Time to look again at the oil situation. How much did nature make for us and how much is left? A simple extrapolation of pumping rates suggests about two trillion barrels, with just over one trillion barrels left in the ground. That's a 40-year supply at current rates of consumption, but that may be the wrong way to look at it. We're close to the half-way point, the point at which the rate of extraction of oil ought to start declining — but demand continues to increase, especially in China and India. There may be hard times ahead.

Nobody seems to know how much oil is actually in the ground.

But let's look again at the one trillion barrels of so-called 'proved reserves' in the ground, waiting to be pumped. That amount suddenly increased by about 400 billion barrels in the late 1980s in the regions represented by OPEC (Organization of Petroleum Exporting Countries) alone. But there were no major oil discoveries in OPEC states during that period. Instead, OPEC changed its quota rules for how much each country could pump so that they were based in part on the country's proved reserves — and the additional reserves appeared as if by magic.

The fact is, we've been pumping oil faster than we've discovered it for the past 25 years. That means the reserves ought to have declined during that period, but instead they have steadily increased. Much of it is obviously political oil, not geological oil. Nobody seems to know how much oil is actually in the ground. The implications of that are truly frightening.

What we need is a 'Manhattan Project'-style effort to kick the fossil fuel habit now, while there are still fossil fuels in the ground. Unfortunately it seems very unlikely that we will have the kind of visionary political leadership to make that possible. Instead we will probably muddle through using oil, coal and other resources until they all start to run out. By that time it may be too late to save our civilization.