by Adam Frank

Peter Ward, a paleontologist at the University of Washington, is nothing if not provocative. In Rare Earth he and astronomer Donald Brownlee argued that the evolution of complex life was not an easy thing to achieve. So many special circumstances were required, they said, that the odds are high that humans are one of the few intelligent species in the galaxy (if not the entire Universe). It was one of the most thought provoking books I have ever read on the subject of astrobiology and has become a point of very serious debate in those circles.

Now Ward has written a new book with an even more controversial thesis. The man certainly cannot be accused of following the herd. I am just starting The Medea Hypothesis and will cover the book in more detail in a later post but for now I wanted to alert readers who might not know about it.

The Medea Hypothesis makes a radical claim: Life is its own worst enemy. Drawing on a detailed study of the geological record Ward argues that rather than James Lovelocks "Gaia" - the supportive Earth-mother - a better image to carry in thinking about life and the planet is Medea the mother in Greek Myth who killed her own children.

A principle point Ward deploys for his unusual thesis is the simple fact that most of the planet's dramatic and dangerous mass extinctions were caused not by outside events but by life itself changing (polluting?) the environment on which it depends. In Ward's view life has "biocidal" tendencies, which over time have led to sharp declines in biomass and diversity.

Before you think "No way" I would encourage you to pick up the book. Ward is always thoughtful and insightful. Even if you don't agree with his argument (and I am hoping I don't) he provides new ways of looking at the Earth and the biosphere. The whole point of science is to see beyond our biases and Ward is certainly willing to hit us right were we are most inclined to blind ourselves.