Matthew Simmons is an investment banker and author specializing in oil services and world markets. His 2005 predictions have largely come true. What else does he know?

We read Twilight in the Desert: The Coming Saudi Oil Shock and the World Economy in 2005 when it was published. It’s not exactly a page turner, but there’s some excellent data. One of the central themes is peak oil.

Simmons compares the historic peak reached in the U.S. in 1970, where we can now see the dramatic fall in output, to the world today. He doesn’t claim we’ve reached it but makes the case that if we haven’t already, we will in the very near future. Admittedly, we were skeptical. After all, the predictions were based on what we know about Saudi oil supplies, which amounts to little in the way of fact. It was debatable whether the Saudis could simply open the spigot wider and feed our addiction with an extra couple million barrels per day.

Three years later, oil has tripled in price and the Saudis are struggling (we assume) to add a couple hundred thousand barrels to world supplies. Most of his predictions have become reality, and it’s likely that the world is in the same place the U.S. was in 1970. This week, The Economist writes its own Simmons recap, since it too was wrong in doubting him.

He magnanimously excuses The Economist’s poor record of predicting the price of oil: our suggestion in 1999 that oil would remain dirt cheap was conventional wisdom at the time, he says soothingly. He also shrugs off our more recent scepticism about his belief that the world’s production of oil has peaked: he, too, hopes that “peak oil” proves to be a myth, he says. But over a 40-year career in investment banking, Mr Simmons adds, he has learnt never to rely on wishful thinking.

We’re fine with admitting that we were wrong, but we also tend to learn from our mistakes. Which is what makes Simmons’ next move so troubling.

Mr Simmons…plans to start up a farm near his house in Maine, in case the supply chain that provides America with food breaks down for lack of fuel. He plans to fertilise his fields with manure, rather than chemicals derived from oil and natural gas. He thinks globalisation must stop, and that as much trade as possible should be conducted by boat, to conserve whatever oil remains.

It’s one thing when a random guy on a street corner claims that “the world as we know it is coming to an end, as least as far as energy is concerned.” It’s quite another when that person is one of the world’s leading oil services experts. Plan accordingly.