This is an extract taken from my new book, written with Alan Murray,  Sustainable Economics: Context, Challenges and Opportunities for the 21st  Century Practitioner. Due out on 15th April, 2015, you can find it at Stylus Publishing in the Americas or Greenleaf Publishing in the UK.

The history of humankind has been a journey of change, as all journeys are, but the drivers of change have altered.  The Hunter-Gatherer Age, in which our race has spent 95% of our time on Earth, was shaped by the environment, and our existence relied on our relationship with nature.  The feedback loops were simple, rapid and direct, stemming from the sun and the rain.  The rest was the outcome of the particular food web of which we were a part. Our energy was mostly dedicated to acquiring the food and water needed to sustain us. We existed in an egalitarian relationship socially and with the environment. Human capital represented the only limit to human economic development (e.g. the number of fishermen limited the number of fish caught), if economics even existed. The environment was a source.

The Agrarian Age still relied on the sun and water, but we began taking control of the food webs, altering them to suit our needs.  Soon these outcomes formed the basis of profits, allowing trade, and settlements facilitated the development of trade routes and export/import. Our energy was spent creating agricultural surplus, or trading this surplus, as an economic system developed.  Inequality entered not only human society, but the human-environment relationship. In the Agrarian Age, the environment was now a source and a sink.  Man-made capital limited economic development (e.g. the number of fishing boats limited the number of fish harvested). While the industrial revolution has often been observed as the most significant transition in human history, in fact the transition from the Hunter-gatherer Age to the Agrarian Age was much more elemental, laying the foundations for all that was to come.  Three developments in particular would pave the way to the modern world:

  1. The onset of agriculture
  2. The onset of urbanization
  3. The onset of economics
The population underwent division of labour (food producers and those not involved in agriculture), and with a sedentary, trading race, social stratification emerged.  With the basics more than taken care of, wealth, power and tokenism prevailed.  This lead to wider uses of renewable and non-renewable resources, and with an increasingly large trading floor, industrialization of production emerged, ushering in the Industrial Age.  Our energy was spent creating wealth either for ourselves or our employers, and inequality increased at both the social and environmental levels. 

The Industrial Age superseded the Agrarian Age by industrializing agriculture, while colonialism all but wiped out the remnants of the Hunter-Gatherer Age, except in areas where the colonial powers could see no exploitative advantage.  In the early Industrial Age, man-made capital limited the potential for economic development (e.g. the ability of an automobile factory to make lots of cars), but in the later stages, it is the natural capital that limits that development (e.g. insufficient lithium to make enough batteries for the new generation of electric cars). It is fossil fuel deposits, not the number of refineries that limit oil production; it is the area of forest, not the number of saw mills, which limits forestry. Yet the Industrial Age was merely an intensification of the Agrarian Age.

The Information Age now controls the financial, industrial, agricultural and cultural domains of our existence, and we live in a largely controlled world. While improving our social interactions and enhancing industrial efficiency, the Information Age has so far not altered our relationship with the environment in any meaningful way.  Its replacement of humans in the workplace may also erode social structure while enhancing economic growth.  It is yet to be seen if this will change, but at present it merely contributes to the source and sink exploitation of our existence, while introducing new risks due to our increasing dependence upon technology.   While the Information Age excludes environmental considerations within its solution space, then its solutions will continue to fail nature, and further erode the natural capital of our planet. Yet again, the information age is merely an intensification and optimization of the Agrarian Age in principle.


The path of the last 12000 years has been one of increasing intensification and optimization of our race at the expense of everything we used to hold dear as hunter gatherers.  The ghosts of our past still walk with us in the form of the indigenous peoples of our world. Each age has brought a population explosion, as technology has raised the carrying capacity by allowing access to greater energy resources for humans. Through the ages of humankind there has been a shift from using portable utilitarian, easily acquired, replaceable, easily recycled artefacts to using heavy, elaborate, multi-resource artefacts requiring prolonged manufacture, maintenance, and increased waste. From the Agrarian Age onwards, with the advent of economics came the age of possession, inequality, envy, greed and individualism: the age of the plastic crown.

The problem with building your house on the backs of four elephants is that you have got to keep feeding them.  Elevating our carrying capacity, by increasing the flow of energy through the Biosphere, in order to produce the food and recreational energy needed to sustain our energy-expensive lifestyles, means that we are no longer living at our natural level.  Many people seem to think that if we freeze the population at where it is today, or even in twenty years time, then there will be no problems.  Wrong on two fronts.  Firstly, we will still need to maintain the massively exaggerated numbers of people.  Secondly, the current global development programme is based on increasing the energy demands of the bulk of the world's population, referred to as the "third" or "underdeveloped" world, in order to make them more like the model, "developed" citizen, the western world.  Thus even with a decreasing population, resource abuse will spiral out of control.

Professor Joel Cohen (Cohen, 1995), from Rockefeller University, New York, writing in Science, has calculated that between 1860 and 1991, the human population quadrupled.  Over that same period, energy usage increased by ninety-three-fold. So the problem isn’t actually the number of people, per se, but rather the amount of energy needed to maintain us in the way that we have become accustomed to.  

The per capita energy use is escalating rapidly, exacerbating the problem of a geometric rise in population.  And, as resources run low, we must work harder to keep the population elevated.  Of course if any kind of large scale disaster should strike, we will be much less resilient to the trauma than if we were living on the ground.  Elephants can die of starvation. 

The energy flow, upon which we are so reliant, leaves behind some rather unpleasant side-effects.  The three greatest causes of extinction at present are global warming, habitat destruction and eutrophication.  Each one of these is directly a consequence of our attempts to maintain the human carrying capacity on the planet. 

Global warming stems from our use of fossil fuels, in industrial processes, including the Haber-Bosch process, used to produce fertilizers for agriculture, on which some forty percent of the world’s population depends for their very existence.  The industrial revolution, hailed by adherents to the Enlightenment philosophy of Hume and Condorcet, has set in motion a technological spiral of consumption.

Habitat destruction is carried out to clear areas for crop plants and animal husbandry.  Rainforest in the Amazon, equivalent to the area of France, has been cleared for cattle ranching alone.  Swamps are drained and forests felled to convert land for industrialized food production.  Habitats are also fragmented by human infrastructure.  Meanwhile our desperate need for water leads us to dam rivers and flood areas of important biodiversity.

Eutrophication is a silent killer.  Here, the powerful fertilizers used to force the soil into greater productivity, leach out into the water, and horrifically distort natural habitats, leading to huge species loss and the crippling of sustainable ecosystem function.

 And so instead of the three horsemen of the Malthusian apocalypse, famine, disease and war, we have introduced these three new destructive characters: global warming, habitat destruction and eutrophication.  It is ironic that in our efforts to free ourselves from the original Malthusian checks, we have engineered three equally blood-thirsty killers across the globe.

What have these deadly dragoons, unleashed by humans in pursuit of that utopia, done to our Biosphere?  David Woodruff (2001) estimates that current extinction rates are fifty to five hundred times higher than background.  The International Union for the Conservation of Nature (IUCN, 2001) reported that over fifty percent of animal species are vulnerable, endangered or critically endangered.  A quarter of all mammals, a third of all fish and up to a third of all plants are predicted to face extinction in the next few decades.

Please take the time to read this last paragraph again, slowly and out loud.  If there is someone else in the room or on the bus, don’t be put off. They need to hear it.  Gary Snyder, writing in 1990, summed up the appropriate reaction powerfully when he wrote “The extinction of species, each one a pilgrim of four billion years of evolution, is an irreversible loss. The ending of the lines of so many creatures with whom we have travelled this far is an occasion of profound sorrow and grief. Death can be accepted and to some degree transformed. But the loss of lineages and all their future young is not something to accept.  It must be rigorously and intelligently resisted.”