January 31, 2008
For the last 10,000 years or so—that is, since the last time the earth was covered in ice—we’ve been in what geologists call the Holocene Epoch. But a group of British geologists writing in GSA Today suggest that because the byproducts of ever-increasing human consumption will leave a lasting mark in the geologic record, a epoch name change is in order. Their suggestion? The Anthropocene Epoch. (The same idea was put forth about five years ago by Nobel Prize-winning chemist Paul Crutzen, whom the authors credit.)
The paper lists specific geological alterations humans have ushered in, including: an increase in erosion through agriculture and dams; an increase in atmospheric carbon, largely from the use of fossil fuels; a host of plant and animal extinctions; and rising sea levels.
The question is when this Anthropocene period should start. In the past, new epochs were marked by a global standard section and point (GSSP), or “golden spike,” in which some quantifiable geologic measure of the era, something that wasn’t present in the previous era, could be measured across the globe. The Anthropocene, for instance, might be defined by its high carbon levels, or by the radioactive isotopes from atomic bombs. But the authors argue that the true start of the Anthropocene was the Industrial Revolution:
In the case of the Anthropocene, however, it is not clear that a GSSP is immediately necessary…It may be that simply selecting a numerical age (say the beginning of 1800) may be an equally effective practical measure. This would allow (for the present and near future) simple and unambiguous correlation of the stratigraphical and historical records and give consistent utility and meaning to this as yet informal (but increasingly used) term.