If disaster nears, do you: grab your trousers, jump up and down or study a fish?

Surviving Armageddon

三月 17, 2006

This is the latest of the many recent books dealing with catastrophes that may threaten the Earth. The author, who is professor of geophysical hazards at University College London, is a well-known writer and speaker on the subject, and is also one of the world's leading volcanologists.

Of the various threats, he is in no doubt about which is the most dangerous: global warming. "We have created a monster that can only be vanquished by nature and rational thinking alongside co-operation, involving all those who share the planet and its resources."

Nobody doubts that at the moment the Earth is going through a period of global warming, just as it has done periodically throughout its long history - after all, the last Ice Age ended a mere 10,000 years ago - but are we responsible? McGuire is in no doubt that human activity is playing a major role, and indeed that this has been proved. Those who disagree are described as "illiterates", "ostriches" and so on. This does not sound convincing and recalls the words allegedly pencilled in the margin of the vicar's sermon: "Argument weak. Shout here!"

Other possible catastrophes are discussed, and there is a long section dealing with asteroids and comets. PHAs (potentially hazardous asteroids) are much more numerous than used to be thought, and the Earth is certainly not immune. There is strong support for the theory that a major impact 65,000 years ago led to a climate change that wiped out the dinosaurs - although here, too, there are some dissentients.

True, the author writes reassuringly that for a really large body "the chances of a collision are so small that we are more likely to die as a result of an argument with our trousers". But the chances are not nil, so what can we do if we see an asteroid coming toward us on a collision course? The obvious method - breaking up the intruder with a nuclear strike - is definitely not to be recommended, as we would then be bombarded by what would amount to a shower of shrapnel. Far better to nudge it aside, making it pass by harmlessly.

The author does mention one idea that does not seem very practicable; it was put forward in China in response to the revelation that asteroid 2003QQ47 might strike the Earth on March 21, 2014. The proposal was to order one and a half billion citizens to jump up and down at exactly the same moment, so shifting the Earth out of harm's way. The experiment was never officially approved, but will be unnecessary in any case, as 2003QQ47 will miss us by a wide margin.

On a more serious note, reference is made to the work of Matt Genge at Imperial College London, who has calculated the amount of thrust required to alter the path of a 1km asteroid. He concludes that a small car engine could do the trick if the thrust could be applied for a sufficiently long period, but it would be impossible to divert a 2km asteroid in this way.

One tiny asteroid, Apophis - not mentioned here, as it had not been discovered when the text was written - will unquestionably make several close approaches within the next 40 years. Some authorities, notably the astronaut Rusty Schweikart, have recommended attaching a booster to it well ahead of time.

Next comes a chapter titled "Tackling the tectonic threat". Earthquakes may not cause global destruction, but they can result in widespread devastation, as has been evident recently. If we could predict them, we could save many thousands of lives, but up to now this has not been possible. There have been some rather bizarre investigations involving the behaviour of living creatures before a quake; some Japanese scientists have been paying special attention to catfish, but, not surprisingly, without any promising results. We still cannot predict violent volcanic eruptions capable of causing huge landslides. Much more research is needed.

The last section of the book returns to global warming, and there is a discussion about "carbon dioxide sequestration" - removing carbon dioxide from the atmospheres and "stashing it away where it can't do any harm". In particular, liquefied carbon dioxide could be stored on the ocean floor.

This sounds ambitious, but at any rate it is more promising than relying on Chinese jumpers or Japanese catfish.

Whether you agree with the author's views, or whether you are one of his "ostriches", this is a book that should be read by anyone who is concerned about the future of the world in which we all live.

Sir Patrick Moore is a fellow of the Royal Society and the author of more than 60 books, mainly on astronomy.

Surviving Armageddon: Solutions for a Threatened Planet

Author - Bill McGuire
Publisher - Oxford University Press
Pages - 238
Price - £14.99
ISBN - 0 19 280571 1

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