Leaving an indelible mark (Image: David Kennerly/Corbis)
VERDUN, The Somme, Passchendaele, Gallipoli – the battles of the first world war have become bywords for death, destruction and human misery. Historically, they are just the tip of the iceberg. There have been countless thousands of battles, and still they go on: around 50 armed conflicts are raging right now. War shapes the past, destroys our present and will determine our future.
But could the scars run deeper? Does conflict leave a permanent mark within Earth itself? It turns out war isn’t just for the history books – it can shape the geological strata in which Earth’s narrative is written.
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The earliest evidence of armed conflict dates back to around 13,000 BC and a mass grave in northern Sudan. Here 59 human skeletons were discovered, many bearing signs of violent death such as spear and arrowheads embedded in their bones.
The wars of the ancients give some guide to how long the marks of war might last. The old battlegrounds were picked over, as the dust and smoke settled, by vultures, rats and human scavengers. Much later, teams of archaeologists moved in, finding smashed human skeletons and the remains of weapons such as flint arrowheads. Could these objects last longer and become geology rather than archaeology?
A few might. The simple materials of the old warriors have good geological analogues. Indeed, some are the essence of geology. There is little that is more hard-wearing than flint: tough and chemically resistant, it is one of the ultimate survivor rocks. A wooden lance can carbonise over time to become a lance-shaped lump of coal. But not everything will last that long: iron weapons, for example, may not fossilise so easily, as iron rusts at the surface and corrodes once buried.
What about the geological legacy of modern warfare? Here we enter uncharted territory. Some of these future fossils will be strange. Some will probably be huge. And some already encircle Earth.
Perhaps the most noticeable legacy comes from the scale and power of warfare. Gunpowder has been around for over a thousand years, and was mainly used to propel shot at people, ships and fortress walls. Then came Alfred Nobel and his discovery of high explosives that could be delivered using artillery. These were able to refashion entire landscapes, as the first world war showed so graphically: the battlefields of the Western Front were turned into muddy quagmires by incessant shelling. Entire hills could lose several metres in height in an intense bombardment.
This transformation was more than skin-deep. In 2006, soil scientists Joseph Hupy of Colgate University in Hamilton, New York, and Randall Schaetzl of Michigan State University in East Lansing compared the effects of shelling to bioturbation – the burrowing activities of worms and other invertebrates – which is widely preserved in the fossil record. They called the explosive production of a distinctive mass of metres-deep craters and churned earth and rock ““. This may also be compared to dinoturbation, the footprints and other disturbances left by giant dinosaurs and preserved for millions of years.
US B-52 bombers pummelled this area of Vietnam (Image: Tim Page/Corbis)
By the time of the Vietnam war, landscape transformation was no longer collateral damage but a primary war tactic to remove cover from the enemy – like the scorched earth practices of old, but carried out with massively greater firepower. Between 1965 and 1971, an area not much bigger than Texas was bombarded with twice as much high explosive as US forces used during the entire second world war. The region was pulverised by some 26 million explosions, with the green Mekong delta turned to “grey porridge”, as one soldier put it. In Iraq, Afghanistan, Syria and elsewhere, bombturbation continues.
A quarter of shells fired in the first world war failed to explode (Image: Paolo Pellegrin/Magnum Photos for the Nobel Peace Center)
Bombturbation can continue even after the guns fall silent. Of the estimated 1.5 billion shells fired in the first world war, perhaps a quarter didn’t explode on impact. Thousands are found every year, and people are still killed by them. Most of this unexploded ordnance lies buried, some 20 metres down. If it stays buried, could it fossilise? This seems likely. Even if the steel eventually dissolves, and the explosive transforms to petroleum, a compressed carbon-impregnated impression will remain, like a crushed and flattened dinosaur skull in a sandstone slab.
Bombturbated mud also contains the bones of fallen soldiers. Of the million killed in the 10-month-long Battle of Verdun, only some 290,000 were ever found. The rest must lie somewhere within that bomb-churned stratum. These layers are akin to bone beds – concentrations of vertebrate fossils found in prehistoric rock. But there is one striking difference: in these human bone beds, the remains are virtually all of young men.
After battles, shattered cities need to be rebuilt. But what to do with the rubble? In some places, there was too much to simply build over. The tallest hill in the German capital, Berlin, stands 80 metres high and a kilometre in length. Called Teufelsberg (Devil’s Mountain), it is now tree-covered and looks natural. But underneath is some 75 million cubic metres of rubble from Nazi Berlin, including the remains of Albert Speer’s unfinished military college. The top of the Teufelsberg was annexed, ironically, for another conflict – it bears the domes of a US-run cold war spy station.
Will these war-derived land formations become the rock layers and fossils of future geology? Surely, over centuries and millennia, erosion will wear away even the deepest bomb crater and highest mountain of rubble? That’s true for tectonically rising ground. But on coastal plains and subsiding deltas, the crust is going down, not up. Here, war-torn landscapes will be buried, first under water and then under new sediment layers, and begin to be preserved as rock strata. These are the kinds of environments that in the geological past entombed ancient landforms, like the debris spread inland by a tsunami. In them, today’s giant bomb craters could easily become fossilised. The likely near-future sea level rise, as global warming bites, will only speed this burial, as land is submerged and taken out of the realm of erosion.
Buried at sea
Deep beneath the sea, fossilisation takes place even more readily. Some of the shipwrecks strewn across the sea floor are the result of naval battles, and these may be entombed and become “technofossils”. But it is another relic of modern war that will likely leave the most striking message to the future. After both world wars, the exhausted armies were left with millions of unused bombs, including chemical weapons. There was neither the time nor the resources to make them safe; most were simply shipped out to sea and thrown overboard (see map).FIG-mg30140601.jpg
There are over a hundred known weapons dumps in the seas around north-west Europe alone. One of them, a submarine hollow called Beaufort’s Dyke in the Irish Sea between Scotland and Northern Ireland, contains over a million tonnes of surplus munitions. Even larger dumping grounds were improvised elsewhere in the world.
How might an undersea bomb leave a lasting mark? Initially, sinking munitions will create impact deformations on the sea floor; rocks dropped from melting icebergs leave similar structures in strata. Later, corroding bombs can explode, especially if they are disturbed by a fishing vessel’s trawling gear, for example. Explosions can continue for centuries afterwards, creating bombturbated layers on the sea floor. Or the explosives and chemical agents can seep out and kill off marine life. Dissolved TNT is highly toxic, to say nothing of mustard and nerve gas. Biological dead zones would be preserved as fossil-free layers of rock.
Bullets, too, may leave their mark. Around a trillion have been fired since the beginning of the second world war – that’s a couple of thousand for every square kilometre of Earth’s surface, both land and sea. How will they end up? Bullets are largely made of lead, which is chemically unstable in surface conditions and rare in nature. In soil, bullets slowly oxidise and corrode, leaving bullet-shaped holes filled with lead minerals, such as the clear crystalline cerussite or the yellow anglesite. Bullets falling into oxygen-starved sea floor muds might turn into silvery galena, or even remain as the metal itself. The killing fields will transform into a mineralogical garden.
War has spurred other kinds of geological novelty, including the transmutation of elements. The development and testing of nuclear weapons spread human-made elements such as plutonium and technetium around the world, leaving a radioactive fingerprint on soils and sediments. For good measure, it also released an extra dose of carbon-14 to be incorporated in the tissues and bones of living organisms.
Little of this pollution relates to war itself – the atomic bombs that destroyed the Japanese cities of Hiroshima and Nagasaki left negligible radioactivity. The worldwide radioactive “bomb spike” in sediment layers is a legacy of the sabre-rattling of the cold war in the 1950s and 1960s, when over 500 nuclear weapons were detonated at Earth’s surface and in the atmosphere. The bomb spike can even be found in Antarctic snow layers. Small wonder that it is being suggested as a primary characteristic for the mooted Anthropocene Epoch, when humans became the primary driver of Earth’s geological processes.
Nevada’s nuclear landscape at Yucca Flats (Image: courtesy Everett Collection/Rex)
In the 1960s, concerns about these rising radioactivity levels forced nuclear tests underground. Around 1350 were carried out at test sites such as Yucca Flats in Nevada and Semipalatinsk in Kazakhstan, leaving a distinctive signature in the rocks. The force of each explosion first created a spherical cavern lined with molten, radioactive rock. The cavern walls and roof usually then collapsed to form an underground mass of radioactive rubble and melt hundreds of metres across, with fracture networks extending outwards. This caused the land surface to subside and form a steep-sided crater, its edge defined by circular fault lines generated by the explosion. Extending up to 2.5 kilometres below ground, these unique geological structures will persist for many millions of years.
“Craters from underground nuclear tests will persist for millions of years”
The cold war nuclear stand-off may yet have a sting in its tail. The Kara Sea, north of Siberia, is a huge dumping ground for nuclear waste. Fourteen rusting nuclear reactors lie there, cut out of obsolete submarines and power stations. An entire Soviet nuclear submarine, K-27, scuttled in 1982, lies nearby in Stepovogo Bay, its reactors still charged with nuclear fuel.
Underwater Chernobyl
More reactors and submarines lie in the Barents Sea to the west, and off the coast of the Kola Peninsula. They won’t explode, but they could go critical and make a kind of underwater Chernobyl. If a massive submarine radiation leak occurred, it would cause environmental havoc, leaving a radioactive layer on the sea floor as a geological legacy.
There are other war-related fossils: hardened concrete bunkers and underground silos, military roads and runways, and the toxic, oil-soaked ground left behind when armies move on. These rock-borne signals won’t be small, for war is big business. is about $1.7 trillion a year – about 2.5 per cent of global GDP – and the associated energy use is enormous. The US Department of Defense accounts for over 80 per cent of the US government’s total energy consumption.
What about the effect on wildlife, the future palaeontology of Earth? This is more complex. In some areas wildlife is devastated, for instance by the carpet bombing and Agent Orange defoliant that destroyed Vietnam’s forests. But peacetime activities of agriculture and urbanisation can devastate biodiversity, too. In fact, wildlife often copes better with sporadic bombs and bullets than it does with chainsaws and tractors. Many military training areas are home to rare species; it has even been suggested that such areas be given official status as nature reserves. War-torn areas, too dangerous for humans, may be havens for some creatures. The landmine-ridden Iran-Iraq border region is a place where the endangered can walk today in relative safely.
Can one avoid the geological impact of war by not fighting with anyone? Seemingly not. Switzerland is a determinedly neutral country, yet many of its mountains are engineered in readiness for war, the bedrock riddled with networks of roads, tunnels and chambers big enough to hide planes and even armies. If anyone tries to invade, weaponised mountainsides will trigger landslides to sweep through valleys.
Perhaps the greatest impact of war on Earth will be indirect, resulting from that characteristic of humanity that has underlain conflict ever since our species arose: tribalism. We segregate into groups and nation-states, compete for resources and guard the interests of our own group jealously. That makes it difficult for us to act together when a common problem arises. In far future times, it might be asked how an intelligent, technologically advanced species clearly saw the signs of imminent climate change and then reacted too little, too late. Inaction on this scale could change the world’s geology as nothing else has in our planet’s history.
Maybe we won’t get that far. Our belligerence could lead to all-out nuclear war. What then, geologically? A thin, soot-stained nuclear winter layer will probably form, rather like the Cretaceous-Tertiary boundary that marks the death of the dinosaurs, though sprinkled with plutonium rather than asteroid-derived iridium. The plutonium will decay away in a fraction of a million years. How future geologists would interpret this layer is hard to know. But they may also notice that the layer also marks the upper limit of a certain type of geological deposit – one of bombs, bullets and human bones.
This article appeared in print under the headline “Battle scars”
