The war in Ukraine has generated nearly 230mn tonnes of CO2-equivalent (CO2e) emissions since Russia's full-scale invasion began, with forest fires significantly contributing to the increase, according to an analysis published on the third anniversary of the conflict.

The study, conducted by the Initiative on Greenhouse Gas Accounting of War, found that in the past year alone emissions linked to the war had reached 55mn tonnes. Researchers attributed much of this increase to widespread fires caused mostly by warfare, exacerbated by extreme heat and dry conditions.

"What stands out in the third year is that we've seen landscape fires, particularly forest fires, escalating," said Lennard de Klerk, lead researcher at the non-profit group, in an interview with The Guardian. "They are double compared to the average of the previous two years and 20-25 times more than in peacetime."

Wildfires, particularly in forested eastern Ukraine, where much of the fighting is concentrated, burned through 92,100 hectares (227,700 acres) of land in 2024, more than twice the annual average of the preceding two years. This led to 16.9mn tonnes of CO2e in emissions over the past year alone, researchers said.

Fires have been difficult to control due to the conflict. "Campfires made by soldiers, ignitions from drones and ammunition, combined with no possibility of deploying firefighters, mean small fires escalate into larger, uncontrollable blazes," de Klerk said to Climate Home News.

Impact of warfare and reconstruction

The largest contributor to emissions remains direct warfare, accounting for 82.1mn tonnes of CO2e, or 36% of the total since 2022. This includes emissions from tanks, warplanes, explosions and the construction of fortifications. Reconstruction, particularly rebuilding homes, hospitals, roads and other infrastructure, accounted for 62.2mn tonnes of CO2e (27%).

"In the first year, reconstruction caused the highest emissions due to large-scale destruction in the early months," de Klerk noted. "Damage rates slowed in the second and third years due to static front lines."

Destruction of energy infrastructure contributed 8% of total emissions, largely the September 2022 Nord Stream pipeline explosion. Civil aviation, which has seen increased emissions due to planes rerouting around Russian airspace, accounted for 6% of total emissions, while refugee movements contributed 2%.

Aviation emissions rose globally after Russia banned Western planes from its airspace. According to a study issued earlier this month, co-authored by climate scientist Nicolas Bellouin at the University of Reading in the UK, about 1,100 flights per day have been affected, with affected aircraft burning 13% more fuel on average. The resulting increase in aviation emissions accounted for approximately 1% of global airline emissions in 2023, researchers found. Bellouin told BBC News that "the impact of these rerouted flights should not be underestimated, as they significantly contribute to global CO2 emissions."

Ukraine calls for accountability

Ukraine’s government has pointed to Russia being responsible for the environmental destruction caused by the war. Minister of Environmental Protection and Natural Resources Svitlana Grynchuk said in a statement to Reuters that the findings support efforts to hold Russia accountable.

"Russia must be held responsible for the harm it is causing to all of us," she stated. Former minister Ruslan Strilets previously has said, separately, that Ukraine has been working on a reparations case.

However, securing reparations for climate-related damage remains a challenge. A spokesperson for Ukraine’s environmental ministry told Earth.org: "It is extremely difficult to hold Russia accountable as there is no relevant international procedure. The first task is to adopt appropriate methodologies and procedures at the international level. Only then can we discuss obtaining reparations."

Researchers estimate Russia’s climate-related liability at over $42bn, based on the social cost of carbon at $185 per tonne of CO2e.

The "fossil fuel war"

Ukrainian climatologist Svitlana Krakovska has repeatedly described the war as a "fossil fuel war," arguing that global dependence on fossil fuels has financed Russian aggression. Speaking at the Intergovernmental Panel on Climate Change (IPCC) session in Hangzhou, China from February 24 to 28, she said: "Three years ago, I warned that climate change and Russia’s ability to accumulate resources for war stem from humanity’s unhealthy dependence on fossil fuels." The IPCC is the primary UN climate crisis agency.

Krakovska added that the war is harming the global fight against climate change, not only through direct emissions but also by diverting financial resources away from climate initiatives toward military spending.

"Investment in the military is rising steeply," de Klerk said in an interview with The New York Times. "The military and the defence industry are already responsible for about 5.5% of global emissions, and as spending grows, emissions could double or more. At some point, 5.5% could become 10% or even 20%. Just imagine what an F-35 consumes in kerosene."

The wider climate impact

The war’s environmental consequences extend beyond Ukraine. Scientists warn that global efforts to combat climate change are being undermined as military spending rises. The conflict has also influenced emissions beyond Europe. Researchers found that conflicts in Libya, Syria and Yemen have similarly increased aviation emissions, though to a much lesser extent than the war in Ukraine.

The IPCC session in China aims to finalise the upcoming Seventh Assessment Report (AR7), which will include sections on carbon removal technologies, carbon utilisation, and storage. Krakovska stressed that global cooperation is essential in tackling both climate change and geopolitical instability.

"The world must understand that the fight for climate security and the fight for peace are interconnected," she said in her speech at the session. "They require joint action and responsibility from the global community."