Will Steffen

Australian National University | ANU · Climate Change Institute

Event stratigraphy is used to help characterise the Anthropocene as a chronostratigraphic concept, based on analogous deep-time events, for which we provide a novel categorization. Events in stratigraphy are distinct from extensive, time-transgressive ‘episodes’ – such as the global, highly diachronous record of anthropogenic change, termed here an...

Event stratigraphy is used to help characterise the Anthropocene as a chronostratigraphic concept, based on analogous deep-time events, for which we provide a novel categorization. Events in stratigraphy are distinct from extensive, time-transgressive ‘episodes’ – such as the global, highly diachronous record of anthropogenic change, termed here an...

Event stratigraphy is used to help characterise the Anthropocene as a chronostratigraphic concept, based on analogous deep-time events, for which we provide a novel categorization. Events in stratigraphy are distinct from extensive, time-transgressive ‘episodes’ – such as the global, highly diachronous record of anthropogenic change, termed here an...

The extensive array of mid-20 th century stratigraphic event signals associated with the 'Great Acceleration' enables precise and unambiguous recognition of the Anthropocene as an epoch/series within the Geological Time Scale. A mid-20 th century inception is consistent with Earth System science analysis in which the Anthropocene term and concept a...

Prudent risk management requires consideration of bad-to-worst-case scenarios. Yet, for climate change, such potential futures are poorly understood. Could anthropogenic climate change result in worldwide societal collapse or even eventual human extinction? At present, this is a dangerously underexplored topic. Yet there are ample reasons to suspec...

The Anthropocene defined as an epoch/series within the Geological Time Scale, and with an isochronous inception in the mid-20th century, would both utilize the rich array of stratigraphic signals associated with the Great Acceleration and align with Earth System science analysis from where the term Anthropocene originated. It would be stratigraphic...

Altered Earth aims to get the Anthropocene right in three senses. With essays by leading scientists, it highlights the growing consensus that our planet entered a dangerous new state in the mid-twentieth century. Second, it gets the Anthropocene right in human terms, bringing together a range of leading authors to explore, in fiction and non-fictio...

The Earth System is a single, self-regulating system comprised of interacting physical, chemical, biological and human components. For the last 11,700 years, the system has existed in a relatively stable state called the Holocene. However, around the mid-twentieth century, human activities – population, economy, resource use, technologies – underwe...

The Anthropocene was conceptualized in 2000 to reflect the extensive impact of human activities on our planet, and subsequent detailed analyses have revealed a sub- stantial Earth System response to these impacts begin- ning in the mid-20th century. Key to this understanding was the discovery of a sharp upturn in a multitude of global socio-economi...

In this wide-ranging interview, the well-known Earth System scientist Professor Will Steffen introduces and discusses the influential planetary boundaries (PB) framework, the potential for a Hothouse Earth pathway and the relevance of the Anthropocene concept. He elaborates on the role of emergence, complexity, feedback and irreversibility and draw...

The destruction of the Amazon is a major global environmental issue, not only because of greenhouse gas emissions or direct impacts on biodiversity and livelihoods, but also due to the forest's role as a tipping element in the Earth System. With nearly a fifth of the Amazon already lost, there are already signs of an imminent forest dieback process...

The COVID-19 pandemic has exposed an interconnected and tightly coupled globalized world in rapid change. This article sets the scientific stage for understanding and responding to such change for global sustainability and resilient societies. We provide a systemic overview of the current situation where people and nature are dynamically intertwine...

The apocalyptic Australian bushfires have challenged the way we plan settlements. What is the future for small urban settlements within fire-vulnerable forests and bushland? Could they create a new model for rural settlements with wider lessons for development in big cities? This paper draws together observations of the 2019/20 bushfire size, inten...

The term Anthropocene initially emerged from the Earth System science community in the early 2000s, denoting a concept that the Holocene Epoch has terminated as a consequence of human activities. First associated with the onset of the Industrial Revolution, it was then more closely linked with the Great Acceleration in industrialization and globali...

Human-driven changes to many features of the Earth system have become so ubiquitous and significant in magnitude that a new era for the planet—the ‘Anthropocene’—has been proposed (Crutzen and Stoermer Crutzen and Stoermer, Glob. Change Newsl. 41:12–13, 2001; Clark et al., Science 293:283–287, 2001). Many of these changes are large in magnitude at...

Stratigraphy provides insights into the evolution and dynamics of the Earth System over its long history. With recent developments in Earth System science, changes in Earth System dynamics can now be observed directly and projected into the near future. An integration of the two approaches provides powerful insights into the nature and significance...

Over the past century, the total material wealth of humanity has been enhanced. However, in the twenty-first century, we face scarcity in critical resources, the degradation of ecosystem services, and the erosion of the planet’s capability to absorb our wastes. Equity issues remain stubbornly difficult to solve. This situation is novel in its speed...

With great interest we have read Ruddiman’s intriguing article which is in favour of placing the start of the Anthropocene at 5–8 millennia BP instead of the late quarter of the 18th century. He shows how land exploitation for agriculture and animal husbandry may have led to enhanced emissions of CO2 and CH4 to the atmosphere, thereby modifying the...

Q. Edward Wang’s unparalleled four-volume survey of historiography examines the nature and significance of history writing from ancient worlds to the present day. Taking a global approach, it presents and contextualizes classic works that portray the traditions of historical writing around the world. The collection also incorporates key essays and...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Supplementary material to Syvitski et al. 2020, see https://www.researchgate.net/publication/344685697_Extraordinary_human_energy_consumption_and_resultant_geological_impacts_beginning_around_1950_CE_initiated_the_proposed_Anthropocene_Epoch

Growth in fundamental drivers—energy use, economic productivity and population—can provide quantitative indications of the proposed boundary between the Holocene Epoch and the Anthropocene. Human energy expenditure in the Anthropocene, ~22 zetajoules (ZJ), exceeds that across the prior 11,700 years of the Holocene (~14.6 ZJ), largely through combus...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Fresh water—the bloodstream of the biosphere—is at the center of the planetary drama of the Anthropocene. Water fluxes and stores regulate the Earth's climate and are essential for thriving aquatic and terrestrial ecosystems, as well as water, food, and energy security. But the water cycle is also being modified by humans at an unprecedented scale...

The planetary boundaries framework proposes quantified guardrails to human modification of global environmental processes that regulate the stability of the planet and has been considered in sustainability science, governance, and corporate management. However, the planetary boundary for human freshwater use has been critiqued as a singular measure...

The planetary boundary framework presents a ‘planetary dashboard’ of humanity’s globally aggregated performance on a set of environmental issues that endanger the Earth system’s capacity to support humanity. While this framework has been highly influential, a critical shortcoming for its application in sustainability governance is that it currently...

Earth System Science (ESS) is a rapidly emerging transdisciplinary endeavour aimed at understanding the structure and functioning of the Earth as a complex, adaptive system. Here, we discuss the emergence and evolution of ESS, outlining the importance of these developments in advancing our understanding of global change. Inspired by early work on b...

Individual organisms on land and in the ocean sequester massive amounts of the carbon emitted into the atmosphere by humans. Yet the role of ecosystems as a whole in modulating this uptake of carbon is less clear. Here, we study several different mechanisms by which climate change and ecosystems could interact. We show that climate change could cau...

The phenomenon of collective action and the origin of collective action problems have been extensively and systematically studied in the social sciences. Yet, while we have substantial knowledge about the factors promoting collective action at the local level, we know far less about how these insights travel to large-scale collective action problem...

The growing threat of abrupt and irreversible climate changes must compel political and economic action on emissions. The growing threat of abrupt and irreversible climate changes must compel political and economic action on emissions. A plane flying over a river of meltwater on glacier in Alaska

We analyse the ‘three flaws’ to potentially defining a formal Anthropocene geological time unit as advanced by Ruddiman (2018). (1) We recognize a long record of pre-industrial human impacts, but note that these increased in relative magnitude slowly and were strongly time-transgressive by comparison with the extraordinarily rapid, novel and near-g...

The Anthropocene, a term launched into public debate by Nobel Prize winner Paul Crutzen, has been used informally to describe the time period during which human actions have had a drastic effect on the Earth and its ecosystems. This book presents evidence for defining the Anthropocene as a geological epoch, written by the high-profile international...

Today, more than ever, ‘Spaceship Earth’ is an apt metaphor as we chart the boundaries for a safe planet¹. Social scientists both analyse why society courts disaster by approaching or even overstepping these boundaries and try to design suitable policies to avoid these perils. Because the threats of transgressing planetary boundaries are global, lo...

We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a "Hothouse Earth" pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher...

Changes to climate–carbon cycle feedbacks may significantly affect the Earth system's response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth system models. Here, we construct a stylised global climate–carbon cycle model, test its output against comprehensive Earth system...

The Anthropocene as a potential new unit of the International Chronostratigraphic Chart (which serves as the basis of the Geological Time Scale) is assessed in terms of the stratigraphic markers and approximate boundary levels available to define the base of the unit. The task of assessing and selecting potential Global Boundary Stratotype Section...

The Anthropocene, as a potential new unit of the International Chronostratigraphic Chart, is assessed in terms of stratigraphic markers and approximate boundary levels available to define the unit base. The task of assessing and selecting potential GSSP candidate sections, a requirement in seeking formalisation of the term, is being actively pursue...

Although a number of different starting points for the Anthropocene have been proposed, arguments and observations from stratigraphy, Earth System science, and human history suggest the mid-20th century as the most logical start date for the Anthropocene, which marks the time when humanity became a geological force on a planetary scale.

Heijung et al. provide a useful discussion of our recent paper, the Anthropocene equation (Gaffney and Steffen, 2017), and they agree with paper’s conclusions. Much of the scientific and public discourse around the Anthropocene focuses on Anthropogenic influence that will be visible in the sedimentary record. This risks downplaying the scale of Ant...

Changes to climate-carbon cycle feedbacks may significantly affect the Earth System’s response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth System Models (ESMs). Here, we construct a stylized global climate-carbon cycle model, test its output against complex ESMs, and i...

Rapid urbanisation generates risks and opportunities for sustainable development. Urban policy and decision makers are challenged by the complexity of cities as social–ecological–technical systems. Consequently there is an increasing need for collaborative knowledge development that supports a whole-of-system view, and transformational change at mu...

This is the link to the press release from University of Leicester for the new AWG paper authored by the above members of the working group: https://www2.le.ac.uk/offices/press/press-releases/2017/march/the-anthropocene-scientists-respond-to-criticisms-of-a-new-geological-epoch

A range of published arguments against formalizing the Anthropocene as a geological time unit have variously suggested that it is a misleading term of non-stratigraphic origin and usage, is based on insignificant temporal and material stratigraphic content unlike that used to define older geological time units, is focused on observation of human hi...

We assess the scale and extent of the physical technosphere, defined here as the summed material output of the contemporary human enterprise. It includes active urban, agricultural and marine components, used to sustain energy and material flow for current human life, and a growing residue layer, currently only in small part recycled back into the...

Stratigraphy provides insights into the evolution and dynamics of the Earth System over its long history. With recent developments in Earth System science, changes in Earth System dynamics can now be observed directly and projected into the near future. An integration of the two approaches provides powerful insights into the nature and significance...

Since it was first proposed in 2000, the concept of the Anthropocene has evolved in breadth and diversely. The concept encapsulates the new and unprecedented planetary-scale changes resulting from societal transformations and has brought to the fore the social drivers of global change. The concept has revealed tensions between generalized interpret...

An Australian Sustainable Development Commission, with authority, adequate funding and broad support, would send a very clear signal domestically and internationally that we are serious about implementing the SDGs and the Paris agreement. There is no better way to ensure a viable and healthy future for all Australians, both current and future gener...

Biospheric relationships between production and consumption of biomass have been resilient to changes in the Earth system over billions of years. This relationship has increased in its complexity, from localised ecosystems predicated on anaerobic microbial production and consumption, to a global biosphere founded on primary production from oxygenic...

The rise of plastics since the mid-20th century, both as a material element of modern life and as a growing environmental pollutant, has been widely described. Their distribution in both the terrestrial and marine realms suggests that they are a key geological indicator of the Anthropocene, as a distinctive stratal component. Most immediately evide...

Human activity is leaving a pervasive and persistent signature on Earth. Vigorous debate continues about whether this warrants recognition as a new geologic time unit known as the Anthropocene. We review anthropogenic markers of functional changes in the Earth system through the stratigraphic record. The appearance of manufactured materials in sedi...

Appreciation of the fact that our planet functions as a system, i.e., the Earth System (ES), defined as “the interacting physical, chemical and biological global-scale cycles (often called biogeochemical cycles) and energy fluxes which provide the conditions necessary for life on this planet” (Oldfield F, Steffen W, The earth system. In: Steffen W,...

While the concept of the Anthropocene reflects the past and present nature, scale and magnitude of human impacts on the Earth System, its true significance lies in how it can be used to guide attitudes, choices, policies and actions that influence the future. Yet, to date much of the research on the Anthropocene has focused on interpreting past and...

Recent global crises reveal an emerging pattern of causation that could increasingly characterize the birth and progress of future global crises. A conceptual framework identifies this pattern's deep causes, intermediate processes, and ultimate outcomes. The framework shows how multiple stresses can interact within a single social-ecological system...

A recently published analysis by Lewis and Maslin (Lewis SL and Maslin MA (2015) Defining the Anthropocene. Nature 519: 171–180) has identified two new potential horizons for the Holocene−Anthropocene boundary: 1610 (associated with European colonization of the Americas), or 1964 (the peak of the excess radiocarbon signal arising from atom bomb tes...

Jaramillo and Destouni claim that freshwater consumption is beyond the planetary boundary, based on high estimates of water cycle components, different definitions of water consumption, and extrapolation from a single case study. The difference from our analysis, based on mainstream assessments of global water consumption, highlights the need for c...

As members of the Anthropocene Working Group, we contend that the proposed new geological epoch should reflect a unique stratigraphic unit that is characterized by unambiguous, widespread and essentially permanent anthropogenic signatures in rock, glacial ice or marine sediments. We therefore find the two dates chosen by Simon Lewis and Mark Maslin...