Chris

You know, about 3,000 years ago the elites of the ancient societies of the Middle East were engaged in a strikingly similar discussion about the relative merits of bronze and iron.

Bronze was seen as a superior material; it was harder to come by than iron, which was to be found just about everywhere, but nobody had quite mastered the efficient use of iron in making anything you might actually want to own (such as a really good sword, or a nice sharp-tipped spear).

Unfortunately, tin, a key component of bronze, is not to be found everywhere. It had to be brought great distances by hazardous sea routes. Its supply was vulnerable to disruption. Such disruption is most likely what led to the switch to iron - much as people wanted to go on using bronze, the raw materials became too rare and expensive.

Three millennia on, and necessity has once again been proved the mother of invention. We are extremely good at using iron as an ingredient in all sorts of stuff you wouldn't want to try to use bronze to make. In fact, try to tell anyone that there was a time when iron was considered too troublesome to bother using at all, and you might get a quizzical or disbelieving look in response. But now it's oil and gas, the key raw materials of our energy-hungry economy, whose supplies are limited and vulnerable.

The point ... our current renewable technologies are in their infancy. wind turbines are big and not very efficient. But if we don't build them and learn from them, that's all the technology will ever be. We need to be brave and, I believe, take as given that if the human race is still here in another 3,000 years, they will find it bizarre and ever-so-primitive of us that we would ever have wanted to hang on to fossil fuel power generation instead of exploring the alternatives.