Amounts of Two New Greenhouse Gases Increasing
Rising Levels of NF3 and SO2F2 are Just Starting to be Measured
Mar 28, 2009
The discovery was made by an international research team led by scientists from the Scripps Institution of Oceanography in the US and CSIRO scientist, Dr Paul Fraser, from the Centre for Australian Weather and Climate Research.
They took measurements – the first atmospheric observations of the two gases – from data collected around the world, and particularly at three places know to have very clean air, Trinidad Head and La Jolla, California, and Cape Grim, Tasmania.
Their findings were presented by Dr Fraser at the GREENHOUSE 2009 conference in Perth, Western Australia during March 2009.
Replacing One Problem Gas with Another
Dr Fraser said the two powerful greenhouse gases were used in industrial processes in place of other, ozone-damaging gases.
NF3 is used in the electronics industry – often as a replacement for perfluorocarbons (PFCs) – particularly in the manufacture of liquid-crystal flat-panel screens.
SO2F2 is used as a replacement for methyl bromide, largely in structural fumigation applications.
“Information about the abundance of these gases in the atmosphere, their growth rates, lifetimes, and emissions is just emerging,” he said.
“Currently the level of these gases in the atmosphere is low, but their concentration is growing. In addition, these gases have significant global-warming potential.”
USA and Korea are probably the greatest emitters of NF3, and USA and the EU the leading SO2F2 emitters.
Industries Need Alternatives to NF3 and SO2F2
Dr Fraser said industries that used NF3 or SO2F2 would have to find less polluting replacements, now that they are known to be greenhouse gases.
“In the case of NF3, less polluting alternatives will be possible, and the electronics industry will be able to survive by ensuring emissions are kept to near zero.”
However, he warned that replacing SO2F2 would be harder to replace, as it is required for quarantine fumigation, “and as such is more important to be used despite greenhouse gas pollution.
“Efforts will have to be made to minimize emissions and technologies already exist to ensure this happens.”
Emissions Targets and The Kyoto Protocol
Dr Fraser said the team’s research is likely to affect the revision of the Kyoto Protocol later this year.
“New emissions targets for the existing ‘basket’ of gases (carbon dioxide, methane, nitrous oxide, PFCs, hydrofluorocarbons, sulfur hexafluoride) are likely, as well as inclusion of these new greenhouse gases,” he said.
A number of new signatories from the developed and developing world are also included in the revised Protocol.
Other Unmeasured Greenhouse Gases
SO2F2 and NF3 are not the only ‘new’ greenhouse gases, he said, and several others remain to be measured for the first time.
“There are probably many other greenhouse gases that have not yet been properly characterized to date.
“The Kyoto Protocol covers many HFCs, PFCs etc not yet measured. Two that I am aware of are C4F8 and CF3SF5.”
C4F8 (Octafluorocyclobutane or Perfluorocyclobutane) is another gas used by the electronics industry in semiconductor manufacturing.
CF3SF5 (Trifluoromethyl sulfur pentafluoride) is a byproduct of the electronics industry, and is most likely a breakdown product of the dielectric molecule SF6 in high-voltage equipment, according to the Royal Society of Chemistry’s journal, Education in Chemistry.
The new measurements of SO2F2 appear in a paper co-authored by Dr Fraser in the 12 March 2009 edition of the Journal of Geophysical Research.
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