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Peter Ward interviewed in on The Medea Hypothesis

Tuesday, December 20, 2022 - 15:00

Biology Professor Peter Ward was interviewed in a article on The Medea Hypothesis.

In the late 2000s, Peter Douglas Ward, a paleontologist and professor at the University of Washington in the geology, biology and astronomy departments, coined the term "Medea hypothesis" to describe the ways that complex life eventually generate the circumstances to drive their own extinction. The term was meant to evoke the Gaia hypothesis, the Medea hypothesis being somewhat of an opposite. 

We see Medea's handiwork all around us in the fossil record. The Great Oxidation Event, some 2.45 billion years ago, is a prime example. Back then, the planet was all but devoid of oxygen, and microbial life metabolized just fine without it. But then cyanobacteria hopped on the scene, which evolved photosynthesis. That ended up spitting out tons of oxygen over millions of years, which was toxic to most life on earth, causing widespread death that shows up in the fossil record.

We also see Medea in the present, as the Earth undergoes its Sixth Mass Extinction, this one caused in large part by human activity. It's why we see billions of Alaskan snow crabs suddenly disappearing or thousands of other examples of ecosystem collapse. It's why climate change is so threatening to our continued way of life and why humanity may even join the dinosaurs in the dustbin of natural history.

"This name thus seems appropriate for an interpretation of Earth life, which collectively has shown itself through many past episodes in deep time to the recent past, as well as in current behavior, to be inherently selfish and ultimately biocidal," Ward wrote in his 2009 book, "The Medea Hypothesis." "A result of this bad mothering, I propose, will be a shortening of the time that life will exist on our planet. Life will do this to itself by unconsciously changing environmental conditions to a point where there can no longer be plant life or, ultimately, any kind of life."

The Medea Hypothesis might be epitomized by the story of photosynthetic life on Earth. As Ward explained in our interview, plant life on Earth has a repeated tendency to evolve in a way that it removes carbon dioxide from the atmosphere. Reducing the amount of carbon dioxide in the atmosphere then freezes the entire planet, killing the majority of life that depends on Earth being, well, not frozen. This has happened many times in the fossil record.

Salon spoke with Ward about the basis for this theory and what it means for life on Earth — but also the implications for finding life on other planets, including Mars.

This interview has been condensed and lightly edited for clarity.

What got you interested in extinction events?

Peter Ward: What really struck me and why I started thinking about Medea, is I really disliked the Gaia hypothesis. Gaia is not even a theory to me, it's just New Age nonsense. So much good came out of it. Lovelock was no fool. But this idea has been bastardized to the point of thinking that life knows that we humans are putzes and will clean up our mess.

One of the really driving definitions of life is that, given a chance, any species will do anything it can to have all the resources. There's no altruism in nature. Take everything you can, reproduce to the point that you control everything. This is what humans have done. Other species have tried it in the past, they've just never had the ability technologically. But where does that drive come from? I think it's so innate within the structure of DNA and how cells are constructed, this dominance principle. Altruism is nonsense.

Read the full interview on

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