南昌市土地利用碳排放效应及其低碳优化对策

Carbon Emission Effect of Land Use in Nanchang and Optimizing Measures

土地利用/覆被变化通过改变生态系统的结构和功能,对全球碳排放产生深刻的影响。以南昌市为例,采用生态系统类型法确定土地生态系统的有机碳排放,2005年南昌市碳排放总量为4.826 2 Tg,2010年为5.535 9 Tg。期间南昌市土地利用变化碳排放量呈现增长的趋势,2010年比2005年增长0.709 7 Tg,年均增长0.141 9 Tg。其中耕地和牧草地的碳排放量在2005—2010年间减少,园地、建设用地表现为增加,水域和其他未利用地的碳吸收功能减弱。根据土地利用规划预测计算得出,2020年为6.697 7 Tg,比2005年增长1.871 5 Tg,年均增长0.141 9 Tg。由于用地结构的差异性,南昌市的碳排放量也有所不同。2005—2010年,全市各县区的碳排放依次以南昌县、新建县、进贤县和青山湖区最多,碳排放总量排名基本保持不变。结合土地利用结构变化和发展规划,南昌市应该采取适度退耕还林、还水、限制建设用地过度扩张、优化城市用地布局、灵活调节土地供应政策、构建碳交易法律体系等碳减排措施,达到土地利用规划与生态建设相结合的目标。

Changes in land use/cover have a profound impact on the global carbon emissions through changing ecosystem structure and function.Taking Nanchang for example,this paper,by using ecosystem types,determines carbon emissions of land ecosystems between 2005 and 2010.It finds that,in 2005 the carbon emission of Nanchang was 4.826 2 Tg,which was increased to 5.535 9 Tg in 2010,indicating a trend of growth among the years.The carbon emission increased by 0.709 7 Tg in 2010 compared to that in 2005,with an average annual growth 0.141 9 Tg.The carbon emissions of cultivated land and grassland was reduced from 2005 to 2010 while those in garden and construction land were increased.The carbon accumulation function of water and other unused land abated.According to the estimate of land use planning,in 2020 the carbon emission of Nanchang will reach 6.697 7 Tg,1.871 5 Tg more than that in 2005,with an average annual growth of 0.141 9 Tg.Due to the differences of land use structure,the carbon emission of Nanchang City was also different.In the period of 2005—2010,the ranking of counties’carbon emission was Nanchang County,Xinjian County,Jinxian County,Qingshanhu District,and the ranking of carbon emission remained unchanged.The carbon emissions in the southern part of Nanchang was the highest,of which the most prominent was Nanchang County.Combined with the land use structure and development plan of Nanchang,it is urgent that the city take such measures to reduce carbon emission reduction as returning farmland to forests or water,limiting excessive expansion of construction land,optimizing the layout of urban land use,adjusting the land supply policy,and establishing a legal system to regulate carbon trading so that the combined goals of land-use planning and ecological construction can be achieved.