New greenhouse gas 4,800 times worse than carbon dioxide

March 12th, 2009 - 5:57 pm ICT by IANS  

Washington, March 12 (IANS) A gas used in fumigation can potentially contribute to future global warming, but because its production has not yet reached high levels there is still time to nip this potential contributor in the bud.
Scientists at MIT, Scripps Institution of Oceanography in San Diego and others have measured the levels of sulphuryl fluoride in the air and determined its emissions and lifetime to help gauge its potential future effects on climate.

Sulphuryl fluoride was introduced as a replacement for methyl bromide, a widely used fumigant that is being phased out under the Montreal Protocol because of its ozone-destroying chemistry.

Methyl bromide has been widely used for insect control in grain-storage facilities, and in intensive agriculture in arid lands where drip irrigation is combined with covering of the land with plastic sheets to control evaporation.

“Such fumigants are very important for controlling pests in the agricultural and building sectors,” said Ron Prinn, director of MIT’s Centre for Global Change Science and a co-author of the new paper.

Researchers “indicate that, tonne for tonne, it is about 4,800 times more potent a heat-trapping gas than carbon dioxide”, said Prinn.

But with methyl bromide being phased out, “industry had to find alternatives, so sulphuryl fluoride has evolved to fill the role,” he said, according to an MIT release.

Until the new work, nobody knew accurately how long the gas would last in the atmosphere after it leaked out of buildings or grain silos. “Our analysis has shown that the lifetime is about 36 years, or eight times greater than previously thought, with the ocean being its dominant sink,” Prinn said.

The study was published this month in the Journal of Geophysical Research.

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