|Anthropogenic emissions by sources and removals by sinks of greenhouse gases|
|<< ÑÍ4 EMISSION >>|
|The biggest ÑÍ4 emissions in the
period of 1990-1998 in Tajikistan were in 1991 (176 Gg), mainly because of enteric
fermentation and manure management.
Totally, in the period under review, the volume of methane emissions decreased more than 25%, as a consequence of structural changes in the agricultural sector and decrease in production and consumption of fossil fuels.
CH4 emission in the Agricultural sector
Agricultural sector is the key source of CH4 emissions in Tajikistan. The highest volume of methane emissions (80-86%) occur in result of enteric fermentation, and in a lesser extent from manure management (10-11%). The volume of methane emissions from rice cultivation depends on numerous factors and comprises 3-8% of all agricultural CH4 emissions in Tajikistan. In 1990-1998, ÑÍ4 emission decreased by 22% which generally corresponds the dynamics of the number of livestock.
Methane is being formed in the process of enteric fermentation. The amount of emitted methane depends on the number of animals, breed, age, type of feeding, quality and quantity of food, climatic conditions within cattle breeding zones and grazing technologies. It should be mentioned that ruminants produce 97-98% of total CH4 emissions from enteric fermentation. Methane emissions from this source decreased in 1990 - 1998 from 83 Gg to 65 Gg.
ÑÍ4 emissions from manure depend on the number of livestock, the way of storage and utilization of manure. If manure is managed as a liquid substance it decays and forms methane. If manure is managed as a solid substance, or is used on the fields as a fertilizer, methane does not occur. Methane emissions from this source in 1990 -1998 decreased from 10 Gg to 9 Gg. The flooding of rice fields leads to decay of organic substances, which results in formation of methane during vegetation. The area under rice crops constitutes 18-22 thousand hectares. Major zones of rice cultivation are northern plains, flood plains of the Vakhsh river and Gissar valley. In comparison with 1992, the rice fields expanded 1,5 times. Variations of methane emissions from rice fields depend on the type and structure of soil, organic and mineral fertilizers, irrigation mode and other factors. In the period of 1990-1998, ÑÍ4 emissions from this source increased from 4 to 6 Gg.
Some of agricultural residues remain on the fields, and usually burned. This leads to GHG emissions in little amount.
ÑÍ4 emissions in the “Energy”sector
Methane emissions related to mining, processing and consumption of fuels, occur in the coal mining and oil-gas systems of Tajikistan. The contribution of this sector into total ÑÍ4 emissions from year to year vary within 5 - 35%.
Coal mining is developed mainly in the north of the country (Shurab and Fan-Yagnob coal deposits). The Shurab mining has been developing for more than 100 years. Since 1950-s, annual volume of coal production amounted to 500 thousand tons, and in certain years reached 1 million tons. However, in 1990-s, due to structural changes in the economy, annual volume of coal production has decreased from 475 thousand tons in 1990 to 18,5 thousand tons in 1998.
Coal in Tajikistan is being mined by underground method, and only few coal deposits are being explored aboveground. According to expert estimates, 1 ton of coal mined underground in local conditions brings 15 cubic meters of methane emissions. ÑÍ4 emission in 1990-1998 has decreased from 4,8 Gg to 0,2 Gg.
The volumes of oil and gas production in Tajikistan are low (25 thousand tons of oil and 35 m3 million of gas in 1998). These volumes of production do not satisfy the growing demands of the country. Methane emissions in the oil-gas systems occurs in the process of mining, transportation, storage and consumption of fuel, due obsolete equipment, leakages accidents, etc. ÑÍ4 emissions from oil-gas systems were the biggest in 1991 - 60 Gg, and by 1998 decreased to 2,3 Gg.
ÑÍ4 emissions in “Waste” sector
Main sources of ÑÍ4 emissions in this sector are solid waste disposal sites and wastewater treatment facilities. Methane is formed in the result of decay of organic substances in anaerobic conditions. There are no waste recycling and waste combusting plants in the country. Solid wastes are being transported to the specialized waste disposal sites with the depth of five and less meters.
Methane which is formed from solid waste is not utilized and emitted into the atmosphere. To assess methane emissions from solid waste sites many types of activity data were considered, taking into account the volume of formation of communal wastes 0,5 kg/person/day. Communal wastes which are formed in rural areas were not taken into account in view of their dispersion over territories.
There are 3 types of waste disposal sites in Tajikistan:
ÑÍ4 emission from solid wastes in Tajikistan for the period of 1990-1998 has changed insignificantly - within 6,1 - 6,8 Gg.
Methane in wastewaters is being formed in aerobic conditions. Amount of organic substances influence methane emission intensity. ÑÍ4 emission from wastewater purification was calculated for 30 settlements with purification facilities. The volume of ÑÍ4 emissions from wastewaters in the period of 1990-1998 is insignificant, and varies from 0,23 to 0,25 Gg.
Methane emission occurs in industrial wastewaters. Wastewater from food processing industry makes 62,9% -76,2%; the lesser contribution is from textile industry 0,28% - 1 %. The volume of ÑÍ4 emission from industrial wastewaters is insignificant: 0,33-0,17 Gg.
Total CH4 emissions in the period of 1990-1998 in the “Waste” sector have decreased from 7,4 Gg to 6,6 Gg.
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