6. Oikos

Human reshaping of ecology has been driving the Anthropocene transition since its very first beginnings. ‘Oikos’ explains that the Anthropocene poses even greater challenges for those working to conserve and restore natural habitats. What does ‘natural habitat’ even mean on a planet transformed by humans? The complex dynamics of human–environment interactions make it a challenge to detect whether a significant ecological change has occurred. The ‘historic range of variability’ or ‘baseline’ state of ecological parameters needs to be characterized. If human societies are now operating as a global force that is transforming Earth to the detriment of both humanity and non-human nature, what, if anything, is to be done about it?

1. Origins

Overwhelming evidence now confirms that humans are changing Earth in unprecedented ways. With such evidence, the proposal to recognize the Anthropocene as a new interval of geologic time—the Anthropocene epoch—would seem without issue. Yet the opposite is true. The Anthropocene remains highly controversial even among Earth scientists. ‘Origins’ considers different origin stories—from the myths of ancient Greece to the First Copernican Revolution to Darwin’s origins of man. The significance of the Anthropocene resides in its role as a new lens through which age-old narratives and philosophical questions are being revisited and rewritten. It concludes that there are good reasons to accept that a new chapter of Earth history might indeed be unfolding, with humans playing a leading role.

5. Anthropos

Humans are the ultimate ecosystem engineers. From land clearing using fire, to domesticating other species, and tilling the soil, there is a long, rich, and diachronous history of human transformation of Earth’s environments. The Anthropocene tells a story about human capacity to transform Earth. But when does the story begin? ‘Anthropos’ considers the archaeological evidence of human impact on Earth and concludes that the Industrial Revolution and the Great Acceleration are merely the latest, and most impactful, chapters in a long, entangled, and evolving history of human transformation of Earth’s environments; a history that is still unfolding.

4. The Great Acceleration

The challenge for the International Geosphere-Biosphere Programme (IGBP) in 1999 was how to integrate the evidence of humans transforming Earth’s functioning as a system into a coherent overview of global environmental change. The IGBP report Global Change and the Earth System: A Planet Under Pressure (2004) identified a dramatic mid-20th-century step-change in anthropogenic global environmental change, which would come to be called ‘The Great Acceleration’. ‘The Great Acceleration’ outlines the complex, multi-causal, system-level set of processes that have altered the Earth system, from domestication of land to human alterations of the atmosphere, hydrosphere, and biosphere. It also discusses tipping points that result in relatively rapid, non-linear, and potentially irreversible ‘step-changes’ in Earth’s climate system.

3. Geologic time

If we are to understand the case both for and against recognizing the Anthropocene as an interval of geologic time, a basic understanding of the science of stratigraphy and how the Geologic Time Scale is established is essential. ‘Geologic time’ outlines the origins of stratigraphy and the publication of the Geologic Time Scale (GTS) that brought together the work of generations of stratigraphers within a single standardized geochronology of Earth history. It explains how the GTS is divided into different time intervals and considers the work of the Anthropocene Working Group whose task is to examine the case for recognizing the Anthropocene as a new interval of geologic time.

8. Prometheus

The Anthropocene continues to be controversial across the many scholarly communities that study social and environmental change, including not only archaeologists, anthropologists, sociologists, geographers, and environmental historians, but also ecologists and Earth scientists. Will creating a new unit of geologic time help to advance scientific efforts to understand Earth’s human transformation? ‘Prometheus’ considers the new challenges faced by Earth System science: the anthroposphere, geoengineering, and the need to guide efforts to adapt to an increasingly dynamic human planet. Given the overwhelming scale, rate, and diversity of harmful global environmental changes produced by human societies, it is hard not to view the Anthropocene as an unmitigated disaster, but could a better Anthropocene be a possibility?

7. Politikos

The concept of the Anthropocene has travelled far beyond its natural sciences origins. Since it was first proposed, the Anthropocene has inspired a barrage of socially relevant questions, stoked intense debates, and served as a muse for artists and designers. ‘Politikos’ explains that the politics of inequality, environmental ethics, and the challenges of responsible action under conditions of potentially catastrophic global change have all been connected with the Anthropocene proposal. Would scientific recognition of the Anthropocene change public perceptions and actions? What would happen if the Anthropocene was not accepted as a new epoch of geologic time? Despite many interpretations, there appears to be a common thread of the Anthropocene as crisis.

2. Earth system

To confirm that humans have altered Earth’s functioning as a system, the causal mechanisms behind these alterations must be demonstrated. Only through a robust understanding of Earth as a system—its fundamental components, their interactions, and most importantly, the processes that keep the Earth system stable or induce change—is it possible to establish the causes of changes in the Earth system. ‘Earth system’ considers the key work of scientists such as Eduard Suess, Vladimir Vernadsky, Carl Sagan, James Lovelock, Lynn Margulis, David Keeling, and Paul Crutzen and their attempts to explain the dynamics of Earth as a system, the importance of the biosphere, and human impact on our planet.