Military Impacts on the Environment

Steve Dutch     Lab Sciences 463      Phone: 465-2246    e-mail:

University of Wisconsin-Green Bay

During the Persian Gulf war of 1991, it was common to hear claims that the war had introduced something new: environmental warfare. Environmental warfare is ancient, and even armies of horse soldiers equipped with spades have modified the environment on a large scale. Here we will develop a conceptual framework for describing military effects on the environment. Within that framework, we can see what was actually new about the Persian Gulf war.

With no exaggeration and little effort, one can assemble a literal ton of material about the effect of the environment on military actions; mountain warfare, jungle warfare, winter warfare, and so on. Surveys of the effect of military operations on the environment are less common. We can identify four broad classes of military effects on the environment: Collateral Effects, Use of Environment as a Weapon, Environmental Modification to Aid Own Operations or Impede Enemy, and Eco-Terrorism. Military actions may include some or all of these components to varying degrees.

Many people wonder why "we just don't let the generals fight and keep politicians out of it." That's asking for something that never was and never can be unless a society is determined to commit military suicide. The German military writer Clausewitz observed that "War is policy carried on by other means." All war is inherently political. The last general who was utterly unconstrained was Napoleon, and that didn't work too well for him (Hitler was a corporal).

Incidental (Collateral) Effects

Collateral Damage

In collateral damage, there is no direct intent to affect the environment.

Collateral Protection

Military activities can sometimes preserve the environment. Along the World War II Siegfried Line, and along Former East European Frontiers are tracts of land not disturbed for decades, some of the little undisturbed land in Europe. Military Reservations are often the last large tracts of undeveloped land in many places. Camp Pendleton, California, is the last large tract of open land between Los Angeles and San Diego. The military has the political power to resist development pressures, and also has a vested interest in preserving a realistic training environment, which means limiting damage to terrain and plant cover.

Operational Modifications

On a small scale, almost all military construction, even digging a foxhole, falls into this category. Earthworks are still visible on many battlefields even after centuries.

Modifications to facilitate own operations

These are generally small-scale and local due to time and materiel constraints. Because tactical situations change so rapidly, there are not too many examples of large-scale tactical modification of the environment to improve mobility. Some of the best were river-modification efforts during the Civil War.

Canal cutting (U.S. Civil War)

One of the first steps in gaining control of the Mississippi during the Civil War was running the bend at New Madrid, Missouri. Above is a late 19th century map of the operation. Island Number 10, southeast of New Madrid, was heavily fortified by the Confederates. To bypass the island, a canal was dug through the marshlands north of New Madrid. It was capable of carrying supply and troop barges, but not gunboats. Nevertheless, the canal allowed the Union to get its troops and supplies past Island Number 10. Unfortunately, they were on the wrong side of the river, and unable to do anything without a gunboat. The commander of a gunboat, the Carondelet, believed he could make the run past Island Number 10. He piled a barge with cotton bales and lashed it alongside for protection, and started out on a dark night. Unfortunately, a thunderstorm broke out and the Confederates spotted the ship by the lightning flashes. Despite a tense ride, the Carondelet made it safely past, and went on to knock out the Confederate guns below New Madrid, Union troops crossed the river, and that was that.

By the summer of 1863, the Confederates held only the city of Vicksburg, Mississippi, which they fortified heavily. General Grant tried numerous approaches, which, while they all initially failed, served to confuse and demoralize the Confederate commander. Grant made a number of attempts to open waterways, two of which are shown here. Grant's Ditch was an attempt to cut off a river meander artificially, bypassing Vicksburg and ultimately leaving it of no importance. The attempt failed, although the present course of the river does cut off the meander. The Duckport Canal connected the Mississippi to a small backwater. It ultimately did allow a ship to pass, but by then Grant had moved his men south of Vicksburg by land.

One of the most remarkable river-modification operations in all military history happened in 1864. For a variety of complex reasons, mostly dealing with access to cotton and a desire to plant the flag west of the Mississippi to send a message to the French, who had installed a puppet ruler in Mexico, Lincoln ordered an advance up the Red River in Louisiana. The operation was rushed and undermanned, and failed. Worse yet, Union gunboats were stranded by low water. Destroying them would be disastrous, abandoning them would be far worse, since it would give the Confederates a gunboat fleet with access to the Mississippi. It would be tantamount to re-opening the battle for control of the Mississippi.

A Colonel Bailey from Wisconsin pointed out that loggers, faced with similar problems, built dams to raise the water level and float logs over rapids. With a few regiments of lumberjacks from Maine, he set about building a dam. The dam raised the river level and when it was broken, the gunboats enjoyed a rough ride to safety.

Road building

Two remarkable road-building operations during World War II were the Burma Road and the Alcan Highway. The Burma Road crossed rugged mountains from Burma to China, allowing supplies to reach China by land. With China's coast occupied by the Japanese, the only other way to get supplies to China was the dangerous air route over the Himalayas (the "Hump"). The Alcan Highway (Alaska-Canada) was the first land connection between Alaska and the continental United States. It was built in 8 months in 1942-1943 by 10,000 troops, of whom about a third were black.


Defoliation operations in Vietnam, including use of the notorious Agent Orange, were designed to eliminate tree cover and deprive Vietnamese Communist forces of concealment.

Modifications to impede enemy

It is usually easier to mess things up instead of improve them, especially in war, so it is no surprise that environmental modification to impede the enemy is so prominent in military history. I will focus on an example of river diversion from each category.

Fortifications and trenches

Diversion of waterways

Destruction of food supplies

The Huang He

The Huang He in northern China has created a flood plain that is actually a gigantic alluvial fan. The river historically has alternated between outlets north and south of the Shandong Peninsula. In July 1938, to impede the invading Japanese, the Chinese blew the levees and diverted the river. The effect on the Japanese was minimal, but perhaps 500,000 Chinese died in the floods. In terms of loss of life, this is arguably the worst act of environmental warfare ever.

This is a frustrating episode to document. Chronicles of natural disasters omit it because it was the result of military action, and histories of World War II omit it because it was militarily ineffective.

The Aral Sea

River diversions improve access to besieged cities, and cut off their water supply. Like the Huang He, the Amu-Darya flows onto a vast alluvial fan. At various times in the past, it has emptied into Lake Sarikamish (where some of the presently-diverted water ends up) and thence to the Caspian via the Uzboy channel. Diversions have been both natural and artificial; for example, the Mongols diverted the river in 1221 during the siege of Urganj.

Of all the volumes written on the Aral Sea ecological disaster, few writers seem to be aware of the complex diversion history of this river, or that there have been previous artificial diversions.

Chemical Warfare

Chemical warfare serves mostly to impede enemy mobility by requiring cumbersome protection. It is devastating against unprotected troops and civilians, but inflicts few casualties on properly protected troops.

Strategic Modifications

When we turn to strategic modification of the environment to enhance mobility, we find massive projects, including probably the largest scale engineering. These are typically undertaken for long-term purposes, often have civilian as well as military applications, and are usually done on friendly or at least secure territory.

Clearing the Red River

The same Red River that saw Colonel Bailey's dam building was also the location of one of the first large scale military engineering operations in the U.S. The Red River forms the boundary between present Oklahoma and Texas and then cuts southeast across Louisiana to the Mississippi. It was an ideal water route into a large, rich agricultural region, except for one problem. For 150 miles the river was choked by an impenetrable raft of debris, a perfect model, by the way, for the formation of some kinds of coal deposits (allochthounous).

Army Engineer Henry M. Shreve devised a ship-mounted grapple and began attacking the log raft in 1833. By 1836 he had cleared seventy miles. The city he made possible was named Shreveport. Annual floods, however, continually reformed the debris raft, and seasonal low water interrupted traffic every summer. It was not until 1872 that a determined effort to clear the entire river was begun, and not until 1900 that the raft was permanently cleared. But by 1914 the river had silted up, owing to disuse as railroads took over transportation. It was reopened to river traffic as far as Shreveport in the 1990's.

Strategic Highways

During World War I, the Army quickly found that U.S. railroads could not serve its logistical needs and turned to truck convoys. Civilian motorists soon found that the convoy routes offered such unheard-of amenities as regular maintenance, snow plowing, and route markers.

Shortly after the war, General Pershing proposed a national network of military and civilian highways. He ranked his routes by priority, shown here in red for highest priority, green for second and blue for third. The differences between this map and today's Interstate system are as interesting as the similarities. They reflect:

In 1919, the Army drove the first truck convoy across the United States, just to see if it could be done. It could, but only barely. The trip took several weeks. One of the participants was a young lieutenant named Dwight Eisenhower. Years later, as President, he signed the act creating the Interstate Highway System, officially called the Interstate and Defense Highway System. It looks very much like the network Pershing proposed. The fact that the system is the Interstate Defense Highway System accounts for the anomaly that Hawaii has Interstate highways: they connect all the major defense installations.

The first superhighways were in the U.S., and they in turn inspired the German Autobahn system, which mightily impressed the U.S. military during World War II. There had actually been plans for an American version in the 1930's, but World War II interrupted the plans. After the war, inspired in part by the Autobahns, Americans began building superhighways. So in reality, American and German superhighways inspired each other.

The U.S. love affair with the auto, with all its social and environmental impacts, would probably have happened anyway, but its actual development was strongly influenced by military considerations. It is all but impossible to overstate the environmental impact of the Interstate System. It is the largest engineering project in history.

The Suez Canal

Connections between the Mediterranean and the Red Sea have been contemplated since antiquity, and a variety of ancient connections between the Nile and the Red Sea existed at different times. The present canal was begun in 1858 and completed in 1869 under the leadership of French engineer Ferdinand de Lesseps. There are no locks on the canal and digging it was an enormous, but not overly challenging, task. The Suez Canal proved instrumental in helping Britain retain its hold on India. The repulse of the German advance on the canal was a pivotal event in World War II.

Sea level is about a meter higher in the Red Sea than in the Mediterranean, and Red Sea species have migrated north. Because they are better adapted to salty water, they displace Atlantic species. The Aswan dam on the Nile has further reduced the influx of fresh water into the Mediterranean, increasing the advantage of Red Sea species.

Panama Canal

The French made the first attempt to dig a canal across Panama but were finally defeated by weather and disease. The project was led by de Lesseps, whose enormous prestige after the success of the Suez Canal kept the project going long after it had bogged down literally and figuratively. Some 22,000 workers died before the project ended in 1893. Although they are usually portrayed in the history books as brave pioneers who ultimately failed, the French actually excavated a good deal of the eventual canal. They also constructed a railroad that proved a backbone of the eventual successful canal project, and some French investors profited tidily from selling right of way for the canal.

To build the canal, the United States had to overcome three obstacles:

In 1903, the U.S. and Colombia negotiated a treaty to build a canal, but the Colombian Senate refused to ratify the treaty. President Theodore Roosevelt sent military forces to the region, just in case a separatist revolt were to break out in Panama. Amazingly enough, one did. The United States promptly recognized the newly independent country of Panama, which in turn quickly approved the construction of a canal. Panama thus became one of the very few countries to switch continents, since as a province of Colombia it was part of South America.


The logistical issues were addressed in typical American fashion - by sheer force. Skilled workers were enticed to come and stay by building neat American style towns and family quarters. It was American expertise in a completely unrelated field - railroading - that moved the vast quantities of earth and rock to excavate the canal. Railroads were continually built and relocated as the excavation continued. Unskilled labor was supplied by workers from the West Indies, who weren't accorded the creature comforts or aggressive health measures provided to Americans.

Use of the Environment as a Weapon

Passive use of the environment as a combat multiplier is an ancient military tactic: waiting for suitable weather or moon phase, channeling the enemy into unfavorable terrain, and so on. That's not the sense implied here. Instead, this category consists of use of the environment itself as a weapon, by deliberately triggering an environmental effect to cause direct damage to enemy forces

Active triggering of environmental effects makes for fun movies like Under Siege II, but is comparatively rare in reality. Until recently we lacked the scientific knowledge and technical capability to trigger environmental effects deliberately. The opportunity to trigger environmental effects arises infrequently, and most of the time environmental effects are inefficient at causing damage, compared to conventional military means. For example, if the enemy is cooperative enough to put his headquarters at the base of an unstable cliff within artillery range, why not just shell the headquarters directly?

Probably the most ancient use of the environment as a weapon was the deliberate spread of natural plagues. Long before germs were known, it was known that disease spread from sick to healthy individuals, and besieging armies hoped not only for natural outbreaks of disease to weaken the enemy, but sought to speed the process up by catapulting dead animals and corpses over walls, contaminating water sources, and so on. 

The winter mountain warfare in the Alps during World War I is probably the best example in history of the use of the physical environment as a weapon. Both Italian and Austrian forces used artillery to trigger snow avalanches on their opponents, with the loss of thousands of lives. This is one of the very rare cases where natural effects amplify a man-made trigger effectively. During World War II, the Allies launched "Dam Busting" raids on dams in the Ruhr valley. To the extent that downstream flooding was militarily effective, this is another example.

Environmental Terrorism

Eco-Terrorism is comparatively modern because only recently have we had the technological capability to create real environmental havoc, and only recently has concern for the environment become serious enough for eco-terrorism to be a credible threat. The thought of Genghis Khan or Tamerlane diverting a campaign to protect vulnerable habitat is grimly humorous. Environmental concerns would simply not have been an issue before the 20th century.

Reasons for employing eco-terrorism:


Scorched earth campaigns have been directed mostly against structures and agriculture, but certainly contain a strong element of eco-terrorism. The Shenandoah Valley campaign and Sherman's March to the Sea during the Civil War are examples from American history. One of the most horrific examples was the Mongol invasion of Iraq. The Iraq of today is not the Iraq of a thousand years ago; until the Mongol invasion Baghdad was one of the cultural centers of the world, supported by an irrigation complex thousands of years old. The Mongols annihilated Baghdad, destroyed the canals, and so thoroughly depopulated the country that the canals were never restored.

Time and again we find the Mongols doing things in a manner or scale that would not be seen again until the Twentieth Century. It's almost as if Patton and Rommel had fallen through a crack in space-time and come out in the Thirteenth Century.

In 1945 Hitler ordered a scorched earth retreat in Germany, which was fortunately disregarded by his subordinates. His orders would have destroyed Germany's infrastructure completely and returned Germany to the Middle Ages. By the time he issued it his ability to enforce his orders was severely diminished, and his subordinates generally disobeyed it.

The events of the Persian Gulf War in 1991 are unique in being pure eco-terrorism. The other examples cited here have at least some military justification, but the Sea Island Oil Spill and firing of the Kuwait Oil Wells were motivated almost entirely by a desire to damage the environment. It is in this respect that the 1991 Persian Gulf War brought something new to warfare. Eco-terrorism is a modern threat since concern for environment has only recently emerged as political force.

Doomsday weapons

Doomsday weapons have figured in military speculation since the 1950's. The most widely discussed is the cobalt bomb, a large nuclear weapon encased in cobalt. Cobalt by itself is merely a metal but cobalt-60 is radioactive with a half life of five years. In principle, a large nuclear weapon would bombard the cobalt casing with neutrons, creating large amounts of cobalt-60 which would cover the earth, or a large part of it, with a lethal blanket of fallout. Cobalt bombs figured in the apocalyptic novel and film On the Beach and the black comedy Doctor Strangelove.

Cobalt bombs were pictured as the ultimate deterrent, but as far as is known, none were ever built, and for obvious reasons, none were ever tested. Doomsday weapons potentially appeal to apocalyptic political and religious movements.

Nuclear Winter

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Created 19 April 2006, Last Update 02 June 2010

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