The Construction Of The Greenhouse Gas Emissions Inventory Of The Urban System

The impacts of human activities on the global climate change and the carbon cycle were far outweighing than the degree of natural variations. The amounts of CO2 changes brought by the industrial revolution were far more than the range of the past 65 years caused by the natural factors. China, as the largest developing country in the world, was increasingly facing with severe pressure from the other countries to reduce its carbon emissions. The GHG emissions will also become an important issue which cannot be avoided in the future international competitions and negotiations. Therefore, in response to global climate change, Chinese government has put forward a series of strategies and policies and induced the index of "the decreased rate of carbon dioxide per unit of GDP" to national economical and social planning. City is the most significant region influence by human activities. Also, it is the center of economic and social activities. Therefore, the city is an important key to implement the carbon emissions reduction. The construction of greenhouse gas inventory is the foundation to carry out carbon reduction strategy which is of great significance to address the global climate change issues.Presently, there were still many deficiencies in constructing the greenhouse gas emission inventories. This research constructed specific urban greenhouse gas emissions inventory from different aspects, including industrial energy activities, urban transportation energy activities, urban living energy consumption, industrial processes, agriculture, livestock, and waste disposal. The greenhouse gas emissions inventory was consisted of three types of greenhouse gases, which were CO2, CH4 and N2O. This paper made breakthroughs on constructing the greenhouse gas emissions inventory based on previous relative researches. What’s more, we made further analysis on gaps between National Economical Statistical System and greenhouse gas emission inventory of IPCC.Based on urban greenhouse gas emissions inventory, this paper selected the Jiangyin City as the study case. Jiangyin City is the National Sustainable Development Experimental Zone pilot cities. We carried out research to calculate the greenhouse gas emissions of Jiangyin City in ten years and analyze the change characteristics of the structure, time series, emissions intensity and the relationship of greenhouse gas emissions with the economic development. This will help our country to establish greenhouse gas emission inventory which was in accordance with the local characteristics and provided a theoretical basis and methods for the other cities to construct greenhouse gas emission inventory in China. The main conclusions of this paper were as follows:(1) From 2002 to 2011, the annual carbon dioxide emissions of Jiangyin City were up to 83,560,400 tons. Over the past decade, carbon dioxide emissions showed a sharp upward trend with an increase rate of 450.81% and an average annual increase rate of 21.68%. The changing curve of carbon dioxide emissions could be roughly divided into three periods:2002 to 2007, the period of rapid growth; 2007 to 2009, the period of slow growth; 2009 to 2011, the period of restoring growth.(2) When we analyzed the structure of carbon dioxide emissions, we could find that the energy activities were the largest source of CO2 emissions in Jiangyin City which was showing a dramatic increasing trend, rising from 17,092,500 tons to 100,609,600 tons. The proportion of the energy activities in the total carbon dioxide emissions was rising from 65.04% to 69.50% in ten years. The industrial processes in Jiangyin City, the second largest source of carbon dioxide emissions, accounted for 33.23% of the total carbon dioxide emissions and showed a rising trend with an increase rate of 383.85% from 2002 to 2011. Among them, iron and steel production is the largest industrial source of carbon emissions, accounting for about 95% of the total carbon emissions of industrial processes. The proportion of the emissions from the waste disposal and human respiratory was less than 1%.(3) The average annual nitrous oxide emissions of Jiangyin City were up to 5556.24 tons. From the point of view of the overall trend, the nitrous oxide emissions showed a slow rising trend after the first decreasing period from 2002 to 2011. From the point of view of the emission structure of the nitrous oxide, the agricultural activities of Jiangyin City were the largest emission sources of nitrous oxide. However, the emissions from agricultural activities were showing a decreasing trend from 2002 to 2011 which was decreasing from 6003.32 tons to 4258.40 tons, the proportion of agricultural activities was decreasing from 95.49% to 76.55%. The energy consumption activities were the second largest nitrous oxide emissions sources. The amounts of nitrous oxide emissions from energy consumption activities were rising up from 283.54 tons to 1,300.44 tons and its proportion from 4.51% in 2002 to 23.38% in 2011. The incineration of the municipal solid waste was the third largest source of nitrous oxide emissions in Jiangyin City, with an average annual proportion for only 0.032% of the total emissions. However, its proportion was rising from 0.00224% to 0.07938%.(4) The average annual methane emissions of Jiangyin City were up to 23,396.06 tons. From the overall trend, we could find that the methane emissions were showing a declining trend from 27,994.21 tons in 2002 to 18,771.17 tons in 2011, with a decrease rate of 32.95%. From the the emission structure, we could find that the agricultural activities were the largest sources of methane emissions, accounting for 70.66% of the total methane emissions in 2002. However, with the rapid development of the industrial economy, gradual decline of paddy and slow weaken of the agricultural economic activities, the methane emissions of the agricultural activities were decreasing year by year from 19,779.79 tons to 11,051.16 tons. The emissions from the waste were the second largest source of methane emissions and the proportion of which slowly rised first and decreased then from 2002 to 2011. The energy activities were the third largest source of methane emissions. The methane emissions of the energy activities were showing an increasing trend and its proportion was rising from 0.92% in 2002 to 6.07% in 2011.(5) According to the GWP of the greenhouse gases, the carbon dioxide was the main greenhouse gas in Jiangyin City, which accounted for more than 90% of the total emissions equivalent and the proportion of carbon dioxide was showing a clear upward trend, rising from 91.30% to 98.58%. Nitrous oxide was the second largest emission source of greenhouse gas and the proportion of Nitrous oxide in the total emissions equivalent was significantly decreasing from 6.46% to 1.12%. Methane was the third largest greenhouse gas in Jiangyin City, accounting for 2.24% of the total emissions equivalent in 2002 and 0.29% in 2011, the proportion of which was showing a clear downward trend from 2.24% to 0.29%.(6) According to the intensity of the greenhouse gas emissions in Jiangyin City, we can find that the greenhouse gas emissions per GDP significantly increased first and then decreased. From 2002 to 2007, the greenhouse gas emissions per GDP were showing a clear upward trend, this may be caused by the overheat development of the economy and irrational industrial structure. From overall trend, the greenhouse gas emissions per GDP were showing a clear downward trend from 2007 to 2011. This may be associated with the phenomenon that some industries of high energy consumption, high emissions and low efficiency, low output died out because of the financial crisis. The trend of the greenhouse gas emissions per GDP could show, to some extent, that the science and technology in Jiangyin City was improved and the energy efficiency was enhanced from 2007 to 2011. The changing trend of greenhouse gas emissions per capita was generally consistent with the trend of total greenhouse gas emissions. The greenhouse gas emissions per capita were rapidly increasing from 24.86 tons/p in 2002 to 121.48 tons/p in 2011, with an increase rate of 388.58%.