Before the daylong event concluded, the audience was pondering an equally significant question: "Where is life on earth going?"

These two questions bracketed a series of presentations that ranged from the primordial rise of oxygen to the impact of increased carbon dioxide and higher global temperatures to alternative energy sources to how humans could "geoengineer" the earth to mitigate climate change. A consistent thread tied together the various topics: conditions on earth led to life and life has changed the earth itself.  Long before we evolved, the planet's biosphere was in a state of flux; humans have, perhaps, just speeded up the rate of change.

As Penny Chisholm, ESI Director, noted in her opening remarks: "You have to know where you have come from to understand where you might be headed."

 

A fundamental issue in tracing the emergence of life is the increase in oxygen in the atmosphere. Paul Falkowski, Professor of biochemistry and biophysics at Rutgers University, outlined what he humorously called "the story of O," or the still mysterious and complicated chemical process by which photosynthesis creates oxygen. Indeed Falkowski called the splitting of the oxygen atom "one of the more enigmatic electron transfers in biology."  But somewhere between 2.3 billion to 3 billion years ago, the increasingly oxygenated atmosphere and a de-nitrification of the oceans helped drive biological evolution. Life, in effect, created conditions for more life.

Expanding on Falkowski's theme, Dianne K. Newman, the John and Dorothy Wilson professor of biology and geobiology at MIT, described her work with banded iron formations in Australia to determine if they were created by organic processes; such a determination would help create a more accurate timetable of when photosynthesis evolved. "What are the molecules in the rock really telling us?" she said. While "the jury is still out" on the banded iron, the research underscores the "catalytic diversity of the microbial world."

Perhaps we humans are, as Falkowski joked, "just big E. coli with eyes and faces," but our effect on the Earth as been as dramatic as that of the emergence of photosynthesis.  In a sobering presentation, Daniel Pauly, director of the Fisheries Centre at the University of British Colombia, described how the use of trawlers and "fishing down" (the taking of smaller, less mature fish), has depleted fish stocks in northern waters and is threatening stock in the southern hemisphere. "Africa is compensating for the destruction of stock in Europe," he said.

While declines in predatory fish can increase the numbers of opportunistic species such as shrimp, crab and squid, Pauly warned of increases in jellyfish and the creation of "dead zones," or ocean areas that would resist recovery. He contends that subsidies to fishermen only induces overfishing and noted that a third of the world's catch is "wasted," that is, turned into animal feed.

Professor Ronald Prinn, co-director of the Joint Program on the Science and Policy of Global noted in his talk that the effects of global warming are already noticeable, something that he would not have thought  possible 10 years ago. For example, computer models had indicated that the polar regions of the planet would heat up more than the equator, and recent photos of the summer ice at the North Pole shows the pole to have the lowest ice coverage ever recorded.  "You don't have to believe the computer models to see that," he said.

While the most important projections for policymakers are those promulgated by the Intergovernmental Panel on Climate Change, which recently shared Nobel Peace Prize honors with former Vice President Al Gore, there are others.  Prinn described the MIT Integrated Global Systems Model as another way to anticipate the potential impacts of climate change.  The complicated model attempts to account for urban air pollution, sea level, volcanic activity and human economics as well as chaotic systems such as cloud formation and mixing of ocean waters. Moreover, "these uncertainties are constrained by observation," he said.

The impact of global warming will also vary widely. The effect on agriculture, for example, will be strikingly different from north to south and could be both beneficial and detrimental, said Cynthia Rosenzweig, of the NASA Goddard Institute for Space Studies.   Higher levels of carbon dioxide may benefit crops in northern latitudes by lengthening the growing season.  In southern latitudes, a faster growing period decreases yields and increases risks of drought and pest infestation.  "Developing countries are more vulnerable to climate change," she said, adding, "Africa is the most vulnerable." Considering all factors, "effects are negative in the long run," she said.

But Rosenzweig struck a positive note by declaring that "we are in the solution phase" in developing ways to mitigate the effects of global temperature changes, which may include new agricultural practices. Even the politically charged debate over biofuels indicates the solution phase has begun, she said.

The symposium explored even more proactive approaches to climate change.  Roger Angel, director of the Center for Astronomical Adaptive Optics at the University of Arizona, described several geoengineering proposals, such as shading the earth with strategically placed space "flyers" or with aerosol sulphur particles in the stratosphere. But, he warned, geoengineering is "hard to stop once you start."

Margaret Leinen, chief science officer of Climos, outlined geoengineering techniques for carbon capture and sequestration, including seeding oceans with iron fertilizer to stimulate phytoplankton growth, which in turn absorbs carbon dioxide.  She also urged that mitigation methods – however controversial – deserve to be considered and subjected to peer review. "The point is these people are not engaging in science fiction," she said. "There is a difference between scientific skepticism and preventing debate."

Daniel Nocera, the Henry Dreyfus Professor of Energy at MIT, noted that discovery of new technologies may prove beneficial in unanticipated ways. The substitution of kerosene for whale oil in lamps in the 1840s, for example, saved whales from extinction.

Today, we are looking for something to save us from reliance on petroleum, he said. Substitutions for fossil fuel can be found, he insisted; photosynthesis is in actuality "a lousy oil well." And "if you give chemists coal we'll make anything you want."

Both Nocera and Angel said the sun remains the ultimate answer to energy needs. The source is abundant but the challenge is collection, storage and distribution at feasible cost.

Angel is currently working on an optic device that would concentrate sunlight when set in a disk. Disks placed on farms in sunny areas, connected to an intra-continental electricity distribution system could use a pump-water system for storing energy overnight. Even allowing for losses in storage and transfers, Angel believes electricity costs could be brought to $1 a watt, making solar energy economically viable.

The symposium, which organizers plan to make an annual event, ended with a quasi-scolding by Braden Allenby, Professor of law and civil and environmental engineering at Arizona State University, who warned against scientific presumption in knowing what's best for the planet. His cautions included: "Only intervene when necessary and then only to the extent required in a complex system."