In the first two weeks of the 2026 US-Israel war on Iran, the conflict released an estimated five million tonnes of CO₂ (translating to 131 million tonnes of CO2 annually) into the atmosphere, equivalent to the combined annual emissions of the world's 84 lowest-emitting nations. Yet the global conversation about this catastrophe has been almost entirely confined to geopolitics and oil prices. The environmental dimension has been barely a whisper. No front page covered the emissions. The climate cost of the conflict was not mentioned in briefing rooms, not debated in parliaments, and not once raised at the Security Council table.
This silence is not accidental. It is structural. And it is making our net-zero targets fictional.
The Iran conflict is the latest in an escalating pattern. Ukraine. Gaza. Sudan. Lebanon. Now Iran. Each war pollutes, destroys ecosystems, disrupts energy systems, and critically triggers fossil fuel infrastructure investments that outlast every peace deal and every climate pledge. Research across these conflicts now documents the scale of what the world's climate accounting system continues to ignore.
Here is a fact that should stop every climate negotiation in its tracks. The combined carbon footprint of world militaries is estimated at approximately 5.5% of global GHG emissions, more than Japan's total annual output, and roughly double that of the entire global civil aviation sector. In 2024, the combined military emissions of NATO, China, and Russia alone were estimated at 551 million metric tonnes of CO₂ equivalent. And yet not a single country is required to report those emissions. The United Nations Framework Convention on Climate Change (UNFCC), the treaty that underpins the Paris Agreement contains a voluntary, not mandatory reporting framework for military emissions, limited only to military fuel use.
A recent ruling by the International Court of Justice (ICJ) in July 2025 made this accountability gap legally untenable. The ICJ determined that military activities contribute to climate change and that countries bear a legal duty to prevent environmental damage from their armed conflicts. It was the first time an international court had articulated this duty so explicitly. The ruling provides the legal architecture for accountability; the question is whether the political will to use it exists.
{{/usCountry}}A recent ruling by the International Court of Justice (ICJ) in July 2025 made this accountability gap legally untenable. The ICJ determined that military activities contribute to climate change and that countries bear a legal duty to prevent environmental damage from their armed conflicts. It was the first time an international court had articulated this duty so explicitly. The ruling provides the legal architecture for accountability; the question is whether the political will to use it exists.
{{/usCountry}}Global military spending in 2024 reached $2.7 trillion, a sum so large that just five percent of it, $135 billion, would exceed the entire developed world's long-standing climate finance pledge. That pledge, originally due in 2020, was only met two years late.
The IPCC's most optimistic 1.5°C pathway (SSP1-1.9) rests on three foundational assumptions: sustainable development, rapid decarbonisation, and robust international cooperation. A peer-reviewed study published in Nature Communications in May 2025 found a statistically significant relationship between global military spending and CO₂ emission intensity across 28 years of data. Every 1% escalation in the military expenditure-to-GDP ratio (MILEX) corresponded to an increase of 0.04 kg per dollar in CO₂ emission intensity. The study further found that if the ratio exceeds 12%, returning temperatures below 1.5°C after mid-century overshoot becomes unachievable by 2100,
The problem is not that net zero 2050 is the wrong goal. It is that the IPCC's emissions pathways did not distinctly model the military sector, a sector that is, by the International Military Council on Climate and Security's own acknowledgement, the largest single institutional consumer of hydrocarbons in the world. The Paris Agreement's SSP1-1.9 scenarios assume the conditions of peace. Those conditions no longer hold across multiple continents simultaneously.
Three changes are urgent, achievable, and do not require a new international treaty.
First: Mandatory military emissions reporting must become binding under UNFCCC frameworks. The ICJ ruling of July 2025 now provides legal grounds for mandatory accountability. UNFCCC member States should be obligated to report military emissions and alongside reporting their Scope 1, 2 and 3 emissions, militaries should also begin exploring how they can begin to track and report the emissions associated with their warfighting activities.
Second: The international community needs a formal war carbon budget, an accounting mechanism capturing not just peacetime military operations, but the full climate cost of conflict including infrastructure destruction, ecosystem damage, energy disruption, and reconstruction.
Third: The climate movement must argue plainly and without apology that a ceasefire is climate action. Every day a conflict continues, it burns fuel, destroys carbon sinks, locks in fossil fuel infrastructure, and disturbs the political conditions that climate cooperation depends on.
This article is authored by Ankit Rao, research associate and Meeta Lavania, associate director, TERI.