Early Human Impact

Humans have transformed the landscape of the Canal de Navarrés, País Valenciano, Spain.

Michael Barton

Humans have brought about massive and obvious global changes, from widespread deforestation to an altered climate. This has prompted researchers to label the latest geological age the Anthropocene, reflecting the scale of human influence on the planet. For the first time, the perspective of archeologists, who piece together how humans have used landscapes, has been incorporated into models that estimate the timing and extent of human transformation of landscapes.

An unprecedented international collaboration called the ArchaeoGLOBE Project used scientific crowdsourcing of the collective knowledge of over 250 archaeologists to map humans’ environmental footprint stretching back 10,000 years. Lucas Stephens, now at the Environmental Law and Policy Center in Chicago, and Erle Ellis of the University of Maryland, Baltimore County, spearheaded the effort, which surveyed archaeologists about land use for ten periods from 10,000 BP [“Before Present” (1950)] to 1850 CE. For each time period, the surveyed archeologists ranked the relative predominance of foraging, agriculture (both continuous and non-continuous cultivation), and pastoralism (raising livestock) within their geographical regions of expertise. The synthesized findings resulted in a historical map of global land use in 146 regions across six continents (all but Antarctica).

The consensus that emerged challenges the popular narrative that the Anthropocene is a phenomenon begotten of the Industrial Revolution. Instead, the ArchaeoGLOBE team concluded that humans had substantially altered Earth’s landscapes by 3,000 BP, when agriculture became widespread. Foraging, which encompasses subsistence-based hunting, gathering, and fishing, was prevalent in most places 10,000 years ago, but then lessened, first in Southwest Asia and then elsewhere. This finding aligns with evidence that the bulk of domesticated plants and animals emerged between 8,000 and 4,000 BP. However, in some places foraging coexisted with agriculture for long periods, and raising livestock dominated, particularly in arid regions such as North Africa, until 3,000 BP.

When the ArchaeoGLOBE team compared their findings to a common earth science-based model of global land use, they found that the archaeological consensus pushed up the arrival of intensive agriculture in many areas, sometimes by a thousand years. “Earth’s transformation by land use is generally much earlier than Earth scientists have previously known,” said Ellis. (Science)