February 28, 2007
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A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999
FROM VOLUME 8, NUMBER 7, JULY 1995
OF GENERAL INTEREST: GREENHOUSE GAS CYCLES
"Atmospheric Reactions and Ultraviolet and Infrared Absorptivities
of Nitrogen Trifluoride," L.T. Molina (Dept. Earth Sci., Mass. Inst.
Technol., Cambridge MA 02139), P.J. Wooldridge, M.J. Molina, Geophys. Res.
Lett., 22(14), 1873-1876, July 15, 1995.
The only significant effect of the escape of NF3 into the atmosphere from
the semiconductor industry is its contribution to the greenhouse effect. It is
stable towards photo-oxidation and relatively unreactive with OH and HO2. The
atmospheric lifetime against photodissociation in the stratosphere is about 700
years. An estimate of greenhouse warming potentials is given.
"Nitrogen Fixation: Anthropogenic EnhancementEnviron-mental
Response," J.N. Galloway (Dept. Environ. Sci., Clark Hall, Univ. Virginia,
Charlottesville VA 22903), W.H. Schlesinger et al., Global Biogeochem.
Cycles, 9(2), 235-252, June 1995.
In the absence of human activities, the transfer of N from unreactive to
reactive forms and back again is about balanced; however, human activities have
changed this situation. This paper addresses four questions: (1) How do the
rates of N fixation by anthropogenic processes compare with those from natural
processes, and how do they impact the environmental distribution of N? (2) Is N
fixed by human activities accumulating in the environment; if so, where? (3)
What are the potential consequences of N accumulation? (4) How will the rate of
N-fixation change in the future? Predicts that N-fixation will increase by about
60% by 2020, primarily due to increased fertilizer use; about 2/3 of the
fixation increase will occur in Asia.
Two related items from Nature, 375(6533), June 22, 1995:
"Interannual Extremes in the Rate of Rise of Atmospheric Carbon Dioxide
Since 1980," C.D. Keeling (Scripps Inst. Oceanog., La Jolla CA 92093), T.P.
Whorf et al., 666-670. The upward trend of atmospheric CO2 increased in the
1980s and then slowed after 1988. Possible causes of this behavior were
investigated using the 13C/12C ratio of CO2 to distinguish the effects of
interannual variations in biospheric and oceanic sources and sinks of carbon.
The changes in the rise of CO2 were apparently caused mainly by interannual
variations in global air temperature (which altered both the terrestrial
biospheric and the ocean carbon sinks), and possibly also by precipitation.
"Dynamics of the Carbon Cycle," M. Heimann, (M. Planck Inst.
Meteor., Bundesstr. 55, D-20146 Hamburg, Ger.), 629-630. Discusses implications
of the previous paper, which must eventually be resolved with conflicting
results of Francey et al. (1995) implying that the carbon cycle is much more
"Empirical Model of Global Soil-Biogenic NOx Emissions," J.J.
Yienger, H. Levy II (GFDL, POB 308, Princeton NJ 08542), J. Geophys. Res.,
100(D6), 11,447-11,464, June 10, 1995.
Reports the first model of global soil-biogenic NOx emissions that resolves
emissions on a synoptic scale and includes schemes to simulate pulsing, biomass
burning, canopy reduction, and exhalation of NOx from N-fertilized soils. Used
6-hour general circulation model forcing to construct a global, temperature and
precipitation dependent, empirical model. By 2025, increasing use of nitrogen
fertilizer may raise total annual emissions to 6.9 Tg N, with agriculture
accounting for > 50% of the global source. Biomass burning may add an
additional 0.6 Tg N by stimulating emissions for a short period after the burn.
"Global Methane Emission from Rice Paddies: Excellent Methodology
but Poor Extrapolation," S.K. Sinha (Water Technol. Ctr., Indian Agric.
Res. Inst., New Delhi 100 012 India), Current Sci., 68(6),
643-646, Mar. 25, 1995.
(See Research News, this issue--July 1995.) A new estimate indicates that
rice paddies of the world emit only about a tenth the amount of methane reported
by the IPCC in 1994. The IPCC estimates are based on excellent techniques of
sample collection and measurement, but the biological and agricultural
considerations needed to extrapolate those results to world emissions are
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