Research by Professors Corey Bradshaw and Barry Brook of the University of Adelaide reveals how resilient the human population is, even in the face of catastrophes. A global ‘one child’ policy or a killer plague that wipes out 2 billion of us in the middle of the century still leads to a global population of 7-8 billion in 2100.

Whether you opt for the current UN estimate of 11 billion people in 2100, the more conservative figure of 9 billion put forward by other demographers, or even the paltry 7 billion of us today appears to be academic. At Western levels of consumption, Bradshaw and Brook estimate that a sustainable human population is just 1-2 billion people, a level last seen in the early 20th century.

Let’s be clear: Bradshaw and Brook are not advocating extreme methods of population reduction. ‘…we merely wanted to know what even the unfathomable could do to the human population trajectory over the coming century’ because ‘… if we can’t get the human population to [a] more sustainable size, most of our efforts to conserve biodiversity will be futile.’

Clearly, something will have to give. If Bradshaw and Brooks are right, it won’t be the total human population. And if it isn’t to be biodiversity, or the aspirations of billions of people to lift themselves out of poverty, it will have to be the level of consumption enjoyed by most of us in the affluent west.

Which begs the question…

Could you cut your consumption by 70-90%?

My immediate reaction was ‘absolutely not’, in which case it’s game over for biodiversity. So that  got me to thinking ‘why not?’

Bear in mind that we are talking not so much about consumption as such, but consumption that has an impact on biodiversity and what remains of the natural environment.

Can we vastly improve the efficiency with which we use energy without reducing our quality of life? Yes. In fact, energy efficiency can improve quality of life.

Can we wean ourselves off extracted forms of energy such as fossil fuels and uranium and power civilization entirely with renewable energy? Yes.

Can we significantly improve the rate and efficiency of materials recovery through recycling? Yes.

Can we significantly reduce the area of land required to feed each person currently wedded to a typical western diet? Yes.

The technology to do all this is available now, and in many cases is cost-effective.

But can we do it without any further resource extraction? Probably not.

I doubt that we have yet mined sufficient iron, nickel, copper, aluminium, silicon, lithium, niobium and a host of other elemental building blocks to achieve enough of the above to provide a reasonable standard of living to 7 billion or 11 billion people. And no, that won’t be the lifestyle that most of us who are culturally ‘western’ are familiar with today. It will mean satisfying ourselves with less physical stuff, and it will require a massive overhaul of economic thinking.

Even so, with commitment and cooperation we might be able to avoid wiping a further 50% of animal species off the face of the planet. That’s a big caveat, however. As Bradshaw points out: ‘Had we seriously addressed the issue before it became so intractable (say, 50 years ago), we might not now find ourselves in such a mess. What can I say? Humanity isn’t notorious for forward thinking.’

I suspect that Nathaniel Hellerstein had his tongue firmly in cheek when he wrote in a letter to New Scientist: ‘This is the Anthropocene age; we might as well get with the programme. The question is not whether we are an evolutionary catastrophe; it is how good an evolutionary catastrophe we shall be.’

Many a true word spoken in jest. If we don’t quickly get very serious about slashing our consumption, the current mass extinction will be a very ‘good’ one indeed.

Image: Pasu Au Yeung via Flickr (CC)