Friday, December 6, 2013

Scientists warn that warming ‘will be hard to reverse’

Tim Radford in Climate Central: A Swiss-American team of scientists has looked far into the future and calculated that the present lukewarm plans to limit climate change may involve too little action, applied too late.

Thomas Frölicher of ETH-Zurich and colleagues from Princeton report in Nature Climate Change that they tried to model the long-term planetary adjustment after carbon dioxide emissions from fossil fuel burning stopped altogether.

They simulated a planet in which greenhouse gas emissions continued to rise, until concentrations in the atmosphere had reached four times the pre-Industrial levels, and a total of 1,800 billion tons had been released into the atmosphere. And then the emissions stopped.

The consequences were unexpected. The carbon dioxide in the atmosphere would indeed gradually be absorbed by forests, crops, algae and other natural CO2 devourers; it would be incorporated into the calcium shells and corals and skeletons in the ocean and then slowly be tucked away as rock.

But after an initial period in which temperatures started to drop, something else happened. The simulated planet started to warm again, and go on warming for another 400 years or more.

That is because although what scientists call “radiative forcing” – CO2 traps infra-red radiation and keeps the Earth’s temperature up – would begin to ease, the polar oceans that play such a powerful role in the climate machine would become less efficient at removing the surplus heat...

A one-way bearing combining sprags and bearing rollers in one race, via the Goddard Space Center

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