from the February 07, 2008 edition -

Has Earth entered a new epoch? What geologists think.

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 
scientific status.

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 
10,000 years.

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 
environmental management.

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 

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.