Carbon Accounting And Space Distribution In Nanning Metropolitan Region Based On Land Cover

As the Increasing of atmospheric CO2 and other greenhouse gas(GHG) concentration reinforced the greenhouse effect, which had a huge impact on the coastal zone, agriculture and animal husbandry, the social economy and so on. The climate warming has caused the worldwide concern of people. City is a major contributor of greenhouse gas emission. It is necessary to establish a unified standard of the city carbon emissions accounting system with the low carbon city having becoming a hot topic all over the word.Accordingly, this study summarized the research about carbon effect of land cover change at home and abroad to analyse the terrestrial ecosystem pattern and carbon storage change during the period of 2003-2013. Furthermore, on the reference of IPCC, ICLEI and GPC inventories, the integrated carbon emission(both natural and anthropogenic) was accounted. The new established urban inventories which is duplicatable, reportable and verifiable has 5 sectors including energy activity, the process of industrial production, agricultural activities, forestry carbon sequestration and land cover change as well as urban waste treatment. Finally, on the basis of Nanning carbon emission and other assistant data including population, transportation, and industry points, the study constructed the correlated framework of "land cover-carbon emission" and innovated in distributing the carbon items into the high-resolution spatial grids which contributing to Numerical simulation of carbon emission.The results show that:(l)The ratio of woodland, grassland and water decreased while arable land and artificial surface were increasing year by year from 2003 to 2013. The vegetation carbon storage of terrestrial ecosystem in Nanning is 13.32TgC. Average vegetation carbon density reaches 2.07 kgC/m2. The soil carbon storage of terrestrial ecosystem in Nanning is 59.79TgC. Average soil carbon density reaches 9.27 kgC/m2. The largest turn rate (16.42%) was the water surface, and most of the turn land was cultivated and artificial surface.(2)Carbon emissions presented increasing trend from 7760450t CO2 of 2003 to 18504951 t CO2 of 2013. The average annual growth rate reached 10.18%. In 2013, the first-level of carbon budget and expenditure items, the largest proportion was energy(81.19%), the contribution of forestry carbon sink and land cover change was Negative(-0.70%). In second-level of carbon budget and expenditure items, highway transportation, industrial energy, and cement production carbon emissions were most significant, the contribution were 33.67%,29.47% and 10.87%(3)Carbon emissions of energy activities sector presented the increasing trend. For the energy structure, the contribution of coal and power were Maximum which reaching 46.99% and 36.9%. For the industry, non metallic mineral products industry etc.6 industries were the most significant. Total carbon emissions accounted for more than 80% of total carbon emissions of industrial energy. In the Forestry carbon sink and land cover departments, forestry carbon sink decreased year by year from 616131 t CO2 of 2003 to 579553 t CO2 of 2013. The carbon emissions from land cover change was 199038 t CO2/yr, and the carbon emissions of vegetation was 251305 tCO2/yr.(4)High carbon emission enterprises are mostly located outside of the downtown area in Nanning, especially in Xixiangtang district and the Jiangnan area. Carbon emission intensity and land cover types, population density has a strong correlation.