Life and Death of Planet Earth


Donald Brownlee & Peter Ward


Non Fiction


Date Reviewed:

November 26, 2004

This non fiction book is about the long term fate of life on planet Earth. The early chapters are very good. They describe the conditions on earth that allow life to thrive (the carbon cycle, plate tectonics, etc). Then the authors describe how current conditions will change in the future. They argue that earth is already into its middle age, that the natural future of our planet will be less diversity and less ideal conditions for earth.

Long ago, the sun was much cooler, and thus appeared smaller in the sky. But there was much greater quantities of carbon dioxide in the atmosphere, so the green house effect efficiently trapped the heat and allowed dinosaurs and jungles to thrive. As the sun ages, it slowly expands and heats up. The earth has correspondingly been removing carbon dioxide from the atmosphere, so temperatures remain optimal for life. (However, the mechanisms for temperature are slow to adjust, and will overcorrect, and thus ice ages or warmer/wetter Earth environments will result. Currently, the Earth is in a period of ice ages, all of humans record history has sprung up in a 10,000 year interval between ice ages. The ice should be returning soon if only natural causes had an effect on global temperatures.) Eventually, the sun will continue to heat the earth, but there will be no more carbon dioxide to remove from the atmosphere as compensation - already the percentage of CO2 in the air is quite low. Once that happens, the Earth has no way to counteract the warmer sun, and surface temperatures will begin to rise. Eventually, land animals will perish, and, much later, the sea will boil away and nothing will remain but hardy bacteria. Much later, the Earth will be sterilized by increasingly higher temperatures when the sun swells to its red giant phase. Thus the end of life of earth is a "rewind" of how life started - a long period where nothing but single celled organisms existed, followed by multicellular sea life, and then plants and animals conquer land.

Unfortunately, the book runs out of material. It seems like the authors are padding the last few chapters. One chapter seems like a summary of Rare Earth, which is their previous book that describes why they believe intelligent life in the galaxy is rare. Rare Earth is very good book, well worth reading, but there is no need for the summary in this book. Of course, the reader wants to know what chance humans have to prevent the end of life on planet earth. The authors are surprisingly negative about the fate of humanity. They don't even seem to believe we would be successful at sending men to Mars, believing that the period of weightlessness and the bombardment of cosmic rays endured during transit would be too much of obstacle. But if we build big, shielded ships and spin them for artifical gravity, of course we can go to Mars. Maybe not with today's technology, but perhaps with technology hundred or 200 years from now. (They say there is no source of power on Mars - too far from the sun for solar, no fossil fuels, no geothermal or hydropower on Mars, and air is too thin for wind power. But then they dismiss nuclear power as an option, because nuclear power is so out of favor here on Earth. But nuclear power is only out of favor here in the US, France and Japan have lots of nuclear plants, and China is rapidly adding more. And why do they assume we will never solve question of fusion power? Give humans another 100 years, lots of technology will become available.) They do describe a clever scheme where the earth orbit is adjusted outward by repeated flying a massive asteroid past the Earth, and dragging Earth out to orbit of Mars to nullify effect of increasingly hot earth. But then they say: But unfortunately, Mars already occupies that orbit. To which I say - if you can move Earth out to orbit of Mars, can't you also move Mars out of the way, stick it halfway between old Mars orbit and Jupiter?

This is an interesting book, and a quick read. But if you haven't read Rare Earth, that is probably a better book, in my opinion.