Demystifying science

Armed conflicts like those in Iran, Ukraine, or Gaza are increasing global greenhouse gas emissions. But is this pollution significant or marginal? In short, does war hinder our efforts to achieve carbon neutrality?

Published on March 22, 2026, at 7:00

The Question

“I am surprised to see that the numerous armed conflicts are not more clearly identified as exacerbating factors in climate change. When Putin attacked Ukraine, I was dismayed to see the amount of greenhouse gases produced by all those Russian tanks consuming large quantities of oil, not to mention the planes, rockets, artillery fire, etc. Meanwhile, I felt guilty using my car to go to the grocery store,” wrote Pierre Turenne.

At least 5.5% of global emissions

Do armed conflicts significantly increase greenhouse gas emissions (GHGs), as Mr. Turenne suggests? The short answer is yes. Before assessing armed conflicts, we must first analyze the emissions associated with permanent military structures, which represent approximately 5.5% of global GHG emissions.

Two British researchers arrived at this conclusion in a 2022 report titled Estimating the Military’s Global Greenhouse Gas Emissions. “If the world’s armies were a single country, this figure would mean that they would have the fourth-largest national carbon footprint in the world, exceeding that of Russia,” they estimated at the time. It’s also equivalent to four times Canada’s annual emissions. The three largest emitters of GHGs are China, the United States, and India.

This assessment is likely higher a few years later. “When we estimated global emissions associated with armed forces, using 2019 data, military expenditures totaled $1.9 trillion in 2019. By 2024, they reached $2.7 trillion and are expected to continue to increase,” says Doug Weir, director of the Conflict and Environment Observatory, a UK-based NGO.

But is this conclusion from the 2022 report reliable? “Yes and no,” responds Doug Weir. “This 5.5% figure corresponds to our best estimate of military emissions in peacetime and is based on 2019 data. It is an estimation because the emissions data disclosed by the military are incomplete, and their publication is optional under the Paris Agreement.” A report unveiled in 2025 also concludes that less than 10% of national armies compile and publish their polluting emissions.

Ongoing Evaluation

The current assessment does not yet include the main ongoing armed conflicts in various regions of the world.

According to Doug Weir, the war in Ukraine marks the first attempt to monitor emissions generated by an ongoing conflict. “The results suggest that these emissions may be higher than the annual emissions of many developed countries,” he says.

Based on the latest estimates, between 2022 and 2026, the war in Ukraine has generated 311 million tonnes of CO₂ equivalent, equivalent to the annual emissions of the United Kingdom.

In Gaza, researchers estimated last year that the first 15 months of the conflict had generated approximately 31 million tonnes of CO₂ equivalent in polluting emissions.

Regarding Iran, researchers are already working on producing a preliminary estimate of GHG emissions associated with the conflict, according to Doug Weir.

For each conflict, one must also consider the emissions produced in the context of reconstruction operations, adds the expert. This is in addition to the impacts on societies and economies, known as the social cost of carbon, explains Mr. Weir. “Only due to the proposed increases in NATO’s military spending, we foresee that climate damages could reach $298 billion per year.”

Iranian Conflict: Uncertain Effects

The military conflict and blockade of the Strait of Hormuz in Iran are affecting oil and gas prices, and their effects on the energy transition are still uncertain. An analysis published in the New York Times indicates that renewable energies and fossil fuels could benefit from the conflict.

Faced with rising oil prices, some countries could accelerate their transition by investing more in renewable energies, such as wind or solar. However, others are likely to increase electricity production from coal to address the crisis.

“In the short term, countries will source energy wherever they can find it. But in the long term, there is room to rethink the situation,” said Kevin Book, general manager of ClearView Energy Partners, in an interview with the New York Times. A recent analysis published by Bloomberg also concludes that the Iranian conflict could boost the shift towards solar energy and batteries, whose costs continue to decrease.