Naming the Turning Point
Almost simultaneously, two large-scale global scientific projects—the International Geosphere-Biosphere Program and the Millennium Ecosystem Assessment—independently identified the middle of the twentieth century as a turning point in Earth history. As the IGBP report said, “The last 50 years have without doubt seen the most rapid transformation of the human relationship with the natural world in the history of the species.”8
In 2005, Will Steffen and Paul Crutzen of the IGBP, together with environmental historian John McNeill and others who had participated in the MEA process, attended an intensive one-week seminar in Dahlem, Germany, with the aim of deepening their understanding of the history of the relationship between humanity and nature. Their workshop, chaired by Steffen, drew on findings from the IGBP and MEA to argue that “the 20th century can be characterized by global change processes of a magnitude which never occurred in human history.” After quoting the MEA, their workshop report gave those processes a name:
These and many other changes demonstrate a distinct increase in the rates of change in many human-environment interactions as a result of amplified human impact on the environment after World War II—a period that we term the “Great Acceleration.”9
Steffen later wrote that the name Great Acceleration was a deliberate homage to The Great Transformation, Karl Polanyi’s influential book on the social, economic, and political upheavals that accompanied the rise of market society in England:
Polanyi put forward a holistic understanding of the nature of modern societies, including mentality, behavior, structure, and more. In a similar vein, the term “Great Acceleration” aims to capture the holistic, comprehensive, and interlinked nature of the post-1950 changes simultaneously sweeping across the socioeconomic and biophysical spheres of the Earth System, encompassing far more than climate change.10
A Two-Stage Anthropocene?
The first peer-reviewed account of the Great Acceleration was the provocatively titled article, “The Anthropocene: Are Humans Now Overwhelming the Great Forces of Nature?” by Steffen, Crutzen, and McNeill, published in 2007. They argued that the Anthropocene had developed in two distinct stages.
Stage 1: The Industrial Era, from the early 1800s to 1945, when atmospheric CO2 exceeded the upper limit of Holocene variation; and Stage 2: The Great Acceleration, from 1945 to the present, “when the most rapid and pervasive shift in the human-environment relationship began.”
(They also—over-optimistically, I’d say—predicted that a third stage, “Stewards of the Earth,” would begin in 2015.)
Steffen, Crutzen, and McNeil left no doubt that their answer to the question in their article’s title was an emphatic yes:
Over the past 50 years, humans have changed the world’s ecosystems more rapidly and extensively than in any other comparable period in human history. The Earth is in its sixth great extinction event, with rates of species loss growing rapidly for both terrestrial and marine ecosystems. The atmospheric concentrations of several important greenhouse gases have increased substantially, and the Earth is warming rapidly. More nitrogen is now converted from the atmosphere into reactive forms by fertilizer production and fossil fuel combustion than by all of the natural processes in terrestrial ecosystems put together….
The exponential character of the Great Acceleration is obvious from our quantification of the human imprint on the Earth System, using atmospheric CO2 concentration as the indicator. Although by the Second World War the CO2 concentration had clearly risen above the upper limit of the Holocene, its growth rate hit a take-off point around 1950. Nearly three-quarters of the anthropogenically driven rise in CO2 concentration has occurred since 1950 (from about 310 to 380 ppm), and about half of the total rise (48 ppm) has occurred in just the last 30 years.11
The term Great Acceleration quickly caught on among Earth System scientists as a descriptive name for the period of unprecedented economic growth and environmental devastation since World War II. Their “two stages” model has not survived, however; as we’ll see in chapter 4 many Earth System scientists, including Steffen, Crutzen, and McNeill, have concluded that the Anthropocene actually began in the middle of the twentieth century, that the beginning of the Great Acceleration is also the beginning of the Anthropocene.
FIGURE 2.1: Earth System Trends
Updates of the 2004 Great Acceleration graphs were published in 2015. As in the original graphs, all the trend lines show hockey stick-shaped trajectories, turning sharply upward in the middle of the twentieth century.12
FIGURE 2.2: Socioeconomic Trends
Acceleration Update
The original Great Acceleration graphs, published in 2004, showed social and environmental trends from 1750 to 2000. In January 2015, Will Steffen and others associated with the IGBP and the Stockholm Resilience Center updated the data to 2010, to show what they labelled “The Trajectory of the Anthropocene.” In a few cases, where better data was available, they changed the indicators, but on the whole the updated graphs provide a good picture of how the socioeconomic and Earth System trends developed in the first decade of this century.
Overall, both the socioeconomic and Earth System trends show continuing acceleration. The authors note in particular that “the rise in carbon dioxide concentration parallels closely the rise in primary energy use and in GDP, showing no sign yet of any significant decoupling of emissions from either energy use or economic growth.”13
Two of the Earth System trends do show small declines between 2001 and 2010. One, stratospheric ozone depletion, appears to be the result of an international treaty banning many of the chemicals that are known to destroy ozone. We’ll discuss that further in chapter 5.
The downtick in another of the graphs, Marine Fish Capture, is actually bad news for the environment: it reflects the growing exhaustion of the world’s ocean fish stocks, leading to a shift from wild fish to farmed fish, which now account for half of global fish consumption.
The amount of domesticated land continues to grow, but unlike the other trends, the rate of growth has been slowing down since 1950. Again, this isn’t good news, as it reflects not more careful use of land but a decline in the amount of arable land available. Most of the land now being converted to agriculture was formerly tropical forest, so the indicator for tropical forest loss continues to accelerate.
The Equity Issue
The 2015 update is particularly noteworthy for the authors’ thoughtful consideration of the fact that the original graphs displayed global totals, and “did not attempt to deconstruct the socioeconomic graphs into countries or groups of countries.” They note that this approach has “prompted some sharp criticism from social scientists and humanities scholars” on the grounds that “strong equity issues are masked by considering global aggregates only.”
Steffen and his associates accepted that criticism of the graphs, and went to substantial effort to separate the socioeconomic indicators into three groups: the rich OECD countries, the emerging (BRICS) nations, and the rest of the world. In addition
