Last updated September 13, 2019 at 3:13 pm
A global project has found that humans began to significantly alter the Earth 3,000 years ago. But it pales into insignificance with our recent effects.
Hadrian’s Wall in north England was built close to 2000 years ago. Credit: Lucas Stephens.
Archaeologists have identified with unprecedented precision the turning point when humans began to transform the Earth beyond recognition, tracing it to around 3,000 years ago.
Prior to this study, scientists suggested that humans began altering the Earth in 1950. Others have pinpointed the Industrial Revolution as the beginning of significant human impact.
However, the international ArchaeoGLOBE project found that hunter-gatherer lifestyles declined across the globe between 10,000 and 3,000 years ago. Continuous farming took its place, with the results suggesting 3,000 years ago most of the globe was affected by agriculture or pastoralism.
Humans put their own advancement ahead of long-term wellbeing
Study co-author Tim Denham from the ANU School of Archaeology says the study provided detailed world maps for land uses including forms of agriculture, pastoralism, foraging and urbanism in time-slices from 10,000 years ago to 1850.
“Our work has documented the long-term history of how humans have increasingly put their own advancement ahead of the environment’s long-term well-being; a trend that continues today.”
Denham says agriculture and widespread pastoralism had started to transform and degrade environments on a global scale thousands of years ago, much earlier than had often been portrayed.
“Too much emphasis has been placed on recent historical periods, such as that following the Industrial Revolution, as a marker of the Anthropocene,” he says.
“Although the Industrial Revolution represents a huge step-change in terms of human-caused climate and environmental change, large-scale deforestation and drainage of wetlands had already transformed the Earth quite dramatically thousands of years earlier.”
Renaud Joannes-Boyau from the Southern Cross University was not involved in the study, however agrees that the impact of hunter-gatherer groups was overlooked in the past.
“Until now, it was considered that early hunter-gatherer-foraging-fishing groups had little impact on the ecosystem and that the human communities were an inherent part of the landscape. The underestimated thump of prehistoric human groups some thousands of years ago, before the widespread appearance of cities is extremely troublesome,” he says.
The different areas of human impact over time. Credit: ArchaeoGLOBE Project
Humans became a primary driver of change later
While the research shows an earlier impact on the environment than previously thought, Will Steffen, an Earth scientist from ANU points out that having an impact on the natural environment is different to being a primary driver of global systems.
“These early human impacts pale into insignificance when compared to the magnitude and rate of the human-driven trajectory of the Earth System as a whole – climate, atmosphere, ocean, ice and biosphere – rapidly away from the Holocene, a globally synchronous trajectory that clearly began in the mid-20th century.”
Steffen is a member of the Anthropocene Working Group, who declared the mid-20th century as the beginning of a new geological period. The Anthropocene identifies a period where significant global change is driven by human actions.
The results of the study are published in Science.
