On Monday I griped about a Sustainability book I was sent for review. The sentence which made my heart drop was ‘basically speaking, Sustainability is a balance between environment, society and economy’. I ploughed on for another couple of chapters, but nothing appeared which made up for that dismal sentence so I gave up.

This sustainability ‘balance is a myth’. It is often called ‘weak Sustainability’ and was popular 10-20 years ago. It generally looks like this:

The problems with this model are many: how do you define the purple area? are these requirements always trade offs? what’s the purpose of the economy if it is not part of society? etc etc. It simply doesn’t give you any steer, conceptually or practically. When this model was popular, it didn’t take too much of stretch to describe any project as an example of sustainable development because you could always find an environmental, societal and economic upside.

‘Strong sustainability’ recognises that there are ecological limits. It comes in several forms, such as the ‘fried egg’ model:

In this model, Sustainability is achieved when the economy works for society and society remains within ecological limits, with a healthy margin for nature. Avariation on this is Kate Raworth’s doughnut economy which also respects societal needs and ecological limits. These models are still high level concepts, but they puncture the idea that you can trade environment and, say, economy. It is impossible to argue something is a sustainable development if it, say, contributes to maintaining the carbon footprint of society outside the threshold of dangerous climate change.

In 2019, it is pretty incredible to hear someone use weak sustainability without the context of strong sustainability. Frankly, weak sustainability is not sustainability and belongs in the history books.

End of sermon.