Another year is drawing to a close and everyone’s thinking about the future a little more. At OTO we spend a lot of time thinking about the future because so much of what we do boils down to risk management and contingency planning. Whether it’s human health risk assessment for a Brownfield site, evaluating potential seismic hazards for a hospital building, or preparing a spill response plan for an oil terminal, the focus of our work is planning for a safer future.
People, particularly engineers, like to think that what we create will last and be sustainable. How long should something be expected to last, though? This is an interesting question in the United States, where there are very few structures more than a century and a half old, and almost none more than two centuries old—my own house was built in 1900 and is considered “old,” but in many parts of the United Kingdom it’s possible to attend church on Sunday in a chapel built eight centuries ago.
Most consumer electronic products made these days can generally be expected to last a few years at most (although our cars definitely last longer than they used to). For example, Apple, despite all the attention given to its trendsetting designs like the smartphone, has been buffeted by a long series of class-action lawsuits over such problems as the batteries in third-generation iPods failing en masse after less than two years, raising questions of sustainability, planned obsolescence, and even unfair trade practices such as ‘designed to fail.’ Although the thought of replacing your cell phone every two to three years used to rankle, by now pretty much everyone seems by now to be used to the idea. I’d be happy to get four years’ use out of a cell phone, but I’m pretty sure that in ten years’ time it won’t even be able to connect with the programming languages in use in 2026 any more than it could connect to one of Alan Turing’s vacuum tube powered Bletchley Park computer prototypes from the Second World War codebreaking project. This isn’t necessarily progress, mind you—just a recognition that making things less backwards-compatible can be part of making them profitable ….but yet, vinyl records are enjoying a surge in popularity.
The design life for most civil engineering projects, such as roads, buildings, and water supply systems, is in the range of 25-50 years, based on judgments made on the expected durability of the materials used in construction, and the capacity of the design versus demand. Take for example a town’s water and sewer system designed in 1950 based on assumptions about projected population growth. If a major new employer relocates to town and as a result the local population spikes, some of the assumptions may no longer hold, and the mains will have to be enlarged and another water source found. Where a lot of infrastructure is created at once, however, this can create major problems further down the road; most of the United States’ modern highway and major bridge infrastructure was built within a roughly 20 year period after the Second World War and is now at or well past the end of its original lifespan, and badly in need of repair or replacement, largely because reinforced concrete is not nearly as inert and eternal as was previously thought.
With environmental issues such as contaminated sites and solid waste landfills, we generally consider a timescale of about a century, which makes sense because most of the contaminants we worry about—gasoline, fuel oils, even many chlorinated compounds—will have geochemically weathered into nothing within that time… yes, someday we will be free of PCE and TCE, though lead and arsenic will always be with us, and PCBs with five or more chlorines seem to be built for the ages. Still, this timespan is reflected in some of the material choices we make. For example, a cap for a landfill or CERCLA site might be constructed of several layers of engineered but ultimately natural materials (a clay layer to prevent water infiltration, venting and drainage layers of sand and gravel, a barrier layer of cobbles to stop burrowing animals, and an outer layer of grassy turf, all graded and contoured to shed water without erosion into grassy swales) because these are durable, and even somewhat self-repairing. By contrast, a simple concrete or asphalt slab, however reinforced, will eventually crack, spall, and buckle, while its stormwater drains into pipes that will silt up, clog, and fail.
Some man-made structures have, of course, endured for much longer. Thomas Telford’s 1,368-foot wrought-iron Menai Bridge, completed in 1826, remains in daily use.
The Pont du Garde aqueduct in southern France, built sometime between 40 and 60 AD (the reigns of the infamous Roman emperors Caligula and Nero), remains pretty much intact, but was maintained over the years, surviving the fall of Rome and the Middle Ages largely because local noblemen could rent it out as a toll bridge.
The Great Pyramid of Giza is somewhere around 4,500 years old; when Julius Caesar met Cleopatra around 48 BC, the pyramid was as ancient to Rome’s most famous dictator as Caesar is to me.
For some projects, however, the design period starts to sound like deep time, where the project needs to remain viable not for years or decades, but for centuries or even millennia.
One of the singular engineering projects of our day is the Onkalo (Finnish for “hiding place”) nuclear waste depository under construction in a sparsely-settled area on the western coast of Finland. Construction began in the 1990s and the facility is planned to be complete in 2020, and eventually reach capacity in 2100. For a country with a small population and no conspicuous natural resource wealth like that enjoyed by oil countries, Finland is no stranger to major engineering projects, though these are generally of a decidedly pragmatic bent in contrast to the half-mile-tall Burj Khalifa superskyscraper in Dubai. The country is, after all, proudly home to one of the world’s largest commercial shipbuilding industries, producing everything from warships to cruise liners (if you ever sailed Royal Caribbean, the liner was probably built in Finland) to nuclear-powered icebreakers. They’re also used to making things that last– for example, the old Nokia 3310 cell phone, best remembered for being almost indestructible…. in stark contrast to the third-generation iPod.
Finland gets a quarter of its electricity from nuclear power plants, and a national law requires Finland to take responsibility for the country’s own nuclear waste, rather than trying to fob it off on someone else. This is accordingly Finland’s third such facility , and is intended to store a century’s worth of spent nuclear fuel from power plants in massive vaults carved into migmatic gneiss bedrock nearly 1,400 feet underground, with the goal of isolating the material for as long as high-level radioactive waste remains dangerous… or “only” about a hundred thousand years.
The US, by contrast, simply buried the reactors used in the initial Manhattan Project research in a forty-foot deep hole in the ground on land in rural Illinois that is now a nature preserve, marked only by little more than a stone tabled inscribed “Do Not Dig,” and has been dithering over a long-term storage facility at Yucca Mountain, Nevada since 1978.
A hundred thousand years is about ten times as long as the period since h. sapiens shook off his Paleolithic frostbite at the end of the last Ice Age, got a dog and started planting wheat, and it’s more than twenty times as long as all of our species’ recorded history. Nothing built by man has lasted even a tenth as long (Stonehenge and the Watson Brake mound complex in Louisiana area are each a comparatively trifling 5,000 years old), and probably very little that exists now will endure other than scars on the land created by mines, canals, and other geoengineering projects. If I can paraphrase the Scottish philosopher and mathematician John Playfair (who publicized the work of James Hutton, “discoverer” of geologic time), our minds grow giddy by looking so far into that abyss of time.
At that point, the matter of a design period is no longer just an engineering question, but a philosophical one too, as explored in the documentary Into Eternity, which explored the Onkalo facility. It’s no longer enough to find a geologically stable location and pick materials that could be expected to last so long. A repository like this would have to survive not just earthquakes and groundwater leaching, but also a nuclear World War Three and another ice age. Can you wager on there even being a government to maintain such a facility, when most of the world’s countries are less than 100 years old, and even the oldest continuously operating human organizations, such as the Roman Catholic Church, are “only” about 1,500 years old? Or, since financial assurance mechanisms may not survive a war, a financial collapse, or a post-apocalyptic new dark age, should the repository be able to endure without any human intervention at all?
How do you keep someone ten thousand years from now from unwittingly opening it? No deed restriction (or any other document, for that matter) will outlast the paper or hard drive it’s recorded on unless it’s regularly recopied onto durable media, and who’s going to do that? How do you design a warning sign when the language you speak now may be as long lost as the Sumerian tongue is today, and the radiation trefoil’s meaning could be as lost to posterity as the story behind Paleolithic cave paintings, and even stone-carved hieroglyphics are weathered into illegibility after five or six millennia? Do you even put up warning signs at all, or just bury it as deeply as possible and hide it as well as you can, hoping the whole thing will never be rediscovered?
The Long Now Foundation was founded to explore these issues in 01996. The 0 isn’t a typo, it’s like the sixth digit on your car’s odometer; the philosophical goal of the foundation is to explore methods by which mankind and its artifacts last long enough for that 0 to tick over into 1. Its signature project is the 10,000 year clock (which is pretty much what it sounds like), which started receiving more attention after some of the foundation’s ideas were included in Neal Stephenson’s 2008 science fiction novel Anathem. If that sounds too quixotic, a similar but more pessimistic-sounding project is the Svalbard Global Seed Vault, a repository of plant seeds built deep underground in an abandoned coal mine on the sub-Arctic island of Svalbard, where seeds would hopefully survive for hundreds or thousands of years, including, natural or man-made disasters and giving mankind a shot at restarting global agriculture, if need be.
How do you design something that may well need to outlast modern civilization (or put even less optimistically, to survive modern civilization, or at least its darker impulses)? Now THAT is engineering for the long term!
….At least the chlorinated hydrocarbons will be gone by then…..
I met a traveler from an antique land,
Who said—“Two vast and trunkless legs of stone
Stand in the desert. . . . Near them, on the sand,
Half sunk a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them, and the heart that fed;
And on the pedestal, these words appear:
My name is Ozymandias, King of Kings;
Look on my Works, ye Mighty, and despair!
Nothing beside remains. Round the decay
Of that colossal Wreck, boundless and bare
The lone and level sands stretch far away.”
–Percy Bysshe Shelly, Ozymandias, 1818