Scientists Discover Potent New Greenhouse Gas
August 24, 2000
Scientists have found rising concentrations of a newly identified gas in the air that traps heat more effectively than all other known greenhouse gases, the dozens of compounds released by industry and the burning of fuels that may be warming the global climate.
According to a study by William T. Sturges, of the University of East Anglia, and others in the journal Science:
- The synthetic gas -- trifluoromethyl sulfur pentafluoride, or SF5 CF3 for short -- is extremely rare, reaching concentrations just over one-tenth of one part per trillion of air.
- But concentrations of the gas are rising by about 6 percent per year, the gas probably takes more than 1,000 years to break down and its source - although certainly from human activities - is a mystery.
- Molecule for molecule, it is 18,000 times as effective at trapping heat in the atmosphere as carbon dioxide (CO2), the most familiar greenhouse gas.
- Scientists calculate that 4,000 tons of SF5 CF3 have been released, with 270 tons emitted each year.
The gas was found in samples taken by instrument-laden balloons 21 miles in the stratosphere and in air trapped under layers of Antarctic snow. Its discoverers found no evidence of the gas in the air before the 1950s, with only a scattering of molecules appearing in the 1960s and then a steady rise.
Although synthesized 40 years ago, SF5 CF3, an inert flourine compound, has never found much use. It was briefly employed about 30 years ago as a chemical tag to track the flow of pollution from smokestacks. Scientists speculate that the atmospheric SF5 CF3 is a byproduct of some industrial process or secret military program.
Source: Andrew C. Revkin (New York Times News Service), "Scientists keeping eye on rare yet potent new greenhouse gas," Dallas Morning News, July 29, 2000.
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