The Life & Death Of Planet Earth
… by Peter Ward & Donald Brownlee.
Books which deal with immense time scales have always fascinated me. As a teenager I spent many happy days collecting fossils at the nearby site of Wenlock Edge, and after I moved away from Shropshire I continued my interest in Earth’s history through a wide range of books. So when a few years ago I spotted The Life & Death Of Planet Earth I knew it was a book for me. It turned out to be one of the most influential books I’d ever read.
A few of my regular readers have noted that I very rarely do “normal SF,” i.e. head out into space, to other planetary systems etc. The vast majority of my work is based on Earth. That’s because the deep past and deep future of our planet is a never-ending source of inspiration to me. I’m not particularly interested in writing about other planets if the truth be told. What interests me is Earth: how it began, how life began, how human life began, how consciousness began.
But I’m also interested in the future, especially the far future. The Life & Death Of Planet Earth was unique as far as I knew in that it speculated about the distant future of life, right up to times a billion years hence. Yes, it was speculation, but that speculation was rooted in what we know about the evolution of stars and about the planet’s use of the carbon cycle. As James Lovelock observed decades ago, the sun is slowly heating up, yet the average temperature of Earth has stayed constant over four billion years. An explanation was required for this remarkable fact: Gaia Theory. But on Earth carbon dioxide is the core of the main temperature regulation system, and over billions of years its average amount in the atmosphere has reduced. Thus, the early Earth needed a greenhouse effect because less solar heat was arriving, but the present Earth needs less of one – and, around one billion years hence, it will need no greenhouse effect. At that point complex life as we know it will face its greatest challenge, since carbon dioxide will vanish from the atmosphere. The germ of this idea goes right back to the original article in Nature written by Lovelock and his co-author Mike Whitfield.
The Life & Death Of Planet Earth deals with many other less distant periods, however: glaciation, continents and supercontinents (including their role in mass extinctions), then the end of plant and animal life, and the evaporation of the oceans as the carbon cycle ends and increasing temperatures turn the atmosphere into a cauldron.
This is quite the most fascinating book I’ve read about planetary evolution. It inspired me to put together two novel scenarios, one of which was written but which is very similar to another published work of mine (and which therefore will likely never appear), and one of which is prepared but as yet unwritten. The Life & Death Of Planet Earth is a highly recommended resource for authors of the deep future.