Nonprofit, nonpartisan journalism. Supported by readers.


Scientists assess planetary tipping points — and find some may have been reached

Bad news about the state of the planet comes at you in waves, and even the most eco-conscious audience must have a hard time keeping up with the latest threat levels.

An international team of researchers, including two University of Minnesota scientists, is attempting to assess where we are and find us a soft place to land.

In an article to be published Thursday in the journal Nature, they call it a “safe planetary operating space” that they say will lead to a sustainable future. The researchers introduce nine issues that have boundaries or thresholds that humans must respect in order to avoid potentially catastrophic consequences. Much of their analysis is gloomy.

“What is unique is that it is not a bunch of individual pieces but a synthesis,” said Jon Foley, co-author and director of the U’s Institute on the Environment (full disclosure: where I am an associate fellow). “We realize how close we are to the edge of the cliff, tipping the earth to something unrecognizable to us.”

The concept sounds like Malcolm Gladwell’s notion of a “tipping point,” only in this case the issues are not ideas but ecological problems. The nine are:

Climate change
Stratospheric ozone
Land use change
Freshwater use
Biological diversity
Ocean acidification
Nitrogen and phosphorus inputs to the biosphere and oceans
Aerosol loading
Chemical pollution

The authors claim that tipping points may have been reached in climate change, biodiversity and nitrogen inputs. “Observations of a climate transition include the rapid retreat of summer sea ice in the Arctic Ocean, the melting of almost all mountain glaciers around the world, and an increased rate of sea-level rise in the past 10 to 15 years,” said co-author John Schellnhuber, director of the Pottsdam Institute for Climate Impact Research, in a release. And what affects one area could also influence another, the authors note.

Foley said his work shows that the nitrogen pollution is “in excess of anything we’ve seen in geologic history.”

The authors, and there are 28 of them, do not claim that the boundaries are completely exact. It’s more like a first attempt at a map with many unexplored regions.

They expect criticism. “We could wait for a few more decimal points before publishing,” Foley said. “But we felt the core message was sound and important to hear.”

It will be interesting to see what happens to the article, whether it has a chance to be seminal, along the lines of “The Tragedy of the Commons,” or if it passes relatively unnoticed. Only time will tell, of course, and in the meantime the experiments and modeling continue.

You can also learn about all our free newsletter options.

Comments (1)

  1. Submitted by Greg Kapphahn on 09/24/2009 - 05:49 pm.

    The challenge of tipping points in conjunction with biospheric science is that they need to be based in chaos theory. Such tipping points work much like an old fashioned clicking wall switch for your ceiling light.

    A switch of this type resists your effort to flip it up to a certain point, then snaps quite forcefully to the opposite position from which you started.

    In terms of the biosphere, there may also be a considerable time lag before the pressure you’ve been placing on the “switch” begins to have a noticeable effect even though, all the while, the switch is moving toward the snapping point.

    In terms of human experience, this means that nothing much happens, nothing much happens, nothing much happens, nothing much happens, (which is where we are now), then a huge amount happens in a very short time, essentially bringing massive, and to us, unpredictable and interrelated changes which will shift ocean levels, the areas where crops can be grown, precipitation patterns, prevailing winds, and likely a large number of things that we won’t know about until we get there. It’s possible massive population upheavals and shifts will be necessary for human survival.

    What’s worse, we don’t know how close we are to the snapping point on any of these fronts. We don’t even know how the switches are wired or what all they’re connected to. Perhaps it would be wise to do what we can to take the pressure off the switches rather than wait to see if we blow fuses, start fires, turn on the freezers, shut down the furnaces, or even ignite a bombs when they snap.

    It really doesn’t matter how much you hope to make selling the house you’ve inherited (economically exploiting planet earth), if you don’t take care of it (protect it against wanton, preventable damage), if you refuse to buy insurance (take precautions against biospheric damage), if the house burns down (the occurrence of massive global biospheric change), you’ll find you’ve not only lost your most valuable asset, but you’re left with no place to live.

Leave a Reply