The Anthropocene hypothesis—that humans have impacted “the environment” but also changed the Earth’s geology—has spread widely through the sciences and humanities. This hypothesis is being currently tested to see whether the Anthropocene may become part of the Geological Time Scale. An Anthropocene Working Group has been established to assemble the evidence. The decision regarding formalization is likely to be taken in the next few years, by the International Commission on Stratigraphy, the body that oversees the Geological Time Scale. Whichever way the decision goes, there will remain the reality of the phenomenon and the utility of the concept. The evidence, as outlined here, rests upon a broad range of signatures reflecting humanity’s significant and increasing modification of Earth systems. These may be visible as markers in physical deposits in the form of the greatest expansion of novel minerals in the last 2.4 billion years of Earth history and development of ubiquitous materials, such as plastics, unique to the Anthropocene. The artefacts we produce to live as modern humans will form the technofossils of the future. Human-generated deposits now extend from our natural habitat on land into our oceans, transported at rates exceeding the sediment carried by rivers by an order of magnitude. That influence now extends increasingly underground in our quest for minerals, fuel, living space, and to develop transport and communication networks. These human trace fossils may be preserved over geological durations and the evolution of technology has created a new technosphere, yet to evolve into balance with other Earth systems. The expression of the Anthropocene can be seen in sediments and glaciers in chemical markers. Carbon dioxide in the atmosphere has risen by ~45 percent above pre–Industrial Revolution levels, mainly through combustion, over a few decades, of a geological carbon-store that took many millions of years to accumulate. Although this may ultimately drive climate change, average global temperature increases and resultant sea-level rises remain comparatively small, as yet. But the shift to isotopically lighter carbon locked into limestones and calcareous fossils will form a permanent record. Nitrogen and phosphorus contents in surface soils have approximately doubled through increased use of fertilizers to increase agricultural yields as the human population has also doubled in the last 50 years. Industrial metals, radioactive fallout from atomic weapons testing, and complex organic compounds have been widely dispersed through the environment and become preserved in sediment and ice layers. Despite radical changes to flora and fauna across the planet, the Earth still has most of its complement of biological species. However, current trends of habitat loss and predation may push the Earth into the sixth mass extinction event in the next few centuries. At present the dramatic changes relate to trans-global species invasions and population modification through agricultural development on land and contamination of coastal zones. Considering the entire range of environmental signatures, it is clear that the global, large and rapid scale of change related to the mid-20th century is the most obvious level to consider as the start of the Anthropocene Epoch.
Jan Zalasiewicz and Colin Waters
V. Kerry Smith
Geologists’ reframing of the global changes arising from human impacts can be used to consider how the insights from environmental economics inform policy under this new perspective. They ask a rhetorical question. How would a future generation looking back at the records in the sediments and ice cores from today’s activities judge mankind’s impact? They conclude that the globe has entered a new epoch, the Anthropocene. Now mankind is the driving force altering the Earth’s natural systems. This conclusion, linking a physical record to a temporal one, represents an assessment of the extent of current human impact on global systems in a way that provides a warning that all policy design and evaluation must acknowledge that the impacts of human activity are taking place on a planetary scale. As a result, it is argued that national and international environmental policies need to be reconsidered. Environmental economics considers the interaction between people and natural systems. So it comes squarely into conflict with conventional practices in both economics and ecology. Each discipline marginalizes the role of the other in the outcomes it describes. Market and natural systems are not separate. This conclusion is important to the evaluation of how (a) economic analysis avoided recognition of natural systems, (b) the separation of these systems affects past assessments of natural resource adequacy, and (c) policy needs to be redesigned in ways that help direct technological innovation that is responsive to the importance of nonmarket environmental services to the global economy and to sustaining the Earth’s living systems.
Colin R. Robins
Soils are the complex, dynamic, spatially diverse, living, and environmentally sensitive foundations of terrestrial ecosystems as well as human civilizations. The modern, environmental study of soil is a truly young scientific discipline that emerged only in the late 19th century from foundations in agricultural chemistry, land resource mapping, and geology. Today, little more than a century later, soil science is a rigorously interdisciplinary field with a wide range of exciting applications in agronomy, ecology, environmental policy, geology, public health, and many other environmentally relevant disciplines. Soils form slowly, in response to five inter-related factors: climate, organisms, topography, parent material, and time. Consequently, many soils are chemically, biologically, and/or geologically unique. The profound importance of soil, combined with the threats of erosion, urban development, pollution, climate change, and other factors, are now prompting soil scientists to consider the application of endangered species concepts to rare or threatened soil around the world.
The animal world is under increasing pressure, given the magnitude of anthropogenic environmental stress, especially from human-caused rapid climate change together with habitat conversion, fragmentation, and destruction. There is a global wave of species extinctions and decline in local species abundance. To stop or even reverse this so-called defaunation process, in situ conservation (in the wild) is no longer effective without ex situ conservation (in captivity). Consequently, zoos could play an ever-greater role in the conservation of endangered species and wildlife—hence the slogan Captivity for Conservation. However, the integration of zoo-based tools and techniques in species conservation has led to many conflicts between wildlife conservationists and animal protectionists. Many wildlife conservationists agree with Michael Soulé, the widely acclaimed doyen of the relatively new discipline of conservation biology, that conservation and animal welfare are conceptually distinct, and that they should remain politically separate. Animal protectionists, on the other hand, draw support from existing leading accounts of animal ethics that oppose the idea of captivity for conservation, either because infringing an individual’s right to freedom for the preservation of the species is considered as morally wrong, or because the benefits of species conservation are not seen as significant enough to overcome the presumption against depriving an animal of its liberty. Both sides view animals through different lenses and address different concerns. Whereas animal ethicists focus on individual organisms, and are concerned about the welfare and liberty of animals, wildlife conservationists perceive animals as parts of greater wholes such as species or ecosystems, and consider biodiversity and ecological integrity as key topics. This seemingly intractable controversy can be overcome by transcending both perspectives, and developing a bifocal view in which zoo animals are perceived as individuals in need of specific care and, at the same time, as members of a species in need of protection. Based on such a bifocal approach that has lately been adopted by a growing international movement of “Compassionate Conservation,” the modern zoo can only achieve its conservation mission if it finds a morally acceptable balance between animal welfare concerns and species conservation commitments. The prospects for the zoo to achieve such a balance are promising. Over the past decade or so, zoos have made serious and sustained efforts to ensure and enhance animal welfare. At the same time, the zoo’s contribution to species conservation has also improved considerably.