Population and agriculture

The human species has surely been the most successful in the Earth history. From a small beginning in Africa, approximately 200,000 years ago, migrations have led modern humans to populate the whole world.
As we all know, early humans were hunter gatherers, a lifestyle which implies a low population density and indeed, in our early days, the human population was very small. Estimates vary, but it is almost certain that up to 10 000 years ago, humans beings on this planets were never more than one million, and probably a lot less. However, around 10,000 years ago, after the last ice age, things began to change and people began to settle down and domesticate plants and animals , first in the Middle East then in China (and later on in New Guinea and America). The rise of agriculture, and the domestication of animals, produced the most important transformation in human culture, and literally, changed the face of the Earth. Some other species did very well too out of it. Thanks to their association with humans, sheep, horses or chicken are more numerous than ever. The potato has successfully colonised Europe from its native America, and the apple tree has colonised North America. Wheat, corn and soya may look very unlikely competitors for tall trees, but thanks to humans, they are now doing far better than any tree species. Other species didn't fare too well. 10 000 years ago, there were far more bears than humans in Britain, and the list of species that have become extinct in the last few decades makes rather depressing reading.
Agriculture spread rapidly, and with its food supplies now more secure, human population started to grow.
Around the time of Christ, the world population had grown to around 300 millions people. By by the year 1800, the billion mark was reached.
However, it is really in the last century that the human population growth has been truly phenomenal. In 1927, world population passed two billion. Sixty years later, in 1987, the world population was five billion, and in May 2009, the Earth's population is estimated by the United States Census Bureau to be nearly 6,8 billions people. The world's population is expected to reach about 9 billion by the year 2040, although this is in fact unlikely to happen.
Agriculture is what has allowed mankind to grow to this phenomenal size and has turned mankind into a force of nature.

It is generally assumed that global warming started in the 19th century with the burning of fossil fuel. But in fact, it probably can be tracked much further back, to the rise of agriculture. For agriculture leads to deforestation, and as we all know, trees absorb CO2 from the atmosphere. Agriculture also made possible this phenomenal rise in human number, which, because it put pressure on resources, eventually lead to the burning of fossil fuels. If it hadn't been for population pressure on resources, we would probably never have taken to burning coal. Let's face it, that stuff stinks when burnt, getting it out of the ground is a very messy and unpleasant job, even when compared to cutting trees, so if it hadn't been for the fact that we no longer had enough trees to cut, we probably would never have bothered.
With coal came the steam engine, and with it, further advance in food security, as we could now reliably transport food over greater distances. We had found yet another way to ward off hunger. Then came oil, an even better fuel for transport, and has it turned out, for agriculture.
From 1950 to 1984, as the Green Revolution, which supported the latest population explosion, transformed agriculture around the world. Grain production increased by 250%. The energy for the Green Revolution was provided by fossil fuels in the form of fertilizers (made mostly from natural gas), pesticides (made mostly from oil), not to mention hydrocarbon-fuelled irrigation and heavy mechanisation of labour.

But, as we all know, oil is running out.
Furthermore, as Dale Pfeiffer put it in his book "Eating Fossil Fuels: Oil, Food and the Coming Crisis in Agriculture": " Modern industrial agriculture is unsustainable. It has been pushed to the limit and is in danger of collapse. We have already appropriated all of the prime agricultural land on this planet... Even without considering energy depletion, our agriculture system is ready to collapse."

In his remarkable book "Collapse", Jared Diamond presents the example of two remote islands in the South Pacific.
Both of them have in common to be very isolated, with no major island within less than several day sailing, and because of this, they had to be totally self sufficient in food, and immigration was never an option. They also have in common to have been colonised by Polynesian, who are farmers and fishermen.
The first of these two islands is a success story. It is called Tikopia and it's barely more than 2 square miles in size. Tikopians practice an intensive system of agriculture similar in principle to forest gardening. Their agricultural practices are strongly and consciously tied to the population density and all Tikopians are fully aware of the need to keep the island population level at around 1200. For hundreds of year, they used various means, including contraception, abortion, infanticide, and suicide to keep their population within this sustainable limit. When European missionaries came along in the 19th century and banned some of these practices, the population increased with disastrous results. Tikopians have now brought their population under control again, at a very slightly lower level than before Europeans arrived.
The second island is far better known. It is Easter island, one of the most isolated island in the world (the nearest habitable land, Pitcairn, is 1300 miles to the West, a 2 weeks sea journey on a Polynesian canoe and only Tristan da Cunha, in the Southern Atlantic is more remote, but Tristan da Cunha has been inhabited only since the 19th century). At over sixty three square miles, Easter is a lot bigger than Tikopia, and therefore could support a much larger population. From the small group of settlers who navigated in canoes, most likely around the 9th century, the population of Easter island grew to several thousands, perhaps as much as thirty thousand, in the 16th century. Such a huge population on such a small piece of land put huge pressure on natural resources. All land bird species and sea bird colonies became extinct. The original subtropical moist broad leaf forests was entirely cut down and all of Easter island unique tree species also became extinct. With no more wood to build the canoes they needed to go fishing, no more birds (other than the chicken they had brought with them) to provide them with protein, and an ecosystem in ruin, the population of Easter island collapsed catastrophically, and by the time the European arrived, it was down to less than three thousand.

The current level of human population on planet Earth is clearly unsustainable and has led to massive environmental damage. If we see Easter island as a metaphor, we can expect a massive reduction in the number of humans living on this planet as resources necessary to sustain such number, such as oil, clean water and arable land, become increasingly depleted. But how is this going to happen?

Although this is still a daily occurrence in Africa and some part of Asia, in the Western world, where practically no one starved to death since the World war II, famine looks unlikely. But a quick look at history should suffice to convince most westerners that they just have been lucky so far. The list of famines on Wikipedia makes though provoking (and sobering) reading.  .
With famines come increased insecurity, because hungry people, having absolutely nothing to loose, will do anything. Already, scores of desperate Africans are taking to sea in overcrowded boats, risking their lives to flee to Europe, while Mexicans face being shot to get to the US.
We need to "connect the dots". Of course, all of use are aware that human population has exploded since the 19th century. Of course, most of us are aware that fossil fuel production is peaking now. Of course most of us are dimly aware that our food production and distribution system is largely dependent of cheap fossil fuels. But most of us fail to connect the dots and see that the inevitable consequences of Peak oil is going to be famines on a scale never seen in human history, and a dramatic reduction in human numbers.
The four horsemen of Apocalypse (Pestilence, War, Famine and Death) will be busy in the 21st century.

Christophe Mouze
Thanks to Tim Rowe for the inspiration!