Tip of the Week #107                   Tip Index       Categorized Tip Catalog

Go to the Prior Tip "Justifying Training with Performance Improvement"
Go to the Next Tip  Decision-making styles of women vs. men
Go to a Related Tip "Last Days on Earth"
Return to MaxValue Home Page

Our Final Hour: A Scientist's Warning: How Terror, Error, and Environmental Disaster Threaten Humankind's Future in this Century—on Earth and Beyond

by Martin Rees, 2003, Basic Books, 228 p., ISBN 0-465-06862-6, US$25.00 list price.

Sir Martin Rees is Royal Society Professor at Cambridge University and England's Astronomer Royal.  He is the author of Just Six Numbers, Before the Beginning, Gravity's Fatal Attraction, and Our Cosmic Habitat written for general readership.

If you like to worry—or think you shouldthen this book is for you. Sir Martin plainly describes a host of threats to civilization. The 21st century might well be our last unless we, as a species, take bold steps to define our values and decide how we want to go forward. He judges that the odds are no better than 50:50 than humankind will survive to the end of the century. "I hope to stimulate discussion on how to guard (as far as is feasible) against the worst risks, while deploying new knowledge optimally for human benefit."

Among his long list of threats are these:

Rees isn't the first to sound the alarm. He gives high praise to the young H.G. Wells who presented a 1902 lecture "Discovery of the Future" at the Royal Institution in London. Wells identified these risks: "something from space, or pestilence, or some great disease of the atmosphere, some trailing cometary poison, some great emanation of vapour from the interior of the Earth, or new animals to prey on us, or some drug or wrecking madness in the mind of man." Late in life, Wells was additionally concerned with cyber risks and human pressure on the environment.

The odds of various risks are presented throughout, though with less precision (in expression) than I prefer.


Among the many illustrations in the book is this version of a "doomsday argument" (pp. 136-7):

Approximately 60 billion people have ever lived, and approximately 10% of those are alive today.  The dead outnumber the living by a factor of ten. Consider two scenarios for humankind's future:

Suppose these ultimate numbers of people to live are represented by two identical-appearing urns: The "Pessimistic" urn contains 10 tickets numbered 1-10. The "Optimistic" urn contains 1000 tickets numbered 1-1000. Each digit represents 10 billion people who will sometime live on Earth. You pick an urn at random and draw a ticket, number 6. Because this is such a low number, you are approximately 100 times more likely to have drawn from the Pessimistic urn. The number 6 represents the 60 billion people who have lived on Earth. Our known place in the birth roll suggests that our species' future will more likely be very short rather than very long.

The argument is attributed to astrophysicist Brandon Carter.  He holds that conditions in the universe must be very special for life and intelligence to emerge.


The central message is to emphasize our responsibility for stewardship: for the Earth and for humanity. There are many threats that one can worry about. Cost-effective actions are available for some of these risks, and I'm hopeful that decision analysis will help us steer a path.

This is a well-written, engaging book. Despite the grim topic, I think all persons interested in risk will enjoy reading this book.


—John Schuyler, March 2005.

Copyright 2005 by John R. Schuyler. All rights reserved. Permission to copy with reproduction of this notice.