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The Great Acceleration

We know that something went wrong in the country after World War II, for most of our serious pollution problems either began in the postwar years or have greatly worsened since then.

—BARRY COMMONER¹

At some point the IGBP team that prepared Global Change and the Earth System decided that their book should “record the trajectory of the ‘human enterprise’ through a number of indicators” from 1750 to 2000.² The result was 24 graphs—twelve showing historical trends in human activity (GDP growth, population, energy consumption, water use, etc.) and twelve showing physical changes in the Earth System (atmospheric carbon dioxide, ozone depletion, species extinctions, loss of forests, etc.) over 250 years.

The authors were surprised by what they found: Every trend line showed gradual growth from 1750 and a sharp upturn from about 1950. “We expected to see a growing imprint of the human enterprise on the Earth System from the start of the Industrial Revolution onward. We didn’t, however, expect to see the dramatic change in magnitude and rate of the human imprint from about 1950 onward.”³ They pointed this out in the book:

One feature stands out as remarkable. The second half of the twentieth century is unique in the entire history of human existence on Earth. Many human activities reached take-off points sometime in the twentieth century and have accelerated sharply towards the end of the century. The last 50 years have without doubt seen the most rapid transformation of the human relationship with the natural world in the history of humankind.⁴

Millennium Ecosystem Assessment

While the IGBP was preparing its synthesis report, another global scientific project was completing its work. The Millennium Ecosystem Assessment (MEA), coordinated by the United Nations Environment Program, was launched in 2001 to collect and synthesize “authoritative scientific knowledge concerning the impact of changes to the world’s ecosystems on human livelihoods and the environment.”⁵ Nearly 1,400 scientists from around the world contributed to the seven synthesis reports, four technical volumes, and many supporting papers that the MEA published in 2004 and 2005.

One of the project’s most important conclusions was highlighted in a final statement from the MEA Board in March 2005. After noting that human societies have always changed the natural systems of the planet to meet their needs, the Board declared that “throughout human history, no period has experienced interference with the biological machinery of the planet on the scale witnessed in the second half of the twentieth century.”⁶

The MEA Synthesis Report on Ecosystems and Human Well-Being made the same point, and listed significant examples:

Over the past 50 years, humans have changed ecosystems more rapidly and extensively than in any comparable period of time in human history, largely to meet rapidly growing demands for food, fresh water, timber, fiber, and fuel. This has resulted in a substantial and largely irreversible loss in the diversity of life on Earth….

• More land was converted to cropland in the 30 years after 1950 than in the 150 years between 1700 and 1850. Cultivated systems (areas where at least 30% of the landscape is in croplands, shifting cultivation, confined livestock production, or freshwater aquaculture) now cover one-quarter of Earth’s terrestrial surface.

• Approximately 20% of the world’s coral reefs were lost and an additional 20% degraded in the last several decades of the twentieth century, and approximately 35% of mangrove area was lost during this time (in countries for which sufficient data exist, which encompass about half of the area of mangroves).

• The amount of water impounded behind dams quadrupled since 1960, and three to six times as much water is held in reservoirs as in natural rivers. Water withdrawals from rivers and lakes doubled since 1960; most water use (70% worldwide) is for agriculture.

• Since 1960, flows of reactive (biologically available) nitrogen in terrestrial ecosystems have doubled, and flows of phosphorus have tripled. More than half of all the synthetic nitrogen fertilizer, which was first manufactured in 1913, ever used on the planet has been used since 1985.

• Since 1750, the atmospheric concentration of carbon dioxide has increased by about 32% (from about 280 to 376 parts per million in 2003), primarily due to the combustion of fossil fuels and land use changes. Approximately 60% of that increase (60 parts per million) has taken place since 1959.

Humans are fundamentally, and to a significant extent irreversibly, changing the diversity of life on Earth, and most of these changes represent a loss of biodiversity.

• More than two-thirds of the area of 2 of the world’s 14 major terrestrial biomes and more than half of the area of 4 other biomes had been converted by 1990, primarily to agriculture.

• Across a range of taxonomic groups, either the population size or range or both of the majority of species is currently declining.

• The distribution of species on Earth is becoming more homogenous; in other words, the set of species in any one region of the world is becoming more similar to the set in other regions primarily as a result of introductions of species, both intentionally and inadvertently in association with increased travel and shipping.

• The number of species on the planet is declining. Over the past few hundred years, humans have increased the species extinction rate by as much as 1,000 times over background rates typical over the planet’s history (medium certainty). Some 10–30% of mammal, bird, and amphibian species are currently threatened with extinction (medium to high certainty). Freshwater ecosystems tend to have the highest proportion of species threatened with extinction.

• Genetic diversity has declined globally, particularly among cultivated species.⁷

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 to publishing current versions of the original aggregated graphs, they have added ten graphs that display the socioeconomic indicators for the three groups of countries separately. (There was insufficient data for the other two indicators.)

In a section headed “Deconstructing the Socioeconomic Trends: The Equity Issue,” they draw this conclusion: “In 2010 the OECD countries accounted for 74% of global GDP but only 18% of the global population. Insofar as the imprint on the Earth System scales with consumption, most of the human imprint on the Earth System is coming from the OECD world.”¹⁴

In the Appendix of this book I consider the claim made by some on the left that Anthropocene scientists have blamed all of humanity for the actions of a small minority. The 2015 update directly contradicts such charges. Steffen and his associates have clearly shown that they understand the importance of including global inequality as a key factor in any discussion of the causes and effects of the Great Acceleration.

Of course, ecosocialists would take the disaggregation further, breaking out inequalities not just between but within countries, stressing the fact that 1 percent of the population owns half of the world’s wealth and that inequality is growing at unprecedented rates. An ecosocialist analysis of the Great Acceleration will build on the decisive issues of class and power that are shaping the Anthropocene and will ultimately determine humanity’s future.