China National Environmental Protection Agency
115 Xizhimennei Nanxiaojie, Beijing 100035, China
Climate has substantial influence on the development of human society. At the same time, the global climate is being affected by human activities. Since industrial revolution large amount of CO2 and other greenhouse gases have been emitted to the atmosphere, causing significant change in its composition. It is recognized that this change might be sufficient to cause change in global climate. Because of the importance of climate change issues, the Chinese government pays great attention to them. As climate change concerns almost all aspects of the social and economic development, in order to coordinate ministries and agencies of the government in their efforts to deal with climate change problems, the Coordinating Group on Climate Change under the Environmental Protection Committee of the State Council was established in February 1990. There are four working groups under the Coordinating Group, working on scientific assessment, impact assessment and response strategies, economic implication and international convention matters of climate change. A number of research and technological development projects related to climate change issues have been organized, including bilateral cooperation projects and projects supported by GEF, UNEP, UNDP, the World Bank, the Asian Development Bank and other international organizations. The Chinese scientists and experts also take active part in the studies organized by IPCC. Some results of research work can be found in the Proceedings of the National Symposium on Climate Change and Environmental Problems held in 1991 and in the reports provided to IPCC. [1, 2]
On the basis of analysis of historic climate data and the synthesis of trends of change in temperature and precipitation, the climate characteristics of the areas south to 40oN can be summarised as given in Table 1. 
Table 1.The climate characteristics in this century in China.
Period Precipitation Temperature Period Precipitatio Temperature n 1910-1919 wet cold 1950-1959 wet cold 1920-1929 dry warm 1960-1969 dry (warm) 1930-1939 dry (cold) 1970-1979 dry cold 1940-1949 wet warm 1980-1989 wet warm
As can be seen in Table 1, the climate in China had a change pattern as: wet and cold--dry and warm--dry and cold--wet and warm--wet and cold, and the cycle is about 40 years. It can be inferred from the pattern of change cycle that the climate in China in 1990's will be wet and cold. But in 1990's, because of the global warming tendency, the climate in China will be warm and show little differences from the global tendency.
Changes of climate from 1951 to 1990 have been analyzed on the basis of the observation of temperature and precipitation from 410 meteorological stations in China. [3,4]
Figure 1 shows the difference between average temperature of 1980's and that of 1990's. It can been seen that the temperature in the area including Henan province, south to Shanxi province and Southwest China (except for some of the coast areas and Hainan province) decreased. Northeast China and West China are the areas where the temperature rose. 
Figure 1.Difference in average temperature between 1980's and 1990.
Figure 2 shows the temperature deviation from the average for January, April, July, and October in recent 40 years in China. The feature is that the general tendency of the temperature change in winter (January) and spring (April) was obviously getting warmer. The magnitude of temperature rise was about 1oC in January and 0.4oC in April from 1950's to 1980's. Summer was getting cooler, and the temperature dropped by about 0.3oC from 1950's to 1980's. The change in autumn fluctuated. The climate was getting warmer from late 1970's with a temperature rise of about 0.3oC from 1950's to 1980's.
Figure 2.Deviation from annual average temperature over past 40 years.
____ large cities, ---- small cities
In summar, winter, spring and autumn in China was getting warmer over past 40 years, especially in Northeast China and North China and winter in Northwest China as well. Summer was getting cooler in Yangtze River basin and the trend was more prominent in Huanghe River basin and the area of the upper reach of the Yangtze River.
The precipitation change over past 40 years in China was as follows: (1) the annual amount of precipitation decreased by 50 mm; (2) the seasonal precipitation change varied, the drying trend in summer was obvious but no distinct trends were observed in other seasons; (3) the precipitation change trends were different in different areas. Figure 3 shows the annual precipitation difference between 1980 and 1992. The middle and lower reaches of the Huanghe River have become drier. The annual amount of precipitation in Hebei and Shandong province decreased by about 200 mm. The annual precipitation in areas south of the Yangzi River also decreased, and the upper and middle reaches of the Yangtze River have become wetter over past 40 years.
Figure 3.Difference in average precipitation between 1980's and 1992.
The relevant analysis of temperature and precipitation in recent 40 years shows that there is a negative correlation between temperature and precipitation, especially in the middle and lower reaches of the Yangtze River, the Huaihe River basin, the middle and lower reaches of the Huanghe River, North China, most of Northeast China and Northwest China.
Human activities and natural changes may influence the climate. Major natural factors that influence the climate are the activities of the sun and volcanoes.
For the prediction of climate change in China in the coming 50 years, methods recommended in the IPCC Report(1990) and Supplement(1992) were used.
Climate effect of doubling of CO2 concentration in China
For the sake of reliability of simulation, a larger area of East Asia, in which China is located, was taken for the calculation with the use of GCMs. Results of simulation were presented in Table 2.
It can be seen from Table 2 that doubling of CO2 concentration might cause an average global temperature rise of 1oC and an average annual precipitation increase of 3.5%. The annual and seasonal temperature rise varies between 0.8-1.6oC, and the seasonal precipitation increase between 1.5-8.2%. Most of the models gave the results that temperature rise is more significant in winter than in summer. Change in precipitation shows similar results. The average values of the seven models show that the global temperature will increase by 1 C when the CO2 concentration doubles, and the temperature in East Asia is about 1.2oC higher than the globe average.
The potential effect of human activities on the climate change in China in the next 50 years
A simple model of global socio-economic development was chosen to analyze the effect of human activities on the climate change in China in the next 50 years. Table 3 shows the average change in temperature and precipitation caused by human activities in 2000, 2010, 2020, 2040 in East Asia.
Table 2.The change in temperature and precipitation in East Asia (70-140 E, 15-60 N, 2 * CO2) simulated by GCMs.
Change in temperature Model (oC) Annual Winter Spring Summer Autumn UKMO-L 1.1 1.1 1.2 1.0 1.2 UKMO-H 1.5 1.6 1.4 1.6 1.6 GFDL 1.2 1.2 1.2 1.2 1.1 GISS 1.0 1.1 0.9 0.9 1.0 OSV 1.1 1.1 1.0 1.0 1.0 LLNL 1.2 1.2 1.1 1.5 1.2 MPI 1.1 1.4 1.2 0.8 1.1 Average 1.2 1.3 1.2 1.1 1.2 Change in precipitati Model on (%) Annual Winter Spring Summer Autumn UKMO-L 3.4 3.0 5.9 4.0 2.4 UKMO-H 5.0 6.9 6.4 4.6 3.1 GFDL 2.2 3.2 1.5 2.5 1.6 GISS 2.7 4.8 3.4 1.8 2.6 OSV 4.3 5.7 4.3 2.8 5.7 LLNL 3.7 4.0 4.8 2.6 4.1 MPI 3.4 4.8 3.4 8.2 1.3 Average 3.5 4.6 4.2 3.8 3.0
Table 3.The predicted change in temperature (oC) and precipitation (%) in East Asia (compared with current situation).
Change in temperature Year (oC) Annual Winter Spring Summer Autumn 2000 0.20 0.21 0.20 0.19 0.20 2010 0.35 0.38 0.35 0.34 0.35 2020 0.65 0.69 0.63 0.62 0.64 2030 0.88 0.93 0.86 0.84 0.87 2040 1.06 1.12 1.04 1.02 1.05 Change in precipitatio Year n (%) Annual Winter Spring Summer Autumn 2000 0.60 0.80 0.70 0.70 0.50 2010 1.10 1.40 1.30 1.20 0.90 2020 1.90 2.60 2.30 2.10 1.60 2030 2.60 3.50 3.20 2.80 2.20 2040 3.20 4.20 3.80 3.40 2.50
The effect of natural changes on the climate in the next 50 years
Table 4 shows the effect of the activities of sunspots and volcanoes on the climate. It can be seen, both natural factors have a cooling effect.
Table 4.Effect of natural change on climate in the next 50 years.
Year 1990's 2000's 2010's 2020's 2030's Sun DT(oC) -0.10 -0.19 -0.25 -0.16 -0.10 Volcano DT(oC) -0.11 -0.16 -0.10 -0.11 -0.18
The possible change of climate in the next 50 years in China
The combined effects of human activities and natural changes on the climate of the world and East Asia (including China) are shown in Table 5 and Table 6.
Table 5.The estimated change of the global temperature in the future 50 years (deviation from 1961-1990) (oC).
Year 1990's 2000's 2010's 2020's 2030's DTa Nature change -0.21 -0.35 -0.35 -0.27 -0.28 DT Human activity 0.20 0.30 0.55 0.75 0.90 Sum -0.01 -0.05 0.20 0.48 0.62
a--combined effect of the Sun and Volcanoes.
Table 6.The estimated temperature change in East Asia in the future 50 years (deviation from 1961-1990) (oC).
Year 1990's 2000's 2010's 2020's 2030's DTa Nature change -0.21 -0.35 -0.35 -0.27 -0.28 DT Human activity 0.20 0.35 0.65 0.88 1.06 Sum -0.01 0.00 0.30 0.61 0.78
a---combined effect of the Sun and Volcanoes.
It can be seen from Table 5 and Table 6, natural changes might compensate the greenhouse effect. However, the temperature will continue to rise after 2010 because of the accumulation of greenhouse effect caused by human activities. The magnitude of temperature rise in East Asia will be larger than in the globe.
It should be pointed out as there still exist many uncertainties in the understanding of the development of human social and economic activities and natural phenomena, these results could serve only as a reference to the probable future climate change.
A report on the assessment of potential impact of climate change on the environment in China based on the available research results had been accomplished by the working group II of the Coordinating Group on Climate Change of China and submitted to the IPCC WG II in 1990.  After that, some other studies have been completed. Some of the results were used for the presentation below.
With the economic development of China, the GHG emissions in China have increased. In order to formulate measures of GHG emission control which are technologically and economically feasible and suitable for the national conditions, it is necessary to have a clear picture of GHG sources in China and their contribution to climate change.
In the estimation of the amount of GHG emissions, only preliminary information could be provided because of the uncertainties of the data of emission sources and the inaccuracy caused by the use of emission coefficients recommended by IPCC to the actual conditions of China. According to the preliminary estimation, the total GHG emissions by human activities in China amounted to 2500-3600 Mt CO2 equivalent in 1990. The largest GHG source is energy consumption, of which the CO2 emissions account for about 73% of the total GHG emissions. The second largest source is paddy-fields, ruminant animal husbandry and coal mining, which emit CH4 in the amount of about 17% of the total GHG emissions. Emissions of CO2 from cement industry, non-CO2 GHG from fossil fuel and biomass burning and fertilizer use account for about 10% of the total GHG emissions. The percentage of CFCs in the total GHG emissions is quite small and, besides, CFCs will be phased out gradually. Table 7 shows the main sources of GHG emissions in China in 1990.
Table 7.Main GHG sources in China.
GHG Source Emission load (%) CO2 Energy consumption 73 Cement production 3 CH4 Coal mining 3 Paddy field 9 Animal emission 5 N2O Biomass burning 2 Others 5
In 1990 CO2 emissions from energy use in China amounted to about 600-700 million tons of carbon. The emissions of CO2 from energy consumption by different sectors are shown in Table 8.
Table 8.Main sectors of CO2 emissions from energy consumption and their emission loads.
Sector of energy Emission load consumption (%) Industry Power industry 24 Energy production 11 Building material 9 Iron and steel 7.5 75 Chemical material 7.5 Food and tobacco 3 Capital construction 3 Others 10 Civil use 14 Transportation 4 Agriculture 3 Others 4
Coal is the main energy source in China, which accounts for 76.2% of the total energy consumption in 1990. Therefore, coal combustion is the main source of CO2 emissions. Industrial sectors constitute 3/4 of the total CO2 emissions from energy consumption. CO2 emission from coal-fired power plants accounts for 32% of the CO2 emission from industry.
Most of the methane emissions come from agriculture and energy exploitation. Paddy field is the main source of methane emission, and the emission level varies with geographical areas and depends greatly on the conditions of cultivation. Observation of methane emissions from paddy fields have been conducted in Sichuan province, Hangzhou, Nanjing and Beijing. The amount of methane emission from paddy fields was estimated at about 12-17 Mt.
Another important source of methane emission is livestock. Methane emissions from ruminant enteric fermentation and animal wastes were estimated to provide about 7.5-9 Mt methane in 1990. According to Chinese experts studies, methane emission from coal mining in 1990 amounted to 3.7-7 Mt, including emission after mining. In 1990, the total amount of methane emission from all kinds of sources is 27-37 Mt. The contribution of each kind of source is presented in Table 9.
Table 9.Methane emission load of different sources in China.
Source Emission load (%) Coal mining 17 Ruminant animal 19 Animal excretion 6 Paddy field 45 Biomass combustion 5 Others 8
The estimation of emission amount of N2O is quite uncertain. For example, estimation of N2O emission from nitrogenous fertilizers differed in the order of magnitude of three. With the use of middle-value for the estimation, N2O accounts for less than 5% of the total GHG emission.
GHG emissions in China were predicted with the use of GCM models. The result of CO2 emission prediction is presented in Figure 4, which shows that the amount of CO2 emitted into the atmosphere has been increasing every year. 
Figure 4.Prediction of CO2 emissions in China (1992-2000).
According to data published by the World Resources Institute in 1992-1993 (Table 10), the global CO2 emissions from human activities amounted to 5962 Mt carbon in 1989, and China contributed 10%. Emission per capita in China was 0.59 tons of carbon, while it is 2.31 tons in Japan, 5.37 tons in the U.S., 3.62 tons in the former Soviet Union. CO2 emission from China, the U.S. and the former Soviet Union accounted for 50.5% of the global emission in 1989. Although GHG emission from China constitutes a large share in the global total, the per capita emission level in China is still far below that in western countries.
Potential impact on water resources
The future water consumption of the country had been estimated on the basis of prediction of population growth and economic development under the assumption of no climate change (Table 11).
Table 10.CO2 emission from industrial process, 1989 (Mtc)*.
Emission (Mtc) Percent (%) Per capital (tc) China 651 10.9 0.59 U.S. 1328 22.2 5.37 Japan 284 4.8 2.31 USSR 1037 17.4 3.62 Europe 1186 19.9 2.38 Other 1476 24.7 World 5962 100 1.15
* Data from the World Resource Institute (1992-1993).
Table 11.Water consumption of the country.
Year 1990 2000 2010 2030 Agricultur Irrigated area (106/h) 47.9 53.23 57.0 57.0 e Water use (109m3) 440 470 500 500 Industry Output value (billion 4989.7 14623.4 31586.6 111184 U.S.$) 210 165 120 90 Index of water use 50.0 116.3 181.2 478.3 (m3/104yuan) Water use (109 m3) Civil use Water use (L/per 25 35 50 70 capital*day) 10.0 16.7 23.0 36.5 Water use (109 m3) Total 500.0 602.0 704.2 1014.8 amount (109 m3)
With the use of GCMs it is predicted that there will be a significant rise in temperature and decrease in precipitation in the area north of Huaihe River, while the situation will be different in the area south of the Yangtze River, where there will be a minor rise in temperature and a significant increase in precipitation. As a result, the south of China will suffer more from flood and water logging while North China from drought. For the illustration of impact of climate change on water resources and the rural and urban water use and supply, an analysis was conducted for the Haihe-Ruanhe basin in North China, the adaptability of which to climate change is fragile.
The volumes of rainfall, surface water resource, ground water resource and total water resource in mountain and plain areas in Haihe-Luanhe basin were calculated for the conditions of 1xCO2 (no climate change) and 2xCO2 with the use of GCM and other hydrologic models. The results were presented in Table 12. It can be seen, doubling of CO2 concentration will reduce the amount of water resources.
Impact of climate change on water use and supply was predicted for the year 2030:
a. The effect of temperature rise of 1.25oC on the amount of runoff is more significant than the effect of 2.5% decrease of precipitation.
b. The effect of temperature rise on the increase of irrigation water use is much more significant than the effect of decrease of precipitation.
Table 12.Water volume in mountain and plain areas in Haihe-Luanhe basin (109m3).
1xCO2 2xCO2 Ratio (%) Precipitation Mountain 103.1 100.39 97.4 Plain 75.1 73.35 97.7 Total 178.2 173.74 97.5 River runoff Mountain 21.41 19.61 91.6 Plain 7.35 5.85 79.6 Total 28.76 25.46 88.5 Ground water Mountain 13.56 12.90 95.1 Plain 15.79 14.05 89.0 Total 29.35 26.95 91.8 Total Mountain 24.64 22.69 92.1 Plain 17.45 14.73 84.4 Total 42.10 37.42 89.0
c. Climate change will result in water shortage of 36.9 billion m3 in moderately dry year.
In comparison with the condition of no climate change, the net shortage of water is 11.7 billion m3.
Climate change will affect the quality of surface waters in North China. Eutrophication in shallow lakes and river mouths and organic pollution in rivers in low water period will be aggravated. Change in runoff by 10% will result in change in intensity of surface sources of pollution by about 5%. In low water period, climate change will reduce the amount of runoff by 10% resulting in the increase of concentrations of pollutants in rivers by more than 10%.
Potential impact of climate change on agriculture
Climate change has both positive and negative effect on agriculture. When the CO2 concentration doubles, climate zones in China will move 4 degree latitude to the north. This will result in the reduction of harm to crop due to frost, and in the increase of types of seeding regimes and the enhancement of photosynthesis processes, if other affecting factors remain unchanged. Most regions of the mainland will become drier except for Yunnan, Sichuan, and Guangxi province. Soil humidity will decrease by 13% annually in the Yangtze River basin, 10% in Huanghe River basin, and 12% in average in the country. The rainfall distribution in East, North and Northwest China will be more uneven, the arid period will be prolonged, which will lead to the further development of soil salinization and aggravate the threat of secondary salinization due to improper irrigation. Salinization would occur mainly in some areas of the north part of central China, in East China and Northwest China. Climate change will lead to aggravation of soil erosion and increase of loss of fertile soil. More severe soil erosion would threat most part of China. In some areas, such as Northeast China, east of Inner Mongolia, east slope of Qinghai and Tibet plateau and southeastern coastal areas, where precipitation will increase, there will be short time of flood every year. In some low-lying areas and areas of poor draining conditions, especially in plain areas of Northeast China and southeastern costal areas, there will be possibility of expansion of marshland. With temperature rising, insect pest and weeds will appear earlier in spring and will be sustained longer in autumn, causing more crop loss and increase of protection costs. Impacts on 7 main crops which account for 92% of the total crop yield of China are given in Table 13. The estimation was based on the assumption of CO2 concentration doubling, temperature rising by 1oC, and 5-10% of precipitation increase. Most factors that affect the growth of plants were taken into account. Generally, the harvest of 7 main crops will decrease by 4.4%. If other crops are included in the estimation, the figure will be larger than 5%.
Table 13.Estimation of change in crops yield.
Rice Wheat Corn Tomato Cotton Oil Fruit crops Rate of change -6 -8 0.6 -0.2 -4 -1 -2 (%)
Potential impacts on livestock husbandry and fishery
The development of livestock husbandry depends on the yield of grain and grass, as well as protein source. Climate has great influence on the production of fodder and livestock raising. The influence of climate change on livestock husbandry is quite complicated, which includes the direct effect of CO2 concentration doubling, and effect of temperature and precipitation changes and natural calamities caused by the change of climate.
According to relevant studies, herbage yield will increase with doubling of CO2 concentration, if there is plenty of sunshine, enough nutrition and water. Taking such factor as soil fertility into account, the herbage yield is estimated to increase by 8-20%, and the production of livestock husbandry will increase at the same rate, if the correlation coefficient between yields of herbage and livestock husbandry is assumed to be 1.
Temperature and precipitation change has different influence on different grass land. The comprehensive effect of temperature and precipitation change will result in the reduction of livestock husbandry production by 10.6% (Table 14).
The frequency of occurrence of disastrous weather events will increase as the result of climate change. It was estimated that the frequency of disastrous weather occurrence in 2030 might be 1.4 times of that at present. The effect of disastrous weather on livestock husbandry is presented in Table 15.
According to the estimation above, the yield of herbage in grazing land of China will be reduced by more than 10%. This will lead to the reduction of the population of livestock at the same ratio. Or to say, to keep the same population of livestock, the cost of additional fodder supply will increase.
Climate change also affects fishery in China. The rise of temperature and increase of precipitation will bring some benefits to the fishery. The Yangtze River basin, which constitutes half of the inland water surface of China, will be affected most. Colder winter and more frequent drought and flood will result in reduction of the rate of fish reproduction by 10% in this area in 2030.
Table 14.Estimation of effect of temperature and precipitation change on livestock husbandry.
Pastoral area type Distribution Portion of Change Contribution to the livestock national (%) husbandry of total China (%) (%) Northern pastoral Meadow 11 8 0.88 area Arid steppe 9 -15 -1.8 Desert 4 -25 -1.6 Western pastoral Basin, 10 -10 -2 area mountain Alpine and sub 6 6 0.36 alpine meadow Qinghai and Tibet Qinghai, 10 5 0.5 plateau Tibet, pastoral area north of Sichuan South pastoral 45 -15 -6.8 area Total 95* -10.6
* The other 5% are large-sized livestock breeding farms in suburbs, which are not considered here.
Table 15.Estimation of influence of disastrous weather on livestock husbandry.
Influence factor Present loss Increase of Loss in 2030 calamity (%) frequency in (%) 2030 (times) Aridity 5 7 Sandstorm 1.5 2.1 Rainstorm 1.5 0.4 2.1 Plant disease and 1.0 1.4 insect pest 1.0 1.4 Others Total 10 0.4 14
Influence of sea level rise in China
Sea level rise is the result of global warming, which will aggravate three major kinds of costal disasters--windstorm tides, sea water intrusion and coastal erosion. According to IPCC estimation, global sea level would rise 20 cm in 2030, and 30-40 cm in 2050. Excessive exploitation of ground water and subsequent ground subsidence in some areas of China will lead to relative sea level rise in these areas. Sea level rise might reduce the disaster resisting ability of the coastal embankments, tide locks, and other engineering infrastructures. As a result, the effect of storm and tidal wave disasters will become much more serious. Large areas in the four major low-lying coastal plains of China will be under severe threat of inundation. If there is a wind storm tide of 1 meter high in addition to the sea level rise, tens of thousands of square kilometres of coastal regions would suffer from sea water intrusion. 14 cities in the Zhujiang River delta (including the city of Guangzhou) and 34 cities in East China (including Shanghai) would be inundated, and about 67 million people would be forced to migrate, which would cause great loss to the society and economy of the country.
Potential impact of climate change on terrestrial ecosystem
Doubling of CO2 concentration has negative effect on wet land, forest, desert and fauna and flora in them. Swamps in China will be more seriously affected with the aggravation of evaporation and eutrophication due to temperature rise. With these changes and the seasonal variation of surface area, water level and location of swamp in addition, some 500 kinds of fresh water fish and 300 kinds of birds that live in marshes and inland shallows will be affected. Mangroves, as important parts of the costal ecosystem, would probably move northwards due to climate warming. At the same time, they will be faced with threats of sea level rise and frequent attacks of tropical rainstorm. Climate change will reduce rainfall in arid and semiarid areas, resulting in soil moisture reduction. Moreover, doubling of CO2 concentration has negative effect on the growth of plants in these areas, causing the expansion of deserted land. Land area favourable for tropical rain forest will increase, but the boreal and temperate forest which take up most of the area of forest in China will decrease.
Climate change will create a lot of disadvantages to global economy and environment. It is the world's common task and responsibility to deal with climate change problems. Environmental protection is attached great importance in China and was declared to be a basic state policy in early 1980's. The Chinese government takes a positive attitude towards international environmental affairs, and pursues the effective ways to solve the global environmental problems through international cooperation. China sighed the Climate Change Framework Convention at the UN Conference on Environment and Development in 1992, and ratified it in 1993. Shortly after the UN Conference on Environment and Development, the Chinese government drew up ten policy measures on the environment and development and started to draft China Agenda 21. Through the efforts of more than 500 experts from above 50 governmental and nongovernmental institutions and after the consultation with famous international experts, the draft of China Agenda 21 was completed at the end of 1993. The China Agenda 21 was reviewed and approved by the State Council in March this year. This is a contribution of China to the implementation of the sustainable development strategy adopted by UN Conference on Environment and Development. How to deal with climate change and protect the global environment constitutes an important part in China Agenda 21.
At present, there still exist many uncertainties about climate change related to factors affecting climate change, the change rate and magnitude, and the impact of climate change. This situation should be taken into consideration when the response measures are formulated. For dealing with problems of climate change, both adaptive and preventive measures could be adopted. Since climate change may affect the environment, society and economy in many aspects, its impact on social and economic development must be taken into account. According to Chinese conditions, the preventive measures, especially those, which not only can reduce the GHG emission, but also are advantageous to social and economic development, have been given priority for consideration. 
China is one of few countries using coal as the main energy source. Coal consumption accounted for 76.2% of the total energy consumption in 1992. With the increase of economic development, the demand for energy increases. Target of quadrupling the national economy in 2000 put forward at the beginning of 1980's will be realized earlier because of the higher speed of development. It is predicted that the energy production can provide only 1.4 billion tons of standard coal in 2000. It means that the goal of doubling the present economy has to be realised under the condition of 50% increase of energy production. Therefore, it is necessary to improve the energy efficiency at the consideration of both economic development and GHG emission reduction.
The potential of energy saving
Over the past 10 years, significant results have been achieved in energy conservation in China. Energy consumption per unit GNP has been decreasing every year. The energy consumption per 10 thousand yuan GNP had fallen to 9.3 tce in 1990 from 13.36 tce in 1980. The percentage of decrease was 30%, and average annual energy saving rate was 3.7%. The accumulated amount of energy saving reached 270 Mtce. However, the average energy efficiency in China is still low, about 30%, and is equal only to two-thirds of that in developed countries. Table 16 shows the energy efficiency of some of the Chinese energy facilities compared with that of industrial countries. The energy use of the main industrial sectors of China is higher than that of developed countries by 30-90%.
Table 16.The efficiency of energy facilities (China vs. developed countries).
Facility China Developed Difference (%) countries (Percentile) (%) Coal-fired power plant 28.51 36-38 6-10 Industrial boiler 55-65 80-85 20-25 Industrial kiln 5-37.5 40-60 40 Fan 65-70 80-90 30 Water pump 65-80 78-90 10
In 1990, industry accounted for 68.5% of the total energy use of the country. Chemical industry, metallurgy and building material industry are the three large consumption sectors, and their energy use constitutes 46.3% of the total industrial energy use and about one-third of the total energy consumption of the country. The industrial sectors accounted for nearly three-quarters of China's CO2 emissions from energy consumption. In high energy using industrial sectors, the proportion of small- and medium-sized plants reaches 70%, which use mostly outdated energy facilities with high energy consumption and low efficiency. In this respect, the potential of energy saving is remarkable which can be shown as follows:
The average figure of energy use per ton steel in China is 1 tce, i.e. 0.3-0.4 tce more than the world advanced level. This means that China consumes 20 Mtce energy more.
The average figure of energy use per ton ammonia (small- and medium-sized plants) in China is 2.0 tce, which is double of the world level. In accordance with the volume of chemical fertiliser production, about 20 Mtce a year are used in surplus.
The energy use for generating 1 kWh of electricity in China is 430 gce/kWh, 100 gce more than the international level. The surplus energy use is 50 Mtce per year.
At present, China has 430 thousand boilers, consuming 300 Mt coal per year. The energy efficiency is only about 50-60%. Moreover, there are 140 thousand industrial kilns, consuming 200 Mt coal per year, and the energy efficiency is 10 percentiles lower than that of developed countries. The energy saving potential of boilers and kilns is more than 100 Mtce. The efficiency of industrial pumps and fans in China is 15% lower than international level and the surplus energy use is 30 billion kWh.
There are 1.1 million automobiles in transportation sector. If the oil efficiency reached the international level, 0.55 Mt oil would be saved per year.
If the proportion of coal briquettes use increased to 50% from the present portion of 28%, 4 Mtce could be saved every year.
If the energy-saving potential of industry, energy production, transportation and civil energy consumption could be realized, the amount of energy saving would be estimated to over 300 Mtce in 2000, equal to one-third of the present energy use.
Use of high efficiency technology.
The Chinese government takes energy saving as a very important task, and has adopted a series of measures, including administrative, legislative, economic and technological ones, to promote energy saving for the improvement of equipment efficiency. The essential way is to accelerate industrial modernisation and to promote the use of high efficiency technology.
Cycled fluidized-bed combustion technology. The technology of 4-75 t/h cycled fluidized-bed combustion has been adopted and developed in China. The efficiency can be raised to 85-90% from 60% of the conventional technology. This kind of burning technology has a series of advantages such as adaptability to different coal types, high desulphurization efficiency of over 80%, about 20% of coal saving, and low NOx (75% lower than usual) and CO2 emission (20-25% lower than usual). It can raise not only the coal use efficiency but also reduce the pollutants emission significantly.
Centralised heating system. Centralised heating system can replace the scattered small boilers for heating, and thus is an effective way to improve the energy efficiency and to reduce pollutant emissions as well. Coal saving can also be realized through technological renovation with the replacement of condensation operation units by back pressure operation units for electricity and heat cogeneration. Table 17 and Table 18 show the results of comparison of energy saving between different heating and generating systems.
Table 17.The coal saving of centralised heating system.
Scattered Centralised Co-generation boilers boilers Boiler heat efficiency (%) 55 70 80-90 Standard coal use for heating 259 204 162.72 (kg/106 kcal) 100 78 63 Comparison of rate of coal use 8469.23 8469.23 8469.23 * (%) 21.93 17.28 13.78 Heat supply ** (106 kcal) 4.66 8.15 Demand for coal (106 tce/a) Coal saving (106 tce/a)
* The coal use rate of scattered boilers is set to 100% for comparison.
** Heat supply of the country in 1984.
Table 18.The coal saving through technological renovation.
Condensation Back pressure operation unit operation unit Coal use for generation 600 210 (g/kWh) 100 42 Rate of coal use * (%) 65 65 Power generation ** (109 32.5 13.6 kWh/a) 18.9 Demand for coal(106 tce/a) Coal saving (106 tce/a)
* The coal use rate of condensation operation unit is set to 100% for comparison.
** The power produced by medium- and low-pressure condensation operation units in 1984.
Coal is the main energy source of China, and the major way of coal use is direct combustion, which not only wastes energy, but also pollutes environment. In order to raise the efficiency of coal use and alleviate environmental pollution caused by coal burning, it is necessary to improve the coal property.
Coal washing and sorting
Coal washing and sorting can cut down the sulphur content about 50% and the ash content more than 10%. The burning property could be improved also. With the increase of effective content, the transportation load of raw coal and the dispersion of pollutants generated by ineffective content will be reduced. This will help to alleviate the burden of coal transportation, increase the efficiency of coal use, reduce pollution control cost and improve the quality of the environment.
In 1988, there were only 17 million tons of raw coal which were washed and sorted. However, the generation facilities, industrial boilers and locomotives in the country use about 600 million tons of coal every year. If this amount of coal could be processed by washing and sorting, the coal saving would be about 10%, i.e. 60 Mt per year.
Coal briquettes for residential and industrial use
Using coal briquettes instead of raw coal is an effective measure to save energy and control pollutants. Replacing raw coal by coal briquette for residential use can save 20-30% of coal, while adoption of coal briquettes for industrial use can save more than 15% of coal. The emission of SO2 and TSP will decrease at the same time.
Developing urban gas system
Use of natural gas, LNG and coal gas to replace direct coal burning is an important approach of pollution control and energy saving. In 1988, the rate of gasification in urban areas was 34.9%, and the population using gas was 50 million. At the end of this century, the percentage of urban residents using gas is expected to reach about 70%, and the population using gas reach 120 million. Urban gasification will be realized in most of the large- and medium-sized cities.
China has plenty of hydropower resources. The explorable potential of hydropower is 378 million kW which can generate 1920 billion kWh of electricity per year. However, only 9% of the explorable resources has been exploited at present. In 1990, 126.4 billion kWh of hydroelectricity was generated which accounted for 4.7% of the total amount of primary energy produced in China. The distribution of hydropower resources is uneven. Most of them are concentrated in the southeast, northeast and central part of China. The hydropower resources are generally remote from the developed regions, the exploition conditions are complicated and for their exploitation a large amount of capital investments is required. These factors have been restricting the rapid development of hydropower electricity generation. In 2000, a number of hydropower plants of different scale will be built. The amount of electricity generation is projected to be 228 billion kWh in 2000, corresponding to about 92 million tce. In addition, there are 76 GW of small scale hydropower resources that could be developed. As the construction of small scale hydropower stations does not require intensive investment, it is easier to develop them in the countryside. Hydroelectricity supply to the countryside can help to reduce the use of coal and biomass as fuel and thus the emissions of GHG.
Besides hydroelectricity, nuclear power is another kind of energy source without CO2 emission. The essential point is to strengthen safety measures. The development of nuclear electricity in China is at the beginning stage. The first nuclear electricity plant in Hangzhou Bay with a generation capacity of 210 MW has been put into operation. By the end of 1990's when the second phase of construction is finished the generation capacity of the plant will reach 600 MW, which will generate about 39 billion kWh per year, corresponding to 14 million tce. The nuclear electricity plant in Daya Bay, Guangdong provence is equipped with generation capacity of 2X900 MW. The facility will be put into operation soon. By 2000, another 2X900 MW generating capacity will be added. It is expected that the amount of electricity generation will reach about 30 billion kWh in 2000, which correspond to 11 million tce.
China is rich in renewable energy resources in its vast territory. The area with solar irradiation over 0.6 MJ/cm2 constitutes about 2/3 of the country's territory. Most of the solar energy is concentrated in West and Northwest China. In 1991, there were 1.5 MW solar photovoltaic cells, 2 million m2 solar water-heaters, 450 thousand m2 passive solar houses and 120 thousand m2 solar warehouses in use. Wind energy is rich in Xinjiang and Inner Mongolia Autonomous Regions, Gansu province, Northeast China and southeastern coastal area, where the average effective wind power density is around 200-300 W/m2. By the end of 1991, 120 thousand small sized and 67 large and medium sized wind power generators had been installed with the total capacity of 6.2 MW. China also abounds with geothermal resources. The estimated potential is 7200 TJ per year.
Forest plays an important role in the regulation of CO2 absorption and emission. Trees sequester CO2 from the atmosphere through photosynthesis and release it back to the atmosphere through respiration. The decay of wood also releases methane and CO2. In the whole, the mature forests absorb and release approximately balanced amount of GHGs. However, during the process of growth, carbon is fixed in trees by carbon accumulation in the form of wood. The rates of carbon fixation are different for different tree species and vary from about 2 to more than 30 tons of carbon per hectare per year. Large scale afforestation and expansion of forest areas can help to prevent the increase of carbon dioxide concentration in the atmosphere and mitigate greenhouse effect caused by human activities. At the same time, forests have the capability to conserve water sources and soil moisture, improve the ecological environment and provide animals and plants with habitat. The Chinese government attaches great importance to afforestation. In 1981, the central government adopted a resolution on voluntary tree planting through out the country. In ten years since then, 10 billion trees had been planted. In northern China, in order to control soil erosion and to protect the farmland against the threat of desertification, the Three Norths (North China, Northeast China, and Northwest China) Protecting Forest Project was started. By the end of 1992, 13.33 million ha of artificially planted forest had been completed. Before 2000, there will be six large afforestation projects in progress, including the second phase of the Three Norths Protecting Forest Project, Protecting Forest along the Middle and Upper Reaches of Yangtze River, the Taihang Mountain Afforestation Project, the Plain Afforestation Project, and the Fast-growing and Highyielding Timber Base Project. By now, forest covers 13.63% of the country's territory with 130.93 million hectares of afforested area. It is planned for the year 2000 that the forest coverage will increase to 17%, and the afforested area will increase by 45 million hectares.
Paddy field CH4 emission is a main CH4 source. For the reduction of methane emission from paddy fields, semi-dry cultivation method or intermittent irrigation method can generally be used. When semi-dry method is used, the water level in the paddy field is relatively low. This can reduce the anaerobic degradation of organic matters effectively and the methane emission rate will decrease by 31-43%. Intermittent irrigation method is based on the fact, that during the growing process of rice, the soil needs to be moist only in a definite interval of time and is allowed to be dry in other time. Proper adjustment of the duration of dry and wet time can raise the harvest and, at the same time, reduce methane emission.
Methane emission from ruminant animals accounts for about 15% of the agricultural methane emission. Through the improvement of breeds of ruminant animals and the use of aminated forage, the productivity of meat and milk of the ruminant animals can be raised. This will have the result of methane emission reduction.
China is a developing country. Because of its large population and rapid economic development, the amount of CO2 emission is expected to increase in the near future. However, the per capita emission level is still much lower than that of the world average. In spite of this, the Chinese government is making every effort to slow down the rate of increase of or to reduce the emission of GHG from different sources and to expand the sinks of GHG. Special attention is given to the improvement of energy efficiency and conservation of energy resources. China is willing to develop international cooperation to solve problems in this field.
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