Back in 1997, ecologist Robert Constanza and a team of researchers set out to quantify a seemingly unquantifiable abundance: the value, in dollars, of the world's ecosystems.
But first they needed a good, concrete list of what exactly it was the ecosystems provide. They came up with 17 discrete categories, which they labeled "ecosystem services," although some are technically goods. There were the obvious things, like food (game, fish, nuts, and so on) and raw materials (timber, fuel, etc.). But there were also more subtle effects, such as how wetlands protect some coastal areas from the battering of storms or how forests convert carbon dioxide into oxygen. Cultural and recreational uses also made the list.
And so what's the value of all that? Or, as the authors framed it, how much would we have to pay to recreate those services if for some reason they didn't occur naturally? Fifteen years ago, they estimated that cost to be around $33 trillion ($48.7 trillion in today's dollars)—more than the GDP of the entire globe at the time.
Now Constanza has returned to this project and, in a new paper co-authored with many of his original collaborators, he concludes that that 1997 estimate fell quite short. Armed with data from a massive international survey of ecosystems and their relationships with human well-being in communities around the world, Constanza and his team now say that ecosystems are worth way, way more than they had thought: $142.7 trillion.