When delegates gathered for COP30 in Belém, Brazil in November 2025, they scrutinized various sectors of the global economy for their contributions to rising greenhouse gases. Agriculture, aviation, steel, cement — all were on the table. One topic not discussed was war.

This isn’t a minor oversight. Militaries are significant contributors to greenhouse gas emissions. Russia’s invasion of Ukraine has generated an estimated 311 million tonnes of what’s known as CO₂ equivalent, comparable to the combined annual emissions of Belgium, New Zealand, Austria and Portugal. CO₂ equivalent is the metric used to compare the warming impact of various greenhouse gases to carbon dioxide.

Recently published research calculated that the first 15 months of Israel’s war in Gaza generated more than 33 million tonnes of CO₂ equivalent, comparable to the combined 2023 annual emissions of Costa Rica and Slovenia.

In February 2026, Israel and the United States launched a war against Iran, joining a long list of other conflicts where emissions go uncounted in global inventories.

These are massive emissions, and they are generated with no formal mechanism to record, report or attribute them, and no accountability for the climate costs that affect people in conflict zones and far beyond.

A recent article by Neta Crawford, a researcher with the Cost of War project at Brown University, highlights how armed forces, militarization and war fuel climate change. She argues that military emissions and conflict-related emissions remain undercounted, even though they undermine efforts to mitigate climate change.

The military emissions gap

Estimates suggest militaries and their supply chains account for approximately 5.5 per........

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