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Nature and Society

Book review - February-March 2006

Overshoot: The ecological basis of revolutionary change
William Catton
University of Illinois Press, 1980

Why would I review for you a book that was published a quarter of a century ago? Three reasons: (1) the passage of time has made it urgently relevant to understanding the present and the future of the human place in nature, (2) I came across the book myself only recently and expect that there are others who have not heard of it and (3) it’s an eye-opener, one of the most significant and fundamental books on NSF themes I’ve read.

Seven years in the writing and encyclopaedic in scope, Overshoot synthesises biological, sociological and cultural perspectives in an ecological analysis. William Catton uses his training in sociology to explicate the web our civilisation has woven between humanity and the planet’s ecology and especially between that growing part of our environment and ourselves that we use and abuse. He shows how we are caught in this web and how it must, inevitably, drag our civilisation down. He does this using an ecological vocabulary to describe and account for events that most people have been accustomed to thinking about in quite non-ecological terms.

Catton rigorously examines our civilisation in its ecosystem. His conclusion is that:

Today mankind is locked into stealing ravenously from the future [by way of] diachronic competition, a relationship whereby contemporary well-being is achieved at the expense of our descendants. By our sheer numbers, by the state of our technological development, and by being oblivious to differences between a method that achieved lasting increments of human carrying capacity [agriculture] and one that achieves only temporary supplements [reliance on fossil fuels and other mined substances], we have made satisfaction of today’s human aspirations dependent upon massive deprivation for posterity. (p.3)

Catton describes the two basic strategies humans have used to increase the carrying capacity of their environments. The first he calls the ‘takeover method’.

Invading and usurping lands already occupied by others was essentially what mankind had been doing ever since first becoming human. Each enlargement of carrying capacity ... consisted essentially of diverting some fraction of the earth’s life-supporting capacity from supporting other kinds of life to supporting our kind. Our pre-sapiens ancestors, with their simple stone tools and fire, took over for human use organic materials that would otherwise have been consumed by insects, carnivores or bacteria. From about 10 000 years ago, our earliest horticulturalist ancestors began taking over land upon which to grow crops for human consumption. That land would otherwise have supported trees, shrubs, or wild grasses, and all the animals dependent thereon – but fewer humans. As the expanding generations replaced each other, Homo sapiens took over more and more of the surface of this planet, essentially at the expense of its other inhabitants. (p.26)

In this takeover process, man was behaving as all creatures do. Each living species has won for itself a place in the web of life by adapting more effectively than some alternative form to a given role ... A given tract of land has greater carrying capacity for the subspecies that can extract more from it than for other portions of the species that happen to be less equipped to exploit it. (p.27)

Around 1800, when takeover was pressing rapidly into its last pristine frontiers, the Americas and Australasia, a new ecological strategy began: the ‘drawdown method’.

Industrialisation made use of fossil energy. Machinery powered by the combustion of coal, and later oil, enabled man to do things on a scale never before possible. ... Products of farm and factory could be transported in larger quantities and for greater distances. Eventually the tapping of this ‘new’ energy source resulted in the massive application of chemical fertilisers to agricultural lands. Yields per acre increased, and in time acreages applied to the growing of food for humans were substantially increased - first by eliminating draft animals and their requirements for pasture land, but also by reclaiming land through irrigation, etc. (p.28)

Using the drawdown method humans rapidly increased – temporarily – the global carrying capacity for humans. The human population had crept to the one-billion mark around 1820; it has since shot up by a factor of six, with most of the greater rate of increase directly or indirectly attributable to drawdown of finite, exhaustible resources. Once the fossil fuels and minerals begin to run out, this transient carrying capacity will vanish as quickly as it appeared. By Catton’s calculations we were using the equivalent of 10 Earths’ energy by the 1970s: this contrasts with 1¼ Earths using the conventional model for the ecological footprint.

What is Catton’s solution? Catton does not ignore unpleasant facts nor does he insert the too-customary and distracting Pollyanna-ish optimism where none is called for. He suggests that our expectation of a solution or that a deal or a compromise can be worked out is a non-ecological way of thinking that has been superseded with the passing of what he calls ‘the age of exuberance’.

Whichever of the two historic approaches we take, either choosing to accelerate drawdown or indulging in additional takeover, our new ecological paradigm enables us to see that eventually we will end up shifting back to the other ... For any lasting solution, we must abandon both of these ultimately disastrous methods. Drawdown bails us out of present difficulties by shortening our future. Takeover was of lasting value earlier in human history, but that time is past. (p.260)

In fact, we have made our continuance of the takeover method dependent upon expanding drawdown – for example, by producing and fuelling tractors to clear and farm more land.

We must learn to live within carrying capacity without trying to enlarge it. We must rely on renewable resources consumed no faster than at sustained yield rates. The last best hope for mankind is ecological modesty. (p.260)

Some readers may quibble with Catton’s analysis because his predictions appear not to have come to pass quite as soon as an inattentive reader might expect. But Catton was not wrong in his timing. Since he wrote, we have increased our takeover, notably in rainforests and fisheries. But we have also increased our drawdown, most spectacularly with the rise of capitalism in the former communist states of USSR and China. Both are now drawing down their fossil fuels and agricultural soils and contracting their traditional welfare net, ensuring a supply of cheap labour by reducing the opportunities for self-sufficiency. Australia now sucks in cheap Chinese consumer goods, destroying in the process three millennia of accumulated horticultural knowledge and soil fertility; our ecological footprint is crunching beneath it the support systems of China as we play our part in bringing its 1.3 billion people closer to ecological ruin.

Readers may also assume that, with rapid developments in technology on the one hand and environmental deterioration on the other, the book would have been superseded by a new generations of writers. Not so: Catton’s ecological principles and his analysis are timeless.

More bold than Diamond or Wright, Catton unapologetically paints a picture of the future of humanity and the biosphere as he sees. Like Diamond and Wright he draws on historical examples. But unlike them he does not indulge in the hubris which assumes that past human civilisations provide the only – or even the best – model. Catton would not reject their models but he requires us first to comprehend the biological and ecological constraints of our species and the biosphere before we consider our social and cultural options.

Catton dismisses alternative energy sources as unsustainable in the long run. This may be because minerals like copper, lithium, silver and platinum which are critical to many high tech alternatives are already approaching exhaustion of known supplies.

Catton makes poetic use of the pluperfect tense, as if he were looking back from an indeterminate date in the future. He carries this trick off very well, underscoring his historian-like detachment. A refreshing aspect of the book is its clarity of language and thought.

Reading this book is like learning a new language: it levers the reader into a paradigm shift in viewing the world and human society in it. Overshoot is not a book for those who must have a happy ending. It is still in print and is truly brain food for anyone wishing to understand our predicament without cultural baggage so that we can identify the behavioral changes that will lead to the best possible future, and initiate them.

Reviewed by Keith Thomas

February-March 2006 edition accessible here

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