The anthropocene: from global change to planetary stewardship

Abstract

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, its global scale and its threat to the resilience of the Earth System. The advent of the Anthropence, the time interval in which human activities now rival global geophysical processes, suggests that we need to fundamentally alter our relationship with the planet we inhabit. Many approaches could be adopted, ranging from geoengineering solutions that purposefully manipulate parts of the Earth System to becoming active stewards of our own life support system. The Anthropocene is a reminder that the Holocene, during which complex human societies have developed, has been a stable, accommodating environment and is the only state of the Earth System that we know for sure can support contemporary society. The need to achieve effective planetary stewardship is urgent. As we go further into the Anthropocene, we risk driving the Earth System onto a trajectory toward more hostile states from which we cannot easily return.

Fig. 1

a The increasing rates of change in human activity since the beginning of the Industrial Revolution to 2000. Significant increases in rates of change occur around the 1950s in each case and illustrate how the past 50 years have been a period of dramatic and unprecedented change in human history (Steffen et al. , and references therein). In the following part figures, the parameters are disaggregated into OECD (wealthy) countries (blue) and non-OECD (developing) countries (red); b Population change from 1960 through 2009, in 1000 millions of people (World Bank 2010); c Increase in real GDP from 1969 through 2010, in trillions 2005 USD (USDA 2010); d Communication: increase in telephones (millions), both land-lines and mobile phones, from 1950 through 2009 (Canning ; Canning and Farahani ; ITU 2010)

Fig. 1

a The increasing rates of change in human activity since the beginning of the Industrial Revolution to 2000. Significant increases in rates of change occur around the 1950s in each case and illustrate how the past 50 years have been a period of dramatic and unprecedented change in human history (Steffen et al. , and references therein). In the following part figures, the parameters are disaggregated into OECD (wealthy) countries (blue) and non-OECD (developing) countries (red); b Population change from 1960 through 2009, in 1000 millions of people (World Bank 2010); c Increase in real GDP from 1969 through 2010, in trillions 2005 USD (USDA 2010); d Communication: increase in telephones (millions), both land-lines and mobile phones, from 1950 through 2009 (Canning ; Canning and Farahani ; ITU 2010)

Fig. 2

I = PAT identity at the global scale from 1900 to the present. Note the difference in volume between the 1990–1950 period and the 1950–2011 period, which represents the Great Acceleration (Kolbert 2011)

Fig. 3

Global-scale changes in the Earth System as a result of the dramatic increase in human activity: a atmospheric CO₂ concentration, b atmospheric N₂O concentration, c atmospheric CH₄ concentration, d percentage total column ozone loss over Antarctica, using the average annual total column ozone, 330, as a base, e northern hemisphere average surface temperature anomalies, f natural disasters after 1900 resulting in more than 10 people killed or more than 100 people affected, g percentage of global fisheries either fully exploited, overfished or collapsed, h annual shrimp production as a proxy for coastal zone alteration, i model-calculated partitioning of the human-induced nitrogen perturbation fluxes in the global coastal margin for the period since 1850, j loss of tropical rainforest and woodland, as estimated for tropical Africa, Latin America and South and Southeast Asia, k amount of land converted to pasture and cropland, and l mathematically calculated rate of extinction (Steffen et al. , and references therein)

Fig. 4

The human domination of land systems in the Anthropocene. Irrigated landscape, USA (photo: Azote)

Fig. 5

Changes in global average surface temperature through Earth history, from ca., 70 million years ago to the present (adapted from Zalasiewicz and Williams 2009). a The most recent 70 million years, showing the long cooling trend to the present, coincident with decreasing atmospheric CO₂ concentration; the Antarctic ice sheets formed about 34 million years ago and the northern hemisphere ice sheets about 2.5 million years ago. b The most recent 3 million years, encompassing the Quaternary period. The late Quaternary, the time during which Homo sapiens evolved, is characterized by ca., 100 000-year rhythmic oscillations between long, variable cold periods and much shorter warm intervals. The oscillations are triggered by subtle changes in the Earth’s orbit but the temperature changes are driven by the waxing and waning of ice sheets and changes in greenhouse gas concentrations. c The most recent 60 000 years of Earth history, showing the transition from the most recent ice age into the much more stable Holocene about 12 000 years ago. The most recent ice age, which humans experienced, was characterized by repeated, rapid, severe, and abrupt changes in northern hemisphere climate (Dansgaard–Oeschger events), with changes in oceanic circulation, periodic major ice sheet collapses, 5–10 m scale sea-level changes, and regional changes in aridity/humidity. d The most recent 16 000 years of Earth history, showing the Holocene and the transition into it from the most recent ice age

Fig. 6

National Human Development Index and Ecological Footprint trajectories, 1980–2007, compared with goal levels. (Global Footprint Network 2011) (see flash video at http://www.footprintnetwork.org/en/index.php/GFN/page/fighting_poverty_our_human_development_initiative/)

Fig. 7

The planetary boundary for climate change is designed to avoid significant loss of ice from the large polar ice sheets. Melting Greenland ice sheet (photo: Bent Christensen, Azote)

Fig. 8

FAO food price index, 1990–2010 (FAO 2011)

Fig. 9

The inner green shading represents the proposed safe operating space for nine planetary systems. The red wedges represent an estimate of the current position for each variable. The boundaries in three systems (rate of biodiversity loss, climate change and human interference with the nitrogen cycle) have already been exceeded (Rockström et al.2009a)

Fig. 10

A stability landscape with two stable states. The valleys, or basins of attraction, in the landscape represent the stable states at several different conditions, while the hilltops represent unstable conditions as the system transitions from one state to another. If the size of the basin of attraction is small, resilience is small, and even a moderate perturbation may bring the system into the alternative basin of attraction (Scheffer 2009)