Can someone explain economics to me?

I’ve just been reading an article on The Register slating New Scientist for a lack of understanding of basic economics (it’s fairly old, but I was away when it was published). Now, I’ve never claimed much understanding of economics, but clearly I’m dumber than I thought, ’cause to me The Register’s argument looks like nonsense.

The Register is attacking the classic green anti-capitalist myth that a system built on economic growth is fundamentally flawed because it requires an ever increasing consumption of finite natural resources. It may well be myth but, if it is, I’m going to need the reasons why explained to me in a little more depth than Tim Worstall gives here. He uses sand as an illustration for his argument, pointing out that a quantity of sand converted into computer chips will add significantly more value to the economy than the same quantity converted into wine bottles.

As a basic illustration, that’s fine, but extrapolated to a larger scale it doesn’t seem to hold much water (or wine). Economic growth is fine in this model as long as you assume a nation to be a closed system. Britain’s resource consumption doesn’t have to increase in line with GDP if we use our sand to make microchips. But building microchips will not reduce the demand for glass. All we’re doing is offshoring glass production, whilst continuing to double consumption of sand. If we all become singers our GDP per capita may increase while our sand consumption goes down, but we still want microchips and glass. In fact we probably want more microchips and more glass because we’re now all so rich from singing that we have more money to spend. Total sand consumption has increased again. The fact that it’s mined and processed abroad won’t negate the impact on our environment. We can not live on singing alone. Or, as put by someone wiser than me, how can you have money if none of you actually produce anything?