Scientists call for new Epoch
February 4th 2008 04:20
A HEATED scientific row is brewing as British geoscientists lead a push to establish a new chapter in the history of Earth - one based on human activity.
Led by geologist Jan Zalasiewicz, of the University of Leicester, the rabble-rousers argue that changes wrought since the Industrial Revolution 200 years ago are so profound they are now visible in the physical and living fabric of the planet.
As a result, they have called for the creation of a new Epoch in the official geological time scale, one they have named the Anthropocene.
Along with Eons, Eras, Periods and Ages, Epochs are classifications of Earth history based on characteristic changes in the layers, or strata, of rocks.
Writing in the latest issue of GSA Today, a publication of the Geological Society of America, Dr Zalasiewicz and 20 like-minded experts claim there is "sufficient evidence" of human-induced changes to plants, animals, oceans and lands to warrant recognition of the Anthropocene by the official geological time lords, the International Commission on Stratigraphy. Their proposal came at the same time as the American Geophysical Union at the weekend released its updated position on climate change.
As the AGU represents the largest society of Earth and space scientists, the statement lent weight to the case for the Anthropocene. In its position, posted online, the AGU says: "The Earth's climate is now clearly out of balance and is warming. With climate change ... the human footprint on Earth is apparent."
Detailed scientific arguments for designation of the Anthropocene are expected to be thrashed out in August at the 33rd International Geological Congress meeting in Oslo, Norway.
"I'll be there," said Jim Gehling, a geologist with the South Australian Museum in Adelaide.
And he'll be barracking against the new Epoch.
"This is just the vanity of the human species ... it matters to us but is irrelevant to the planet," Dr Gehling said.
"We don't need a geological Epoch to describe a single historical event, however long- or short-lasting it might be."
In contrast, Dr Gehling was part of a group that successfully called for establishment of the Ediacaran Period, that signalled the origin of complex life forms 635 million years ago.
As revealed by The Australian in 2003, the Ediacaran was the first change to the geological time scale in 120 years and was based on Australian rocks.
While Dr Gehling disputed the need for the Anthropocene, geologist Richard Alley of Pensylvania State University told the ScienceNow online site that the case had merit: “In land, water, air, ice and ecosystems the human impact is clear, large and growing.
“A geologist from the far distant future almost surely would drarw a new line, and begin using a new name where and when our impacts show up,” Professor Alley said.
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