In my new book, published this week by Hodder in the UK, I put forward a idiosyncratic view: I suggest that we are wrong to conflate sustainability and the living of an ethical life. Sustainability is essentially a problem of engineering. Can we build an economy that allows all 9 billion people in 2050 to live with approximately the same standard of living as the richest 1 billion of today? I think the answer to this question is unambiguously ‘yes’, but with one important caveat to which I will return. An ethical life – perhaps one which rejects standard Western norms of high levels of consumption of material goods – is a set of rules we may as individuals wish to follow. But such a lifestyle is very little to do with sustainability. If global society manages to achieve sustainability I suggest it will not come from millions of people living better lives (which we all ought to do anyway) but from using science and economic growth to help us dramatically reduce the impact we have on the planet’s operations.

The crucial finding in the book – and one which I was very surprised to come across – was that the earth’s crust is very likely to contain enough minerals to provide the world of 2050 with all that it needs. With reasonable care, we won’t run out of anything important. Some metals will get quite scarce, but humankind will simply switch to reasonable alternatives. There are few materials that cannot be substituted quite easily by others. Even rare earths are abundant and distributed across the globe. It is simply that only China is mining them at the moment (partly because of the highly polluting nature of some extraction techniques). If we build a proper recycling and reuse infrastructure – ‘the circular economy - we can expect to be able to manage quite well.

Another finding which I didn’t expect is that there is quite strong evidence that wealthy human societies reach a peak in their consumption of material resources. Perhaps the best way of putting it is that we need a stock of important metals, of which steel is the best example, and once attained, our needs fall sharply. In the case of steel, even the richest countries require about 10 tonnes per person and no more. So we don’t need ever increasing amounts of metals or other materials to live an increasingly prosperous life. There is a natural limit on human material requirements. We really don’t have infinite needs.

I know this is a contentious view which is rejected by almost everybody working in the field of sustainability. I’m suggesting that economic growth is perfectly compatible with sustainability. In fact I go further, saying that the improvements in science that come with GDP growth will enable us to face the challenges of sustainability more effectively. Once we have reached a certain standard of living, more economic growth doesn't result in us using more natural resources. We may even require less. Growth is good, I tentatively hypothesise.

What about the stresses and strains put upon the earth’s natural systems by thoughtless human exploitation? Aren't we likely to disrupt vital but little understood ecologies by, for example, our horrifying indifference to falling biodiversity? Perhaps with slightly more confidence than warranted, I say no, the loss of biodiversity is a tragedy and an ethical disaster but is not likely to affect mankind’s ‘sustainability’.

There’s one important exception to my optimism. Climate change seems to me to represent a threat to human life. Market mechanisms and good sense may enable us to live reasonable lives in 2050 were it not the threat from increased temperatures, rising sea levels and magnification of weather extremes. I conclude that reducing the rate of increase in global concentrations of greenhouse gases is the only really difficult challenge posed by the requirement for sustainability. Everything else I think we can deal with.

In the space allowed by the publisher I could only write a short book. I couldn't include much of the numerical analysis my thesis really requires. And so perhaps I won’t convince anyone that we need to separate out the really good reasons to live simpler and less material lives from very different challenge of using advances in science and technology to enable us to reduce our impact on the planet. And I won’t make any friends by emphasising that many things we regards as ‘natural’, such as cotton, are actually far more destructive of the world’s sustainability than manufactured alternatives such as polyester. Unfortunately perhaps, a sustainable world is a less natural one than one we might ideally want. But as writers such as Stewart Brand and Mark Lynas have pointed out, this is Anthropocene and humankind has to engineer itself out of its problems.