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The Life and Death of Planet Earth: How the New Science of Astrobiology Charts the Ultimate Fate of Our World by Peter D. Ward and Donald Brownlee. Times Books. 2003. 240 pages. Check price/buy book
The Long Goodbye: The End of Life on Earth
Chances are, this world of ours will come to a bad end. Fortunately, we (meaning all the many forms of life we know today) won’t be around to see it.
Reviewed by Lane JenningsIn The Life and Death of Planet Earth, astrophysicist Don Brownlee and paleontologist Peter Ward, both from the University of Washington, attempt to construct a plausible 12-billion-year birth-to-death biography of our home planet. To do this, they combine evidence of the earth’s history preserved in layers of rock, soil, and ice with data from observations of the solar system and analysis of light from distant stars and galaxies.
Using an ordinary clock face to visually represent the earth’s existence, the authors place the origins of life (in the form of primitive bacteria) at about 1 a.m.--about a billion years after the planet first condensed from dust and gases swirling around the sun. They estimate that the era of multicelled plants and animals only began about 4 a.m. and will end by 5 a.m.
Already, they believe, the high point in terms of total numbers and variety of life forms has passed. As the sun ages and expands, Ward and Brownlee expect conditions on Earth to grow increasingly less hospitable to life. By 8 a.m. on their clock, the last trace of ocean will evaporate into space, leaving the planet's surface a barren wasteland. The final 4 billion years will see Earth grow ever hotter, lose its atmosphere, and finally, at high noon on their clock, be swallowed by the sun.
The idea that the period during which Earth could sustain life in any form makes up only a small fraction of our planet’s existence reinforces the authors’ contention that intelligent life may be extremely rare in the universe. Their reasoning on this point is outlined more fully in an earlier book entitled Rare Earth (Copernicus, 2000).
Since all the achievements of human civilization to date have been accomplished in only a few thousand years, we might hope that, given another 7.5 billion years to work with, continued ingenuity combined with new discoveries might enable humans to save their planet--or at least find ways to preserve life and culture in some form. But Ward and Brownlee offer little hope for this. Not only are humans now actively killing off other life forms and destroying habitable environments at an alarming rate, it appears that the relatively mild climate conditions that make civilization possible at all are highly unusual in the planet’s history. While the fires of the sun will ultimately consume Earth (as they once created it), it is ice that will most likely scrape away the planet’s thin veneer of human civilization.
At least twice in history, the planet's entire surface has been covered with ice. And the record obtained from drilling ice cores from Antarctica, matched against ocean sediments, reveals that even the past 400,000 years have mostly been times of extreme cold. The last great ice age ended about 12,000 years ago--and we are seriously overdue for another. While some scientists speculate that global warming due to the burning of fossil fuels and other human activities could conceivably delay the return of the glaciers for as long as 50,000 years, Ward and Brownlee expect that global cooling--with catastrophic results for agriculture and massive disruption of human society across the planet--remains our likely fate.
While the authors’ theories are highly controversial, and tend to be presented through scenarios and detailed descriptions in a way that is purposely provocative, their book certainly offers a cautionary perspective for anyone who tends to worry too much about contemporary issues like terrorism, SARS, or economic slowdown.
Contemplating the end of the world is a bit like contemplating one’s own death--not necessarily cheering, but worthwhile because it is a future that must be reckoned with. As British poet Philip Larkin put it: "Most things may never happen: This one will."
About the Reviewer
Lane Jennings is the research director of THE FUTURIST and the production editor of Future Survey.
[from THE FUTURIST, November-December 2003]return to top
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