During the 1990s it was fashionable to scoff at the notion of limits to growth. A knowledge-based economy was coming into being in which natural resources didn't matter. The future would be driven by a search for new ideas rather than the struggle for control of the planet's assets. We were entering an era defined by information technology, in which rapid economic growth could continue for ever. It was never easy to square this fanciful philosophy with historical reality: the 1990s began with the first Gulf war, which was fought solely to secure oil supplies, and cheap oil was the basis of the prosperity of that feckless decade. Yet somehow or other these facts were forgotten, until Iraq.
With the launching of the second Gulf war, the crucial role of oil in the world economy was exposed. From statements made by a number of its American supporters, it seems clear that the strategic objective of the Iraq war was to enable the United States to withdraw from Saudi Arabia, which had come to be seen as an unreliable ally. According to the game plan, Saddam Hussein would be toppled, Iraq would be pacified in a few months and oil would fall to $10 a barrel. The global economy would then take off in another boom with the US in firm control of the world's second-largest oil reserves.
This was always a far-fetched scenario, and things have not worked out as envisaged. Iraq is a failed state in the grip of an intractable insurgency, and the price of oil is roughly $60 a barrel. The scramble to secure energy supplies is more frenzied than ever. The Great Game has been resumed, not only in central Asia but also in the Gulf. If Iran is attacked by the US in the course of the coming year or so, one reason for this will be to stymie energy supply agreements that Tehran may be planning with America's competitors, notably China and India.
The limits to growth have not gone away. They have re-emerged as classical geopolitics - a condition of continuous rivalry among the great powers for control of the world's most valuable natural resources. In this intensifying struggle, no country is more important than Saudi Arabia. The kingdom is the world's pivotal oil producer. Any disruption in supplies of its oil would be hugely destabilising to global markets. Even more crucially, it is the most important resource base for the oil that will be tapped to meet growing world demand. As emerging countries industrialise, their energy use increases exponentially. Saudi Arabia is the site of the planet's largest low-cost oil reserves, and in effect acts as the energy bank of worldwide industrialisation.
Matthew R Simmons is convinced that Saudi oil production is near its peak, or indeed may have passed it, a development with awesome implications. Simmons, a veteran oil finance insider who has been an important adviser to the Bush administration, has done a huge amount of research and bases his conclusions on carefully sifted evidence, not large theories. Yet his view is consistent with the theory of M King Hubbert, a Shell geophysicist who argued in 1956 that production rates for oil and other fossil fuels exhibit a bell curve: when roughly half the oil has been extracted, production declines. No one took much notice of Hubbert at the time, but he predicted that oil production in the continental United States would peak and start declining in the late 1960s or early 1970s - as it did. Since then a number of large oilfields have also peaked, including the North Sea in 1999. When oil peaks it does not run out - there is usually a slow decline that can be spun out by new technologies - but the unavoidable result is falling production.
Could we be near a global oil peak? Simmons believes that point may already have passed and warns that the idea that technology can arrest the decline may be a delusion. In his view, Saudi oil production has been boosted by the use of technologies which actually reduce the future supply of recoverable oil. The impli-cation is that Saudi production has peaked, and with it global oil production, at a time when demand is rising inexorably.
Twilight in the Desert is not always easy to read. It largely consists of highly technical discussion of the history and condition of Saudi oilfields. Yet its impact is to transform our view of the world. Many in the oil industry - and particularly Aramco, the Saudi oil company - will dispute Simmons's claim that Saudi production is near its peak sustainable volume. For most readers the question will be whether Simmons can be trusted. I am certain that he can. He is not the only oil expert to say that a peak in global production may be near (Dr Colin Campbell of the London-based Oil Depletion Analysis Centre is another) and, unlike many in the oil industry, Simmons has no axe to grind. This is a ground-breaking book by an analyst of unimpeachable authority.
Simmons's analysis suggests that the current phase of worldwide industrialisation is crucially dependent on the uncertain reserves of a single Gulf kingdom facing vast and potentially insuperable challenges. As he shows in a superb digression, the most formidable of these is population growth. The kingdom's current population of roughly 22 million is expected to rise to roughly 50 million by 2030, and unless there is a large and sustained rise in the oil price, living standards are bound to fall steeply - as they have been doing since the early 1980s. The Saudi rentier economy is facing a Malthusian crunch, and against a background of already high unemployment the result so can only be a con-dition of chronic instability. If the most obvious effect of our dependency on oil is a series of resource wars, another could be an upsurge of revolutionary movements in oil-producing countries. While it would be an error to think that the Saudi regime is on the brink of collapse, in a few decades the kingdom could well be an Islamist republic - or, perhaps more likely given its origin as an artefact of the colonial era, another failed state.
Simmons makes a formidable case for the pivotal importance of Saudi Arabia, but he may actually have understated the impact of peak oil. One reason is the central role of oil in intensive farming. Contemporary agriculture relies heavily on oil-based fertilisers, pesticides and herbicides. At bottom, the green revolution was about the extraction of food from petroleum, and a peak in world oil production could trigger a peak in world food production. A second is climate change. As oil supplies are becoming scarcer and less secure, many countries are looking to other fossil fuels such as coal. New technologies can make coal much cleaner, but a large increase in coal use alongside continuing dependency on oil could magnify the greenhouse effect. In other words, peak oil could accelerate global warming.
The conjunction of peaking global oil production with quickening climate change poses fundamental challenges that no section of opinion has adequately confronted - including the Greens. The energy-intensive lifestyle which is now spreading throughout the world cannot be sustained with non-renewable and polluting fossil fuels, but it is sheer fantasy to imagine that a human population of between six and eight billion can be supported on a combination of windfarms, solar power and organic agriculture. As Simmons notes, we may be approaching the limits of growth that the Club of Rome identified more than 30 years ago, and we are no better prepared to adjust to them now than we were then.
John Gray's latest book is Heresies: against progress and other illusions (Granta)