New greenhouse gas threat

Greenhouse gases prevent heat escaping from Earth

Scientists have discovered a potent new greenhouse gas in the Earth's atmosphere.

The UK, German and US researchers stumbled across the molecules while they were studying other greenhouse gases.

Trifluoromethyl sulfur pentafluoride is said to be 18,000 times better at trapping heat than the main human contribution to the greenhouse effect, carbon dioxide.

One of the researchers, Dr Bill Sturges, from the University of East Anglia, UK, says only tiny amounts of the gas have been detected in the atmosphere so far. He believes it has only been present for the past 40 years.

This suggests, Dr Sturges believes, that trifluoromethyl sulfur pentafluoride is a by-product of a human activity; possibly generated by high-voltage equipment. Apart from their heat-trapping abilities, the new molecules are also thought to be very long-lived are growing in number by about 6% per year.

But, although trifluoromethyl sulfur pentafluoride is a potent greenhouse gas, Dr Sturges says its current low levels are unlikely to have a significant effect on global warming.

The greenhouse effect is the term that describes the role the atmosphere plays in insulating and warming the Earth's surface. The atmosphere is largely transparent to incoming solar radiation which strikes and warms the planet's surface. The surface then re-emits the radiation at longer wavelengths which can be trapped by certain trace gases in the atmosphere, such as water vapour and carbon dioxide.

It is this absorption of infrared radiation by the atmosphere that keeps our planet at a habitable temperature.

However, most, but not all researchers, believe human activity is now raising average global temperatures by increasing the load of trace gases in the atmosphere.

The trifluoromethyl sulfur pentafluoride research is published in the journal Science.