DEEP TIME: How Humanity Communicates Across Millennia

Gregory Benford
Avon Books ($20)

by Rudi Dornemann

Physicist/novelist Gregory Benford has written a nonfiction book that circles around the idea of "Deep Time"—that is, the future far beyond the planning horizon for most human activities. Benford's argument is that we should develop a habit of thinking in the very long term, of envisioning the distant effects of human endeavors.

He discusses four such Deep Time endeavors, either proposed or actual, in the course of the book. Two are projects with which Benford has been involved personally—the question of how to mark a proposed nuclear waste repository in the New Mexico desert with warnings that would still be understood 10,000 years from now, and the designing of a plaque to be attached to the Saturn-bound Cassini spacecraft. You might expect a science fiction writer like Benford to lead the reader through some interesting speculations on who the audience of these messages might turn out to be, and he does. But both projects eventually come down to questions of how to build messages that are their own Rosetta stones—able to teach their readers how to decipher them--and Benford develops these ideas provocatively.

The other two projects he describes don't fit as neatly under the book's subtitle, How Humanity Communicates Across Millennia, since they do not concern communicating specific messages. Still, the "Library of Life" and "Stewards of the Earth" proposals are imbued with a Deep Time perspective. The first concerns preserving biological information from animals, plants, even bacteria, that may soon be extinct. Ironically, here Benford proposes sending a message that will mean more to future eyes than it does to us, compiling a bank of living and frozen samples "to salvage biodiversity out of catastrophe." What we are unable to save in our time, he argues, we can at least preserve for the future to revive.

In Deep Time's final section, subtitled "The World as Message," the message becomes almost entirely metaphorical. Benford's subject is the conscious shaping the environment to sustain it (and humankind) into the future, and of all the projects he discusses, this is the one with the shortest timeline, offering results that could begin to be seen within a lifetime. He points out how, even in the prehistoric past, human activities have left their mark on the environment, and that very few places on earth have really been in an untouched "natural" state at any time in the last several thousand years. He proposes making carefully planned interventions in the natural world to reverse some of the unplanned side effects of past human activities. Benford backs up his arguments with intriguing facts and proposals that are surprisingly down-to-earth for all their potentially world-changing results—like dumping iron supplements into ocean water to stimulate algae growth which would then absorb some of the excess carbon dioxide in the air, or lightening the color of roads and roofs to absorb less heat in cities. As with the other projects outlined, this "Earth Stewardship" is the result of Benford's somewhat iconoclastic, perspective—a good start toward a Deep Time way of seeing the world and our place in it.