Geologists from the University of Portsmouth are proposing that humankind has so changed the earth that it has brought about an end to one epoch of earth’s history and marked the start of another. They believe that human dominance has so physically altered the earth that the Holocene epoch has ended and we have entered a new epoch - the Anthropocene.
Dr Andrew Gale of the University of Portsmouth and his colleagues on the Stratigraphy Commission of the Geological Society of London identified the major causes of human impact on the planet and discovered that the last 200 years had caused more impact then previously understood.
They examined phenomena such as changes in the patterns of sediment erosion and deposition, major disturbances to the carbon cycle and global temperature, ocean acidification and wholesale changes to the world’s plants and animals.
“Human activity has become the number one driver of most of the major changes in Earth's topography and climate, said Dr Gale. “You can’t have 6.5 billion people living on a planet the size of ours and exploiting every possible resource without creating huge changes in the physical, chemical and biological environment which will be reflected dramatically in our geological record of the planet.”
The researchers examined the stratigraphic layers in the earth’s geological record which reflect the conditions of the time it was deposited. They painstakingly pieced together years of geologic history to offer a glimpse into earth's past.
The geologists found numerous examples of mankind’s effect on the planet, such as tiny particles of plastic in our sand which they say could easily get into the food chain. By examining the earth’s strata they were even able to identify the start of atomic testing in the 1950s.
Dr Gale said: “The impact in the last 200 years is such that there is increasingly less justification for linking pre- and post-industrialized Earth within the same epoch.”
The research scientists presented their research in the journal GSA Today in which they say that their findings present the scholarly groundwork for consideration by the International Commission on Stratigraphy for formal adoption of the Anthropocene as the youngest epoch of, and most recent addition to, the earth's geological timescale.
The argument has merit, says geologist Richard Alley of Pennsylvania State University in State College. "In land, water, air, ice, and ecosystems, the human impact is clear, large, and growing," he says. "A geologist from the far distant future almost surely would draw a new line, and begin using a new name, where and when our impacts show up."
The scientists analysed a proposal made by Nobel Prize-winning chemist Paul Crutzen in 2002. He suggested the Earth had left the Holocene and started the Anthropocene era because of the global environmental effects of increased human population and economic development.
The researchers argue that the dominance of humans has so physically changed Earth that there is increasingly less justification for linking pre- and post-industrialized Earth within the same epoch - the Holocene.
The scientists said their findings present the scholarly groundwork for consideration by the International Commission on Stratigraphy for formal adoption of the Anthropocene as the youngest epoch of, and most recent addition to, the Earth's geological timescale.
They state: "Sufficient evidence has emerged of stratigraphically significant change (both elapsed and imminent) for recognition of the Anthropocene--currently a vivid yet informal metaphor of global environmental change--as a new geological epoch to be considered for formalization by international discussion."
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