Last Updated:
February 28, 2007

GCRIO Program Overview

Library 
Our extensive collection of documents.

Privacy Policy

Archives of the
Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999

FROM VOLUME 8, NUMBER 7, JULY 1995

PROFESSIONAL PUBLICATIONS...
OF GENERAL INTEREST: GREENHOUSE GAS CYCLES

Item #d95jul23

"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.

Item #d95jul24

"Nitrogen Fixation: Anthropogenic Enhancement—Environ-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.

Item #d95jul25

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 quiescent.

Item #d95jul26

"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.

Item #d95jul27

"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 deficient.