Exponential growth in the use of minerals and natural resources

A small thought on that idea that human society is just going to have to stop using those natural resources because they’re going to run out. We have dealt with this at length by outlining quite how much there is out there to use before. Here though the point is just about that idea of exponential growth.

We use more of a resource each year, then more again, then more - and so it doesn’t matter how vast the total resource is, that multiplication of use over time is simply going to bring us up, hard, against that limit then, obviously, we all die.

Aiee!

This does depend upon the idea that usage rises exponentially of course. It isn’t true of certain materials. Thorium usage has declined substantially since we stopped using it to make gas mantles. Mercury usage is declining so much that there are - real and honest - plans to dispose of the recycled excess back into the mines it first came from. But those are minor metals and so could be said to not illustrate the concept properly. That they are minor metals because we don’t use much of them and even that in declining quantities won’t hold much weight with the catastrophists.

So, something much more basic. Iron ore. Global usage is rising, yes, it is. Building out a civilisation for the first time - as China is a long way through the process of, India is perhaps starting - takes a lot of steel. But do we get to a point at which consumption of that necessary raw material, the iron ore, declines?

As it happens yes, apparently we do. US iron ore consumption stats for this year are here. US production, including a net export, is around 50 million tonnes a year. US resources are 110 billion tonnes. So, that can go on for a very long time without problem. Except, of course, for that pesky exponential growth. So, does that occur?

Historical statistics are here. Current production of iron ore appears similar to what it was in 1906. Well under half what it was in 1955. Imports and exports in 1905 were trivial, the US was a - large - net importer in 1955 and is currently a net exporter.

We appear to have something akin to the Kuznets curve here concerning basic resource consumption. Yes, it rises as civilsation is built. Then it falls again.

As to why, yes, the US does recycle much scrap steel these days. The majority of steel used now comes from this source. No, this wasn’t because the hippies demanded it - Nucor’s first electric arc furnace that works only on scrap was opened in 1969 when the hippies were still coming down off those first bong hits.

But the US also uses less steel than it did back then. 25 million tonnes in 1906, 28 million tonnes today but in 1955 it was 70 million tonnes. It isn’t just the rise of recycling, it’s not replacement with imports, it is just true that as a society matures it uses less of these most basic of products, iron ore, iron and steel.

We agree that global production and consumption of iron ore - of iron and steel - is larger than it used to be. It’s also true that iron ore resources are around 800 billion tonnes. Exhaustion of that will require that exponential growth in production and consumption. Which appears not to be what does happen. Rather, consumption rises as a society is built then tails off again.

Resource consumption does not rise exponentially. Therefore the catastrophists are wrong. Which is a welcome and cheerful thought, isn’t it?