“…climate change is causing more climate change…”
— Nancy Fresco, Professor of Arctic Research, University of Alaska
When you were a kid, did you ever walk out on a cantilevered log to see how far you could go before it tipped? If you did, you quickly learned that you couldn’t tell where the tipping point was until you were beyond it, and your support toppled. (If you were a smart kid, the log would be only a couple of feet above the ground.)
Soon, you probably discovered a little balancing game: by spreading your feet apart, you could position your center of gravity above the point of no return and shift your weight so you could push the support down and, just before it tipped, shift your weight back and keep it horizontal.
We’re playing that game, in a far more dangerous way, with the environment. We’ve pushed environmental degradation close to the tipping point where the global ecosystem will continue to collapse on its own.
That bears repeating, because the best working definition of the environmental tipping point might be this: It is the point at which the biosphere starts to die off — becomes significantly degraded — due to its own feedback mechanisms, irrespective of harmful or helpful human interference. Once we’ve done a certain amount of damage, nature takes over and damages itself at an accelerating pace that we are helpless to correct.
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Have we reached that point? Like the kid making his or her first foray onto a log, we have no way to tell whether we’ve passed the point of no return until we have, in fact, passed it. But a good indicator that we’re on the brink is when we see our policies and activities triggering feedback loops that propel environmental collapse.
This summer’s subarctic and tropical wildfires — exacerbated by our warmer, drier climate — are generating feedback loops that, combined, have potential runaway consequences for the entire planet.
The fires burning in Alaska and northern Canada, but primarily in Siberia, are contributing to climate change in three ways: (1) through the release of carbon dioxide, which adds to global heating: (2) through the release of “black carbon” (soot) which lands on glaciers and ice fields, darkening them and causing them to melt faster and (3) through deforestation which leads to direct warming in the fire areas. And of course, increased global heating means more, and more intense wildfires — feedback in action.
Now, wildfires occur naturally in northern forests. But what’s unprecedented is the scale of this summer’s events. By mid-August, an area roughly the size of West Virginia had burned in Siberia. The conflagrations had released an estimated 138 megatons of carbon dioxide, far more than can be absorbed through natural reforestation for several decades.
Alaskan wildfires released 50 megatons of carbon in June alone, more than the total released by wildfires in the previous eight years. (Note that process acceleration is one characteristic of feedback behavior.)
Meanwhile, by mid-August there were more than 72,000 fire outbreaks in Brazil, an 84% increase over last year’s numbers. For decades, scientists have predicted that if Amazonian deforestation reaches a certain level, the entire forest will no longer be able to maintain its self-sustaining hydrological cycle and will die, leaving an arid wasteland in its stead.
Ecologists who study the Amazon region have determined that at the rate deforestation has been occurring over recent decades, that tipping point might be reached in 25 years. But some experts predict that this summer’s fires alone could shave five years off that estimate, setting off an unimaginable series of feedbacks throughout the biosphere.
Playing balancing games on a log that’s teetering over an abyss can prove fatal at our ecological house.
Philip S. Wenz is the author of the E-book "Your Ecological House," available at all major electronic book distributors.