MELISSA BLOCK, host:
From NPR News, this is ALL THINGS CONSIDERED. I'm Melissa Block.
ROBERT SIEGEL, host:
And I'm Robert Siegel. Here's a puzzle for you. What do sardine populations, Wall Street and Antarctica have in common? Well, the answer is, they can all reach a critical moment — a tipping point — and change dramatically and unexpectedly. Fish populations can crash. Markets obviously can, too. And Antarctic ice shelves can melt with little warning. Those sudden changes have an enormous impact. So, it would be great to know about them before they happen. As NPR's Richard Harris reports, some scientists believe that tipping points might be predictable.
RICHARD HARRIS: At first blush, a financial market and a melting ice shelf may seem to be so utterly different that there's nothing to learn about one, if you study the other. But look a little more closely and there are deep patterns. Ice can stay stable for long periods of time, but with the right trigger, it can melt down rapidly. And George Sugihara at the Scripps Institution of Oceanography says, we all know that financial markets can do the same.
Professor GEORGE SUGIHARA (Biological Oceanography, Scripps Institution of Oceanography): What really sort of captures my imagination about all of this is the fact that you get similar kinds of behavior across many different kinds of systems.
HARRIS: Sugihara, like colleagues around the world, has been trying to describe mathematically how tipping points occur. And he's not just interested in what a system looks like as it goes over a catastrophic tipping point. He's interested in what happens right before that moment.
Prof. SUGIHARA: What's intriguing is that a lot of these things have similar precursors, or similar early signals.
HARRIS: For example, in certain kinds of systems, there's an eerie quiet — the calm before the storm. Other systems behave differently. Financial markets start behaving erratically right before they reach a tipping point, he says.
Prof. SUGIHARA: There are a number of papers citing an increase in volatility just prior to a large systemic event, although there's some evidence to the contrary also.
HARRIS: The challenge is to look at a system that still seems to be stable and tell whether it's running headlong toward a tipping point. Sugihara is optimistic about our ability to predict that. He was among the authors of a recent report in the journal Nature that explores that possibility. And the stakes are huge. Think of possible tipping points in the global climate. A catastrophic change in Greenland ice-melting could rapidly raise sea level. A dramatic shift in rainfall patterns could plunge areas into perennial drought. Ocean circulation shifts could actually make Europe get chilly.
Professor JONATHAN OVERPECK (Atmospheric Sciences, University of Arizona): These things all would make the impacts of climate change much worse if they were to occur.
HARRIS: That's Jonathan Overpeck at the University of Arizona.
Prof. OVERPECK: So it would be wonderful if we could see them coming.
HARRIS: Overpeck says, for example, water resource managers can plan ahead if they can tell the difference between a temporary drought and a permanent new climate regime. But advance knowledge can only help so much. Say, rainfall shifted away from the Amazon rain forest, as some scientists project. The result would be that one of the most lush, diverse and productive ecosystems on Earth could turn into grassland.
Prof. OVERPECK: That could occur very quickly, in the matter of just, you know, years to decades.
HARRIS: If you could see that that was coming, would you still have time to do something about it?
Prof. OVERPECK: Well, probably not.
(Soundbite of laughter)
HARRIS: And that's just one of the drawbacks about predicting ecological tipping points. Another is that it is really hard to do. Rob Jackson at Duke University says scientists have been on this quest for many decades.
Professor ROB JACKSON (Biology, Duke University): Our track record in predicting tipping points, however, is weak. We missed the ozone hole, we missed the rapid melting of the North Pole in the last few years. And we missed last year's stock market crash. So, I can't help but wonder, what will we miss this year.
HARRIS: Fortunately, you don't need to predict a specific catastrophe to make use of tipping point math. George Sugihara from Scripps says, for example, even if you can't predict that a particular fishery is on the verge of collapse, we know more broadly that laws that regulate fishing are pushing fish populations too close to their tipping points. And that's flirting with disaster.
Prof. SUGIHARA: Fishing up to the tipping point is a really bad idea. You want to fish well below the tipping point.
HARRIS: So, he says we should revisit the laws that put these fisheries at risk. Sugihara says we also need better data for all systems that are in jeopardy. Unfortunately, in some cases information is getting worse. For example, we're losing climate-monitoring satellites faster than they're being replaced. And even the financial world has paid little attention to systemic tipping points, Sugihara says.
Prof. SUGIHARA: There's very little being thrown at this problem in any intelligent way. To me that's a total mystery.
HARRIS: He's hoping this quiet field of research will reach its own tipping point, and finally get the attention it needs.
Richard Harris, NPR News.
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