War has been a constant for all of human history. While war has been the source of many historical crises, the defining crisis of the 21st century will be the impact of climate change. While carbon emissions, the primary cause of contemporary climate change, started rising after the invention of agriculture, the Industrial Revolution transformed this steady rise into something catastrophic. As well as increased emissions, the Industrial Revolution also caused a huge amount of pollution and while some of this pollution has been reduced in post-industrial countries like the UK, it has not elsewhere in the world. In the popular imagination, the environmental crisis and armed conflicts are often perceived separately, this should not be the case. Not only is war one of the most destructive things that can happen to the environment, but armed forces in peacetime are significant causes of emissions. An understanding of this, and action to decrease military emissions, is essential to mitigate climate change. 

The Conflict and Environment Observatory reports that militaries are responsible for 5.5% of all global emissions. While this is less than some industries such as energy and transportation, it is nevertheless a significant number and cause for concern. Fuel consumption is a major portion of those emissions, especially as military vehicles like tanks, planes, and ships use huge amounts of fuel during regular operations. For example, the F-35B Lightning II, the primary strike fighter used by the Royal Air Force and Royal Navy, uses approximately 5000 lbs (2268 kg) per hour during regular flight operations. This does not take into account what would likely be heavier fuel usage during combat, as weapons increase the weight, and thus fuel consumption.. This is of course just one aircraft, and for one of the Royal Navy’s two Queen Elizabeth-class aircraft carriers to launch its complement of twenty-four F-35s, it needs to consume fuel itself, as do its helicopters and an escort fleet of 4-6 other ships (most of which also have a helicopter). Therefore, the fuel consumption of just one Aircraft Carrier task group during regular operations is already astronomical, and this does not take into account the elevated figure that would be used during combat scenarios like the Invasion of Iraq in 2003 or NATO operations in Libya in 2011.

As well as contributing to carbon emissions, armed forces also cause alternative forms of environmental damage during peacetime. While Pearl Harbor is most famous for the 1941 attacks that led to the American entry into World War II, Joint Base Pearl Harbor-Hickam is still a large and important US military base. Hawaii is under serious environmental threat from over-tourism, and environmental damage caused by military activities has not helped. In 2022, the US military accidentally discharged over a thousand tons of firefighting foam into Hawaii’s water supply; firefighting foam contains PFAS, a group of chemicals with harmful effects to both the environment and humans. While there have been efforts to clean up this spillage, the fact remains that this incident, which is not the only incident of military-related environmental damage in Hawaii, damaged the environment and put lives at risk. This is a danger in many places around the world, as accidental (or intentional, as in the case of Bikini Atoll where the US tested nuclear weapons in the 40s and 50s, rendering it uninhabitable from nuclear fallout) releases of harmful substances have caused environmental damage even in peacetime. 

As well as these inadvertent peacetime effects, there have been cases of environmental warfare. During the Vietnam War, environmental warfare was a deliberate strategy utilised by the United States as they cleared 325,000 ha of land primarily using the incinerator chemical napalm and the herbicide Agent Orange to deprive the Viet Cong of cover in the jungle and to try and interdict their supply lines. Agent Orange contains the harmful chemical Dioxin which has caused lasting health issues for both the Vietnamese and US veterans. The Vietnam War was one of the most environmentally damaging wars, especially through tactics like carpet bombing, 11.3 million tons of munitions were dropped by the US, and incendiary bombing used. These tactics are now frowned upon by Western powers. This, as well as Agent Orange which was only used for warfare in Indochina, led to the Vietnam War having a staggering environmental cost.

Another war with a huge environmental cost was the Gulf War. This war was an example of purposeful environmental destruction for destruction’s sake; in contrast, the United States’ actions in Vietnam did have a military goal. When the tide of the war turned against him, Saddam Hussein, Iraq’s dictator, began burning Kuwaiti oil fields, setting over 500 on fire which led to between two and six million barrels of oil being wasted per day. Also, they purposefully spilled 7 to 9 million barrels of oil into the Persian Gulf. These actions had no strategic rationale and were an act of state terror. The coalition soldiers’ exposure to these oil fires and harmful ‘burn pits’ led to the development of a condition that has been termed Gulf War Syndrome. Due to a combination of symptoms such as fatigue, cognitive problems, and Post Traumatic Stress Disorder, Gulf War veterans have a poorer quality of life than other veterans. There are an estimated 33,000 people in the UK with Gulf War Syndrome. Therefore, while environmental damage primarily affects the theatre of war, the legacies of this damage can be brought home by returning veterans and have a multi-generational effect.

These case studies show that war is incredibly environmentally damaging, and that this damage leaves a legacy that does not disappear once the war is over. In addition to the emissions caused by military activities, warfare can damage natural habitats, sometimes permanently, kill flora and fauna, and lead to a poorer quality of life in affected areas long after the war has ended. This is not an issue easily solved by climate initiatives like Net Zero or the COP conferences as the roots of warfare and global instability run deeper. While armed forces should take some steps to reduce their emissions, minimising the climate impact of military activity can only be achieved by lowering the need for military activity altogether which is more challenging.