The Scripps team analyzed air samples gathered over the past 30 years, working under the auspices of the NASA-funded Advanced Global Atmospheric Gases Experiment (AGAGE) network of ground-based stations. The network was created in the 1970s in response to international concerns about chemicals depleting the ozone layer. It is supported by NASA as part of its congressional mandate to monitor ozone-depleting trace gases, many of which are also greenhouse gases. Air samples are collected at several stations around the world. The Scripps team analyzed samples from coastal clean-air stations in California and Tasmania for this research.
The researchers found concentrations of the gas rose from about 0.02 parts per trillion in 1978 to 0.454 parts per trillion in 2008. The samples also showed significantly higher concentrations of NF3 in the Northern Hemisphere than in the Southern Hemisphere, which the researchers said is consistent with its use predominantly in Northern Hemisphere countries. The current observed rate of increase of NF3 in the atmosphere corresponds to emissions of about 16 percent of the amount of the gas produced globally.
In response to the growing use of the gas and concerns that its emissions are not well known, scientists have recently recommended adding it to the list of greenhouse gases regulated by Kyoto.
"As is often the case in studying atmospheric emissions, this study shows a significant disagreement between 'bottom-up' emissions estimates and the actual emissions as determined by measuring their accumulation in the atmosphere," Weiss said. "From a climate perspective, there is a need to add NF3 to the suite of greenhouse gases whose production is inventoried and whose emissions are regulated under the Kyoto Protocol, thus provi
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University of California - San Diego