War is on the rise globally and showing little sign of slowing down as conflict persists in the Ukraine and Middle East and as cold war looms between the U.S. and China.

The coming decades spell trouble for the two billion or so people living in or near conflict zones, and they also paint a dire picture for one of the frequently unheeded casualties of war—the environment.

Despite the fact that military expenditures rank high among all government expenditures globally, greenhouse gas emissions from military activities are not included in global emissions totals—a huge blindspot for states that claim to care about mitigating climate change.

The figures are stark: If the world’s militaries were a single country, they’d be the fourth-largest greenhouse gas emitter in the world, producing some 5.5% of annual emissions. That’s because it takes billions of gallons of fuel to power a modern military.

The first three years of the conflict in Ukraine produced some 230 million tons of CO2—the equivalent of burning a half-billion barrels of oil. This wasn’t just from warfare, but from wildfires that raged out of control due to weakened emergency services and emissions from reconstruction.

But it’s not all about emissions: Warfare destroys vital waterways, soils, and ecosystems. During the war in Vietnam, the United States destroyed 14-44% of Vietnam’s forest cover using chemical defoliants. Israel’s occupation of Palestine has destroyed countless olive groves, orchards, wells, and greenhouses.

The pain, suffering and casualties of war are of course undeniable—but the significant impacts of war on the environment are not yet a major part of the conversation.

As global tensions rise and conflicts intensify, it’s more vital than ever that states factor peacemaking into their decarbonization efforts. The survival of organized human society might just depend on it.