The world is the most violent it has been in decades. A report by the Peace Research Institute Oslo recorded 61 conflicts across 36 countries last year – the highest level since 1946. Given the number of conflicts currently active worldwide, this figure could well be taken to new heights again this year.
Wars carry an obvious human cost. Almost 65,000 Palestinians have been killed in Gaza since Israel began its assault on the territory in October 2023, while the lives of up to 250,000 Russian troops are thought to have been lost in Ukraine.
We’re all familiar with these figures. This is because they’re the ones that tend to dominate news headlines. But wars are also incredibly environmentally destructive – and the damage often goes unnoticed until it’s too late to remedy.
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There are three reasons why the climate crisis must reshape how we think about war, says Duncan Depledge of Loughborough University. His first point is that war degrades the environment. The fighting itself causes considerable damage to land, while hostilities can fragment international cooperation on climate change.
The emissions associated with military operations worldwide – such as those generated by military aircraft – also probably rival some of the highest-polluting countries.
Depledge, a senior lecturer in geopolitics and security, acknowledges that it’s not easy to calculate the footprint of military activities. China and Russia’s military emissions, for instance, have proved almost impossible to assess due to the lack of data they report.
“But the crucial point is that recognition of the climate costs of war increasingly raises moral and practical questions about the need for more strategic restraint and whether the business of war can ever be rendered less environmentally destructive.”
His second point is that the effects of climate change may well intensify the risk of violence in certain parts of the world. “Some conflicts in the Middle East and Sahel have already been labelled ‘climate wars’, implying they may not have happened if it were not for the stresses of climate change.”
And third, he suggests that military forces could soon be rendered less effective due to more extreme and unpredictable climate conditions. Depledge says that these factors are together leaving researchers “with the uncomfortable prospect of having to rethink how military force can – and ought to be – wielded” in a changing world.
Read more:
Three reasons why the climate crisis must reshape how we think about war
Has climate change always led to violence? This was the question I put to Jay Silverstein, an expert on the archaeology of warfare at Nottingham Trent University. “There is a wide consensus that climatic stress contributes to regional escalations of violence when it has an impact on food production”, he told me in response. “Yet historical evidence reveals a more complex reality.”
Silverstein explains that looming crises have often spurred human ingenuity. This has enabled some civilisations to survive and others to thrive. “Water-lifting technologies – from the Egyptian shaduf to Chinese water wheels and Persian windmills – expanded arable land and intensified production”, he notes as an example.
However, climate stress has also triggered violence that has helped wipe entire civilisations from the map. “As humanity confronts an escalating environmental crisis driven by global warming, the reflexive response to climate stress – political instability and conflict – should be challenged by a renewed commitment to adaptation, cooperation and innovation.”
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War’s lasting legacy
While travelling down the coast of Vietnam a few years ago, I stopped off in the small rural province of Quảng Trị. The area was a major battleground during the Vietnam war and was pretty much bombed flat by American forces. The province remains littered with unexploded ordnance today.
Unexploded bombs continue to kill and injure people throughout Vietnam, as well as in many other places around the world. They also cause considerable damage to the environment. Sarah Njeri and Christina Greene of SOAS, University of London and the University of Arizona respectively explain that this manifests in different ways.
Unexploded bombs and landmines “can leak heavy metals and toxic waste into the soil, polluting land and water”. And even the methods for clearing unexploded ordnance can contribute to land degradation, they say, drawing on evidence of the release of hazardous metals into the soil in northeastern Iraq following demining activities.
Climate change is making matters worse. Floods and heavy rainfall can unearth or displace landmines, while extreme heat can cause abandoned or unexploded munitions to explode.
Evidence of this came just weeks ago. Wildfires on the North Yorkshire moors in the UK – where we’ve just endured our hottest summer on record – caused 18 bombs to explode that had been lodged in the soil since the second world war.
“Explosive remnants of war have a lasting impact”, say Njeri and Greene. “Climate change is only making the threat more unpredictable and challenging to address.”
Read more:
How unexploded bombs cause environmental damage – and why climate change exacerbates the problem
Another lasting effect of war is that it displaces people from their homes. These people, writes Kerrie Holloway of the ODI Global thinktank, are particularly vulnerable to the effects of climate change.
According to Holloway, a research fellow in the Humanitarian Policy Group, displaced people “are likely to have used up whatever money and other assets they had prior to their displacement, leaving them unable to make the same adaptations as those who have not been displaced.”
They also often find themselves settling on land that is only available because existing residents do not want it. Holloway points to the Iraqi city of Mosul – where Yusuf, a refugee I got to know some years ago, was forced to flee from – as an example.
“Stagnated reconstruction following the liberation of the city from the Islamic State militant group in 2017 has resulted in a scarcity of adequate housing. This has left many displaced people residing in unfinished or makeshift shelters on unpaved roads that are prone to flooding during heavy rains.”
And finally, displaced people are often overlooked in disaster management plans. This, Holloway writes, “can result in them not heeding early warnings when they are given”.
Read more:
Why people displaced by conflict are particularly vulnerable to climate risks
The post “Introducing War on Climate, a new series that explores how conflict interacts with environmental issues around the globe” by Sam Phelps, Commissioning Editor, International Affairs, The Conversation was published on 09/11/2025 by theconversation.com