Living in the Anthropocene

by W. John Kress

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  Together the three phenomena described above form the canon of atmospheric consequences of anthropogenic activities: greenhouse warming affects heat and circulation; atmospheric pollution causes chemical and physical changes to the air; and depletion of the stratospheric ozone layer allows increased surface ultraviolet radiation. They are often conflated, but they are distinct, albeit deeply intertwined. The major feedback mechanism is that increased greenhouse warming increases pollution. Droughts, for instance, increase forest fires, which increase pollutants. Heat increases power usage (to run air conditioners, for example), which also increases pollution, although increasing nighttime and winter temperatures can reduce power use for domestic heating. Heat also increases stress on vegetation, which increases volatile organic compound production (of isoprene and related compounds), which increases ground-level ozone production. However, aerosol pollution generally acts to cool the climate. Greenhouse warming may also exacerbate stratospheric ozone depletion by odd hydrogen (HOx) chemistry as increased convection injects water vapor into the stratosphere; decreased stratospheric ozone, however, increases tropospheric ultraviolet radiation, which acts photochemically to reduce tropospheric methane, a greenhouse gas. Pollution may increase greenhouse warming by ozone in the lower atmosphere.

  Drawing conclusions is more difficult than framing questions, as the future depends heavily on human capacity and political action, but questions must be asked. Will denial of anthropogenic consequences fade? Will plans to lessen emissions work in the face of a growing population? Will feedbacks of greenhouse carbon dioxide and methane from land reservoirs accelerate? Most important, will alternate energy sources prove economical and effective? A positive answer to this last question may be our greatest hope for mitigating both global greenhouse warming and atmospheric pollution.

  BEYOND THE BIOSPHERE

  EXPANDING THE LIMITS OF THE HUMAN WORLD

  LISA RUTH RAND

  The idea of the Anthropocene as a potential geologic epoch indicates the global scale of human influence on the geophysical world. Although the official start date of the Anthropocene continues to be a topic of controversy among scientists, some measurable changes to the planet simply cannot be chalked up to natural variations in the Holocene. Perhaps the most compelling—and incontrovertible—hallmark of this proposed new epoch circles hundreds, thousands, and even millions of kilometers overhead and out of sight. Beginning in the mid-twentieth century, a small club of spacefaring nations used new technologies to launch satellites and other anthropogenic objects into the nearest reaches of outer space, extending the spatial dimensions of human-driven change outward. As the anthropologist Alice Gorman has argued, the Anthropocene cannot truly be understood without considering the place of outer space in geophysical change.

  Recent scholarship in environmental history has connected the pronounced acceleration of global environmental change during the Cold War to the shifting geopolitics and environmental movements of the era. During the first decades of the Cold War space race, the United States and the Soviet Union shaped the true wilderness of outer space into a landscape: Beginning with the launch of Sputnik in the autumn of 1957, the reach of anthropos expanded beyond the tenuous boundaries of the biosphere. Although the nearest reaches of outer space are popularly portrayed as an empty void—the opposite of the green-and-blue nature portrayed by environmentalists and artists alike—in truth they support an abiotic ecosystem defined by energy exchanges, radioactivity, natural rocky objects and energetic plasmas, and gravity variations. Regular solar cycles drive the “weather” of near-Earth space, which is home to most artificial satellites and uncontrolled orbiting waste, colloquially known as space junk. However, the climate in space and climates on Earth are not separately impacted by human activity, and terrestrial climate change has affected the near-Earth ecosystem: Increased carbon dioxide emissions during the Great Acceleration have caused the planet’s thermosphere to contract, reducing the altitude at which atmospheric drag brings space junk out of orbit and diminishing the resilience of this ecosystem. Indeed, these exchanges suggest an interactive continuum of natural and anthropogenic exchange between Earth and space environments in what the anthropologist Valerie Olson calls “the extended ecological heliosphere.”

  By 1961, some 380 trackable anthropogenic objects circled the planet. By the end of 1963, that number had mushroomed to 685—not including debris too small to be detected by the space surveillance technology of the time. At most recent count, the Space Surveillance Network estimates that nearly seventeen thousand objects large enough to be tracked orbit the planet. Of these, 77 percent have been confirmed as space junk—objects with no designated use or purpose. Another approximately five hundred thousand pieces of debris between one and ten centimeters (0.4 and 4 inches) in diameter and more than one hundred million anthropogenic particles smaller than one centimeter make up the system of artificial waste in near-Earth space. These minute, largely invisible bits of anthropogenic material orbit alongside the empty rocket bodies, dead satellites, and other large objects speeding overhead. Awareness of this accumulating debris drove the first debates, in the late 1950s, over what counts as pollution in outer space.

  As soon as the first satellites had reached orbit, both the United States and the Soviet Union sought to use this new environment for both peaceful and nefarious purposes. High-altitude and exoatmospheric nuclear weapons tests began in 1958 and ended in 1963 with the Partial Test Ban Treaty. New forms of satellites—from giant, shiny inflatable balloons to a ring of hundreds of millions of tiny copper fibers—tested the use of space for communications while spurring controversy over whether they could interfere with astronomy, crowd the electromagnetic spectrum, or present a collision hazard to other spacecraft. Current geoengineering proposals intended to correct atmospheric change by “seeding” orbital space with reflective material recall some of these early controversies and could spur similar debate over the environmental protection of near-Earth space. As outer space became a site of technological utility, scientists around the world came to embrace Earth orbit as a valuable site of investigation and rapidly abandoned the idea of a physically isolated Earth.

  As the Space Age wore on, the larger objects became a threat—not just to other objects in orbit but to people, property, and environments on the ground. The natural geophysical ecosystem of the Earth-Sun environment accelerated into overdrive during the peaks of the first eleven-year solar cycle to take place after the launch of Sputnik. As the atmosphere expanded, uncontrolled objects succumbed to friction and fell back to Earth through the destructive upper atmosphere. With no control over where surviving fragments might land, orbital space became a site from which pollutants could cross geographic boundaries and extraterritorial regions. In cases such as that of the nuclear-powered satellite Cosmos 954, which fell over the Northwest Territories of Canada in 1978, reentry raised the very real specter of radioactive contamination of ground, sea, and sky—with little more than the caprice of the natural geophysical forces of Sun and space to blame. From nuclear weapons tests to the reentry of radioactive debris, the markers of the nuclear Great Acceleration extended from underground to outer space.

  Many current space-policy analysts claim that orbital debris is a recent problem—a result of the ignorance or negligence of the spacefaring nations of the 1960s. However, this argument ignores the early transnational discourse on environmental risk that began with the first attempts to measure, understand, and use the near-Earth space environment. As the first pieces of space junk circled the planet, newly minted space scientists reached the consensus that the physical influence of our planet extends dozens of kilometers into a physically interactive solar system. Just as the Great Acceleration has coincided with the rise of mainstream environmentalist movements around the world, concern over environmental risk was extended into the nearest reaches of outer space from the first moments of the Space Age. The satellite and probe technologies that
humankind launches into space both expand our understanding of the universe and make up an information infrastructure that supports modern globalism as we currently know it. Should the orbital environment change to the point that it can no longer sustain the satellite infrastructure, many large technological systems would fail, with repercussions for industries from communications and finance to agriculture and disaster relief. Bruno Latour has suggested even further consequences should a space debris crisis occur—perhaps permanently closing humankind off from the rest of the cosmos, without an extraterrestrial future should we render the biosphere uninhabitable.

  As difficult as it may be to visualize human-driven global change, thinking about the Anthropocene also requires shaking up a more basic, seemingly innate set of assumptions about the world around us. It requires us to reconsider our ideas about nature and the natural and redraw the limits of the human environment to include even those places most alien, most empty, most seemingly antithetical to verdant nature as we know it. The Earth of the Anthropocene is a much larger world than can be bounded by biology, geology, or atmosphere. Through the production, use, and discarding of spacecraft and space junk, humanity has broadened the boundaries of anthropogenic geophysical change into the universe, rendering our species truly, if virtually, cosmopolitan.

  In the Anthropocene, societies will face an array of unfamiliar and often stressful environmental conditions, many of which their cultural, political, and economic systems were never designed to address. Moreover, the impacts of global environmental change will not be equally distributed across the planet. Future responses to this change may be novel or may incorporate lessons drawn from prior adaptations to climate fluctuations and other environmental upheavals. Archaeologists have documented humankind’s long history of deliberately (and often unintentionally) modifying our surroundings in response to change. The world’s indigenous peoples, many of whom occupy lands hard hit by the early impacts of global warming, have much to say about adaptive practices. Groups and individuals who have been displaced to foreign lands are no less concerned about their immediate environments than those who remain on their native soil. In the United States, the insidious and often subtle influences of racism have hampered the effectiveness of society’s pursuit of environmental protection by defining the cause as a white concern, thereby limiting the development of broader and stronger coalitions. The mounting stresses that threaten the resiliency of the world’s forested landscapes highlight the necessity of cooperative action infused with scientific understanding, as exemplified by the movement to adopt a socioecological approach to human intervention in forest succession. Agriculture constitutes the single greatest use of land by humans, who have been “gardening the planet” for millennia, and thus developing sustainable agricultural and horticultural responses to climate change is a paramount challenge as communities strive to provide sufficient food, fuel, and shelter for rapidly expanding populations. Similar interventions will be necessary in marine habitats, as anthropogenic environmental change imperils them, too. Planetary transformations will also have significant consequences for human health, both physical and psychological, especially in urbanized areas, where negative impacts are often magnified. As human populations increase to numbers never reached before, not only will we face the threat of new and possibly more virulent infectious diseases, but unprecedented efforts will be required to build healthy lifestyles in an ever more crowded world.

  ARCHAEOLOGY AND THE FUTURE OF OUR PLANET

  TORBEN C. RICK

  Where and how do humans fit into the natural world? These questions have long puzzled philosophers, historians, artists, biologists, and others who have sought to understand our place on the planet and beyond it. The massive challenges that face Earth’s biodiversity and ecosystems today give these questions added relevance, especially as people grapple with an uncertain future in the Age of Humans.

  The question of where humans fit into the natural world guides the research of many archaeologists. Archaeology provides an important perspective on basically everything that makes us human, from where our species came from to the origins of hierarchy, written language, economics, animal and plant domestication, and agriculture. It also provides insight into how people have interacted with their environments over centuries and millennia, evidence of which is often found in the plant and animal remains that are preserved in the archaeological record and the information we glean from them through identification and quantification, including genetic, isotopic, and other technical analyses.

  Archaeologists have long focused on understanding how past fluctuations in climate and other environmental changes have influenced human societies. We have also increasingly explored the ways that humans in the past altered and modified their environments—both intentionally and unintentionally. The archaeological record abounds with examples of the successes and failures of peoples over millennia of occupation and evolution. The Classic Maya in Mesoamerica are a prime example: some two thousand years ago, they were an impressive and sophisticated society with monumental architecture, social hierarchy, and complicated political and ritual systems. Although debate rages about the precise causes of their decline, a combination of persistent drought, overexploitation of resources, and deforestation likely contributed to the dramatic reorganization or collapse of Maya polities.

  Several publications, both scientific and popular, have explored the ways in which the Maya, the Easter Islanders, the Southwest Anasazi, and other groups altered their environments, often using these examples as cautionary tales for our own potential fate. Some of the popular accounts are oversimplistic, painting a picture of humans as always overusing resources or as perpetually shortsighted. While we cannot deny this scenario, the archaeological record also contains many remarkable success stories for human societies—such as the persistence of the Maya for centuries. Archaeology can help us to understand the major issues of the Anthropocene through such cautionary tales of success and failure and can provide direct links to contemporary conservation and management. Bones, shells, and other animal and plant remains, which offer clues to how past peoples managed, altered, or depleted resources, also allow us to understand long-term environmental change and better prepare for changes forecast for the next few decades to centuries.

  Many archaeologists study hunter-gatherers, who are not generally known for the massive landscape and ecological changes of early states and more complex groups such as the Egyptians, Maya, and Aztecs. Still, much remains to be learned from their archaeological record, as is illustrated by knowledge generated over the past ten years that has helped to contextualize modern-day environmental problems. Shell middens—an archaeological site type containing the remains of all the trash that people left behind, usually fish, mammal, and bird bones, shells, plant remains, and artifacts—and other archaeological sites serve as vast repositories that shed light on past human-environmental interactions across space and over long periods of time. Analysis of the animal and plant remains documents which types of organisms lived in the past, whether humans had an impact on their abundance, and how human activities and climate change affected prehistoric patterns of biotic distribution. Like snapshots of the past, these data can be compared to modern-day patterns to show how we arrived at the present moment and how ecosystems have changed through time.

  Such comparisons can help us to establish baselines or targets for conservation and restoration. For instance, we know that some species are declining today, many are near extinction, and we are living through our planet’s sixth mass extinction. To understand and transcend this situation, we need to know how we got here. What do species’ histories tell us about the composition of natural communities? Which environmental and cultural targets are we trying to achieve? Why do we choose to conserve the organisms and ecosystems that we do? All such questions come down to desired future conditions—that is, what do we want the ecosystems of the future to look like? Will they be places of great abundance and high biodiv
ersity? Will they represent what environments were like before humans arrived (which would mean going back well over one hundred thousand years ago in some cases)? Determining desired future conditions is a key challenge and goal of the Age of Humans. It is also one that should involve a wide cross-section of society, from the public to policymakers to scientists. Archaeologists, as a group uniquely positioned to document long-term human-environmental interactions, potential sustainability, and the interplay of human activities and climate change, will have an important role to play.

  Interdisciplinary teams of researchers and scholars including archaeologists, biologists, ecologists, geneticists, historians, paleobiologists, and many more will help us to answer these questions. One example of such a team investigated the ecosystems, organisms, and people of the Channel Islands, five of which compose a national park off the coast of California. This project used archaeological and fossil samples, modern biological specimens, and genetics to understand species of conservation concern, such as the island fox (Urocyon littoralis). Its work has unraveled the history of the fox and other species, both with and without the presence of people and under a range of climatic conditions, and the data now serve as benchmarks for the management plans of the National Park Service and the Nature Conservancy. This investigation is a potent example of success at the local level; however, climate change and the other challenges of the Age of Humans are global problems.