₂ emissions reduced by electric vehicles also increased from 30 million tons in 2019 to 190 million tons in 2025, and is expected to reach 240 million tons in 2026.

The research team then estimated that between 2025 and 2028, emissions will increase by 2.59 billion tons just due to the increase in gross domestic product (GDP) and the trend of changes in the intensity of CO₂ emissions compared to GDP.

However, in a scenario that reflects the current clean technology deployment trend, electric vehicles and solar and wind power generation are expected to offset 63% (1.64 billion tons) of this increase, and in a scenario where clean technology deployment is faster, they are expected to offset 79% (2.04 billion tons).

The research team explained that this means that although clean energy technology is significantly suppressing the increase in carbon dioxide emissions, the pace of deployment is not yet sufficient to cover all increasing energy demand.

He went on to emphasize that the future emission trend will depend on how much of the increase in energy demand is covered by fossil fuels, and that the supply of clean energy must continue and accelerate so that global fossil fuel CO₂ emissions can return to a stable decline after reaching its peak.

◆ Source: Nature Climate Change, Corinne Le Quéré et al., "A further acceleration of clean energy is needed for global CO2 emissions to peak and decline", https://www.nature.com/articles/s41558-026-02821-8