NASA points finger toward greenhouse gas nitrogen trifluoride

By William Atkins
Friday, 24 October 2008 03:25

Science - Climate

NASA also states, “It survives in the atmosphere about five times longer than carbon dioxide. However, current nitrogen trifluoride emissions contribute only about 0.15 percent of the total global warming effect caused by current human-produced carbon dioxide emissions.”

Dr. Ray Weiss of the Scripps Institution of Oceanography in La Jolla, California, U.S.A. led the research team that performed the research based on a more accurate technique that was performed for the first time.

Weiss commented on the efforts of the past and this new measurement technique when he stated, “Accurately measuring small amounts of nitrogen trifluoride in air has proven to be a very difficult experimental problem, and we are very pleased to have succeeded in this effort.”

Specifically the NASA article states, “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 are in the atmosphere, a quantity that is increasing at a rate of about 11 percent per year.”

The Weiss team analyzed air samples collected over the last thirty years from stations in California and Tasmania. These collections included the data from the NASA-funded Advanced Global Atmospheric Gases Experiment network of ground-based stations.

The researchers discovered that concentrations of nitrogen trifluoride gas increased from about 0.02 parts per trillion (ppt) in 1978 to 0.454 ppt  in 2008.

NASA states that “The samples also showed significantly higher concentrations of nitrogen trifluoride in the Northern Hemisphere than in the Southern Hemisphere, which the researchers said is consistent with its use predominantly in that hemisphere. The current observed rate of increase of nitrogen trifluoride in the atmosphere corresponds to emissions of about 16 percent of the amount of the gas produced globally.”

Dr. Weiss stated, "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.”

The research performed by the Weiss-led team will be published October 31, 2008 in the American Geophysical Union's Geophysical Research Letters .