LCD TVs, praised as being greener than old-style tellies because they consume much less power, may actually be speeding climate change, a chemical expert has warned.

Michael Prather of the University of California at Irvine has completed a study which claims that atmospheric quantities of the gas Nitrogen Trifluoride (NF3) are booming. He reports his findings in the latest issue of the journal Geophysical Research Letters.

NF3 is 17,200 times better at trapping heat in the atmosphere over a hundred-year period than is carbon dioxide, the best known greenhouse gas. NF3 has a characteristic mouldy smell and is thought to be highly harmful to the liver and kidneys.

The chemical is used in the production of flat-panel displays which, in turn, are used to make today's TV screens. Prather believes that exploding demand for HD TVs around the world has created a huge need for NF3, and that's sending emission levels sky high.

The problem is, NF3 emission levels aren't being measured by the worldwide greenhouse-gas monitoring programme put in place by the Kyoto Protocol on climate change.

When the agreement was signed by 181 countries in 1997, NF3 wasn't included on the list of gases that should be tracked because at that time the compound's manufacture was miniscule.

But, says Prather, thanks to NF3's use in flat-panel display production, that's no longer the case. NF3's global-warming potential is second only to sulfur hexafluoride (SF6), the nastiest greenhouse has on the Kyoto list.

Most TV manufacturers already sell sets by pushing their eco-credentials. But while vendors tout their sets energy efficiency, NF3 is rarely mentioned.

'HD TV gas' 17,000 times worse for planet than CO2