Long-lived carbon dioxide warms the world for many millennia By Tim Radford

Gun the engine, and the ignition of fossil fuel produces not just working energy but heat that dissipates quickly into the atmosphere. But it also produces carbon dioxide that dissipates into the atmosphere.

And in less than two months, according to new research, that pulse of carbon dioxide will have engendered more heat for the planet than the original touch of the accelerator. Xiaochun Zhang and Ken Caldeira of the Carnegie Institution at Stanford, California, in the United States report in Geophysical Research Letters that the carbon dioxide warming exceeds the heat released by a single act of oil combustion in just 45 days.

Light the gas in the cooking stove and the heating cost to the planet is exceeded in 59 days. Burn a lump of coal, and the atmosphere feels the greater heat in just 34 days. And in all three cases, the pulses of carbon dioxide will go on heating the planet – and on, and on.

“Ultimately, the warming induced by carbon dioxide over the many thousands of years it remains in the atmosphere would exceed warming from combustion by a factor of 100,000 or more,” said Professor Caldeira.

No escape

Caldeira and another colleague only recently calculated that the average interval between the combustion of fossil fuel and the consequent global warming was about 10 years. The latest research involves no contradiction.

“It takes a decade before we feel the maximum amount of warming caused by a CO2 emission (and it stays warm for many centuries, if not millennia). Energy is added to the atmosphere from the heat given off when a lump of coal is burned. Meanwhile, the CO2 given off in that burning prevents energy from escaping the atmosphere and going into outer space.

“This also results in more energy in the atmosphere. It only takes a month-or-so time scale before the greenhouse effect caused by CO2 emitted upon combustion prevents an amount of energy from escaping to space equivalent to the amount of energy released upon combustion.

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