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Paleontologist Peter Ward’s “Medea hypothesis”: Life is out to get you

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The Medea Hypothesis, Peter D. WardWhat if the only thing life has to fear is life itself?

At a lecture Monday evening at the American Museum of Natural History in New York City, paleontologist Peter D. Ward laid out the argument that life as we know it serves to make Earth less habitable—a downward spiral that might spell the eventual end of life on the planet. Ward, a professor at the University of Washington, calls this the Medea hypothesis, named for the murderous mother of Greek mythology. It is a direct challenge to scientist and futurist James Lovelock’s Gaia hypothesis, which asserts that life constantly tweaks the dials on Earth’s control systems to keep the planet in a nice, habitable homeostasis.

Ward has a recent book on the subject, The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive? (Princeton University Press, 2009). To illustrate the difference between his theory and Lovelock’s, the traveling Ward, in town to make the media rounds for his book, used a hotel analogy for Earth. Gaians, Ward says, think that hotel guests are likely to repaint their rooms and leave fresh flowers before checking out, whereas Medeans think that guests are liable to throw furniture out the window, trashing the room like Keith Moon in his prime.

At the lecture, moderator Neil deGrasse Tyson, an astronomer and the director of the museum’s Hayden Planetarium, struggled to define the work of the polymath Ward, finally settling on "paleobiogeoastronomer."

And indeed, Ward’s dour claim rests on analyses of carbon isotopes, paleofossils, asteroid impact rates and geologic formations. Most of the mass extinctions in history, Ward says, were caused by microorganisms, not by asteroid or comet impacts. Here is how: When Earth warms to the point that it no longer has cold poles and warm tropics, as the result of geologically released greenhouse gases, the oceans stop mixing. Without mixing, only the uppermost layer of the ocean remains oxygenated, and anaerobic bacteria that produce poisonous hydrogen sulfide gas thrive. Before long, the level of hydrogen sulfide in the atmosphere becomes lethal, simultaneously poisoning living creatures and shredding the ozone layer. "This is life killing itself off," Ward says.

As with today’s climate crisis, carbon dioxide is the culprit in the ultimately catastrophic warming. Of course, the ultimate source of Earth’s massive die-offs wasn’t anthropogenic or even the fault of life—Ward points to volcanic floods that churned out enough CO2 to shut down ocean mixing driven by temperature differentials. But thanks to the actions of humankind, the delicate balance that keeps Earth habitable is once again in danger. "All you need is enough [warming] to reduce the temperature difference between the poles and the equator, and the whole system goes down," Ward says.

Thankfully, perhaps, such dire predictions for climate change—not displacement, war or even famine but a nearly wholesale elimination of life of Earth—rest on equally dire forecasts for CO2 levels. Whereas many experts set 350 parts per million as the maximum acceptable level for atmospheric CO2 (today’s atmosphere is at about 390 ppm), Ward says that these warming-driven catastrophes arise at about 1,000 ppm. That’s not to say that things won’t get ugly along the way, with arable land disappearing and rising seas rewriting maps of the world, but there may at least be some air to breathe for another two centuries or so.

As for fixes, Ward did not have any ready answers other than hoping that currently iffy technologies can take off. Practicable nuclear fusion would help a lot, as would advances in bioengineering. "We can convince microbes to do some very interesting things," he says, pointing specifically to their promise in systems to produce food and fuel. Ward is aware that betting on currently untenable technologies as the way out may seem like pie-in-the sky dreaming. "Look, if you don’t have hope, you don’t do anything," he says. "You go out and get a drink."

Cover image: Princeton University Press


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  1. 1. jimofadel 4:01 pm 01/13/2010

    Life is (so far) an unexplainable phenomenon that causes groups of molecules to form complex ordered groups that can and do, reproduce themselves and multiply in numbers. It seems to act against the second law of thermodynamics. It seems likely that a planet can only support so much life. But maybe as more complex life forms go extinct, the total number of living cells on a planet doesn’t drop that much; maybe life just gets re-distributed. Maybe that’s natural.

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  2. 2. kieryn 4:20 pm 01/13/2010

    I think the theory of evolution supports the Gaia hypothesis more than anything else… If an organism comes into existence that changes it’s environment it will need to evolve further to the adapt to the new environment or it will die out. This is an unstable condition and so evolution ultimately favors organisms that do not alter the environment too much, or change it in favorable ways. Even if an organism comes along that destroys it’s enviroment and slashes biodiversity (not pointing any fingers) the worst that could hapeen is an eco-collapse, possibly destroying offending organism and many others, but there is no way it will destroy every lifeform on the planet and so from those that are left, diversity will recover and in the long term stability will resume… at least until the Sun blows up or some other external destructive event occurs. A species may kill itself, but for all of life to die it would take an external event.

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  3. 3. jtdwyer 4:39 pm 01/13/2010

    Going back to some of the earliest life on Earth, simple algae produced oxygen as a waste product, poisoning their own environment but producing a new environment capable of supporting complex life. Could it be that we are simply an intermediate result, not the final product?

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  4. 4. mike cook 11:09 pm 01/13/2010

    The final product of course is meant to be a cyber-intelligence that unfortunately will take many more megawatts of power to reach its full potential than humans can provide unless we go exclusively to unlimited coal, natural gas, and nuclear power plants, plus we must rebuild every hydroelectric dam to be 100 feet taller.

    Even then the emergent cyber-mind may not be satisfied with our efforts and may replace us with an upgraded species of ant capable of supporting the silicon superintelligence more adequately.

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  5. 5. rlb2 11:32 pm 01/13/2010

    Her is Ron’s theory:

    Find yourself a secluded cave and move into it.

    Human activity will cause a runaway global warming followed by a runaway global cooling.

    Methane retains 28 times more heat than CO2 and the biggest contributors are oil fields, coal mines, cows and rice fields. It’s kind of ominous when you look at it, cows emit a huge amount of methane into the air every day. Now go back millions of years dinosaur activity may have done the same thing, their extinction may have been caused by their over supplying the atmosphere with methane from their foraging on plant matter causing a runaway global warming causing a super volcano to go off followed by thousands of years of an ice age……

    This is how I got there.

    Increase global temperature will bring the magma closer to the surface in areas like Yellowstone, super volcano. Yellowstone right now is registering the most earthquakes in its recorded history, in some cases an increase in earth quakes like this is a precursor to an imminent eruption. If a super volcano goes off like Yellowstone’s, then the change in global weather would be devastatingly cold for thousands of years — a new ice age is born…

    This will be mother nature’s way of controlling global warming, she did it in the past she will do it again. It’s the perfect way to carbon capture CO2 gas and remove it from the atmosphere and get rid of the methane problem by killing it off at the source. Because methane is a light gas the remaining methane would leak out of the atmosphere into space in about a thousand of years. The extreme cold from the ice age will tame super volcanoes by freezing the surface driving the magma back deep into the subsurface….

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  6. 6. mo98 7:10 am 01/14/2010

    Genetic modification, optimizing microorganisms, was it Stalin that studied ants to develop a theory of communism?
    How swarm intelligence helps us think outside the box? In this case, the box is the spherical object under our feet and calculating the cost of finding more food and land elsewhere in space has just begun. In the meantime, the swarm may really benefit from existing in a hibernation mode, conserving and repairing damaged resources for its full-blown survival, health and functionality, while going into a quality dream state of an earthborn equivalent of a brain alpha state. Computing devices are just amplifiers of our own intelligence, and related networks are the result of our belonging to it. We all are addicted to something, but new children might be more apt to master our fate long after we are gone without being cursed by them that all us ancestors did was to engage in bar talk. Let’s keep thinking.

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  7. 7. danbloom 8:27 am 01/14/2010

    This was a very good post re the differences between Lovelock and Ward. As "James Lovelock’s Accidental Student" I wonder if you could one day look into the idea of polar cities to house survivors of global warming in the distant future. Much has already been said about these climate refuges but the mainstream media and the PhD industry refuse to discuss them. Why? Google the phrase and see.

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  8. 8. batura 9:47 am 01/14/2010

    I find these hypotheses very entertaining but far short of what’s really going to happen. Mankind reached the zenith of his existence back in the 90′s. This coincides with economic growth of all nations and the availability of oil.

    Oil is the center of our civilization’s well being. As the availability of oil decreases so to will the numbers of man decrease. Oil is the only reason why we have the ability to create, support so many human beings on this planet.

    Once the oil is gone, and by gone I mean only available in sparse amounts, we will first see starvation, panic followed by mass extinctions in places like Europe, Northern Asia, Canada followed by the same in southern hemisphere. Man will not be fully removed from the planet but he will not be able to multiply like he was from 1870 to 2020.

    The truth is we have seen this cycle occur before in history: Greenland, Easter Island, Incas & Mayans to name a few. So these theories are interesting to hear, but do not reflect what will happen to this world.

    P.S. Keep your eye on the price of oil and gold.

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  9. 9. parcellular 3:07 pm 01/14/2010

    Is it a surprise to anyone that life propagates by "killing itself off"? Is not self-destruction built into the biology of all lifeforms? In a finite habitat, individual death – of cells or animals – is essential to the development of persons, cultures and races, and the deaths of species are essential to the evolution of the biosphere as a whole. If the terrestrial biosphere is programmed to be self-destructive perhaps this tells us that the proper arena of evolution is a much larger habitat than one little planet. In a cosmic perspective the deaths of individual biospheres may have no more significance than does my own in the context of human life. Extinction may be nature’s way of telling us to go forth out of this little gravity well and multiply. Gaia may be just one iteration or avatar of Cosmo-gaia! ;-)

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  10. 10. mike cook 8:21 pm 01/14/2010

    Build your survival city on dry land in Antarctica, right next to one of the many seams of coal and adjacent to a lake that is frozen over so that you don’t have to melt water.

    But doesn’t expect shirt-sleave weather there anytime soon. If anything, it’s getting colder around the South Pole. Studies which purport to show recent warming did it by jiggering data fields in which very few measurements were actually taken back in the decades BEFORE the 1980′s. If you make things a lot colder back in the 1950′s, you ipso facto make today’s temps look to be warming.

    Nice trick if you can do it, which you can, because today’s peer reviewers are all in on the self-lubricating hysterical bandwagon.

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  11. 11. ramesam 9:22 pm 01/14/2010

    We know "Life" exists by devouring "Life."
    That is to say that the "Life" in one living creature can continue by the destruction of another living creature. In this process, the living organism may be gone, but "Life" itself never disappears!

    So far so good. But what exactly is "Life"? There are no clear answers except definitions in terms of ‘effects’ of life.

    The second point is with regard to the Second Law of Thermodynamics. As per this law, Life cannot come into existence because in a system with increasing disorder since the Big Bang, how can highly ordered local intermediate form as a living creature come into existence? An Harvard astrophysicist suggested that the birth of organism(s) here is compensated by the explosion of a supernovae somewhere in the heavens, thus conserving the system as a whole. How can we establish this as a fact?

    In view of these imponderables, is it not still too early to talk about "the purpose or scheme of things in the Universe" in terms of Medea or Gaia, as if we have already the knowledge of all the factors involved?

    And what if the Universe is neither evolution nor creation but a mere "illusion" as some of the ancient Indian Sages held?

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  12. 12. mike cook 11:38 pm 01/14/2010

    By the way, the strong Gaia interpretation holds that inanimate matter is as much under compulsion to cooperate with life as life is under compulsion to arise and evolve through stages to some end known only to the mind of Gaia.

    In this sense Gaia may be compatible with the view of Einstein’s general relativity that spacetime is a totally predetermined, frozen tableau. This is to say that past, present, and future are all fixed. Strong spacetime of the frozen tableau variety disposes of the messiness of QM, because there never was an event that had two possible outcomes necessitating some sort of choice.

    The whole concepts of randomness, probability, and chance are mere artifacts of human consciousness. Invariably we observers look at similar events which seem to have had a variety of outcomes and we make up stories and actuarial tables which are, in their own way, capable of very accurate predictions about a distribution of results but which do not after all prove that it is not the destiny of my wayward nephew to smoke three packs of cigarettes ever day of his life yet still die in bed at the age of 102 while tightly lying in bed between two 25-yr-old ladies who have assisted him in consuming a gallon of tequila.

    In other words, every die in a dice game is loaded, every nag in a horserace can not escape running a particular speed on the given day, and the fault for the course of our lives is in the stars and not ourselves, to the contrary of Shakespeare’s assertion.

    The question begged by strong spacetime is that if all of existence is a dense and complicated Turing Tape with trillions of stories etched along every micron of its length, then who or what created this endless scroll?

    Perhaps it is Gaia again. The stories are what they are because Gaia is what she is, a whimsical storyboard where the imaginations and fancies of demi-urges for a time create fantastic microbial bugs and insects to battle across the counterpane, at times huge varieties of dinosaurs, or whales vs squid, or Neanderthals versus fellow bipeds, or men vs. women, or the sober versus the giddy, at which cue I bid thee all fair good night til the morrow.

    Should it be my lot to be entombed by earth trembles in a particular room, may it be my winecellar. And may all of you attain such a good end yourselves.

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  13. 13. DAVEINCAPS 12:42 am 01/15/2010

    Life can be thought of as the current stage of geologic evolution. Gravity pulls gases together to form the accretion disk that becomes our solar system. In its early days the planet is bombarded with leftovers of this creation. The planet finally cools down and eventually life appears. If all life here is doomed to extinction then the next phase of this evolution, the artificial intelligences we create, will be left to ponder their intelligent design.

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  14. 14. DAVEINCAPS 12:50 am 01/15/2010

    Life can be thought of as the current stage of geologic evolution. If all life here is doomed to extinction then the next phase of this evolution, the artificial intelligences we create, will be left to ponder their intelligent design.

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  15. 15. DAVEINCAPS 12:54 am 01/15/2010


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  16. 16. royniles 4:15 pm 01/19/2010

    The human brain that takes control of its destiny with a mistaken view of its purpose may well kill off the "humanly" structured super-organisms, but biological systems that have engineered themselves in ways that have now covered the planet are effectively smarter than some of their larger structures that have tried to take over that engineering function. Better engineered structures such as bacteria, insects and the like will still prevail

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  17. 17. Monkeerench 5:09 pm 01/19/2010

    Where’s the contradiction? If Gaia abhors pestilences (including humans) She sluffs them away — then life goes on, whether daisies or anerobic bacteria.

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  18. 18. motie 7:36 am 01/20/2010

    Batura, I agree. Fossil fuels have enabled a 500% increase in human population since 1900, along with a meteoric rise in per capita consumption. Products essential to our survival, such as fertilizers and pesticides, come from fossil fuels. Assuming that fossil fuels are finite, our present population and consumption must collapse. Haiti is a window into the future of humanity. If only we would control our numbers. Too obvious, I guess.

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  19. 19. motie 7:37 am 01/20/2010

    Batura, I agree. Fossil fuels have enabled a 500% increase in human population since 1900, along with a meteoric rise in per capita consumption. Products essential to our survival, such as fertilizers and pesticides, come from fossil fuels. Assuming that fossil fuels are finite, our present population and consumption must collapse. Haiti is a window into the future of humanity. If only we would control our numbers. Too obvious, I guess.

    Link to this
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