Jan Zalasiewicz and Mark Williams from the University of Leicester Department of Geology; Will Steffen, director of the Australian National University’s Climate Change Institute and (right) Paul Crutzen, 1995 Nobel Prize-winning atmospheric chemist of Mainz University provide evidence for the scale of global change in their commentary in the American Chemical Society’s’ bi-weekly journal Environmental Science & Technology (print edition April 1st).
 
The scientists propose that, in just two centuries, humans have wrought such vast and unprecedented changes to our world that we actually might be ushering in a new geological time interval, and alter the planet for millions of years. 
 
Zalasiewicz, Williams, Steffen and Crutzen contend that recent human activity, including stunning population growth, sprawling megacities and increased use of fossil fuels, have changed the planet to such an extent that we are entering what they call the Anthropocene (New Man) Epoch.

 The epoch scenario, courtesy TimesOnLine
Proposed by Crutzen more than a decade ago, the term Anthropocene has provoked controversy. However, as more potential consequences of human activity - global climate change, sharp increases in plant and animal extinctions - emerge, Crutzen’s term has gained support. Currently, the worldwide geological community is formally considering whether the Anthropocene should join the Jurassic, Cambrian and other more familiar units on the Geological Time Scale.
 
The scientists note that getting that formal designation will likely be contentious. But they conclude, “However these debates unfold, the Anthropocene represents a new phase in the history of both humankind and of the Earth, when natural forces and human forces became intertwined, so that the fate of one determines the fate of the other.

"Geologically, this is a remarkable episode in the history of this planet.”

And the joke could be on us.