What is it about the Earth that has allowed life to continue for such long periods of time? The most important factor is plate tectonics.
When we thought up the Rare Earth Hypothesis, it was simply taking a look at what happened on this planet that allowed us to have multi-cellularity. Part of it was that we had conditions allowing habitability for billions of years. It took a long time to get to something as simple as a two-celled creature. A long time.
If you really look at the history of life on this planet, you see a lot of biologically-produced catastrophes. Where do they come from? From life itself.
I think all life is suicidal. I thought up something tongue-in-cheek I call the Medea Hypothesis. Medea, Jason’s wife, was probably the worst mother in Greek History. She murdered her children because of Jason’s infidelities. Jason was probably not very good at anything, apparently, except making women fall in love with him. He was good at that.
Peter Ward: Not going extinct doesn’t mean you’re not going to be miserable, and by misery I mean, wholesale, enormous human mortality.
I think we’re going to survive. I don’t think climate change can make us go extinct, unless we produce so much Co2 in the atmosphere that we shut down the conveyor belt currents. These are the largest scale currents in the ocean. They are from the surface to the bottom currents, not just sideways currents. The current conveyor that takes oxygen from the top and takes it to the bottom - if we lose that, then the bottoms of the ocean go anoxic and you start down this road toward what we call a greenhouse extinction, which is the hydrogen sulfide events. It would take tens of thousands of years to get to that.
We now think the big mass extinctions were caused by hydrogen sulfide bacteria. Two hundred hydrogen sulfide molecules among a million air molecules is enough to kill a human.
Most of the big mass extinctions have been caused by nasty volcanic events. The last one didn’t cause a mass extinction. It was in the Tertiary Period. This was in my own home state, Washington State, the Columbia River Basalts.
Peter Ward has been active in Paleontology, Biology, and more recently, Astrobiology for more than 40 years. Since his Ph.D. in 1976, Ward has published more than 140 scientific papers dealing with paleontological, zoological, and astronomical topics.
He is an acknowledged world expert on mass extinctions and the role of extraterrestrial impacts on Earth. Ward was the Principal Investigator of the University of Washington node of the NASA Astrobiology Institute from 2001-2006, and in that capacity led a team of over 40 scientists and students. His career was profiled by the Pulitzer Prize winning reporter William Dietrich in The Seattle Times article "Prophet, Populist, Poet of Science."
Peter has written a memoir of his research on the Nautilus for Nautilus magazine's "Ingenious" feature entitled "Nautilus and me. My wonderful, dangerous life with the amazing Nautilus."
His books include the best-selling "Rare Earth: Why Complex Life Is Uncommon in the Universe" (co-author Donald Brownlee, 2000), "Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future" (2007), and "The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive?" (2009).