Two new greenhouse gases – one emitted by the electronic industry and the other used in pest control – are rapidly accumulating in the atmosphere, say researchers.
And they say countries should consider including these gases for control in the revision of the Kyoto Protocol due later this year.
Climate scientist Dr Paul Fraser of CSIRO Marine & Atmospheric Research reports the measurements of nitrogen trifluoride (NF3) and sulfuryl fluoride (SO2F2) at the Greenhouse 2009 conference in Perth this week.
“Although their abundance in the atmosphere is quite low their growth rates are relatively high,” says Fraser, who worked with a team at the Scripps Institution of Oceanography in the US.
Fraser says industry began using the two industrial gases from the late 1990s, partly as alternatives to other harmful greenhouse and ozone-depleting gases.
He says NF3 was chosen by the electronics industry to replace perfluorocarbons (PFCs), particularly in the manufacture of circuit-boards in liquid-crystal flat-panel screens.
SO2F2 was chosen to replace methyl bromide as a fumigant.
Fraser says the International Panel on Climate Change identified the greenhouse potential of NF3 and SO2F2 over a decade ago, but he and colleagues have only recently begun measuring their atmospheric accumulation.
They measured the gases, which are circulating the globe, at various locations including Trinidad Head, La Jolla in California, and Cape Grim in Tasmania.
“[The gases are] in the clean air coming off the Southern Ocean in Tasmania,” says Fraser.
He says NF3 is 17,000 times more potent than CO2, while SO2F2 is 5000 times more potent.
They are currently only present at a concentration of 10 parts per trillion in the atmosphere, but are growing at around faster than any of the greenhouse gasses included in the Kyoto Protocol, says Fraser.
NF3 is growing at 11% a year, while SO2F2 is growing at 5% a year, he says.
Research on SO2F2 is published in the 12 March edition of the Journal of Geophysical Research.
Kyoto Protocol revision
Currently the Kyoto Protocol sets emission targets for six gases – carbon dioxide, methane, nitrous oxide, PFCs, hydrofluorcarbons and sulfur hexafluoride.
It does not cover greenhouse gases such as chlorofluorocarbons (CFCs) as these are already being controlled by the Montreal Protocol.
Fraser says consideration has to be given to whether NF3 and SO2F2 should be included in a future version of the Kyoto Protocol.
“Whether we control them or not, we have to take into account their current and future impact if we want to be able to predict climate change,” he says.
Fraser says while the new gases would have less than 1% impact on climate by 2050, controlling NF3 is particularly important because it persists for hundreds of years in the atmosphere.
“Mitigation efforts to achieve a 1% reduction in emissions are quite significant, so I guess here’s an opportunity to avoid that mitigation by not allowing it to happen,” he says.