The Flooded Earth

Now, with waters sufficiently high to render assistance enormously expensive, the embattled U.S. government could no longer bear the costs of defending the drowned metropolis against the small-time tyrants who had risen to power amid decades of economic chaos, social displacement, and political breakdown. America was in a state of triage. The nation's leaders had to decide which American coastal cities to fight for, and which to surrender to the rising waters. Miami did not make the list.

Nature was besieging the drowning city—the federal government could not afford to save a city like Miami, not with such a significant portion of the U.S. gross national product dedicated to building dikes for those urban areas of the eastern and western seaboards still somewhat less affected by the relentlessly encroaching waters. Miami had joined New Orleans and Galveston as cities given over to the rapidly rising sea and to the mobs that burgeoned in the resulting chaos. It was under no flag now. The city itself—and Miami Beach, or the thin ribbon of land that remained of it—had become a strange new entity, a variant of the old city-states of ancient Greece, but with its own peculiar problems.¹

The sea, annually emboldened by hurricanes, had transformed the city entirely over the previous hundred years. The geography was now quite different than it had been as late as the mid-twenty-first century. To its east, Miami Beach was vastly reduced in size: Collins Avenue south to Washington Avenue was still on land, but the terrain was denuded of any but the fastest-growing vegetation and the hulks of the hotels that had once provided its economic sustenance. The vertical storm surge from hurricanes now routinely swept over the entire narrow island. The five main bridges from Miami proper, Florida highways 922 and 934, U.S. 195 and 41, and Venetian Way, had all been severed, as had the Rickenbacker Causeway, thus isolating Key Biscayne. On the other side of the onetime urban center, West Miami was the last dry land before the gigantic salt marshes that now encircled the city from southwest to northwest, effectively making Miami its own island. Miami International Airport was long gone (although its runways were still visible from the air, just under the clear water), devoured by the enlarging of Lake Joanne and Blue Lagoon along an arm from the sea parallel to the old Dolphin Expressway. Lehigh Lake had expanded northeast to meet up with the Amelia Earhart ponds to form a large brackish lake, too saline for freshwater life, not salty enough for marine life. The same was true of all the old lakes: Lake Ruth was now enlarged, with the Weston Hills the only dry land well to the northwest of the city. The numerous toxic waste sites had long ago been inundated, making the vast swamps carcinogenic until rain and freshwater hurricane flooding cleansed them of the more liquid toxins. The sediments leavened with heavy metals and arsenic were another matter.

Miami's most immediate problem was freshwater. The rising sea levels had caused the city to finally lose all semblances of municipal freshwater and sewage systems in 2106. Without freshwater from any kind of municipal system, Miamians resorted to other means. Personal swimming pools became personal freshwater reservoirs, with each residence using a combination of solar power and rainwater collectors to store water in its pool and then pump it into the house. Septic systems rarely worked well in the wet ground, so each house now had an outdoor privy, and warm afternoons filled with the stench of thousands of gallons of untreated human waste.

While the defense against the rising sea throughout the late 2000s had been heroic in its own way, the combination of loss of all personal home insurance, coupled with the crippling costs of keeping a water system running against the unceasing lateral movement of salt water into the normal aquifers and reservoirs, bankrupted the city. The federal government, with so many problems elsewhere, gave the city up as well. One relatively minor commercial decision destroyed the region's entire economic equation: the cancellation of home insurance throughout South Florida in 2073, following the enormous mortality and billions of dollars of damage from Hurricane George. Homeowners who had liquid capital (gold was the preferred coin of the realm, at $4,500 an ounce) fled the state for higher ground. Colorado was booming, for instance. Those people whose entire capital was invested in their now valueless homes (which is to say most people) either stayed and prayed or fled onto the great American road, looking for work amid the crippling national depression brought on by the battle against the rising seas. The fight for New York alone had necessitated cuts to national defense to the point that the United States had completely withdrawn from its foreign bases, defaulted on its Social Security obligations, and abandoned its short-lived national health care system. Coldly logical decision-making had led to the governmental desertion of Miami. It would not be the last such abandonment.

Here and there, the rich mansions of Key Biscayne and other upscale neighborhoods remained palaces of luxury for those whose fortunes remained. As always, enough money could still make a difference, even in a drowning city. But with no middle class to sustain a police force or any sort of municipal presence, the wealthy who remained did so with lethal defense. Money still flowed through Miami, enough to keep it from totally dying economically. But much of it came from the leading cash crop of South America, illegal drugs. Coca, that valuable crop, now covered huge regions of South America, and Miami was one of its chief ports of entry. The Miami police force had ultimately succumbed to the same realities that had brought down South American and Mexican big-city police forces in the early twenty-first century—there was just too much money, and too many well-armed soldiers employed by the cartels.

If anything, the Keys had fared even worse. All the islands were reduced in size, and a large section of the long highway connecting the mainland to Key West had collapsed, with no federal money to repair it. Key West had reverted to its old ways, once again becoming a haunt for sailors and smugglers.

There was no agriculture in South Florida at all. The rising salt levels in the soil saw to that. But perhaps the greatest change to the entire region lay to the west of Miami. Visible from the diminishing, still functioning satellites (Cape Canaveral had been leveled by the great hurricane of 2045) was the great brown-to-black smudge that had been the Everglades. Once a seemingly endless green landscape, the Everglades was now dead. It had been the first victim of the rising seawater, with all its huge expanse of freshwater plants dying quickly, while the mangroves that replaced them were still too young to make a green dent in the mass of dead vegetation. So profound was this change that the level of atmospheric oxygen over Florida had undergone a still minor but nevertheless measurable dip, joining other huge regions on Earth, such as the lower reaches of the Amazon, Nile, Mississippi, Mekong, and Ganges rivers—all these rich deltas losing all their green plants, which had been a significant portion of the world's oxygen-producing vegetation.

The sea had "only" risen 10 feet in South Florida by 2120. But the rise was accelerating. The open city of Miami was destined to become no city at all.

Much of what we know about the new increase in sea level comes from what we have discovered about the very old rises and falls of the sea. Recent studies of the deep past have told us much about how the earth and its life have responded to changes in sea level. Such changes in the sea level, and thus to land geography as well, have sometimes been a boon to life, but sometimes they have led to quite the opposite effect, the most extreme being mass extinction. History, then, opens one door to the explorations we will make in this book.

There are many axioms about the importance and the place of using history to contemplate current and future actions. These maxims contradict each other. We are told that those who ignore the past are destined to relive it. We also learn that the past is an unknown country, and thus a place of no relevance at all to the present. But for more than two centuries the key principle of geology has held that the changes occurring in the past are composed of processes that continue today. This is known as the Principle of Uniformitarianism, first codified by Charles Lyell, and then championed by his fellow early nineteenth-century savant, James Hutton. The principle indicates symmetry, telling us that if we can understand geological events of the past only in terms of modern-day physical processes, then the reverse must hold as well—that in terms of processes occurring too slowly to be observed in any human lifetime, the past must inform us. So it is with any change in sea level—and in the world's current predicament, the rise in sea level.

The geological record, written in rocks of many kinds and ages, tells us that the level of the sea can change in only two ways.² One happens as a result of the swelling or shrinking of the vast mountain chains found amid the deep ocean basins, such as the Mid-Atlantic Ridge, the long line of submarine volcanoes where hot magma erupts onto the sea floor daily and is then carried through continental drift either east or west. For reasons unknown, the heat that accompanies this ocean-long line of volcanoes waxes and wanes across the millennia. When it increases, it causes the rocks of the ridge itself to swell, decreasing the volume of the basins that hold the world's oceans. The amount of water stays the same—just the worldwide vessel holding those oceans changes in size. It is like putting a large brick in a bathtub; the level of the water rises. Conversely, with a loss of heat, the mid-ocean ridge is reduced in size, and the water level declines globally. The rate of change of sea level from this process is very slow indeed—with changes of several feet or more taking millions of years—but nonetheless significant over time.

The second method of change in sea level happens faster, coming from the accumulation or melting of continental ice sheets.³ When snow falling in cold climes accumulates faster than it melts during the warm seasons, an ice sheet will form. All that water ultimately comes from the sea, so a growing ice sheet causes the level of the sea to drop. The opposite process also occurs: a melting ice sheet causes sea level to rise.

Long before the modern era, a time when humans began to play their own role in climate change, the seas rose and fell thanks to their own entirely natural inclinations. We can see examples of these processes in many places on the planet. Consider two American examples. The first is North Dakota, a place as far from the ocean as any place in North America—as remote, in fact, as almost any place on Earth. But a glance at the geological record of the North Dakota badlands shows that this part of the planet was once anything but landlocked.

Near the North Dakotan border with Montana, the present-day landscape is made up of the eroded beds of ancient sea bottoms—which are overlain and underlain by a different kind of sedimentary bedding, one that was deposited in river valleys. Both seabed and riverbed have their own stark beauty. They are made up of mesas and cuestas that, at sunrise and sunset, are flocked in sandstone and shale from brown to dun and seem to glow in the late-afternoon sun. The fossil and sedimentary record tells us that the lighter-colored beds were deposited in richly vegetated river valleys near the end of the Cretaceous Period, over a time interval from about 68 million to 65 million years ago, and these rocks contain the most famous of all fossils, Tyrannosaurus rex, as well as its more numerous prey, the herbivorous dinosaurs of the time. Yet both stratigraphically above and below the riverbeds, you can see a change in the appearance and type of the fossil content as the strata entombing them change as well. Far darker in color, these sedimentary beds are no longer the remains of river deposits, but instead are clearly the remains of a seabed, a seabed where land had been. The fossils of these darker beds have a spectacular beauty. The most common are the beautifully iridescent fossil shells of ammonites, now extinct cephalopods whose nearest living relative is the chambered nautilus of the tropical Pacific. Like a modern-day nautilus shell, these fossil ammonites sparkle in the sun when they are exhumed. But they are not alone. Among the mollusk shells are the more rare bones of giant sea lizards, Mosasaurs, as well as the biggest crocodile of all—a behemoth named Deinosuchus, which must have competed with the mosasaurs for food, and perhaps for breeding sites as well. Both of these seagoing reptiles had to painfully wade ashore on legs turned to flippers to lay their precious eggs, always alert for the marauding tyrannosaurs of fearsome fame.

These seabeds underlying the last dinosaur-bearing beds of North America thus tell us something profound. This far inland was once shallow ocean. It was part of the great Western Interior Seaway, a thick branch of the world ocean that existed throughout the Cretaceous—which is to say almost as long as the dinosaurs have been dead. These old strata tell us that the Western Interior Seaway was not a static entity: it rose and fell with the level of the global ocean. Thus, while the dinosaur beds of the great American West were deposited on land, they in fact sit atop the remains of the vast inland sea, one that originated more than 100 million years ago—and was caused by a rise in sea level. In this case it was not the melting of ice that raised the water, but that slight shrinkage of the volume of the ocean basins described above. At its high-water mark in the Cretaceous Period between 125 million and 65 million years ago, the North American inland sea was hundreds of feet deep and hundreds of miles across. It separated eastern North America from the western parts, creating what were really two continents. The water rose and fell, but did so very, very slowly, its oscillating history taking hundreds of thousands of years to unfold, with the final draining that resulted in our modern-day geography occurring tens of millions of years ago.⁴

But there is another place that tells us not only that the change in sea level can be vast, but also that such change can happen very, very quickly compared to those stony, primeval North Dakotan beds. That place is in a small quarry tucked into one of southern Florida's famous line of islands: the Florida Keys.

If you go down to Key Largo and don a mask and fins in John Pennekamp State Park—the first underwater park in America—and look past the 9-foot-tall, 4,000-pound bronze statue of Jesus (a second casting of the Italian bronze Il Cristo Degli Abissi, donated by Italian scuba entrepreneur Egidi Cressi and placed in its current location in 1965), you can behold the richness of variety of the only true coral reef in the continental United States. Its immense stone ramparts compose an invertebrate tenement occupied by untold tiny, anemone-like coral polyps, their tentacles withdrawn during the dangerous daylight, awaiting the cloak of darkness before they creep outward in search of floating meat. These enormous Montastrea coral are hundreds of years old and are surrounded by many other smaller corals: the blocky Siderastrea, the hornlike Acropora of two types, the more stag-like A. cervicornis, and a few moose-horn-like A. palmata, whose fronds make spiky thickets around the flank of the Montastrea. The corals, the Montastrea most of all, have lived in this region for millions of years. But now is the time to see them, because this reef is dying fast. The welcoming, warm ocean of apparent peace and biological plenty covers trouble brewing, because most of the Acropora corals in Pennekamp are quite dead, the ocean has been slowly warmed over the previous decades, and this Florida reef tract was one of the first to experience what would become known as coral bleaching.

The Florida sea was home to another American coral reef whose condition is a veritable graduate course in the effects of sea level increase. A short distance from Key Largo is the smaller Lone Pine Key. At one side is a flattened area that looks the entire world like an abandoned quarry (which it was). You are greeted by a mass of white rocks blazing in the sun. Up close, you'll see that the large white walls are made up of gigantic coral skeletons intermingled with a profusion of smaller coral, shell, and unidentifiable limestone crags of all sizes and orientations—a reef, a fossil reef. The largest of the fossils are enormous heads that, if you look closely, show the distinctive pattern of Montastrea. One of the most prominent heads is the shape of a mushroom and measures nearly 10 feet in length. This is clearly the cemetery of a reef that is identical in composition to one that exists offshore of this very key.

Yet corals of this size—surrounded and lithified with all of the framework builders and binders that make any reef, new or old, a three-dimensional, wave-resistant structure built by life and cemented by tropical ocean chemistry—develop only underwater. The components of this reef show it to be similar in structure to the offshore reefs now found at least 10, and sometimes as much as 30, feet beneath the sea. But this old reef now sits at least 10 feet above sea level. Was it lifted here by storm? By earthquake? By the simple lifting of the Florida Keys due to some unknown, deep-seated heating of the underlying earth?

The answer is simple, yet unnerving. The giant corals on Lone Pine Key have not moved a bit since the days when they were growing in water 10 to 30 feet at this very place—about 125,000 years ago. The land had not gone up. The sea had gone down. Somehow the level of the oceans—not just here in Florida, but all over the world—had risen 30 feet, stayed that way for more than a few centuries, and then receded, exposing and killing these once-lush reefs.

The world climate of our era is the aftermath of a geologically recent episode of continental glaciation informally called the ice ages, but technically termed the Pleistocene epoch. But that event, which ended about 10,000 years ago, with wholesale melting of glaciers, was just one of many that made up the ice ages. An even more significant change in climate (and in the amount of the world's ice) occurred about 125,000 years ago, when a rapid melting of continental ice sheets and glaciers caused the sea level rise that led to the formation of reefs on now solid land. These sheets must have disappeared quickly indeed, causing the world's oceans to rise and encroach on the land, carrying sea creatures with them.⁵ It was not the first time such a process happened on this planet, and certainly it would not be the last, but it is the last time that a change of this magnitude happened so quickly. Now all evidence suggests that a similar rise is beginning. When the world warms, ice melts. When ice melts, the sea rises. It is this second kind of increase in sea level that promises to flood the world that our grandchildren and great-grandchildren will inherit. What might make it unique is the rate at which it is happening. There is every reason to believe that we are on the cusp of the most rapid rate of sea level rise in Earth history—that ice is and will continue to melt faster than at any previous time.

The second chapter discusses carbon dioxide—what it is, what it does, and how it contributes to the so-called greenhouse effect and global temperatures. It is the amount of carbon dioxide that is most pertinent to global climate, and every single human on the planet produces the stuff, one way or another. Hence, the number of humans on the planet is a large part of the story to come, and thus the second chapter hands off to the third, which deals with human population change and its effect on energy demand.

In Chapter 4 I look at how even a modest increase in sea level will dramatically affect world agricultural yields. In Chapter 5 I examine the confluence of global temperature increase and the makeup of continental ice sheets on Greenland and Antarctica, which hold the greatest volume of potentially meltable frozen water on the planet. I explore how and when they formed in the first place, and how fast and at what rate they will melt. When this ice melts, not just fields will be flooded, but cities as well, and that is the subject of Chapter 6.

Chapter 7 again looks back in deep time, by examining previous epochs when there were no ice sheets. Those times inevitably led to mass extinctions, and I examine whether conditions of the past leading to those mass extinctions are in any way similar to what the earth is experiencing now. This chapter shows what the very worst effect of global warming could be in the near future.

In Chapter 8 I change gears away from the science of sea level change and global warming to illustrate the potential "fixes" being proposed to remedy or manage the rise in sea level, through both local and global engineering. And I explore ways that we might yet stop the rising of the seas to levels that cause the calamitous loss of agriculture, and the equally calamitous flooding of coastal cities, and, if we cannot do that, how we might at least buy civilization more time by slowing the rate of rise. There is hope, if we act now. But the train is leaving the station. Perhaps forever.

In a way, this book is meant to be a sort of geological version of Dickens's A Christmas Carol. Call it "A Christmas Carol on Ice." We do have ghosts of floods past, present, and future to reckon with. The ghost of the future offers us a vision of the Chrysler Building emerging from a troubled green-and-white-capped sea, or the new island of Miami. The choice is entirely ours whether we accept that vision or create a more positive one.