The Snovian disjuncture and State of the Planet Remarks at the State of the Planet Conference, Columbia University, 1999

John C. Mutter

    When the organizers of the State of the Planet conference first put together an agenda I think its fair to say that it wasn't universally well received. Our idea was to gather together some of the world's leading natural scientists together with scholars and opinion leaders from many intellectual domains, some very distant from the Earth Sciences, and have each provide a unique perspective on the condition of this planet that sustains our existence. The issue of concern was, of course, the one that C. P. Snow identified in his famous Rede Lecture of 1959, "The two cultures and the Scientific Revolution". What we were told was that we were mixing oil and water; that putting together thinkers from the physical sciences with those from social sciences, humanities and the liberal arts and expect anything worthwhile to come of it was a dream. No doubt Baron Snow of Leicester would have thought it would never work either. But now, fifty years after the birth of the Lamont-Doherty Earth Observatory and forty years after the Snovian disjuncture was illuminated, and on the eve of the new millennium we very much felt that the need for the gulf between these two intellectual domains to be bridged had become urgent.

    The need arises because the future of society as we know it today on our planet may depend on it. I appreciate that may sound overly dramatic, but consider the following: In the closing moments of the 20th century we have heard Wally Broecker suggest that the present day climate in which our society emerged is unusually warm and stable. For most of the last several hundred thousand years the Earth's climate was cold and highly unstable. The temperature record from the Greenland ice cores is a stunning icon of our time that proclaims that we are living in a climatic aberration. As active agents in this environment we are well capable of unintentionally destabilizing the life-sustaining ether around us. The very fact that there is debate between Jim Hansen and Dick Lindsen about whether human activity has caused global warming implicitly acknowledges that human activity can modify the climate; in the most alarming scenarios we might even send the planet back into a very hostile, very cold state. Apart from inconvenience, a rapid change to a cold state would bring huge global disruption as crop-producing areas would dramatically shift. A resource rich country could well become resource poor in a couple of decades. It took only three successive drought years (together with some extremely bad farming practices) to create the Oklahoma Dust Bowl which led to the largest internal population re-distribution in U.S. in the twentieth century. The ability of society to re-adjust to a new rapidly developed cold climatic phase is unknown and the potential for deadly conflict arising over greatly diminished resources is very plausible.

    If humankind's activities are putting our planet at risk, and many scholars from a wide range of disciplines believe we are doing just that, we know that we can be sure of two things. One is that the natural science must provide the key role of understanding the physical processes that cause the risk and estimating the magnitude. The second is that we have come to realize that scientists cannot simply sound a warning and expect Congress or society at large to listen and take action merely because of what they have said. The authority of scientists statements is not absolute. Mitigating the risks associated with human interaction with Earth processes will require changes in human behavior. Effecting such changes is well outside the realm of the natural sciences, requiring intellectual domains that deal with the human condition.

    It's not difficult to conjure up any number of similar scenarios in other areas. We have build great centers of commerce and culture in geologically active settings where cities can be lain flat by earthquakes that our science still cannot predict. The recent tragedy in Turkey is a timely example. Human activity doesn't normally cause earthquakes (the filling of large dams is an important exception), but we are responsible for the associated tragedy because we populate areas subject to earthquakes. Even if we had reasonable prediction skill, how would society react to an announced date (with statistical uncertainty) on which an earthquake was to happen? Would that rid the world of unscrupulous builders and government officials who erect dwellings built to kill in earthquake-prone areas? Similar remarks could be made about volcanoes. Generally we know approximately when a volcano is about to erupt, but not how large the eruption will be. Mt. Rainier, just outside Seattle, is a volcano that is in many ways very similar to Mt. Saint Helens. While the damage from the Saint Helens' eruption was immense the loss of life was low because the surrounding areas were relatively unpopulated. Not so for Mt. Rainier where the growth of Seattle has put many people at risk from a modest eruption. So how would a warning be handled? How would a large population be moved perhaps a month before an eruption of unknown size was to occur? In general, is it possible to somehow discourage people from living in harm's way in the first place? These are not questions for seismologists or volcanologists. They are questions that can only be answered by those who deal with human behavior along with scientists who understand the risks.

    On the other hand we can predict the phase of the ENSO to what we say is a useful skill level. This is a huge scientific achievement, one of the singular contributions to climate science of this century But what does useful skill mean? A 90% consistency in forecasting accuracy may seem useful in probabilistic terms, but it is not really useful until we learn how to take advantage of that skill to mitigate the economically harmful effects of extreme events? We are just learning how to do this now at the International Research Institute for climate prediction located on Lamont's campus where climate scientists work together with social scientists to advance forecasting capability and develop tools that allow those forecasts to be effectively used in countries that suffer economic disruption and human suffering when unprepared for the extremes brought on by the events. We know that every inch of our planet's surface biosphere has been touched by human activity. Even those parts that may appear to be natural are that way because we allow them to be. Ecosystem fragmentation and bio-diversity loss in a world where population climbs exponentially could harbor serious consequences for life on our planet. And if that's true, and ecologists tell us it is, then reversing the loss and rejoining the fragments (if that's even realistic) requires the management of human activity; not one of the disciplines of the natural sciences. Finally, the future will surely see clean water become scarce. Hydrologists can tell us just how clean and just how scarce, but managing a planet with scarce clean water is a challenge for policy makers globally.

    As Joel Cohen has observed, at the end of this century all of the things we used to be able to assume about drinkable water and breathable air and the many other natural assets that sustain life on the planet, can no longer be assumed. Securing the health of society in a world where the usual assumptions have failed, where humankind is too often desperately unhappy and near death, is an issue of monumental complexity but prodigious importance and grave urgency.

    In the last half of the century humankind has made a critical passage from tenants on the Earth, occupying space that nature provided, to both tenant and landlord. We are now part of the Earth system in every conceivable way. Our effect on the planet has become "geological" in scope and magnitude. We have become "geology". The ramifications of this transition from disengaged observer and experimenter, to one who is part of the experiment is a culture shock that echoes around the academe.

    All of this suggests to me that Baron Snow's chasm will need to be crossed because the need to cross it has become urgent. Until now there has been no real need to cross the divide - now there is. The natural sciences must strive to learn all there is to know about the way the Earth functions, from its inner core to its outer atmosphere, in all it wondrous complexity. Everything counts, everything matters. But to understand predict and manage those components of the Earth systems that sustain life, that humans modify through their activity, and that present risks to our society, the natural science must develop a true union with the social sciences and humanities. We recognize that the two epistemic cultures are utterly different; their methods and styles of knowledge construction and the metrics by which knowledge is valued exist in completely different spaces. But I believe those spaces must be merged because the solutions we require do not lie exclusively in one or the other. The poet's voice will need to be heard along with scientists' quantified caution.

    I would like to close with a single simple thought: Although our planet may seem vast and robust, and surely it is under the actions of any single individual. But when subjected to the actions of 6, 8 or 10 billion people it is a fragile place. We need to understand it completely in its entirety through the natural sciences, and at the Lamont-Doherty Earth Observatory we have just completed 50 years of achievement doing just that and plan to continue in that mode in the new millennium. And we also need to learn how to treat the planet well through science coupled to social process. We have spent 50 years attempting to understand the natural world; the "acts of God". Now we will tackle the more challenging task of understanding the actions of humans. This represents a new challenge for the Observatory, but one that we must accept, for if the planet were to break in our hands I don't think we'd know how to fix it.

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