Messing with Probabilities, Impacts, Black Swans

Shuffling cards (Lee Daniel Crocker)How do you prepare for “high impact-low probability” events? That’s a phrase that crops up regularly in global warming research and insurance industry talk. It’s also one that’s given me increasing pause, especially since I’ve begun reading Nassim Nicholas Taleb’s “The Black Swan: The Impact of the Highly Improbable.”

Taleb’s argument is this: that it’s the low-probability, high-impact, random and unpredictable events that have shaped human history, rather than the events everyone “saw” coming (only in retrospect, typically).

Thinking about this, I realized the same argument applies to Earth’s history. How, after all, do we slice up 4.5 billion years of geological time? We use geologic periods whose boundaries are usually catastrophic — low-probability but high-impact — events.

For instance, the “Great Dying” between the Permian and Triassic ages around 250 million years ago, caused more species to die out than any other mass extinction event on Earth. One theory for its cause was a huge meteor impact — something that wasn’t predictable then, but might be today. Another hypothesis, though, suggests a sudden and massive release of clathrates, which are basically greenhouse gases stored in crystalline form under the floors of the oceans.

Now, consider the present day. There are still clathrates under the oceans and methane stored in permafrost. There are also tons of human-created carbon that has — until now — been safely stored away in the seas, soils, plants and trees. And there’s a body of scientific opinion that states we’re already in the midst of the Earth’s sixth mass extinction.

To all the uncertainties that already guide Earth’s path through time, we’re now deliberately throwing gasoline onto the fire in fhe form of ever-rising greenhouse gas emissions. In a recent study on “Florida and Climate Change,” Tufts University researchers Elizabeth A. Stanton and Frank Ackerman put it this way: we’re changing our deck of climate cards — already impossible to predict for each individual draw — by adding more cards that change the odds further.

That sounds to me like we’re making the “low probability-high impact” event even more probable. What do you think?

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