Has Earth entered a new epoch?
from the February 07, 2008 edition -
Has Earth entered a new epoch? What geologists
The Anthropocene epoch would mark the period when humans became the
predominant force over the Earth's environment.
By Robert C. Cowen | Columnist
Geologists wonder if they should add a new epoch to the geological
time scale. They call it the Anthropocene - the epoch when, for the
first time in Earth's history, humans have become a predominant
geophysical force. Naming such a new epoch would also recognize that
humans now share responsibility with natural forces for the state of
our planet's ecological environment.
Geologists have been using the term informally for at least half a
decade. Now members of the Stratigraphy Commission of the Geological
Society of London have laid out the case for giving the term official
Presenting that case in the February issue of GSA Today magazine, the
team notes that "since the start of the industrial revolution,
Earth has endured changes sufficient to leave a global stratigraphic
signature." It is different from anything found in the entire
geological record up to that point. That means the team expects future
geologists examining this record will recognize a distinct break with
the Holocene ("recent whole") epoch that covers the past
Atmospheric chemist and Nobel Prize winner Paul Crutzen at Germany's
Max Planck Institute for Chemistry in Mainz says this presents
humanity with an awesome challenge. He has pointed out that what the
London team calls the "novel biotic, sedimentary, and geochemical
change" now being written into the geological record reflects the
emergence of human intelligence and technology as a geophysical force.
On his website, he explains this means that "to develop a
world-wide accepted strategy leading to sustainability of ecosystems
against human stresses will be one of the great future tasks of
mankind." He adds that it will take "intensive research and
wise application of the knowledge" gained to develop sustainable
Soil scientist Daniel Richter at Duke University in Durham, N.C.,
would agree. In an announcement of his work last month, he explained
that human-induced changes to the world's soils are enough in
themselves to justify saying we have entered the "Anthropocene
(or man-made) age." He notes, "With more than half of all
soils on Earth now being cultivated for food crops, grazed, or logged
for wood, how to sustain Earth's soils is becoming a major scientific
and policy issue."
He adds, "If humanity is to succeed in the coming decades, we
must interact much more positively with the great diversity of Earth's
Dr. Richter cites Africa as an example of this challenge. There,
widespread farming without nutrient recycling threatens continent-wide
soil infertility. He adds that, globally, "expanding cities,
industries, mining, and transportation systems all impact soil in ways
that are far more permanent than cultivation." Richter is part of
an international group that has set up the first global long-term soil
research network. This will help develop the knowledge needed for
worldwide soil management.
In making the case for a new epoch, geologists such as the London
team cite many other aspects of human geophysical impact. It will be
up to the International Commission on Stratigraphy to decide whether
or not to establish a new Anthropocene epoch. But it is clear that
Earth has taken an unprecedented geological turn in our time and there
is no turning back.