Lucas Stephens, Erle Ellis, Dorian fuller, The Deep Anthropocene, Aeon.
ArchaeoGLOBE reveals that human societies transformed most of Earth’s biosphere much earlier and more profoundly than we thought – an insight that has serious implications for how we understand humanity’s relationship to nature and the planet as a whole.
Just as recent archaeological research has challenged old definitions of agriculture and blurred the lines between farmers and hunter-gatherers, it’s also leading us to rethink what nature means and where it is. The deep roots of how humanity transformed the globe pose a challenge to the emerging Anthropocene paradigm, in which human-caused environmental change is typically seen as a 20th-century or industrial-era phenomenon. Instead, it’s clearer than ever before that most places we think of as ‘pristine’ or ‘untouched’ have long relied on human societies to fill crucial ecological roles. As a consequence, trying to disentangle ‘natural’ ecosystems from those that people have managed for millennia is becoming less and less realistic, let alone desirable.
Somewhat later, after discussions of various kinds of evidence and techniques:
These transitions were not linear or absolute. It’s now clear that there was usually a long continuum of exploitation, translocation and management of plants, animals, landforms and ecosystems well before (and often after) domestication occurred. This makes it harder to draw solid lines between hunter-gatherer and farmer societies, or between societies who practised different subsistence strategies. Over archaeological timescales spanning hundreds to thousands of years, land use can be thought of instead as a tapestry of ever-evolving anthroecosystems with higher or lower degrees of transformation – more or less human-shaped, or ‘domesticated’ environments.
In 2003, the climatologist William Ruddiman introduced the ‘early anthropogenic hypothesis’: the idea that agricultural land use began warming Earth’s climate thousands of years ago. While some aspects of this early global climate change remain unsettled among scientists, there’s strong consensus that land-use change was the greatest driver of global climate change until the 1950s, and remains a major driver of climate change today. As a result, global maps of historical changes in land use, and their effects on vegetation cover, soils and greenhouse gas emissions, are a critical component of all contemporary models for forecasting Earth’s future climate.
Deforestation, tilling the land and other agricultural practices alter regional and global climate because they release greenhouse gases from vegetation and soils, as well as altering the exchange of heat and moisture across Earth. These effects reverse when land is abandoned and vegetation recovers or is restored. Early changes in agricultural land use therefore have major implications in understanding climate changes of the past, present and future.
3,000 to 10,000 years ago...
By 3,000 years ago, Earth’s terrestrial ecology was already largely transformed by hunter-gatherers, farmers and pastoralists – with more than half of regions assessed engaged in significant levels of agriculture or pastoralism. For example, the Kopaic Basin in the Greek region of Boeotia was drained and converted from wetland to agricultural land in the 13th century BCE. This plain – roughly 1,500 hectares (15 sq km) in size – surrounded by steep limestone hills, had been a large, shallow lake since the end of the last Ice Age. Late Bronze Age residents of the area, members of what we call the Mycenaean culture, constructed a hydraulic infrastructural system on a massive scale to drain the wetland and claim it for agriculture. They channelised rivers, dug drainage canals, built long dikes and expanded natural sinkholes to direct the water off what would have been nutrient-rich soil. Eventually, when the Mycenaean civilisation collapsed at the end of the Bronze Age, the basin flooded again and returned to its previous wetland state. Legend has it that Heracles filled in the sinkholes as revenge against a local king. The area was not successfully drained again until the 20th century.
These examples highlight a general trend we found that agriculture and pastoralism gradually replaced foraging-hunting-gathering around the world. But the data also show that there were reversals and different subsistence economies, from foraging to farming, operating in parallel in some places. Moreover, agriculture and pastoralism are not the only practices that transform environments. Hunter-gatherer land use was already widespread across the globe (82 per cent of regions) by 10,000 years ago. Through the selective harvest and translocation of favoured species, hunting (sometimes to extinction) and the use of fire to dramatically alter landscapes, most of the terrestrial biosphere was already significantly influenced by human activities, even before the domestication of plants and animals.
The pristine myth is wrong:
In the ‘pristine myth’ paradigm from the natural sciences, as the geographer William Denevan called it, human societies are recent destroyers, or at the very least disturbers, of a mostly pristine natural world. Denevan was reacting against the portrayal of pre-1492 America as an untouched paradise, and he used the substantial evidence of indigenous landscape modification to argue that the human presence was perhaps more visible in 1492 than 1750. Recent popular conceptions of the Anthropocene risk making a similar mistake, drawing a thin bright line at 1950 and describing what comes after as a new, modern form of ecological disaster. Human changes to the environment are cumulative and were substantial at different scales throughout our history. The deep trajectory of land use revealed by ArchaeoGLOBE runs counter to the idea of pinpointing a single catalytic moment that fundamentally changed the relationship between humanity and the Earth system.
The pristine myth also accounts for why places without contemporary intensive land use are often dubbed ‘wilderness’ – such as areas of the Americas depopulated by the great post-Columbian die-off. Such interpretations, perpetuated by scientists, have long supported colonial narratives in which indigenous hunter-gatherer and even agricultural lands are portrayed as unused and ripe for productive use by colonial settlers.
The notion of a pristine Earth also pervaded the thinking of early conservationists in the United States such as John Muir. They were intent on preserving what they saw as the nobility of nature from a mob of lesser natural life, and also those eager to manage wilderness areas to maintain the trophy animals they enjoyed hunting. [...]
Humans have continually altered biodiversity on many scales. We have changed the local mix of species, their ranges, habitats and niches for thousands of years. Long before agriculture, selective human predation of many non-domesticated species shaped their evolutionary course. Even the relatively small hunter-gatherer populations of the late Pleistocene were capable of negatively affecting animal populations – driving many megafauna and island species extinct or to the point of extinction. But there have also been widespread social and ecological adaptations to these changes: human management can even increase biodiversity of landscapes and can sustain these increases for thousands of years. For example, pastoralism might have helped defer climate-driven aridification of the Sahara, maintaining mixed forests and grassland ecosystems in the region for centuries.
This recognition should cause us to rethink what ‘nature’ and ‘wilderness’ really are. If by ‘nature’ we mean something divorced from or untouched by humans, there’s almost nowhere on Earth where such conditions exist, or have existed for thousands of years.
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