The news media has been abuzz this week with reports of a NASA-funded study predicting global collapse. The authors—Safa Motesharrei, Jorge Rivas, and Eugenia Kalnay—do believe the future of global civilization is in danger (which is essentially a consensus view among ecologists, geologists, political scientists, historians, and anyone else who's paying attention), but if you read the study you'll find a lot of humble speculation, several disclaimers, and an honest attempt to wrestle quantitatively with questions that numbers have not traditionally been able to answer.
It all started with Easter Island. Anthropologists have long attempted to figure out what happened to the thriving network of indigenous communities that created the mysterious moai. In the late 1990s, as evidence of a once-thriving ecosystem began to emerge, it became clear that the people of the island simply ran out of natural resources. This clip from a National Geographic documentary on Easter Island sums up the tragic story, which has become a cautionary tale for the rest of us:
In 1998, economists James A. Brander and M. Scott Taylor published a landmark paper on Easter Island. Titled "The Simple Economics of Easter Island: A Ricardo-Malthus Model of Renewable Resource Use," it attempted to determine the mathematical relationship between the island's population and use of resources, using a formula that had been used in the past to accurately predict the relationship between predator animals and their prey. In this case, human beings are treated mathematically as predators, natural resources as prey.
Motesharrei, Rivas, and Kalnay asked a fairly logical question: assuming the mathematics behind the Brander-Taylor paper are sound, what would need to be done in order to apply this kind of formula on a global scale? What they came up with was a mathematical model, which they call Human and Nature Dynamics (HANDY), that they believe can be used to predict the likelihood that we'll all meet the same fate as Easter Island. They think there's a good chance that we will if we don't clean up our act, but it's reasonably safe to say that they already thought this before they wrote the paper, and so did most of the people reading it. What is interesting is the fact that they are trying to explore a challenging interdisciplinary question in a linear and quantitative way. This is bold stuff, and it's exactly the sort of work NASA should be funding, but its conclusions don't carry much predictive weight.
There are various obvious flaws with the study that limit its global applicability. Among them:
But I don't think the authors had intended to give us the last word on the matter. What they did give us was a new way to look at human consumption of natural resources, and they did so in a way that honored what we already know about the persistent urgency of the situation. As W.H. Auden wrote in 1939: "Hunger allows no choice / To the citizen or the police; / We must love one another or die."