Washington: A new study has indicated that the human-dominated geological epoch known as the Anthropocene probably began around the year 1610.
The study conducted by University College London (UCL) showed that previous epochs began and ended due to factors including meteorite strikes, sustained volcanic eruptions and the shifting of the continents.
The study authors systematically compared the major environmental impacts of human activity over the past 50,000 years against these two formal requirements. Just two dates met the 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.
The scientists said that the 1492 arrival of Europeans in the Americas, and subsequent global trade, moved species to new continents and oceans, resulting in a global re-ordering of life on Earth and this rapid, repeated, cross-ocean exchange of species is without precedent in Earth's history.
The researchers also found a golden spike that can be dated to the same time i.e. a pronounced dip in atmospheric carbon dioxide centred on 1610 and captured in Antarctic ice-core records and the drop occurred as a direct result of the arrival of Europeans in the Americas. 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.