Guardian: The rising demand for flat-screen televisions could have a greater impact on global warming than the world’s largest coal-fired power stations, a leading environmental scientist warned yesterday. Manufacturers use a greenhouse gas called nitrogen trifluoride to make the televisions, and as the sets have become more popular, annual production of the gas has risen to about 4,000 tonnes. As a driver of global warming, nitrogen trifluoride is 17,000 times more potent than carbon …