Methane anthropogenic emission

Over the last three decades, GHG emissions increased by an average of 1.6% per year, with C02 emissions from fossil-fuel use growing at 1.9% per year. Total GHG emissions in 2004 (Kyoto gases)8 amounted to 49.0 Gt C02-equivalent (C02-eq.), a 70% increase since 1970 and a 24% increase since 1990. Total C02 emissions in 2004 amounted to 26.1 Gt (see Fig. 2.7). Emissions of C02 have grown by approximately 80% since 1970 (28% since 1990) and represented 77% of total anthropogenic emissions in 2004. Total methane (CH4) emissions rose by about 40% from 1970 sectorally there was an 84% increase from combustion and the use of fossil fuels,... 

Etheridge D. M., Steele L. P., Francey R. J., and Langenfelds R. L. (1998) Atmospheric methane between 1000 AD and present evidence of anthropogenic emissions and climatic variability. J. Geophys. Res.-Atmos. 103, 15979-15993. 

Subak S. (1994) Methane from the House of Tudor and Ming Dynasty anthropogenic emissions in the sixteenth century. Chemosphere 29, 843-854. 

Etheridge, D.M., L.P. Steele, R.J. Francey, and R.L. Langenfelds, Atmospheric methane between 1000 AD and present Evidence of anthropogenic emissions and climate variability. J Geophys Res 103, 15 979, 1998. 

The urban and regional atmosphere is characterized by anthropogenic emissions of NO and non-methane organic compounds. Also, biogenic... 

Recent estimates by The Intergovernmental Panel on Climate Change (IPCC, 1992), suggest that landfill contributes at 30-70 Tg methane.yr , and that this represents 8-20% of the total anthropogenic emissions. 

Another area of current interest is that of global change. Anthropogenic emissions of trace gases such as carbon dioxide, methane, nitrous oxide, and fluorocarbons are believed to be partly responsible for the observed warming of the troposphere in the past century. In the stratosphere. 

Fig. 6.4 Schematic illustration of the key pathways in the atmospheric cycle of S involving (7) the natural emissions of reduced S compounds such as H2S frran terrestrial biota and dimethyl sulfide (CH3SCH3) from oceanic biota (2) anthropogenic emissions of S compounds, principally SO2 (3) the oxidation of reduced S compounds by OH and other photochemical oxidants leading to the production of intermediate oxidation state S compotmds such as SO2 and methane sulfonic acid (MSA) (4) the oxidation of these mtermediate oxidation state compounds within the gas phase by OH-producing H2SO4 vapor (5) the conversion of intermediate oxidation state compounds within liquid could droplets, which upon evaporation yield sulfate-containing particles (6) the conversion of H2SO4 to sulfate-containing particles and (7) the ultimate removal of S fiom the atmosphere by wet and dry deposition (Chameides and Perdue 1997)...

Klimont, Z., Streets, D.G., Gupta, S., Cofala, J., Lixin, F., and Yoichi Ichikawa, Y. (2002) Anthropogenic emissions of non-methane volatile organic compounds in China. Atmos. Environ., 36, 1309-1322. 

The VOC reduction emphasis world-wide is very commendable. But one should question the rational behind taking it to the ultimate limit. Most countries in the Western world are committed to reducing VOC s by 60-70%, by the year 2001 at the latest. In 1990 solvents accounted for 30% of the total anthropogenic, non-methane VOC emissions in Europe [Bouscaren 1990]. The surface coating industry accounted for 36% of the solvent emissions, making this industry s emissions less than 11% of the total European VOC s. Petrol and diesel emissions are one of, if not, the largest source of VOC s. 

This is a very broad conclusion, and additional measurements must be made. Some of this effort (which is current) should address the problem of other pollutants and condensation nuclei that accompany the nonurban oxidant. Interpretation of these measurements will increase the specificity of separating anthropogenic sources from natural background sources. Theoretical assessments of the existing observations will shed light on the relative roles played by stratospheric injection, plant emission, background methane, and diy deposition on surfaces in the natural portion of the tropospheric ozone cycle. 

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