THE ECOLOGICAL AFTERMATH - Dark Age America: Climate Change, Cultural Collapse, and the Hard Future Ahead - John Michael Greer

Dark Age America: Climate Change, Cultural Collapse, and the Hard Future Ahead - John Michael Greer (2016)

Chapter 2. THE ECOLOGICAL AFTERMATH

LIKE EVERY OTHER PROCESS IN THE REAL WORLD, HISTORY IS shaped partly by the pressures of the environment and partly by the way its own subsystems interact with one another and with the subsystems of the other ecologies around it. That’s not a common view; most historical writing these days puts human beings at the center of the picture, with the natural world as a supposedly static background, while a minority view goes to the other extreme and fixates on natural catastrophes as the sole cause of this or that major historical change.

Neither of these approaches seems particularly useful. As our civilization has been trying its level best not to learn for the past couple of centuries, and thus will be learning the hard way in the years immediately ahead, the natural world is not a static background to human history. It’s an active and constantly changing presence that responds in complex ways to human actions. I’d like to propose, in fact, that history might best be understood as the ecology of human communities, traced out along the dimension of time.

Human societies are just as active and equally changeable as their natural environments, and respond in complex ways to nature’s actions. The strange loops generated by a dance of action and interaction along these lines are difficult to track by the usual tools of linear thinking, but they’re the bread and butter of systems theory, and also of all those branches of ecology that treat the ecosystem rather than the individual organism as the basic unit.

The easiest way to show how this perspective works is to watch it in action, and it so happens that the systems approach makes unusually clear sense of one of the most important factors that will shape the history of North America over the next five centuries. The factor I have in mind is climate.

Now, of course, that’s also a political hot potato just at the moment, due to the unwillingness of a great many people across the industrial world to deal with the hard fact that they can’t continue to enjoy their current lifestyles if they want a climatically and ecologically stable planet to live on. It doesn’t matter how often the planet sets new heat records, nor that the fabled Northwest Passage around the top of Canada and Alaska—which has been choked with ice since the beginning of recorded history—is open water every summer nowadays and is an increasingly important route for commercial shipping from Europe to the eastern shores of Asia.1 Every time the planet’s increasingly chaotic weather spits out unseasonably cold days in a few places, you can count on hearing well-paid corporate flacks and passionate amateurs alike insisting at the top of their lungs that this proves that anthropogenic climate change is nonsense.

To the extent that this reaction isn’t just propaganda, it shows that too many people have forgotten that change in complex systems does not follow the sort of nice straight lines that our current habits of thought prefer. A simple experiment can help show how complex systems respond in the real world, and in the process make it easier to make sense of the sort of climate phenomena we can count on seeing in the decades ahead.

The next time you fill a bathtub, once you’ve turned off the tap, wait until the water is still. Slip your hand into the water, slowly and gently, so that you make as little disturbance in the water as possible. Then move your hand through the water about as fast as a snail moves, and watch and feel how the water adapts to the movement, flowing gently around your hand.

Once you’ve gotten a clear sense of that, gradually increase the speed with which your hand is moving. After you pass a certain threshold of speed, the movements of the water will take the form of visible waves—a bow wave in front of your hand, a wake behind it in which water rises and falls rhythmically, and wave patterns extending out to the edges of the tub. The faster you move your hand, the larger the waves become, and the more visible the interference patterns as they collide with one another.

Keep on increasing the speed of your hand. You’ll pass a second threshold, and the rhythm of the waves will disintegrate into turbulence: the water will churn, splash, and spray around your hand, and chaotic surges of water will lurch up and down the sides of the tub. If you keep it up, you can get a fair fraction of the bathwater on your bathroom floor, but this isn’t required for the experiment! Once you’ve got a good sense of the difference between the turbulence above the second threshold and the oscillations below it, take your hand out of the water, and watch what happens: the turbulence subsides into wave patterns, the waves shrink, and finally—after some minutes—you have still water again.

This same sequence of responses can be traced in every complex system, governing its response to every kind of disturbance in its surroundings. So long as the change stays below a certain threshold of intensity and rapidity—a threshold that differs for every system and every kind of change—the system will respond smoothly, with the least adjustment that will maintain its own internal balance. Once that threshold is surpassed, oscillations of various kinds spread through the system, growing steadily more extreme as the disturbance becomes stronger, until it passes the second threshold and the system’s oscillations collapse into turbulence and chaos. When chaotic behavior begins to emerge in an oscillating system, in other words, that’s a sign that real trouble may be sitting on the doorstep.

If global temperature were increasing in a nice smooth line, in other words, we wouldn’t have as much to worry about, because it would be clear from that fact that the resilience of the planet’s climate system was well able to handle the changes that were in process. Once things begin to oscillate, veering outside usual conditions in both directions, that’s a sign that the limits to resilience are coming into sight, with the possibility of chaotic variability in the planetary climate as a whole waiting not far beyond that. We can fine-tune the warning signals a good deal by remembering that every system is made up of subsystems, and those of sub-subsystems, and as a general rule of thumb, the smaller the system, the more readily it moves from local adjustment to oscillation to turbulence in response to rising levels of disturbance.

Local climate is sensitive enough, in fact, that ordinary seasonal changes can yield minor turbulence, which is why the weather is so hard to predict. Regional climates are more stable, and they normally cycle through an assortment of wavelike oscillations: the cycle of the seasons is one, but there are also multiyear and multi-decade cycles of climate that can be tracked on a regional basis. The further up this geographical scale turbulence starts to show itself, the closer to massive trouble we are likely to be—which is why the drastic swings in regional and continental climate patterns in recent years deserve more attention than they generally get.

I’m not generally a fan of Thomas Friedman, but he scored a direct hit when he warned that what we have to worry about from anthropogenic climate change is not global warming but “global weirding.”2 A linear change in global temperatures would be harsh, but it would be possible to some extent to shift crop belts smoothly north in the Northern Hemisphere and south in the Southern. If the crop belts disintegrate—if you don’t know whether the next season is going to be warm or cold, wet or dry, short or long—famines become hard to avoid, and cascading impacts on an already strained global economy add to the fun and games. At this point, for the reasons just shown, that’s the most likely shape of the century or two ahead of us.

In theory, some of that could be avoided if the world’s nations were to stop treating the skies as an aerial sewer in which to dump greenhouse gases. In practice—well, I’ve met far too many people who claim to be deeply concerned about climate change but who still insist that they have to have SUVs to take their kids to soccer practice, and I recall the embarrassed silence that spread across the media a while back when British climate scientist Kevin Anderson pointed out that maybe jetting all over the place to climate conferences was communicating the wrong message at a time when climate scientists and everyone else needed to decrease their carbon footprint.3 Until the people who claim to be passionate about climate change start showing a willingness to burn much less carbon, it’s unlikely that anyone else will do so, and so I think it’s a pretty safe bet that fossil fuels will continue to be extracted and burned as long as geological and economic realities permit.

The one bleak consolation here is that those realities are a good deal less flexible than worst-case scenarios generally assume. There are two factors in particular to track here, and both unfold from net energy—the difference between the energy content of fossil fuels as they reach the end consumer and the energy input needed to get them all the way there. The first factor is simply that if it takes more energy to extract, process, and transport a deposit of fossil carbon than the end user can get out of it by burning it, the fossil carbon will stay in the ground. The poster child here is kerogen shale, which has been the bane of four decades of enthusiastic energy projects in the American West and elsewhere. There’s an immense amount of energy locked up in the Green River shale and its equivalents, but every attempt to break into that cookie jar has come to grief on the hard fact that, if everything is included in the analysis, it takes more energy to extract kerogen from shale than you get from burning the kerogen.

The second factor is subtler and considerably more damaging. As fossil fuel deposits with abundant net energy are exhausted, and have to be replaced by deposits with lower net energy, a larger and larger fraction of the total energy supply available to an industrial society has to be diverted from all other economic uses to the process of keeping the energy flowing. Thus it’s not enough to point to high total energy production and insist that all’s well. The logic of net energy has to be applied here as well; the total energy input that gets used up in energy resource extraction, processing, and distribution has to be subtracted from total energy production, to get a realistic sense of how much energy is available to power the rest of the economy—and the rest of the economy, remember, is what produces the wealth that makes it possible for individuals, communities, and nations to afford fossil fuels in the first place.

Long before the last physically extractable deposit of fossil fuel is exhausted, in other words, fossil fuel extraction will stop because it’s become an energy sink rather than an energy source. Well before that latter point is reached, furthermore, global and national economies will no longer be able to produce enough wealth to meet the rising energy costs of fossil fuel extraction. Demand destruction, which is what economists call the process by which people who can’t afford to buy a product stop using it, is as important here as raw physical depletion; as economies reel under the twin burdens of depleting reserves and rising energy costs for energy production, carbon footprints will shrink willy-nilly as rapid downward mobility becomes the order of the day for most people. Combine these factors with the economic impacts of “global weirding” itself, and you’ve got a good first approximation of the forces that are already massing around us and will terminate the fossil fuel economy with extreme prejudice in the decades ahead.

What that means for the future climate of North America is difficult to predict in detail but not so hard to trace in outline. From now until the end of the twenty-first century, perhaps longer, we can expect climate chaos, accelerating in its geographical spread and collective impact until a couple of decades after CO2 emissions begin to decline, due to the lag time between when greenhouse gases hit the atmosphere and when their effects finally peak. As the rate of emissions slows thereafter, the turbulence will gradually abate, and some time after that—exactly when is anybody’s guess, but 2300 is as good a guess as any—the global climate will have settled down into a “new normal” that won’t be normal by our standards at all. Barring further curveballs from humanity or nature, that “new normal” will remain until enough excess CO2 has been absorbed by natural cycles—a process that will take millennia to complete.

An educated guess at the shape of the “new normal” is possible because, for the past few million years, the paleoclimatology of North America has shown a fairly reliable pattern.4 The colder North America has been, by and large, the heavier the rainfall in the western half of the continent. During the most recent Ice Age, for example, rainfall in what’s now the desert Southwest was so heavy that it produced a chain of huge pluvial (rain-fed) lakes and supported relatively abundant grassland and forest ecosystems across much of what’s now sagebrush and cactus country. Some measure of the difference can be caught from the fact that 18,000 years ago, when the last Ice Age was at its height, Death Valley was a sparkling lake surrounded by pine forests. By contrast, the warmer North America becomes, the dryer the western half of the continent gets, and the drying effect spreads east a very long way.

After the end of the latest Ice Age, for example, the world entered what nowadays gets called the Holocene Climatic Optimum. That term’s a misnomer, at least for this continent, because conditions over a good bit of North America then were optimum only for sand fleas and Gila monsters. There’s been a running debate for several decades about whether the Hypsithermal, to use the so-called Optimum’s other name, was warmer than today all over the planet or just in some regions. Current opinion tends to favor the latter, but the difference doesn’t actually have that much impact on the issue we’re considering: the evidence from a broad range of sources shows that North America was significantly warmer in the Hypsithermal than it is today, and so that period makes a fairly good first approximation of the conditions this continent is likely to face in a warmer world.

To make sense of the long-term change to North American climates, it’s important to remember that rainfall is far more important than temperature as a determining factor for local ecosystems. On average, if a given region gets more than about 40 inches of rain a year, no matter what the temperature, it’ll normally support some kind of forest; if it gets between 40 and 10 inches a year, the usual ecosystem is grassland or, in polar regions, mosses and lichens; with less than 10 inches a year, you’ve got desert, whether it’s as hot as the Sahara or as bitterly cold as the Takla Makan.5 In the Hypsithermal, as the West dried out, tallgrass prairie extended straight across the Midwest to western Pennsylvania, and much of the Great Plains were desert, complete with sand dunes.

In a world with ample fossil fuel supplies, it’s been possible to ignore such concerns by such expedients as pumping billions of gallons of water a year from aquifers or distant catchment basins to grow crops in deserts and the driest of grasslands. As fossil fuel supplies sunset out, though, the shape of human settlement will once again be a function of annual rainfall, as it was everywhere on the planet before 1900. If the Hypsithermal’s a valid model, as seems most likely, most of North America from the Sierra Nevada and Cascade ranges east across the Great Basin and Rocky Mountains to the Great Plains and south through most of inland Mexico will be sun-scorched desert, as harsh as any on today’s Earth. Human settlement will be accordingly sparse: scattered towns in those few places where geology allows a permanent water supply, separated by vast desolate regions inhabited by few hardy nomads or by no one at all.

Around the Great Desert, grassland will extend for a thousand miles or more, east to the Allegheny foothills, north to a thinner and dryer boreal forest belt shifted several hundred miles closer to the Arctic Ocean, and south to the tropical jungles of the Gulf Coast. Further south, in what’s now Mexico, the Gulf Coast east of the Sierra Madre Oriental will shift to tropical ecosystems all the way north to, and beyond, the current international border. Between the greatly expanded tropical zone along the coasts and the hyperarid deserts of the north, Mexico will be a land of sharp ecological contrasts.

Climate isn’t the only factor governing human settlement, though. Two other crucial factors will also shape the future environments of North America—rising sea levels and the deadly legacies of today’s frankly brainless handling of nuclear and chemical wastes. We’ll examine them one at a time.

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History, as noted earlier, can be seen as human ecology in its transformations over time, and every ecosystem depends in the final analysis on the available habitat. For human beings, the habitat that matters is dry land with adequate rainfall and moderate temperatures; we’ve talked about the way that anthropogenic climate change is interfering with the latter two, but it promises to have significant impacts on the first of those requirements as well.

It’s helpful to put all this in the context of deep time. For most of the last billion years or so, the Earth has been a swampy jungle planet where ice and snow were theoretical possibilities only. Four times in that vast span, though, something—scientists are still arguing about exactly what it was—turned the planet’s thermostat down sharply, resulting in ice ages millions of years in length. The most recent of these downturns began cooling the planet maybe ten million years ago, in the Miocene epoch. A little less than two million years ago, at the beginning of the Pleistocene epoch, the first of the great continental ice sheets began to spread across the Northern Hemisphere, and the Ice Age was on.

We’re still in it. During an ice age, a complex interplay of the Earth’s rotational and orbital wobbles drives the Milankovich cycle, a cyclical warming and cooling of the planet that takes hundreds of thousands of years to complete, with long glaciations broken by much shorter interglacials. We’re approaching the end of the current interglacial, and it’s estimated that the current Ice Age has maybe another ten million years to go; one consequence is that at some point a few millennia in the future, we can pretty much count on glaciers pushing south across the face of North America once again. In the meantime, we’ve still got continental ice sheets covering Antarctica and Greenland, and a significant amount of year-round ice in mountains in various corners of the world. That’s normal for an interglacial, though not at all normal for most of the planet’s history.

The back- and-forth flip-flop between glaciations and interglacials has a galaxy of impacts on the climate and ecology of the planet, but one of the most obvious comes from the simple fact that all the frozen water needed to form a continental ice sheet has to come from somewhere, and the only available “somewhere” on this planet is the oceans. As glaciers build up and spread across the land, sea level drops accordingly; 18,000 years ago, when the most recent glaciation hit its final peak, sea level was more than 400 feet lower than today, and roaming tribal hunters could walk all the way from Holland to Ireland on dry land and keep going, following reindeer herds a good distance into what’s now the northeast Atlantic.6

What followed has plenty of lessons on offer for our future. It used to be part of the received wisdom that ice ages began and ended with, ahem, glacial slowness, and there still seems to be good reason to think that the beginnings are fairly gradual, but the ending of the most recent Ice Age involved periods of very sudden change.7 As already mentioned, 18,000 years ago, the ice sheets were at their peak; about 16,000 years ago, the planetary climate began to warm, pushing the ice into a slow retreat. Around 14,700 years ago, the warm Bölling phase arrived, and the ice sheets retreated hundreds of miles; according to several studies, the West Antarctic ice sheet collapsed completely at this time.

The Bölling gave way after around 600 years to the Older Dryas cold period, putting the retreat of the ice on hold. After another six centuries or so, the Older Dryas gave way to a new warm period, the Alleröd, which sent the ice sheets reeling back and raised sea levels hundreds of feet worldwide. Then came a new cold phase, the frigid Younger Dryas, which brought temperatures back to their Ice Age lows, cold enough to allow the West Antarctic ice sheet to reestablish itself and to restore tundra conditions over large sections of the Northern Hemisphere. Ice core measurements suggest that the temperature drop hit fast, in a few decades or less.

Just over a millennium later, right around 9600 BC, the Boreal phase arrived, and brought even more spectacular change. According to oxygen isotope measurements from Greenland ice cores, global temperatures spiked 7°C in less than a decade, pushing the remaining ice sheets into rapid collapse and sending sea levels soaring.8 Over the next few thousand years, the planet’s ice cover shrank toward its current level, and sea level rose a bit above what it is today; a gradual cooling trend beginning around 6000 BCE brought both to the status they had at the beginning of the industrial era.

Scientists still aren’t sure what caused the stunning temperature spike at the beginning of the Boreal phase, but one widely held theory is that it was driven by large-scale methane releases from the warming oceans and thawing permafrost. The ocean floor contains huge amounts of methane trapped in unstable methane hydrates; permafrost contains equally huge amounts of dead vegetation that’s kept from rotting by subfreezing temperatures, and when the permafrost thaws, that vegetation rots and releases more methane. Methane is a far more powerful greenhouse gas than carbon dioxide, but it’s also much more transient—once released into the atmosphere, methane breaks down into carbon dioxide and water relatively quickly, with an estimated average lifespan of ten years or so—and so it’s quite a plausible driver for the sort of sudden shock that can be traced in the Greenland ice cores.

If that’s what did it, of course, we’re arguably well on our way there, since methane is already being released from the Arctic Ocean and Siberian permafrost in spectacular amounts. On top of the carbon dioxide being pumped into the atmosphere by human industry, a methane spike would do a fine job of producing “global weirding” on the grand scale. Meanwhile, two of the world’s three remaining ice sheets—the West Antarctic and Greenland sheets—have already been destabilized by rising temperatures.9 Between them, these two ice sheets contain enough water to raise sea level around 50 feet globally, and the likely anthropogenic carbon dioxide emissions over the next century provide enough warming to cause the collapse and total melting of both of them. All that water isn’t going to hit the world’s oceans overnight, of course, and a great deal depends on just how fast the melting happens.

The predictions for sea-level rise included in recent IPCC reports assume a slow, linear process of glacial melting. That’s appropriate as a baseline, but evidence from paleoclimatology shows that ice sheets collapse in relatively sudden bursts of melting, producing what are termed “global meltwater pulses” that can be tracked worldwide by a variety of proxy measurements.10 Mind you, “relatively sudden” in geological terms is slow by the standards of a human lifetime; the complete collapse of a midsized ice sheet like Greenland’s or West Antarctica’s can take five or six centuries, and that in turn involves periods of relatively fast melting and sea-level rise, interspersed with slack periods when sea level creeps up much more slowly.

So far, at least, the vast East Antarctic ice sheet has shown only very modest changes, and most current estimates suggest that it would take something far more drastic than the carbon output of our remaining economically accessible fossil fuel reserves to tip it over into instability. This is a good thing, as East Antarctica’s ice fields contain enough water to drive sea level up 250 feet or so. Thus a reasonable estimate for sea-level change over the next five hundred years involves the collapse of the Greenland and West Antarctic sheets and some melting on the edges of the East Antarctic sheet, raising sea level by something over 50 feet, delivered in a series of unpredictable bursts divided by long periods of relative stability or slow change.

The result will be what paleogeographers call “marine transgression”—the invasion of dry land and fresh water by the sea. Fifty feet of sea-level change adds up to quite a bit of marine transgression in some areas, much less in others, depending always on local topography. Where the ground is low and flat, the rising seas can penetrate a very long way; in California, for example, the state capital at Sacramento is many miles from the ocean, but since it’s only 30 feet above sea level and connected to the sea by a river, its skyscrapers will be rising out of a brackish estuary long before Greenland and West Antarctica are bare of ice. The port cities of the Gulf Coast are also on the front lines. New Orleans is actually below sea level—only extensive levees keep it above water now, and it will likely be an early casualty, but every other Gulf port from Brownsville, Texas, (elevation 43 feet) to Tampa, Florida, (elevation 15 feet) faces the same fate, and most East and West Coast ports face substantial flooding of economically important districts.

The flooding of Sacramento isn’t the end of the world, and there may even be some among my readers who would consider it to be a good thing. What I’d like to point out, though, is the economic impact of the rising waters. Faced with an unpredictable but continuing rise in sea level, communities and societies face one of two extremely expensive choices. They can abandon many billions of dollars of infrastructure to the sea and rebuild further inland, or they can invest roughly the same amount in sea walls and flood-control measures. Because the rate of sea-level change can’t be anticipated, furthermore, there’s no way to know in advance how far to relocate or how high to build the barriers at any given time, and there are often hard limits to how much change can be done in advance: port cities, for example, can’t just move away from the sea and still maintain a functioning economy.

This is a pattern we’ll be seeing over and over again in this survey. Societies descending into dark ages reliably get caught on the horns of a brutal dilemma. For any of a galaxy of reasons, crucial elements of infrastructure no longer do the job they once did, but reworking or replacing them runs up against two critical difficulties that are hardwired into the process of decline itself. The first is that, as time passes, the resources needed to do the necessary work become increasingly scarce. The second is that, as time passes, the uncertainties about what needs to be done become increasingly large.

The result can be tracked in the decline of every civilization. At first, failing systems are replaced with some success, but the economic impact of the replacement process becomes an ever-increasing burden, and the new systems never do quite manage to work as well as the older ones did in their heyday. As the process continues, the costs keep mounting and the benefits become less reliable; more and more often, scarce resources end up being wasted because the situation is too uncertain to allow them to be allocated where they’re most needed. With each passing year, decision makers have to figure out how much of the dwindling stock of resources can be put to productive uses and how much has to be set aside for crisis management, and the raw uncertainty of the times guarantees that these decisions will very often turn out wrong. Eventually, the declining curve in available resources and the rising curve of uncertainty intersect to produce a crisis that spins out of control, and what’s left of a community, an economic sector, or a whole civilization goes to pieces under the impact.

It’s not too hard to anticipate how that will play out in the century or so immediately ahead of us. If, as I’ve suggested, we can expect the onset of a global meltwater pulse from the breakup of the Greenland and West Antarctic ice sheets at some point in the years ahead, the first upward jolt in sea level will doubtless be met with grand plans for flood-control measures in some areas and relocation of housing and economic activities in others. Some of those plans may even be carried out, though the raw economic impact of worldwide coastal flooding on a global economy already under severe strain from a chaotic climate and a variety of other factors won’t make that easy. Some coastal cities will hunker down behind hurriedly built or enlarged levees; others will abandon low-lying districts and try to rebuild further upslope; still others will simply founder and be partly or wholly abandoned—and all these choices impose costs on society as a whole.

Thereafter, when sea level rises only slowly, the costs of maintaining flood-control measures and replacing vulnerable infrastructure with new facilities on higher ground will become an unpopular burden, and the same shortsighted appeal that drives climate change denialism today will doubtless find plenty of hearers then as well. When sea level surges upwards, the flood-control measures and relocation projects will face increasingly severe tests, which some of them will inevitably fail. The twin spirals of rising costs and rising uncertainty will have their usual effect, shredding the ability of a failing society to cope with the challenges that beset it.

If human beings behave as they usually do, what will most likely happen is that the port cities of North America will keep on trying to maintain business as usual until well after that stops making any kind of economic sense. The faster the seas rise, the sooner that response will tip over into its opposite, and people will begin to flee in large numbers from the coasts in search of safety for themselves and their families. My working guess is that the Eastern and Western seaboards of dark age America will be much more sparsely populated than they are today, with communities concentrated in those areas where land well above sea level lies close to the sea. The Gulf Coast, where very little rises much above sea level and marine transgression will therefore swallow large areas very quickly, may be all but abandoned until the seas stop rising.

These factors make for a shift in the economic and political geography of the continent that will be of quite some importance. In times of rapid sea-level change, maintaining the infrastructure for maritime trade in seacoast ports is a losing struggle; maritime trade is still possible without port infrastructure, but it’s rarely economically viable; and that means that inland waterways with good navigable connections to the sea will take on an even greater importance than they have today. In North America, the most crucial of those are the St. Lawrence Seaway, the Hudson River-Erie Canal linkage to the Great Lakes, and whatever port further inland replaces New Orleans—Baton Rouge is a likely candidate, due to its location and elevation above sea level—once the current Mississippi delta drowns beneath the rising seas. Even in dark ages, maritime trade is a normal part of life, and that means that the waterways just listed will become the economic, political, and strategic keys to most of the North American continent.

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The rising seas set in motion by anthropogenic climate change are one part of a broader pattern, which is the impact of today’s actions on tomorrow’s environment. Civilizations normally leave a damaged environment behind them when they fall, and ours shows every sign of following that wearily familiar pattern. The nature and severity of the ecological damage a civilization leaves behind, though, depend on two factors, one obvious, the other less so. The obvious factor derives from the nature of the technologies the civilization deployed in its heyday; the less obvious one depends on how many times those technologies had been through the same cycle of rise and fall before the civilization under discussion got to them.

There’s an important lesson in this latter factor. Human technologies almost always start off their trajectory through time as environmental disasters looking for a spot marked X, which they inevitably find, and then have the rough edges knocked off them by centuries or millennia of bitter experience. When our species first developed the technologies that enabled hunting bands to take down big game animals, the result was mass slaughter and the extinction of entire species of megafauna, followed by famine and misery; repeat the same cycle dozens of times, and you end up with the exquisite ecological balance that most hunter-gatherer societies maintained in historic times. In much the same way, early field agriculture yielded bumper crops of topsoil loss and subsistence failure to go along with its less reliable yields of edible grain, and the hard lessons from that experience have driven the rise of more sustainable agricultural systems—a process completed in our time with the emergence of organic agricultural methods that build soil rather than depleting it.

Any brand-new mode of human subsistence is thus normally cruising for a bruising, and will get it in due time at the hands of the biosphere. That’s not precisely good news for modern industrial civilization, because ours is a brand-new mode of human subsistence; it’s the first human society ever to depend almost entirely on extrasomatic energy—energy, that is, that doesn’t come from human or animal muscles fueled by food crops. In my book The Ecotechnic Future, I’ve suggested that industrial civilization is simply the first and most wasteful of a new mode of human society, the technic society. Eventually, I proposed, technic societies will achieve the same precise accommodation to ecological reality that hunter-gatherer societies worked out long ago and that agricultural societies have spent the last eight thousand years or so pursuing. Unfortunately, that doesn’t help us much just now.

Modern industrial civilization, in point of fact, has been stunningly clueless in its relationship with the planetary cycles that keep us all alive. Like those early bands of roving hunters who slaughtered every mammoth they could find and then looked around blankly for something to eat, we’ve drawn down the finite stocks of fossil fuels on this planet without the least concern about what the future would bring—well, other than the occasional pious utterance of thought-stopping mantras of the “I’m sure they’ll think of something” variety. That’s not the only thing we’ve drawn down recklessly, of course, and the impact of our idiotically short-term thinking on our long-term prospects will be among the most important forces shaping the next five centuries of North America’s future.

Let’s start with one of the most obvious: topsoil, the biologically active layer of soil that can support food crops. On average, as a result of today’s standard agricultural methods, North America’s arable land loses almost three tons of topsoil from each cultivated acre every single year. Most of the topsoil that made North America the breadbasket of the twentieth-century world is already gone, and at the current rate of loss, all of it will be gone by 2150.11 That would be bad enough if we could rely on artificial fertilizer to make up for the losses, but by 2150 that won’t be an option: the entire range of chemical fertilizers are made from nonrenewable resources—natural gas is the main feedstock for nitrate fertilizers, rock phosphate for phosphate fertilizers, and so on—and all of these are depleting fast.

Topsoil loss driven by bad agricultural practices is actually quite a common factor in the collapse of civilizations. Sea-floor cores in the waters around Greece, for example, show a spike in sediment deposition from rapidly eroding topsoil right around the end of the Mycenean civilization, and another from the latter years of the Roman Empire.12 If archeologists thousands of years from now try the same test, they’ll find yet another eroded topsoil layer at the bottom of the Gulf of Mexico, the legacy of an agricultural system that put quarterly profits ahead of the relatively modest changes that might have preserved the soil for future generations.

The methods of organic agriculture mentioned earlier could help very significantly with this problem, since those include techniques for preserving existing topsoil and rebuilding depleted soil at a rate considerably faster than nature’s pace. To make any kind of difference, though, those methods would have to be deployed on a very broad scale and then passed down through the difficult years ahead. Lacking that, even where desertification driven by climate change doesn’t make farming impossible, a very large part of today’s North American farm belt will likely be unable to support crops for centuries or millennia to come. Eventually, the same slow processes that replenished the soil on land scraped bare by the Ice Age glaciers will do the same thing to land stripped of topsoil by industrial farming, but “eventually” will not come quickly enough to spare our descendants many hungry days.

The same tune in a different key is currently being played across the world’s oceans, and as a result my readers can look forward, in the not too distant future, to tasting the last piece of seafood they will ever eat.13 Conservatively managed, the world’s fish stocks could have produced large yields indefinitely, but they were not conservatively managed. Where regulation was attempted, political and economic pressure consistently drove catch limits above sustainable levels, and of course, cheating was pervasive and the penalties for being caught were merely another cost of doing business. Fishery after fishery has accordingly collapsed, and the increasingly frantic struggle to feed seven billion hungry mouths is unlikely to leave any of those that remain intact for long.

Worse, all of this is happening in oceans that are being hammered by other aspects of our collective ecological stupidity. Global climate change, by boosting the carbon dioxide content of the atmosphere, is acidifying the oceans and causing sweeping shifts in oceanic food chains. Those shifts involve winners as well as losers; where calcium-shelled diatoms and corals are suffering population declines, seaweeds and other forms of algae, which are not so sensitive to changes in the acid-alkaline balance, are thriving on the increased CO2 in the water14—but the fish that feed on seaweeds and algae are not the same as those that feed on diatoms and corals, and the resulting changes are whipsawing ocean ecologies.

Close to shore, toxic effluents from human industry and agriculture are also adding to the trouble. The deep oceans, all things considered, offer sparse pickings for most saltwater creatures. The vast majority of ocean life thrives within a few hundred miles of land, where rivers, upwelling zones, and the like provide nutrients in relative abundance. We’re already seeing serious problems with toxic substances concentrating up through oceanic food chains, and unless communities close to the water’s edge respond to rising sea levels with consummate care, hauling every source of toxic chemicals out of reach of the waters, that problem is only going to grow worse. Different species react differently to this or that toxin; some kind of aquatic ecosystem will emerge and thrive even in the most toxic estuaries of deindustrial North America, but it’s unlikely that those ecosystems will produce anything fit for human beings to eat, and making the attempt may not be particularly good for one’s health.

Over the long run, that, too, will right itself. Bioaccumulated toxins will end up entombed in the muck on the ocean’s floor, providing yet another interesting data point for the archeologists of the far future; food chains and ecosystems will reorganize, quite possibly in very different forms from the ones they have now. Changes in water temperature, and potentially in the patterns of ocean currents, will bring unfamiliar species into contact with one another, and living things that survive the deindustrial years in isolated refugia will expand into their former range. These are normal stages in the adaptation of ecosystems to large-scale shocks. Still, those processes of renewal take time, and the deindustrial dark ages ahead of us will be long gone before the seas are restored to biological abundance.

Barren lands and empty seas aren’t the only bitter legacies we’re leaving our descendants, of course. One of the others has received quite a bit of attention of late—since March 11, 2011, to be precise, when the Fukushima Daiichi nuclear disaster got under way. Nuclear power exerts a curious magnetism on the modern mind, drawing it toward extremes in one direction or the other; the wildly unrealistic claims about its limitless potential to power the future that have been made by its supporters are neatly balanced by the wildly unrealistic claims about its limitless potential as a source of human extinction on the other. Negotiating a path between those extremes is not always an easy matter.

In both cases, though, it’s easy enough to clear away at least some of the confusion by turning to documented facts. It so happens, for instance, that no nation on Earth has ever been able to launch or maintain a nuclear power program without huge and continuing subsidies. Nuclear power, in other words, never pays for itself; absent a steady stream of government handouts, it doesn’t make enough economic sense to attract enough private investment to cover its costs, much less meet the huge and so far unmet expenses of nuclear waste storage, and in the great majority of cases, the motive behind the program, and the subsidies, is pretty clearly the desire of the local government to arm itself with nuclear weapons at any cost. Thus the tired fantasy of cheap, abundant nuclear power needs to be buried alongside the Eisenhower-era propagandists who dreamed it up in the first place.

It also happens, of course, that there have been quite a few catastrophic nuclear accidents since the dawn of the atomic age just over seventy years ago, especially but not only in the former Soviet Union.15 Thus it’s no secret what the consequences are when a reactor melts down, or when mismanaged nuclear waste storage facilities catch fire and spew radioactive smoke across the countryside. What results is an unusually dangerous industrial accident, on a par with the sudden collapse of a hydroelectric dam or a chemical plant explosion that sends toxic gases drifting into a populated area; it differs from these mostly in that the contamination left behind by certain nuclear accidents remains dangerous for many years after it comes drifting down from the sky.

There are currently 69 operational nuclear power plants scattered unevenly across the face of North America, with 127 reactors among them; there are also 48 research reactors, most of them much smaller and less vulnerable to meltdown than the power plant reactors. Most North American nuclear power plants store spent fuel rods in pools of cooling water onsite, since the spent rods continue to give off heat and radiation and the project of building long-term storage facilities for high-level nuclear waste has been at a standstill for decades. Neither a reactor nor a fuel rod storage pool can be left untended for long without serious trouble, and a great many things—including natural disasters and human stupidity—can push them over into meltdown, in the case of reactors, or conflagration, in the case of spent fuel rods. In either case, or both, you’ll get a plume of toxic, highly radioactive smoke drifting in the wind, and a great many people immediately downwind will die quickly or slowly, depending on the details and the dose.

It’s entirely reasonable to predict that this is going to happen to some of those 175 reactors. In a world racked by climate change, resource depletion, economic disintegration, political and social chaos, mass movements of populations, and the other normal features of the decline and fall of a civilization and the coming of a dark age, the short straw is going to be drawn sooner or later, and serious nuclear disasters are going to happen. That doesn’t justify the claim made by some people that every one of those reactors is going to melt down catastrophically, every one of the spent-fuel storage facilities is going to catch fire, and so on—though, of course, that claim does make for more colorful rhetoric.

In the real world, we don’t face the kind of sudden collapse that could make all the lights go out at once. Some nations, regions, and local areas within regions will slide faster than others, or be deliberately sacrificed so that resources of one kind or another can be used somewhere else. As long as governments retain any kind of power at all, keeping nuclear facilities from adding to the ongoing list of disasters will be high on their agendas; shutting down reactors that are no longer safe to operate is one step they can certainly do, and so is hauling spent fuel rods out of the pools and putting them somewhere less immediately vulnerable.

It’s probably a safe bet that the further we go along the arc of decline and fall, the further these decommissioning exercises will stray from the optimum. I can all too easily imagine fuel rods being hauled out of their pools by condemned criminals or political prisoners, loaded on flatbed rail cars, taken to some desolate corner of the expanding western deserts, and tipped one at a time into trenches dug in the desert soil, then covered over with a few meters of dirt and left to the elements. Sooner or later the radionuclides will leak out, and that desolate place will become even more desolate, a place of rumors and legends where those who go don’t come back.

Meanwhile, the reactors and spent-fuel pools that don’t get shut down even in so cavalier a fashion will become the focal points of dead zones of a slightly different kind. The facilities themselves will be off-limits for some thousands of years, and the invisible footprints left behind by the plumes of smoke and dust will be dangerous for centuries. The vagaries of deposition and erosion are impossible to predict; in areas downwind from Chernobyl or some of the less famous Soviet nuclear accidents, one piece of overgrown former farmland may be relatively safe while another a quarter-hour’s walk away may still set a Geiger counter clicking at way-beyond-safe rates. Here I imagine cow skulls on poles, or some such traditional marker, warning the unwary that they stand on the edge of accursed ground.

It’s important to keep in mind that not all the accursed ground in deindustrial North America will be the result of nuclear accidents. There are already areas on the continent so heavily contaminated with toxic pollutants of less glow-in-the-dark varieties that anyone who attempts to grow food or drink the water there can count on a short life and a wretched death. As the industrial system spirals toward its end, and those environmental protections that haven’t been gutted already get flung aside in the frantic quest to keep the system going just a little bit longer, spills and other industrial accidents are very likely to become a good deal more common than they are already.

There are methods of soil and ecosystem bioremediation that can be done with very simple technologies—for example, plants that concentrate toxic metals in their tissues so they can be hauled away to a less dangerous site and fungi that break down organic toxins—but if they’re to do any good at all, these will have to be preserved and deployed in the teeth of massive social changes and equally massive hardships. Lacking that, and it’s a considerable gamble at this point, the North America of the future will be spotted with areas where birth defects are a common cause of infant mortality and it will be rare to see anyone over the age of forty or so without the telltale signs of cancer.

There’s a bitter irony in the fact that cancer, a relatively uncommon disease a century and a half ago—childhood cancers were so rare that individual cases were written up in medical journals—has become the signature disease of industrial society, expanding its occurrence and death toll in lockstep with our mindless dumping of chemical toxins and radioactive waste into the environment. What, after all, is cancer? A disease of uncontrolled growth.

I sometimes wonder if our descendants in the deindustrial world will appreciate that irony. One way or another, I have no doubt that they’ll have their own opinions about the bitter legacy we’re leaving them. As they think back on the people of the twentieth and early twenty-first centuries who gave them the barren soil and ravaged fisheries, the chaotic weather and rising oceans, the poisoned land and water, the birth defects and cancers that embitter their lives, how will they remember us? I think I know. I think we will be the orcs and Nazgûl of their legends, the collective Satan of their mythology, the ancient race who ravaged the Earth and everything on it so they could enjoy lives of wretched excess at the future’s expense. They will remember us as evil incarnate—and from their perspective, it’s by no means easy to dispute that judgment.