Can “Tipping Points” Accelerate Global Warming?

OSLO – Rising temperatures trigger a runaway melt of Greenland’s ice sheet, raising sea levels and drowning Pacific islands and cities from New York to Tokyo.

In Siberia, the permafrost thaws, releasing vast frozen stores of greenhouse gases that send temperatures even higher. In the tropics, the Amazon rainforest starts to die off because of a warmer, drier climate.

Such scenarios may read like the script of a Hollywood disaster movie but many scientists say there are real risks of “tipping points” — sudden, catastrophic changes triggered by human activities blamed for warming the planet.

“Even small risks in the climate need to be considered, just as we try to avert accidents at nuclear power plants,” said Stefan Rahmstorf, a professor at the Potsdam Institute for Climate Impact Research and an expert in ocean currents.

“I don’t think this is scaremongering. We don’t really understand the system,” he said of risks that the warm Gulf Stream current in the North Atlantic might shut down in one possible “tipping point” scenario.

Melting ice in Greenland could send a sudden flow of cool water into the North Atlantic, disrupting the giant current that pulls warm water northwards to create the Gulf Stream.

This might shut down the warm current and could also make parts of Europe and North America sharply colder, despite an overall warming of the climate.

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research credit to MD – thx

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