ALLEY: “What we’re concerned about is the possibility that in the earth’s system, there are switches that if we push a little too far, something will tip or something will jump, and we get a different world.”

That’s geologist Richard Alley of Penn State University.

On and off lightbulb

He compares the climate system to a light, and says we typically think of it as being controlled by a dimmer dial: you add a little CO2, it warms accordingly. But the climate is also controlled by switches.

ALLEY: “A switch is different. You push a little bit, and nothing happens. You push a little bit more, and it goes snap, and you get a different state: the light is on or the light is off.”

Think of it like the straw that breaks the camel’s back. For example, if the west Antarctic ice sheet melts, sea levels could rise by more than ten feet – devastating coastal cities.

Some scenarios, such as a giant methane release from the Arctic, currently seem unlikely. But many large and small-scale threats are very real. Like after a forest fire, when grass grows back instead of trees – altering the entire ecosystem.

There are even social tipping points – like a sudden war that breaks out as a result of drought. There are many uncertainties about what tipping points we’ll face when. But Alley says their existence should help motivate action to make them less likely to occur.

Reporting credit: ChavoBart Digital Media.
Photo: Copyright protected.

More Resources
Abrupt Impacts of Climate Change: Anticipating Surprises
Panel Says Global Warming Carries Risk of Deep Changes
Global warming: it’s a point of no return in West Antarctica. What happens next?
Climate change in the Fertile Crescent and implications of the recent Syrian drought

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