Potent greenhouse gas more prevalent in atmosphere than previously assumed

October 23, 2008,

Different generations of collection cylinders used to collect air samples from locations around the world over the past 30 years. Scripps Institution of Oceanography at UC San Diego geochemistry researchers Ray Weiss and Jens Muehle led a study that found that the greenhouse gas nitrogen trifluoride, used in the manufacture of flat-panel monitors, escapes to the atmosphere at levels much higher than previously assumed. Credit: Scripps Institution of Oceanography, UC San Diego
(PhysOrg.com) -- A powerful greenhouse gas is at least four times more prevalent in the atmosphere than previously estimated, according to a team of researchers at Scripps Institution of Oceanography at UC San Diego.

Using new analytical techniques, a team led by Scripps geochemistry professor Ray Weiss made the first atmospheric measurements of nitrogen trifluoride (NF3), which is thousands of times more effective at warming the atmosphere than an equal mass of carbon dioxide.

The amount of the gas in the atmosphere, which could not be detected using previous techniques, had been estimated at less than 1,200 metric tons in 2006. The new research shows the actual amount was 4,200 metric tons. In 2008, about 5,400 metric tons of the gas was in the atmosphere, a quantity that is increasing at about 11 percent per year.

"Accurately measuring small amounts of NF3 in air has proven to be a very difficult experimental problem, and we are very pleased to have succeeded in this effort," Weiss said. The research will be published Oct. 31 in Geophysical Research Letters, a journal of the American Geophysical Union (AGU).

Emissions of NF3 were thought to be so low that the gas was not considered to be a significant potential contributor to global warming. It was not covered by the Kyoto Protocol, the 1997 agreement to reduce greenhouse gas emissions signed by 182 countries. The gas is 17,000 times more potent as a global warming agent than a similar mass of carbon dioxide. It survives in the atmosphere about five times longer than carbon dioxide. Current NF3 emissions, however, contribute only about 0.15 percent of the total global warming effect contributed by current human-produced carbon dioxide emissions.

Nitrogen trifluoride is one of several gases used during the manufacture of liquid crystal flat-panel displays, thin-film photovoltaic cells and microcircuits. Many industries have used the gas in recent years as an alternative to perfluorocarbons, which are also potent greenhouse gases, because it was believed that no more than 2 percent of the NF3 used in these processes escaped into the atmosphere.

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 providing meaningful incentives for its wise use."

"This result reinforces the critical importance of basic research in determining the overall impact of the information technology industry on global climate change, which has already been estimated to be equal to that of the aviation industry," added Larry Smarr, director of the California Institute for Telecommunications at UCSD, who was not involved in the Scripps study.

Michael Prather is a UC Irvine atmospheric chemist who predicted earlier this year that based on the rapidly increasing use of NF3, larger amounts of the gas would be found in the atmosphere. Prather said the new Scripps study provides the confirmation needed to establish reporting requirements for production and use of the gas.

"I'd say case closed. It is now shown to be an important greenhouse gas," said Prather, who was not involved with the Scripps study. "Now we need to get hard numbers on how much is flowing through the system, from production to disposal."

Paper: dx.doi.org/10.1029/2008GL035913

Provided by University of California - San Diego

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4.6 / 5 (12) Oct 23, 2008
"NF3 was originally chosen in about 2000 as an environmentally preferable substitute for perfluorocarbons such as hexafluoroethane and sulfur hexafluoride."

haha, whoops. This calls for radical knee-jerk reaction.
4.4 / 5 (7) Oct 23, 2008
...nitrogen trifluoride, used in the manufacture of flat-panel monitors...

And solar panels.
4.2 / 5 (6) Oct 23, 2008
clean green
4 / 5 (8) Oct 24, 2008
These clowns have managed to get almost everything wrong under the Sun but now they are going to demand government regulation of yet another component of the environment. Presumably that will mean more bureaucrats wandering around the floors of factories doing tests and puttering about the halls of Congress gesticulating wildly with alarm and more international conferences now on the evils of NF3. These guys are like a plague of locusts, not scientists.

You want to do some research on this and subject it to long term testing and peer review, fine. But I see in the article that they are pushing for new regulations of something they barely can measure accurately let alone understand.
4.3 / 5 (8) Oct 24, 2008
Velanarris: That's strange with the required educational background for news reporters.

I know they don't have to have a real post secondary education... or even have read a book. But you know they can sort of read, since they read the prompter. I don't blame the TV faces it the jerk intern typing the teleprompts in.

Interns have taken control of the media. And all this time everyone has been fighting over whether is the GOP, Dems, or machines, ignoring the real threat.
3.5 / 5 (6) Oct 24, 2008
Ultimately most of the reasonable steps to prevent AGW are good for us. I support "Green" power because I loathe our dependence on foreign oil and I hate paying for gas when I commute to work everyday.

The problem comes when false markets (ie cap and trade) and unnecessarily restrictive legislation comes into play. I agree with Velanarris' statements about the effect of the alarmist media and have commented on this problem before.

In the mean time I have the perfect solution to placate those that fear AGW will destroy us all. Methane is a potent greenhouse gas. Everyone of us produce it. If you really want to save the planet from AGW I suggest you get one of these for yourself, your friends, and your family.
3.3 / 5 (7) Oct 24, 2008
... I don't blame the TV faces it the jerk intern typing the teleprompts in.

Interns have taken control of the media. And all this time everyone has been fighting over whether is the GOP, Dems, or machines, ignoring the real threat.
You are absolutely off your rocker if you think interns run the media.

No, he's off his teleprompter.
3 / 5 (4) Oct 26, 2008
Pretty soon all energy will be produced in India, China, Russia and Texas. Come on down. In spite of Global Warming the weather is great here in Texas.
1.6 / 5 (7) Oct 28, 2008
I'm freezing my butt off in England with blizzards forecast. I think I'll ask for my green taxes back because the greenhouse gases are not "fit for purpose".
Millebrain is going to cut CO2 by 80% by 2050. At this rate we will be under the new ice age glaciers by then.
1.6 / 5 (7) Oct 30, 2008
I'm doing my bit.I run a 1994 Lexus GS300 to keep my corner of the world warm,but,as I said "it aint working".
Sorry for the sarcasm,but common sense does not seem to work either.

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