Systems Dynamics Research Of Chong Qing’s Carbon Emissions By Land Use Change

Carbon dioxide is the main greenhouse gas. Global warming causes extreme events and bad weather have become one of the challenges of human survival and development. The land use change plays an important role on the carbon dioxide emissions in the atmosphere. About one-third of carbon dioxide emissions contributes to land use change. Chongqing is the fourth municipality city. The city at the stage of speedy development with the feature of large countryside surrounding the large city. In the process of rapid urbanization, there are many issues, such as uneven distribution of land use structure and land-use efficiency. The land use change’s carbon emissions could evaluate the land use efficiency. Therefore understanding the capacity of land use carbon emission or absorption, the effect of the carbon emission and absorption by human activities on different land use patterns, which will benefit land use planning, control and change the high carbon emission of land use and to guide the low carbon mode of production.Therefore, this paper based on the data of land use change during 1997-2010 and the data of economy, population and energy during 1997-2012 in Chongqing, By using the method of system dynamics to calculate carbon dioxide emissions caused by the different land use patterns in 1997-2012. According to the historical data in 1997-2012 in Chongqing, established the system dynamics model which could simulate and forecast the changes in carbon emissions in the next 17 years. And then through the test of history data, the system dynamic model of carbon emissions is reliable. So it could simulated carbon emissions changes under different scenarios. Such as the change of energy structure, crop planting structure and the land use structure.According to the different land use patterns by human activities to divide the carbon sinks and carbon source system. The result is based on the system dynamics and through indirectly calculation.(1) From 1997 to 2005 Chongqing city is mainly in the stage of carbon sequestration. In 2006-2030 year the Chongqing city is mainly in carbon emission phase. The carbon emission is 5 times more than the carbon sink in 2030 year by model forecast.(2) The land use of construction was divided into the carbon emission land. Construction land scale from 1997 to 2010 continued to grow, The average annual growth rate was 1.6%. Construction land carbon emissions growth much faster than growth in the area. Carbon emissions in 2020 is 9 times than 1997, and in 2030 which are growth more than 24 times than 1997. Construction land is under severe pressure, Such as population growth, economic development, urbanization. The ultimate cause of carbon emissions in construction land is the original energy consumption. Energy consumption structure would influence the carbon source intensely.(3) Cultivated land-agricultural inputs system is a carbon sink system in Chongqing. Cultivated land area was reduction at an average annual rate of 0.26% in 1997-2010. Due to climate, crop species and cropping pattern in Chongqing, the carbon sink during crops growth was more than carbon emission by agricultural inputs. Finally, the agricultural production system of cultivated land is carbon sinks system in Chongqing. With the development of modern agriculture, the growth of agricultural inputs, so the production of crops will be increased in the future. According to the forecast by the system dynamics model in 1997,2010,2020,2030 the carbon sinks by crops growing are 3.8,3.6,3.4,2.9 times than carbon emissions by agricultural inputs and livestock. Further more, the dietary structure will also influence the carbon emissions by cultivated land-agricultural inputs system. Such as increasing in meat food, reducing grain and so on.(4) The forest, garden land system is the carbon sink system steady. Forest land area was increased at an annual average rate of 0.3% in 1997-2010. The carbon sink by forest land, garden land and grassland was about 50% of the total amount of carbon sinks in 1997-2010. Due to the increase of crop yield in future years, the carbon sinks by forest land, garden land and grassland was at around 46% of the total amount of carbon sinks in 2013-2030. The area of forest land, garden land is stability, the affected by human activities is small in Chongqing. So forest, garden land system’ total carbon sinks is more stable than cultivated land-agricultural inputs system. And the capacity of forest carbon sink will increases with the plant growth period.