Anthropologist Terry Hunt of the University of Hawaii tells a good scientific tale in American Scientist. He came to Easter Island, aka Rapa Nui, believing–as we’ve been told for years–that it was a poster child for how overpopulation and overuse of scarce resources can lead to ecological collapse. But over several years he’s found converging strands of evidence that introduced rats may have had more to do with the deforestation of Easter Island than did its Polynesian settlers. (There may have been a peak rat population of more than 3 million on the small island.)

“The human population probably reached a maximum of about 3,000, perhaps a bit higher, around 1350 AD and remained fairly stable until the arrival of Europeans,” Hunt writes. “The environmental limitations of Rapa Nui would have kept the population from growing much larger [as previously thought]. By the time Roggeveen arrived in 1722, most of the island’s trees were gone, but deforestation did not trigger societal collapse, as Diamond and others have argued.” If Hunt’s findings hold up, Easter Island isn’t a microcosm of the planet, but it may still be a more prosaic warning about invasive species.

Diamond, of course, is Jared Diamond, author of Collapse: How Societies Choose to Fail or Succeed, reviewed in the Reader March 4, 2005. Hunt is a credible critic, as he’s a professional anthropologist who doesn’t have an ax to grind.

Unfortunately there are plenty of ax-grinders out there, such as “slithering reptile” at Not PC, who are happy to use Hunt’s findings just as Diamond used the reports he drew on: as confirmation of stuff they already believed.

The research on Easter Island has made it out of the academic anthropology journals because it’s ammo for these two sides. For want of better labels, they are:

 

  • “Environmentalists” who think we’re in a world of trouble, and the way to deal with it is to conserve and cut back on our use of natural resources, and

  • “Antienvironmentalists” who think we’re in very little trouble, and if we are the way to deal with it is to put a price tag on everything and let the capitalists sort it out.

 

I have one foot firmly in each camp–I’ve criticized Diamond for selecting just-so stories from the historical record and disregarding the parts that don’t fit his thesis. So my strongest sympathies lie with neither. We need more people like Terry Hunt.  I don’t just mean scientists; I mean people who can take seriously evidence that doesn’t fit their pre-ordained worldviews.  Hunt’s conclusion: 

“I believe that the world faces today an unprecedented global environmental crisis, and I see the usefulness of historical examples of the pitfalls of environmental destruction. So it was with some unease that I concluded that Rapa Nui does not provide such a model. But as a scientist I cannot ignore the problems with the accepted narrative of the island’s prehistory. Mistakes or exaggerations in arguments for protecting the environment only lead to oversimplified answers and hurt the cause of environmentalism. We will end up wondering why our simple answers were not enough to make a difference in confronting today’s problems.

“Ecosystems are complex, and there is an urgent need to understand them better. Certainly the role of rats on Rapa Nui shows the potentially devastating, and often unexpected, impact of invasive species. I hope that we will continue to explore what happened on Rapa Nui, and to learn whatever other lessons this remote outpost has to teach us.”

Will Jared Diamond acknowledge new evidence and be part of this solution?  His friend Paul Ehrlich never did.