Kindle Notes & Highlights
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January 1, 2019
Haber won the Nobel Prize in 1918 and the Haber–Bosch process transformed Earth’s nitrogen cycle.
Moreover, global mean temperatures are now substantially higher than they were 100 years ago, and probably higher than they have been throughout the entire Holocene Epoch
Even as you read this, it is likely that Earth is now hotter, on average, than at any other time in more than 100,000 years.
The relatively stable and moderate interglacial temperatures of the Holocene therefore stand out as an island of climate stability within a sea of extremes.
Ultimately, the system leaves, permanently, its earlier, more stable state (the Holocene), and tips into a new, less stable state (the Anthropocene).
His prescient 2000 book Something New Under the Sun documented an unprecedented shift in the scale and intensity of social and environmental change in the 20th century together with its acceleration after 1950. Steffen, Crutzen, and McNeill later combined forces, further establishing the Great Acceleration as the leading narrative explaining the rise of humans as a ‘great force of nature’ and an Earth system transition to the Anthropocene after 1950.
Preindustrial societies never produced the scales or intensities of anthropogenic environmental changes needed to ‘rival the great forces of Nature’.
In a 2016 paper in Science, the Anthropocene Working Group endorsed the Great Acceleration as the main scientific narrative
explaining Earth’s transition to the Anthropocene.
‘When exactly did humans attain dominance of the earth’s environments?’ asked archaeologists Bruce Smith and Melinda Zeder in 2013 in the journal Anthropocene.
From their perspective as archaeologists, the onset of the Anthropocene ought not to be defined solely by the environmental consequences of human activities, but rather by the emergence of unprecedented human capacities to alter Earth’s environments.
dam-building beavers and burrowing earthworms,
The very earliest stone tools were manufactured by our distant ancestors in the genus Australopithecus more than 3.3 million years ago or even before. The first stone tools manufactured by Homo sapiens closely resembled hand axes produced 1.6 million years earlier by our ancestors in the genus Homo. Controlled use of fire is well documented more than 400,000 years ago, and may have originated 2 million years ago or even before.
Fourteen thousand years ago, before the Pleistocene had ended and the Holocene began, human populations were established on every continent except Antarctica.
Many of these species, especially the larger animals prized as human prey—the megafauna—would soon be extinct, from the Glyptodon, a giant relative of the armadillo, to the elephant-sized ground sloths of the genus Megatherium.
In the Late Pleistocene and Early Holocene, hunter-gatherers probably caused the extinction of about half of Earth’s large-bodied mammals and a number of large bird species in Australia. The Americas and Australia lost the most species—from 70 to almost 90 per cent of all their mammalian megafauna—while Eurasia lost less than 40 per cent and Africa only about 20 per cent.
The degree to which human hunter-gatherers caused the mass extinction of megafauna remains a subject of ongoing debate among scientists.
Neanderthals, who coexisted with and even bred with us for thousands of years following human arrival in Eurasia, becoming functionally extinct only about 40,000 years ago.
Multiple scientific proposals now aim to recognize the global environmental consequences of human-driven megafauna extinctions and enhanced fire regimes, especially across the Americas, as the basis for an Anthropocene start date near the end of the Pleistocene, approximately 14,000 years ago.
According to Smith and Zeder, it is the ‘domestication process … that provides the archaeological signature for major human manipulation of terrestrial ecosystems, and the onset of the Anthropocene’.
Some developed at the Pleistocene–Holocene transition, as in Southwest Asia, South America, and North China,
The widespread presence of anthropogenic soils has been suggested as a golden spike for the Anthropocene, circa 2,000 years ago, though the prospects for a successful GSSP proposal based on anthropogenic soils are not strong, owing to their diachronous origins.
Agricultural transformation of Earth began more than 10,000 years ago and continues to convert natural habitats to agricultural landscapes engineered and managed to support populations of domesticated species (Figure 28).
Ruddiman claimed that by clearing forests for agriculture and irrigating rice paddies, ancient farmers produced emissions of carbon dioxide and methane sufficient to significantly alter greenhouse gas concentrations in Earth’s atmosphere (Figure 29).
If emissions are estimated based on a constant amount of land used per person, early land clearing and carbon emissions are much too small to support Ruddiman.
The colonization of new lands by a complex agricultural society profoundly transformed landscapes and ecosystems by fire, land clearing, the cultivation of domesticates, and the introduction of rats and other new species of animals and plants which both consumed and outcompeted large numbers of native species.
The introduction of smallpox and other Old World diseases is estimated to have killed 50 million native Americans between 1492 and 1650 in epidemics of European diseases to which they had never before been exposed.
In 2015, an ecologist and a geographer, Simon Lewis and Mark Maslin, in a Nature review of Anthropocene GSSP proposals, also introduced their own: ‘the Orbis spike’
Columbian Exchange,
In other words, the archaeosphere might be considered a dividing line between the stratigraphic expertise of geologists and archaeologists.
In Edgeworth’s view, and that of archaeologists in general, diachroneity defines not only the archaeosphere, but also the Anthropocene itself.
There is a general system of archaeological ‘ages’, the first of which begins with the first stone tools in the Palaeolithic, or ‘old’ stone age, which ends with the Pleistocene. The Holocene begins with Epi-Palaeolithic societies, which largely continued Palaeolithic lifeways, and Neolithic societies, which adopted agriculture. Bronze and Iron Age societies are recognized by the capacity to produce these metals and concomitant shifts in societal scale and complexity.
But for archaeologists, anthropologists, geographers, geologists, and others focused on the long-term causes, rather than the consequences, of anthropogenic global environmental change, the Anthropocene begins long before 1950.
Others, including Ruddiman, have proposed that because of the continuous nature of anthropogenic environmental change, the Anthropocene should not be formalized at all, but used informally, as a lower case ‘anthropocene’. The one thing that unites all of these proposals is their common focus on recognizing the long, rich, and diachronous history of human transformation of Earth’s environments.
From an archaeological point of view, there is nothing recent or unusual about human alteration of Earth’s environments. The human world has always been anthropogenic. Nearly every human society in Earth history has lived in environments transformed by their ancestors.
But conservation’s continuing focus upon preserving islands of Holocene ecosystems in the age of the Anthropocene is both anachronistic and counterproductive.
understanding interactions among organisms and their environments, including the ‘food chains’ that connect carnivores, herbivores, and plants; the spatial patterns of plant and animal populations; and the biogeochemical fluxes among organisms and their abiotic environments.
In 1778, Comte de Buffon was already prepared to claim that ‘the entire face of the Earth bears the imprint of human power’. In 1997, ecologist Peter Vitousek and colleagues published a hugely influential Science paper offering evidence ‘that we live on a human-dominated planet’. And the first person to name the Anthropocene was not Paul Crutzen, but lake ecologist Eugene Stoermer.
Even in many regions where human influences appear to be absent, palaeoecological evidence regularly demonstrates that contemporary ecological patterns and processes were shaped by earlier human societies.
‘The Pristine Myth: The Landscape of the Americas in 1492’.
human disturbance of communities and ecosystems is complex, dynamic, diachronous, and sustained over long periods of time.
Ecologists learned a hard lesson: disturbance plays an important role in ecosystems and communities, and suppressing disturbances can disrupt communities and habitats.
Extinction is not new. Ninety-nine per cent of all species that have ever lived on Earth have gone extinct.
Earth’s sixth mass extinction has not yet arrived. Nevertheless, human societies are accelerating extinction rates well beyond their historical baselines, especially for vertebrates.
If these rates of species loss are not curtailed, Earth’s six mass extinction and a biosphere drastically reduced in biodiversity will come to define the ecology of the Anthropocene.
In the Temperate Zone at least, definitions of native vs invader are challenged by a climate changing so rapidly that staying in one place is a recipe for extinction.
Ecologists are increasingly probing the causes and consequences of anthropogenic ecological change and developing new paradigms that embrace the coupling of human and natural systems. In the 1950s, ecologist Eugene Odum highlighted human dependence on ecosystems in the textbook that helped make ecology a household word in the 1960s and 1970s. He also studied ‘old field
succession’, the recovery of vegetation on abandoned farmland. Rachel Carson brought an ecologist’s understanding of the widespread consequences of industrial chemicals to the public with Silent Spring in 1962. Ecosystem research in the Hubbard Brook watershed led to the discovery of acid rain in the 1970s. And in 1986, Peter Vitousek went global with his estimate that humans were ‘appropriating’ nearly 40 per cent of Earth’s terrestrial photosynthesis by harvesting forests and using land for agriculture. Before Crutzen’s Anthropocene, Vitousek made the case for an Earth reshaped by humanity
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In the 1990s, Carl Folke developed a popular framework for ‘social-ecological systems’, accelerating collaborations among ecologists and social scientists to solve real world problems involving environmental management and social change (Figure 37).
Ecologists, economists, geographers, and others are now developing approaches to observing, understanding, and modelling a global ecology actively shaped by human societies, including changes in human use of land—the largest driver of biodiversity change and anthropogenic carbon emissions to the atmosphere until 1950.
