Contrary to popular belief, this is not like the 1970s. Then, only two commodities really spiked in this way: oil and gold. The rest did not experience the same correlated upward surge. In fact, the last time that commodities experienced this kind of really substantial correlated upward surge was the early 1940s. The really interesting thing about recent trends in commodity prices, in other words, is that it looks as if we are in the middle of a world war. Except, there is no war. Or is there?

Now, it is true that the so-called War on Terror has produced quite small wars by 20th-century standards. What has happened in Afghanistan and what has happened in Iraq amount to little more than a couple of colonial policing operations. But these small wars are having big economic effects because they are coinciding with another war – the one I call China’s War on Nature.

If the United States has a War on Terror, China has a War on Nature, by which I mean that the environmental effects of China’s breakneck industrialisation resemble an unprecedented assault on the natural world. And it does feel a little bit like a War on Nature when you visit China. I was in Beijing not long after the Sichuan earthquake happened, on the day of that extraordinary and universally observed public silence. It reminded me strongly of the atmosphere in the United States after the terrorist attacks of 9/11. But who was the enemy? All the extraordinary, formidable devices of the government's propaganda machine were deployed to extol the virtues of the rescue workers and to emphasise the suffering of the victims. But there was no enemy except nature. It is nature, I suspect, that will resist China's industrialisation far more effectively than anything else. But until environmental constraints begin to bite, Chinese growth represents a huge challenge to the world's ability to produce commodities and extract fuels. That is the main reason why commodity prices look as if there is a war on.

What are the geopolitical implications of all this? One is that the great reconvergence between East and West is speeding up. If you go back to the very first “BRICs” – Brazil, Russia, India, China – report that Jim O'Neill and his colleagues at Goldman Sachs produced in 2003, China was projected to overtake the United States in terms of gross domestic product in 2040. But in more recent reports, that has been brought forward to 2027. And maybe that makes sense. One logical consequence of the credit crunch is that the United States will grow more slowly for the foreseeable future. Whether this is a short recession or a long recession, a deep one or a shallow one, is beside the point. The point is that there is simply no way the United States can grow at 4 per cent per annum over the next five years. It is more likely to be closer to 2 per cent. By contrast, China's planned economy seems unlikely to be significantly affected by that slowdown because net exports are no longer the key driver of China's growth. The only true constraint on China’s planned economy, as I have said, is environmental.