Climate policy discussions overwhelmingly focus on energy, transport, agriculture and industry — and rightly so. But one of the largest and least-reported sources of greenhouse gas emissions is armed conflict itself, and the renewed hostilities between the United States, Israel and Iran that began in late February 2026 offer a stark, current illustration of exactly how large that footprint can be.
The Numbers Behind the First Two Weeks
An analysis by the Climate and Community Institute found that the first fourteen days of the conflict alone generated an estimated 5.1 million tonnes of carbon dioxide equivalent — more than several smaller nations emit in an entire year. The breakdown is instructive: destroyed civilian buildings account for the single largest share, with the Iranian Red Crescent Society reporting around 20,000 damaged or destroyed structures, including over 16,000 residential buildings, plus commercial units, medical centres and schools. The embodied carbon that will be released once this rubble is cleared and rebuilt is estimated at 2.4 million tonnes CO₂e on its own.
Beyond building destruction, the burning of oil stored in bombed refineries and tankers released a further 1.88 million tonnes of CO₂e, with fires consuming between 2.5 and 5.9 million barrels of crude. Military fuel consumption for combat and support operations — aircraft flying missions from bases as far away as western England, naval vessels, and ground transport — is estimated to have burned between 150 and 270 million litres of fuel in just the first two weeks, adding roughly 529,000 tonnes CO₂e.
Beyond Carbon: Toxic Rain and Water Stress
The climate impact is only part of the story. When Israeli strikes hit fuel storage depots near Tehran, a city of nearly ten million people, thick black smoke mixed with precipitation to produce what residents and journalists described as toxic black rain — a mixture of unburned hydrocarbons, sulfur oxides and particulate matter settling over homes, farmland and water sources. Reports of headaches and respiratory difficulty followed almost immediately, with longer-term risks to soil, groundwater and food security still being assessed. Strikes on desalination infrastructure in the region have separately raised concerns about water security, while the closure and militarisation of the Strait of Hormuz — the route for roughly a fifth of the world's seaborne oil — pushed global oil prices above $110 a barrel, with cascading effects on fuel and food costs far beyond the immediate conflict zone.
The Accounting Gap
Perhaps the most troubling finding is how little of this is formally counted. Military emissions reporting to the UNFCCC remains largely voluntary and inconsistent; the United States, having withdrawn from the framework, submitted no emissions inventory in 2025, while other major military spenders have historically reported such emissions as negligible or unmeasured. Together, the two largest military spenders account for roughly half of global military expenditure — meaning the carbon cost of a substantial share of the world's defence activity sits almost entirely outside international climate accounting. Research on comparable conflicts in Gaza and Lebanon suggests post-war reconstruction alone can generate over twenty times the emissions of the fighting itself, a multiplier that, if it holds here, points to a far larger climate bill still to come once rebuilding begins.
Why This Matters for Climate Policy
The war on Iran is not an isolated case — it is a reminder that fossil-fuel-dependent geopolitics and climate stability are deeply intertwined. Wars fought over or fuelled by oil infrastructure tend to entrench, rather than reduce, dependence on fossil fuels in their aftermath, as governments prioritise energy security over long-term decarbonisation. For climate negotiators and policymakers, closing the military emissions accounting gap, and factoring conflict-driven emissions into national and global carbon budgets, is increasingly being recognised as unfinished business on the road to any credible net-zero pathway.