If you want to fight global warming, don't buy a flat-screen TV. The nitrogen triflouride used in their production could have a greater impact on climate change than coal-fired power stations.

That's the message from Michael Prather, director of the environment institute at the University of California, Irvine, who points out that with demand for the new technology "exploding", so is production of this dangerous gas - a gas 17,000 times more potent than carbon dioxide, and which lasts about 550 years in the atmosphere.

Some 4,000 tonnes of nitrogen triflouride are now made annually, and with production of flat-screen TVs expected to double next year, likely so too will the gas supply. Moreover, unlike common industrial greenhouse gases such as sulphur hexafluoride (SF6) and perfluorocarbons (PFCs), emissions of NF3 are not restricted by the Kyoto protocol or in national reporting under the United Nations Framework Convention on Climate Change (UNFCCC).

Prather and colleague Juno Hsu, of the Earth System Science Department at Irvine, writing in the journal Geophysical Research Letters (June 26), state that this year's production of the gas is equivalent to 67m tonnes of carbon dioxide, meaning it has "a potential greenhouse impact larger than that of the industrialised nations' emissions of PFCs or SF6, or even that of the world's largest coal-fired power plants."

While concerns have led Toshiba Matsushita Display Technology to avoid using the gas, Air Products, which produces it for the electronics industry, told New Scientist that very little nitrogen trifluoride is released into the atmosphere. But Prather argues that as the gas is not controlled in the same way as other greenhouse gases, companies may be careless with it.

They say it is urgent that atmospheric observations are made to document NF3 emissions, as currently there are only such subjective anecdotal claims that little is being released.