What Is the Environmental Cost of War?

Poisoned wells, scorched earth campaigns, and residual radioactivity... the list goes on.
Christopher McFadden

War is one of the most destructive activities our species has ever devised. It destroys cities, infrastructure, and, worst still, literally and figuratively destroys the lives of soldiers and civilians unfortunate enough to be in the wrong place at the wrong time. 

In addition, and to the surprise of nobody, war is not that great for the environment either. While arguably a secondary consideration when compared to impacting human life, the damage caused to the environment through conflict is certainly worth highlighting. 

Prepare yourself, things are about to get a little violent. 

How does war impact the environment?

As you can appreciate, two armed groups, whether organized armies or not, engaging in an all-out effort to destroy one another are not the best places to be for any living organism, human or otherwise.

Huge explosions, flying bullets, missile barrages, etc., are obviously very destructive things, but, there are some other less obvious impacts on the environment that the human occupation with war can also have. 

Let's take a look at some of the most notable examples. The following list is far from exhaustive and is in no particular order. 

1. Large scale burning of stuff is incredibly bad for the environment

environmental impact of war kuwait
Source: Felton Davis/Flickr

The wars of antiquity and those of the Middle Ages were likely less destructive when compared to today, but even they had significant impacts on the environment. Scorched earth tactics, for example, have been a common tactic of many an army throughout history. 

This tactic, as the name suggests, involves the systematic destruction of farmland, and other useful infrastructure, by an invading or retreating army to deny the enemy of their use. Any assets that could be used by the enemy would be targeted and destroyed. 

This can include the obvious, as we described above, but can also include vehicles, weapons, communication sites, industrial resources, water supplies, and even civilians. 

Scorched earth policies should be distinguished from punitive destruction which, while similar, is normally performed as a political policy rather than a tactical/strategic one. 

For example, punitive destruction might also often involve a practice called "salting the earth". This practice would render farmland unusable for a time, leaving the land in question very difficult to rebuild and resettle. 

Salting large areas of land was impractical, but there are some examples of parcels of land owned by specific people or families, usually traitors, being salted to the point where it might have made the land unusable, but this would likely not have been done to large areas of land. The historical accounts where this is mentioned have largely been questioned for their accuracy.

However, salt was also a symbol of purity. "Salting the land" of an enemy usually involved ceremoniously plowing a field and scattering some salt. This sent the message that the land was "cleansed" of its previous rule and was a much more common practice.

However, other types of scorched earth practices are very ancient, with some notable examples in history including during the Wallachian-Ottoman Wars of the 15th-century. The famous — well, infamous — ruler of Transylvania, Vlad the Impaler conducted a systematic scorched earth policy during his retreat from the invading Ottoman army of Sultan Mehmet, torching crops, poisoning wells, and evacuating villages, in order to deny them the ability to resupply and provide a form of brutal psychological warfare. 

In a practice that would cement his moniker, he also reportedly left behind a "forest" of dead or dying captured Ottoman soldiers, impaled on stakes (he may also have been stockpiling bodies from previous raids to use for the display). The invading Ottomans were so amazed by the sight that they withdrew from the region (although Vlad's people were also so disgusted by the destruction of their land that they rebelled and Vlad was deposed by his brother, who was an Ottoman subject). 

Another more recent example was the famously devastating Invasion of Russia by Napolean Boneparte in 1812. Russian Emperor Alexander 1 was able to render Boneparte's attempted invasion of Russia impotent by destroying everything of use as his forces retreated deeper and deeper into Russian territory. 

The French army's policy of "living off the land", once a strength, now became a very serious handicap. Combined with the harsh Russian winters, and logistical problems of a very long supply chain, the French army soon starved and was forced to retreat. A lesson that also fell on deaf ears when the German army attempted the same thing during the Second World War, to the same effect. 

Even more recently, during the First Gulf War, retreating Iraqi forces systematically set oil wells ablaze in Kuwait in 1991. Faced with overwhelming Coalition military supremacy, the Iraqi forces engaged in a form of economic destruction of the main resource of the Kuwaitis. 

environmental impact kuwait fires
Satellite image taken 9 months after the Kuwait oil fires were extinguished showing the extent of the damage. Source: NASA/Flickr

Around 600, or so, wells were set alight, with many burning for most of the year before they could be extinguished. 

While the actual environmental impact of scorched earth policies in the distant past is very difficult to estimate, more modern examples, like the Gulf War can be quantified to some extent.

For example, in a 1992 study on the subject, daily emissions of sulfur dioxide from the fires was equal to around 57% of that from all electrical generation in the United States that year, or around 2% of total global carbon dioxide emissions, and 3,400 metric tons of soot were released into the atmosphere. 

Not all wells were set alight, but some were left to gush oil uncontrollably for months on end. Large amounts of oil were left to sink into surrounding soils, contaminating groundwater and lakes. So-called "tarcrete" was also produced from the burning wells that caked around 5% of Kuwait's landmass before being brought under control. 

All of these environmental impacts devastated local animal and plant life for many years, and the impacts are still seen today. 

2. We really need to talk about blood and soil (no, not that kind)

One of the unavoidable parts of war is the taking of life. Whether that be enemy combatants or, sadly the "collateral damage" of innocent civilians.

Whether by the sword or bullet, battles and campaigns will leave many dead bodies littering an area until they can be buried or cremated. A damnable phenomenon, but one that is sadly unavoidable as long as human beings deem it necessary to go to war. 

But what, if any, impact does this have on the environment? Let's start with blood. 

Large pitched battles of the olden times would involve massed bloodshed over a fairly short period of time. This blood doesn't just pool under the body but would seep into the soil underneath. Is this a potential disaster for local ecosystems?

Human blood is rich in some substances that are vital for keeping you alive while inside your body but are, as it turns out, not that nice for the natural environment when released in large quantities. In fact, it can prove to be fairly toxic if ever consumed — sorry vampires. 

blood and soil impact
Source: 2H Photography/Flickr

One of the main problems is that blood is rich in iron. The main constituent of hemoglobin (the protein that helps you carry oxygen around your body), iron in large enough doses is pretty bad for living creatures. 

Like most toxins, the concentration of iron in a living creature's system directly determines how dangerous something is. For example, animals that regularly consume blood, for example, run a very great risk of iron overdose which is potentially fatal. 

In humans, high doses of iron can lead to a condition, called hemochromatosis, which can cause a wide variety of diseases and problems, including liver damage, the buildup of fluid in the lungs, dehydration, low blood pressure, and nervous disorders. For organisms that do feed on blood, it's a different story; they have evolved special mechanisms for dealing with high levels of iron and excreting it accordingly. 

In vampire bats, for example, the blood goes through a tract that's adapted for extracting nutrients. Their intestinal tracts also have a special membrane that prevents too much iron from being absorbed into their own bloodstream.  But how does blood affect the soil and plant life? 

You may, or may not, be amazed to find out that both human and animal blood is an excellent fertilizer for plants. Bloodmeals are a fairly common fertilizer, but must be used sparingly. Partly because blood also contains high levels of salt. You can, after all, have too much of a good thing. 

It is very easy to overfertilize plants. A constant supply is good, but oversupply can be a very bad thing. Soil can quickly become saturated with salts and minerals if not constantly flushed with water. 

After all, blood contains many other minerals other than iron too that, while in small concentrations, can be toxic in large enough quantities. Calcium, chromium, copper, magnesium, potassium, selenium, vanadium,  and zinc are all prime examples. 

This can lead to a dangerous build-up in the concentration of some minerals that can, in turn, kill the plant. With regards to blood, it is an organic substance and its decomposition can promote the build-up of all sorts of microorganisms some of which can lead to the spread of disease and infections in plants. And, of course, blood spilled in battle is not pure blood, but contains all sorts of bacterial contaminants as well.

battlefields poppies
Source: peter castleton/Flickr

This may also lead to nitrogen deficiency in the soil that will also eventually starve plants. However, it should be noted, this would probably require a constant supply of large amounts of blood over a long period of time. 

However, the scale of a battle needed for this kind of "system overload" would most certainly involve the wholesale scarring of the landscape through trampling, horses, vehicles, and in the modern-day, high explosives, all of which would destroy plant life before this would become an issue. 

However, there may be, under certain circumstances, some benefits to human conflict once hostilities have ended. One famous example is the proliferation of poppy growth on the battlefields of France following the end of WW1.

The war, as it turned out, created the prime conditions for poppies to flourish in places like Flanders and northwestern France (and Gallipoli in Turkey). The continual bombardment disturbed the soil enough to bring poppy seeds to the surface for germination. 


The large concentrations of nitrogen in the explosives, and lime from shattered buildings and other infrastructure, then helped to fertilize the saplings, leading to the perfect growing conditions for the plant. This is why, in part, the poppy was chosen as a symbol of remembrance for WW1. 

3. Other than poppies, artillery shells and landmines are not great for the planet

artillery shells bad for environment
Source: The National Guard/Flickr

While large-scale use of ordnance might have been good for poppies in places like France and Belgium, it hasn't been the best thing for crops. While the farmlands of France were not rendered completely unusable over the long run, the ghosts of WW1 still haunt farmers today. 

During the war, somewhere in the region of a billion shells were fired. Of these, it has been estimated that 30% didn't explode and were left, buried in the landscape. 

Apart from the odd exhumation of a long-lost soldier, one of the biggest problems today is unexploded shells and bombs. Hundreds of tonnes of the old ordnances are still found and destroyed on an annual basis in France even today.

Much of this tends to be found in the northeast of the country and it is a constant ongoing problem for farmers and locals. 

However, another issue is the large amounts of metals and other toxic compounds found in soil. This can get so bad that, from time to time, farmers are ordered to destroy that year's crops for fear of poisoning the food supply. 

In 2015, for example, seven farms had to destroy their year's supply of produce like carrots. Milk also had to the thrown away, as the grass the cattle had grazed on was also thought to have been potentially contaminated. 

But the problem with ordnances is not just isolated to the places they were used. In many places of the UK, old munitions factory sites are heavily contaminated to this day. Most of these sites may eventually be reused for other contaminating industries like nuclear power stations or industrial estates, but any development of them usually requires expensive and time-consuming remediation works. 

In more modern times, leftover munitions are also a very serious hazard for the environment and local inhabitants on a daily basis. One of the biggest problems is old land mines. 

During large conflicts, land mines are often deployed as defensive measures to protect strategically important areas like borders, camps, bridges, etc. to restrict the movement of enemy forces. While many are removed after a conflict, it is not feasible to keep detailed records of the exact location of every single mine. 

land mines are bad for environment
Source: Anti-Personnel Mine Ban Convention/Flickr

Today, thousands of people (many of them children) are killed or maimed by unexploded landmines every year, and mined areas may be left undeveloped for fear of injury. While the deployment of antipersonnel landmines is banned under international law, such laws are only as good as long as they can be enforced, and many of the mines are placed by non-governmental actors, who are not signatories to the law. 

Unsurprisingly, leftover landmines are also not the best thing for the environment either. Antipersonnel landmines are quite capable of either killing or maiming animals if they are unlucky enough to step on them. 

They also cause environmental damage through soil degradation, deforestation, pollution of water resources with heavy metals, and may even affect an entire species population by generally altering habitats and food chains.  

4. Littering the battlefield with dead bodies is not great either

From the mass casualties of past wars to the atrocities of genocide in more recent conflicts, war tends to lead to a large number of dead people in a very short period of time. Whether these bodies are left to rot on the battlefield until cleaned up, or buried in mass graves, this large influx of dead bodies is, from the environment's point of view, not ideal.

Dead bodies do not stay "fresh" for a long time, and quickly start to decompose. This action attracts pests like rats and insects and will also lead to an increase in the number of "necrobiome" microorganisms. 

A sudden influx of large amounts of pests can upset the natural balance, destroy the local habitat for other organisms by depleting natural resources, reducing water quality, and causing soil erosion. 

mass death is bad
Source: Tee Cee/Flickr

A rotting body, over time, also releases gases like methane and some heavy metals into the soil. While this is a natural part of the circle of life for all animals and plants, large mass killings in confined areas, on the scale seen in wartime, can "overload" the system in much the same way we discussed with blood. 

In fact, studies from the soil around the Stutthof concentration camp in Northern Poland, which was used to systematically exterminate the Jewish population in WW2 have been noticeably changed to this day. 

Another environmental issue with large-scale killings, but more so in the past, is the activity of cremating bodies. In the past, this was a common way to dispose of a large number of corpses, following a battle, as it was faster and required less than burial.

Cremation, it turns out, is not the best way to dispose of a body from an environmental perspective. The act releases many noxious gases, soot, particulate matter, carbon monoxide, and heavy metals into the air. If done on a large scale, the environmental damage is obviously magnified accordingly. 

So far we've focussed on the conflict on land. But, what, if any, impact do sea battles have on the environment? 

5. Battles at sea are not that much better

From the epic marine battles of antiquity to more modern conflicts like the Battle of Jutland and beyond, humans have been killing each other on the water for almost as long as on Terra Firma

While sea battles in antiquity involving wooden ships probably had a very small impact on the environment, the advent of steam engines and metal ships of our modern age certainly has.

naval battles and the environment
Source: US Navy/Wikimedia Commons

A warship's (or any large ship for that matter) impact on the environment begins before it has even begun to fire at the enemy. The noise of their engines is known to cause serious distress for many marine animals, like whales and dolphins, for example. And that's before we even get into the emissions released from a ship's engine(s)

Though, nuclear-powered ships seem to be a bit better, as far as emissions are concerned. Not to mention the impact of invasive species taking joyrides on ocean-going vessels — but that's is a story for another time. 

However, the battles are sea is clearly far worse. 

Modern ships are filled with various chemicals, fuel, and other materials that are all pretty bad for the environment.

Lead, cadmium, zinc, lead, and copper are some common examples. These heavy metals are usually found in things like paint, coating, insulation, batteries, and other electrical components onboard. Many ships, especially older ships, have large amounts of asbestos used as insulation as well. 

Mercury is often used in thermometers, electrical switches, level switches, and light fittings too. Warships also have the added problem of various armaments and the associated chemicals and other toxic materials. 

If a ship is fatally wounded in a naval battle, these metals can leak into the sea with relative ease. More and more of them will continue to leak out of the ship once it has sunk.

environmental impact of naval battles
Source: Hossein Zohrevad/FARS News Agency

To give you an idea of the problem, take the case of the MS Sea Diamond that sunk in 2007. After running aground on a volcanic reef in the Aegean, the ship was allowed to sink, carrying an estimated 1.7 tons of batteries and 150 cathode ray tube televisions to the seafloor. 

Including its cargo, the vessel is thought to have taken 2.82 oz (80 grams) of mercury, 35 oz (1 kg) of cadmium, and over a ton of lead with her. A study of the wreck some years later found that lead and cadmium levels around the wreck were far in excess of safe thresholds set by the Environmental Protection Agency. 

To help mitigate the problem, a pollution barrier was installed around the ship, many critics have complained that it is not enough to mitigate the damage. 

Large amounts of heavy metal contamination in the environment can cause very serious harm to any organism that is unlucky enough to come into contact with it. Mercury, for example, in a high enough dosage can cause severe damage to a living creature's nervous system. The same is true for things like lead. And these materials can move up the food chain, as the animals that ingest them are eaten.

While this is all bad news, it is important to note that seawater does contain a low concentration of heavy metals naturally. 

Since around the 1970s, many ships also contain large amounts of a substance called tributyltin (TBT). This is a very aggressive biocide and is used in antifouling paints to prevent the build-up of barnacles and algae on the ship's hulls. This substance is incredibly bad for living creatures and is widely considered one of the most toxic substances found in aquatic ecosystems. 

TBT damages the endocrine system of marine shellfish leading to the development of male characteristics in female marine snails, for example. It also impairs the immune system of organisms. Needless to say, this is not good for the environment. 

Depending on the vessel, ships can also carry large amounts of oil and fuels that are readily leaked into the sea should the vessel sink. Oil and fuel spills can have disastrous impacts on marine life that are well studied and documented.

The degree to which fuel and oil impact the ocean do vary, however. Distillate fuels, like diesel, tend to evaporate and dissolve much faster than heavy fuel oils (HFO). It also does not emulsify on the ocean surface. 

Distillate fuels also tend to form slicks on the sea surface that can take up to 3 days to disappear naturally. 

damage of sinking ships
Source: Don McCrady/Flickr

HFOs, on the other hand, tend to solidify rapidly and form tar lumps in marine environments. They may or may not float, and usually take about 20 days, or so, to dissipate. The long-term effects of sunken oil are very complicated but can include the incorporation of oil in the ocean and coastal sediments. 

Whether sunken oil or oil slicks, these materials can wash ashore, coating shorelines and animal life in oil and severely damaging or destroying local habitats. 

Ships are also very large and heavy things. The very act of sinking can cause some pretty serious damage to a marine environment as well. As the ship's hull, or bits of it, impact the seafloor, they can impact tens of thousands of square feet of ocean habitat. Coral reefs and other fragile habitats can be severely impacted.

So, naval battles are, pretty unsurprisingly, not that the best for the environment. However, it is important to remember that the world's oceans are massive expanses of water. Even the high concentrations of nasty stuff found in a single ship will have only a very limited impact on the oceans as a whole. At the same time, if enough oil or other chemicals are involved, a single ship can destroy an entire local ecosystem.

When it comes to the loss of human life during sea battles, it turns out the impact on the ocean environment isn't that bad — all things considered. In fact, burial at sea is widely considered one of the most "environmentally-friendly" methods of disposing of the dead. 

This does come with some caveats, of course. Bodies must be buried in locations that are far enough away from land so they don't wash ashore, and embalming of bodies is usually discouraged, though not forbidden. 

There are also some benefits to shipwrecks, however. Depending on where the ship settles, it can become an artificial reef over time, providing shelter and homes for many marine animals. But, it should be noted that purposely sunken ships are often stripped of all the nasty stuff inside first.

6. Aerial combat is also not entirely "environmentally-friendly"

Modern warfare is increasingly fought — some might argue, dictated — by the events that transpire in the air too. Whether through bombing campaigns or maintaining aerial supremacy, the impact of aircraft on warfare can prove to be the difference between victory and defeat. 

aircraft impact on environment
Source: Tim James/iStock

But, from an environmental point of view, aerial combat offers some unique pressures on ecosystems. 

One of the largest impacts is, obviously, from aircraft engine emissions. Piston-engined aircraft, for example, release much the same emissions as a car engine, but to a much great extent. 

Depending on the fuel they use, aviation gasoline (avgas) or motor gasoline (mogas), the Federal Aviation Administration has estimated that such engines release around 70% carbon dioxide, 29% water, and less than 1% carbon monoxide and NOx emissions. 

Some can even release large amounts of lead into the air as well. While it is important to note that there are far fewer piston-engined aircraft than automobiles, they release their emissions higher in the atmosphere, where it does more damage. 

Jet engines can be even worse. According to some studies a commercial jet engine releases about 200 lb (90 kg) of pollution for every hour it is running. Most of this is carbon dioxide, but they also release small amounts of other pollutants like volatile organic compounds (VOCs), sulfur dioxides, nitrous oxides, polyaromatic hydrocarbons (PAH), and particulate matter. 

These pollutants are bad for the environment if released in large enough quantities, but can also have a marked impact on human health too. 

The global aviation industry produces around 2% of all human-induced carbon dioxide (CO2) emissions, but 12% of CO2 emissions from all transports sources. However, most of this is from civilian aviation, rather than the military. It has also been shown that the impact of military aviation (in the U.S.) on the environment has been decreasing over time. 

But there are other impacts on the environment as a result of fielding aircraft in battle. One important example is the space (and noise) needed to land and takeoff. 

Airports and military airfields need a lot of space on the ground. Building these facilities obviously requires the complete relandscaping of a particular site, destroying local habitats and impacting biodiversity.

Planes are also pretty noisy things, so the act of takeoff and landing, and the associated noise pollution, can severely impact the tranquility of areas immediately around an airfield. When a military aircraft is airborne, "sonic booms" have also been shown to seriously impact wildlife and domestic animals. 

Another issue with operating military aircraft is the waste generated. Apart from the environmental impact associated with their weapons systems, air fleets also generate other waste that needs to be disposed of. 

Some of this can be pretty toxic, like, for example, deicing fluids or other specialist waste (some radioactive) associated with maintaining military aircraft. Unless properly handled and disposed of, any leaks or accidental spillage, or leakage of these materials could be disastrous for any surrounding wildlife and plants. 

environmental impacts of bombers
Source: AllenJMSmith/iStock

And that is just for starters. Military aircraft are built for one main purpose — to deal death-from-above. The impacts of this are much the same as those for other entries above that we've already discussed, but practices like carpet bombing or the use of incendiary bombs (like napalm) have fairly obvious environmental consequences. 

All pretty bad, but we've saved the best, well worst, for last — nuclear weapons. 

7. Nukes are obviously very bad news for the environment

Since we are on the subject of war and environmental impact, we would be remiss to not briefly discuss nuclear weapons. While nuclear weapons have only been used twice in war, they are some of the most destructive and potentially cataclysmic things humans have ever devised. 

danger of nukes
Source: US Department of Energy

Apart from the raw destructive potential of these weapons at their target sites, the environmental impact of nuclear weapons can be fairly wide-reaching. A nuclear explosion produces an enormous fireball, shockwaves, and intense radiation that will effectively wipe out all life within the blast radius of the weapon. 

As bad as all that is, one of the worst environmental impacts of a nuclear blast is the aftermath. 

The initial explosion generates an enormous mushroom cloud that sends vaporized debris, radioactive particles, and ash far into the atmosphere. This material can travel for very long distances, blocking out the sun and raining back down to Earth, contaminating air, soil, water, and food supplies over a very large area over days, weeks, or even years. 

Radioactive contamination from such a blast (like the various nuclear test conducted throughout the 1940s to 1990s) has been shown to have long-lasting effects on the environment and cause very serious health effects for the people and animal life involved.

What's worse, it doesn't take many nuclear weapons detonating at any one time to cause a potentially human civilization-ending event. According to the International Committee of the Red Cross (ICRC), "modern environmental modeling techniques demonstrates that even a 'small-scale' use of some 100 nuclear weapons against urban targets would, in addition to spreading radiation around the world, lead to a cooling of the atmosphere, shorter growing seasons, food shortages and a global famine."

To date, according to some estimates, there are currently 13,150 nuclear warheads currently stockpiled around the world. While it is difficult to give an average yield of these weapons, most of the U.S. inventory tends to be in the 400-500 kiloton range.

Even using this conservative estimate, that is a lot of destructive potentials. However, like anything our species has developed, it pales in comparison to the power of nature, namely volcanoes.

When Krakatoa went off in 1883, the explosion unleashed as much energy as about 200 megatons of TNT. The explosion was so violent it could be heard thousands of miles away, and it threw so much material into the air that global temperatures were affected for years to come. 

If the entire nuclear arsenal of the planet were unleashed the nuclear winter that would follow it would make even the Krakatoa eruption seem mild. Most experts believe the aftermath would be very, very bad for our species. It might even push us into extinction, though this is hotly debated.

But that is a story for another time

If the devastation of life and society from war is not enough, its impact on the environment is arguably worse, as it is potentially longer-lasting. While some argue that war is becoming less common, if history is anything to go by it will be with us for some time to come.

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