OSLO • The indelible imprint left by human beings on earth has become so clear that it justifies naming a new geological epoch after mankind, experts have said.
The dawn of the "Anthropocene" would signal the end of the Holocene epoch, considered to have begun 11,700 years ago at the end of the Ice Age. The new term, suggested in 2000, is based on the Greek word "anthropos", meaning "man".
"Human activity is leaving a pervasive and persistent signature on earth," said a report in the journal Science by an international team led by Dr Colin Waters of the British Geological Survey. "We are becoming a geological agent in ourselves," he told Reuters.
The start date could be around the mid-20th century, the authors wrote. Adjunct Professor Will Steffen, of the Australian National University and a co-author of the research, said the Anthropocene
epoch was quite unlike previous eras that were defined by natural processes, reported the Sydney Morning Herald.
"There is a whole lot of evidence that says there were human imprints (on earth) at various points, some of it quite significant," Prof Steffen said. "But you really don't see the earth's system as a whole being affected until the second half of the 20th century and beyond."
The paper said the atomic age, starting with a bomb test in New Mexico in the United States on July 16, 1945, and the post-war leap in mining, industry, farming and use of man-made materials, such as concrete or plastics, all left geological traces.
Concrete is now so ubiquitous that it would amount to 1kg for every sq m of the planet's surface if spread out evenly, they said. In addition, roughly 300 million tonnes of plastic are produced annually.
Meanwhile, wildlife is being pushed into an ever smaller area of earth, resulting in rates of extinction far above the long-term average. However, "potentially the most widespread and globally synchronous anthropogenic signal is the fallout from nuclear weapons testing", the paper said, reported The Guardian.
Any formal recommendation to adopt the Anthropocene as a new geological epoch would require years of extra research, partly to pin down a start date, Dr Waters said.
Dr Erle Ellis of the University of Maryland, a co-author of the study released on Thursday, said pinning down the Anthropocene would transform understanding of humanity's role on the planet.
He said it was a "challenge no smaller than a second Copernican revolution". In the 16th century, Nicolaus Copernicus helped show the earth rotates around the sun.