A new study by University College London (UCL) has pegged year 1610 as the beginning of human domination also known as the geological epoch Anthropocene on planet Earth.
Unlike the beginning and ending of previous epochs which were due to factors such as meteorite strikes, sustained volcanic eruptions and the shifting of the continents, the Anthropocene began due to the impacts of human activities on planet Earth.
As a part of their study the authors systematically compared the major environmental impacts of human activity over the past 50,000 years against these two formal requirements – long-lasting changes to the Earth and that date of global environmental change that has been captured in natural material, such as rocks, ancient ice or sediment from the ocean floor.
Scientists revealed that only two dates met the two criteria i.e. 1610, when the collision of the New and Old Worlds a century earlier was first felt globally; and 1964, associated with the fallout from nuclear weapons tests. The researchers conclude that 1610 is the stronger candidate.
Some of the reasons cited were the arrival of Europeans in the Americas in 1492 and the subsequent global trade, movement of species to new continents and oceans. This movement resulted in global re-ordering of life on Earth and this rapid, repeated, cross-ocean exchange of species is without precedent in Earth’s history.
Further, the scientists also revealed that the pronounced dip in atmospheric carbon dioxide centred on 1610 and this drop was a direct result of the arrival of Europeans in the Americas. Scientists say that there was an abrupt near-cessation of farming across the continent and the subsequent re-growth of Latin American forests and other vegetation removed enough carbon dioxide from the atmosphere to produce a drop in CO2 – a fulfillment of the second criteria.
Further, colonisation of the New World led to the deaths of about 50 million indigenous people, most within a few decades of the 16th century due to smallpox.
Lead author, Dr Simon Lewis (UCL Geography and University of Leeds), said that in a hundred thousand years scientists will look at the environmental record and know something remarkable happened in the second half of the second millennium and they will be in no doubt that these global changes to Earth were caused by their own species and the Anthropocene probably began when species jumped continents, starting when the Old World met the New.
The beginning of the Industrial Revolution, in the late 18th century, has most commonly been suggested as the start of the Anthropocene. This linked a clear turning point in human history, and the rise of atmospheric carbon dioxide from fossil fuel use is a long-term global environmental change of critical importance.
However, the researchers did not find a golden spike at that time because most effects were local, while the global exponential rise in carbon dioxide was too smooth an increase to form a precisely dated marker.
The study is published in the journal Nature.
