My argument is simple: for the first time in history, we can improve human wellbeing while reducing our environmental impact.

It’s common to think that sustainability — or, rather, our lack of sustainability — is a new problem. For most of human history, our ancestors lived sustainably, and only recently has that been knocked off-balance.

Coming from an environmental background, I would have said the same. Look at any series of graphs on environmental pressure, and it’s not hard to see why people would frame it as a new problem. Plot global curves of carbon dioxide emissions, land use, air pollution, global temperatures, or fertiliser use, and they all rise sharply in the last century. It creates the impression that things were fine, but now they’re really not. It’s these curves that often make people — especially young people — feel fatalistic about the future. I was certainly one of them.

By this definition of environmental pressure, it is true that the world has become much less sustainable in modern history. But that only captures half of the story.

To me, sustainability means more than that. Yes, I care deeply about the environment: to protect opportunities for future human generations that come after us, but also to preserve a liveable world for other species and ecosystems. But I also care about the billions of people who are alive today. I want them to be able to live a good life; healthy, well-fed, poverty-free, content, and with opportunities to flourish in whatever way they wish.

By this broader definition, humans have never been truly sustainable. Yes, many generations of our ancestors had a lower environmental impact than we do today. But by many basic metrics of human wellbeing, life was not good.