While washed up in Manaus, I’ve taken a few hours to catch up on some recent papers in the (technical) ecological literature. A new paper by Egbert van Nes et al. in the most recent issue of Trends in Ecology and Evolution caught my attention. Entitled “What do you mean, ‘tipping point’?“, van Nes et al. encapsulate well the competing ideas and definitions of tipping points in the ecological and broader literature, but then end up arguing for a broad definition: “any situation where accelerating change caused by positive feedback drives the system to a new state.” But they then go on to say that their “proposed definition essentially boils down to the necessary conditions for [Malcom] Gladwell’s examples where a small initial change makes a big difference.”
I think this is unfortunate. They give too much credence to Gladwell’s sloppy handling of tipping points in his book, their broad definition will lead to a proliferation of “tipping points,” and such vagueness can only result in so much watering down of the term as to render it meaningless.
So with that in mind, I offer up for today’s posting an essay I wrote three years ago but never published. I post it here, unedited from 11 September 2013 (albeit with a few [editorial clarifications]). Perhaps an updated version could find a broader audience somewhere; suggestions welcome!
On tipping points, regime shifts, and the balance of nature
“Five-nine” doesn’t have quite the cadence as “nine-eleven,” but when we look back on the early 21st century, May 9, 2013—the day that the concentration of carbon dioxide (CO2) in the atmosphere exceeded 400 parts per million (ppm) for the first time in recorded history—may be seen as a far more important date than September 11, 2001. If the scenario described in the Scientific Consensus on Maintaining Humanity’s Life Support Systems in the 21st Century by Anthony Barnowsky and his colleagues at Berkeley[1], along with more than 500 other scientists, including Nobel laureates, members of the National Academies of Sciences, and other luminaries is true, Five-nine will be seen as the long-anticipated tipping point whereby human impacts have caused irrevocable harm to our planet. Or perhaps not. Perhaps there is still time to take the concrete, immediate actions Barnowsky et al. suggest—suggestions echoed by President Barack Obama in his June 25 [2013] speech at Georgetown University—that would ensure a sustainable, high-quality future. Or maybe we’ll just keep muddling along, slowly and steadily acclimating to our new lives on a now unfamiliar world, which, to distinguish it from our familiar “Earth,” Bill McKibben christened “Planet Eaarth”: durably, sturdily, stably, hardily, and robustly.




