Section 1
Species Unbound: Humanityâs Environmental Impact
Politics is many things. At its heart, it is about the problems that arise and the virtues that are possible when people live together. We are living together like never before. What was once a smattering of tribes across the vast expanse of the planet is now a teeming population of more than seven billion people knitted together through trade, communication, and globe-spanning concerns. Everywhere we turnâwhether physically or virtuallyâwe run into each other. When we do so, wonders and horrors emerge.
The wonders are mind-blowing. Today, cultures are melding to produce pioneering ideas, innovative technologies, and transboundary movements devoted to human betterment. In the palm of our hands we can hold devices that report the weather, provide directions, play music from around the world, and share messages of love independent of geography.
At the same time, the conjunction of billions produces friction. Cultural conflict, economic competition, arguments over scarce resources, and differences of opinion magnify as humanity grows more concentrated and spreads to all corners of the planet. Politics has its work cut out for it in a globalizing world.
Perhaps no virtues and problems are as challenging these days as ecological ones. The earth is our home. Everything we eat, use, or simply come into contact with originates from land, water, soil, air, and other species. For this reason, the earth provides the parameters of human possibility. For millennia, we did not have to pay attention to this because the earth was so vast and our consumptive habits were so circumscribed that we could ignore natureâs imperatives with impunity. To be sure, certain parts of the planet suffered as our ancestors depleted fertile soils, polluted particular streams, contaminated air in specific cities, and ruined landscapes in distinct places. But the materiality of the earth itself was never in question. It provided the large backdrop for human activities and thus we neither had to listen carefully to it for enhancing our intellectual, moral, social, or even economic lives nor worry about overshooting its carrying capacity. The earth was the always-giving provider.
This is changing. Humanity has turned into an ecological force in its own right. We have joined the carbon cycle, ocean currents, weather patterns, and even seasons themselves as shapers of the planetâs ecosystemic character. This significantly raises the stakes of our actions. At a minimum, we face unprecedented dangers as we inexorably assume more and more of the reins of eco-planetary governance. Concomitantly, greater consciousness about our new status opens the possibility for unparalleled opportunities to direct collective life and build more compassionate, just, and humane societies. Our ability to avoid dangers and create opportunitiesâto governâdepends upon how skillfully we wield power. The word governance means to steer; it involves using power to shape widespread thought and behavior. In a globalized world, we must find ways of steering that both take advantage of and respect the limits of the earthâs material gifts.
The measure of our ecological footprint can be gauged along three lines: sources, sinks, and sites. Sources are those things we use to live our lives. They are the raw materials out of which we build homes, produce paper, fuel vehicles, and cook food. All of them regenerate and thus are not strictly finite, but they do so at tremendously varying rates. For example, treesâwhich provide wood for paper, construction, and furnitureâcan regenerate within a few years. In contrast, oilâwhich is used to create motor fuel, detergents, fertilizers, and plasticsâis fossilized life and takes millions of years to produce. Material substances like oil are effectively nonrenewable when viewed from a human timescale. Today, we face diminishing resources. From a global perspective, we are using almost every material resource faster than it can be replaced. Thus, three-quarters of global fisheries face imminent collapse, water tables in all countries are dropping, deforestation claims twenty-five acres per minute, and deposits of easily extractable oil are harder to find. In a globalized world with billions of people increasingly drawing more and more resources from the earth, the planet is reaching its productive and reproductive limits.
If sources have to do with what we draw from the planet, sinks involve what we put back into it. Sinks represent the air, water, soil, and host of organisms that absorb waste. Every act of production and living metabolism generates some type of waste. This is an implication of the second law of thermodynamics. So, while cars burn fuel (and thus use up resources), they also spew out waste in the form of heat, carbon dioxide, nitrous oxide, and other gases. Similarly, while growing food uses fertile soil and seeds, modern methods release fertilizers and often pesticides and herbicides into the air, soil, and waterways. The earth has the ability to absorb some of this; it can dissipate or assimilate waste across various media and organisms. At some point, however, like a kitchen sink when too much stuff flows into it, the earthâs absorptive capacity reaches its limit. When this happens landfills grow, air gets polluted, water becomes contaminated, soils lose fertility, and species die off. Today, the earthâs key sinks are stopping up. For example, by cutting down trees and burning unprecedented amounts of fossil fuels, humanity has overloaded the planetâs carbon system. Forests, oceans, and the atmosphere have assimilated their fill, leading to climate change. Using up sinks in this way leads to significant environmental dangers.
Sites are places of beauty, ecological significance, or simply value. Traditionally, we think of these as mountain ranges, quiet valleys, deep canyons, or open green fields. However, they include any landscape, seascape, or spot on earth that we care about or have come to appreciate. Perhaps all of us have favorite locations that dazzle, calm, or inspire us. For professional ecologists, sites are places of biological significance. They are âecological hotspotsâ that house an inordinate number of species, represent a unique ecological expression, or provide a key service to upholding healthy ecosystems. In a globalizing world that spreads its consumptive fingers further across and deeper into the earth for resources, and disseminates its wastes in every nook and cranny of the planet, too many sites are becoming endangered. We are despoiling an increasing number of beautiful, biophysically consequential, and appealing places. The defiling of sites adds an important dimension to environmental harm in that it undermines not just the organic infrastructure of the earth that supports life, but also those amenities of the planet that enhance the quality of life.
In the chapters that make up this section, we have pulled together three voices to help us appreciate todayâs pressures on sources, sinks, and sites, and more generally provide a sense of the magnitude and character of current environmental affairs. These readings make clear that humanity is having an immense impact on the earthâs abilities to sustain life. The effect is so profound that many see us living in a new and distinct geological epoch known as the Anthropocene. The term, as journalist Elizabeth Kolbert writes in the first chapter, highlights the fact that human beings have become the central force shaping the planetâs condition. Those who look back on the current age from some future time will see indelible signs of our collective activities etched into the planetâs geologic features. Our carbon and other forms of pollution will be present in future ice cores and tree rings, our fabrications of steel and copper sandwiched in layers of future rock. The Anthropocene means not only that humanity reigns supreme over the rest of the living world, but that its dominance has achieved geologic significance. This has huge implications for environmental conditions.
Science writer Charles C. Mann, in his chapter, traces the roots of the Anthropocene to the âunusual successâ of our species. Our big brains and capacity for cooperative social arrangement enabled humanity to develop and practice agriculture, and this was simply the beginning of our ability to take control over and increasingly transform the earth. The problem with this success is that we are collectively pushing up against hard ecological limits. Humanity cannot infinitely colonize the earthâs productive and absorptive capacities without severely degrading its biophysical functioning and, in the extreme, threatening large-scale ecosystem collapse. Mann concludes that the earth is in extremely poor health and getting sicker by the day.
What, then, is the nature of the world to come? Alex Steffen argues that while the future is certainly not rosy in an ecological sense, there is still a remarkable human capacity for innovation, hope, and even joy. Tapping into such capacity, suggests Steffen, demands that we imagine new ways of being on and with the earth, and this begins with identifying genuine forms of social and political engagement that can make a difference. Steffen outlines the trajectory of such efforts and challenges us to get excited about working on behalf of planetary ecological well-being.
1
Enter the Anthropocene
Elizabeth Kolbert
The path leads up a hill, across a fast-moving stream, back across the stream, and then past the carcass of a sheep. In my view itâs raining, but here in the Southern Uplands of Scotland, Iâm told, this counts as only a light drizzle, or smirr. Just beyond the final switchback, thereâs a waterfall, half shrouded in mist, and an outcropping of jagged rock. The rock has bands that run vertically, like a layer cake thatâs been tipped on its side. My guide, Jan Zalasiewicz, a British stratigrapher, points to a wide stripe of gray. âBad things happened in here,â he says.
The stripe was laid down some 445 million years ago, as sediments slowly piled up on the bottom of an ancient ocean. In those days life was still confined mostly to the water, and it was undergoing a crisis. Between one edge of the three-foot-thick gray band and the other, some 80 percent of marine species died out, many of them the sorts of creatures, like graptolites, that no longer exist. The extinction event, known as the end-Ordovician, was one of the five biggest of the past half billion years. It coincided with extreme changes in climate, in global sea levels, and in ocean chemistryâall caused, perhaps, by a supercontinent drifting over the South Pole.
Stratigraphers like Zalasiewicz are, as a rule, hard to impress. Their job is to piece together Earthâs history from clues that can be coaxed out of layers of rock millions of years after the fact. They take the long viewâthe extremely long viewâof events, only the most violent of which are likely to leave behind clear, lasting signals. Itâs those events that mark the crucial episodes in the planetâs 4.5-billion-year story, the turning points that divide it into comprehensible chapters.
So itâs disconcerting to learn that many stratigraphers have come to believe that we are such an eventâthat human beings have so altered the planet in just the past century or two that weâve ushered in a new epoch: the Anthropocene. Standing in the smirr, I ask Zalasiewicz what he thinks this epoch will look like to the geologists of the distant future, whoever or whatever they may be. Will the transition be a moderate one, like dozens of others that appear in the record, or will it show up as a sharp band in which very bad things happenedâlike the mass extinction at the end of the Ordovician?
That, Zalasiewicz says, is what we are in the process of determining.
The word âAnthropoceneâ was coined by Dutch chemist Paul Crutzen about a decade ago. One day Crutzen, who shared a Nobel Prize for discovering the effects of ozone-depleting compounds, was sitting at a scientific conference. The conference chairman kept referring to the Holocene, the epoch that began at the end of the last ice age, 11,500 years ago, and thatâofficially, at leastâcontinues to this day.
ââLetâs stop it,ââ Crutzen recalls blurting out. ââWe are no longer in the Holocene. We are in the Anthropocene.â Well, it was quiet in the room for a while.â When the group took a coffee break, the Anthropocene was the main topic of conversation. Someone suggested that Crutzen copyright the word.
Way back in the 1870s, an Italian geologist named Antonio Stoppani proposed that people had introduced a new era, which he labeled the anthropozoic. Stoppaniâs proposal was ignored; other scientists found it unscientific. The Anthropocene, by contrast, struck a chord. Human impacts on the world have become a lot more obvious since Stoppaniâs day, in part because the size of the population has roughly quadrupled, to ⌠seven billion. âThe pattern of human population growth in the twentieth century was more bacterial than primate,â biologist E. O. Wilson has written. Wilson calculates that human biomass is already a hundred times larger than that of any other large animal species that has ever walked the Earth.
In 2002, when Crutzen wrote up the Anthropocene idea in the journal Nature, the concept was immediately picked up by researchers working in a wide range of disciplines. Soon it began to appear regularly in the scientific press. âGlobal Analysis of River Systems: From Earth System Controls to Anthropocene Syndromesâ ran the title of one 2003 paper. âSoils and Sediments in the Anthropoceneâ was the headline of another, published in 2004.
At first most of the scientists using the new geologic term were not geologists. Zalasiewicz, who is one, found the discussions intriguing. âI noticed that Crutzenâs term was appearing in the serious literature, without quotation marks and without a sense of irony,â he says. In 2007 Zalasiewicz was serving as chairman of the Geological Society of Londonâs Stratigraphy Commission. At a meeting he decided to ask his fellow stratigraphers what they thought of the Anthropocene. Twenty-one of 22 thought the concept had merit.
The group agreed to look at it as a formal problem in geology. Would the Anthropocene satisfy the criteria used for naming a new epoch? In geologic parlance, epochs are relatively short time spans, though they can extend for tens of millions of years. (Periods, such as the Ordovician and the Cretaceous, last much longer, and eras, like the Mesozoic, longer still.) The boundaries between epochs are defined by changes preserved in sedimentary rocksâthe emergence of one type of commonly fossilized organism, say, or the disappearance of another.
The rock record of the present doesnât exist yet, of course. So the question was: When it does, will human impacts show up as âstratigraphically significantâ? The answer, Zalasiewiczâs group decided, is yesâthough not necessarily for the reasons youâd expect.
Probably the most obvious way humans are altering the planet is by building cities, which are essentially vast stretches of man-made materialsâsteel, glass, concrete, and brick. But it turns out most cities are not good candidates for long-term preservation, for the simple reason that theyâre built on land, and on land the forces of erosion tend to win out over those of sedimentation. From a geologic perspective, the most plainly visible human effects on the landscape today âmay in some ways be the most transient,â Zalasiewicz has ...