Friday, July 04, 2008

Flat screen TVs causing global warming?

The paper "NF3 , the greenhouse gas missing from Kyoto" (Michael J. Prather and Juno Hsu, GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L12810, doi:10.1029/2008GL034542, 2008) suggests a chemical used in making plasma and LCD panels needs to be monitored. The chemical is Nitrogen trifluoride and is a powerful greenhouse gas (17,200 times that of CO2). It was introduced to replace nastier chemicals: hexafluoroethane and sulfur hexafluoride. It is used to clean the Chemical vapor deposition (CVD) equipment which deposits thin high purity films on the flat panel displays.

The extent of the problem is not known, as the production of NF3 is not reported and it is also not known how much is lost in the production process. Prather's paper is not the first to raise the issue, with:
  1. Estimates of US emissions of high-global warming potential gases and the costs of reductions (Harvey, 2000),
  2. Keeping Cool without Warming the Planet: Cutting HFCs, PFCs, and SF 6 in Europe
    (Anderson, 2000)
  3. How to Do Environmental Innovation Journalism (Forsberg)

GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L12810, doi:10.1029/2008GL034542, 2008

NF3, the greenhouse gas missing from Kyoto

Michael J. Prather
Earth System Science Department, University of California, Irvine, California, USA

Juno Hsu
Earth System Science Department, University of California, Irvine, California, USA


Nitrogen trifluoride (NF3) can be called the missing greenhouse gas: It is a synthetic chemical produced in industrial quantities; it is not included in the Kyoto basket of greenhouse gases or in national reporting under the United Nations Framework Convention on Climate Change (UNFCCC); and there are no observations documenting its atmospheric abundance. Current publications report a long lifetime of 740 yr and a global warming potential (GWP), which in the Kyoto basket is second only to SF6. We re-examine the atmospheric chemistry of NF3 and calculate a shorter lifetime of 550 yr, but still far beyond any societal time frames. With 2008 production equivalent to 67 million metric tons of CO2, NF3 has a potential greenhouse impact larger than that of the industrialized nations' emissions of PFCs or SF6, or even that of the world's largest coal-fired power plants. If released, annual production would increase the lower atmospheric abundance by 0.4 ppt, and it is urgent to document NF3 emissions through atmospheric observations.

Received 5 May 2008; accepted 27 May 2008; published 26 June 2008.

Keywords: greenhouse gases; nitrogen trifluoride; Kyoto Protocol; climate change.

Index Terms: 0317 Atmospheric Composition and Structure: Chemical kinetic and photochemical properties; 3305 Atmospheric Processes: Climate change and variability (1616, 1635, 3309, 4215, 4513); 6620 Public Issues: Science policy (0485); 1610 Global Change: Atmosphere (0315, 0325).

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Citation: Prather, M. J., and J. Hsu (2008), NF3, the greenhouse gas missing from Kyoto, Geophys. Res. Lett., 35, L12810, doi:10.1029/2008GL034542.

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