区域土地利用结构的碳效应评估及低碳优化

区域土地利用是引起碳排放的重要因素,土地利用结构优化能在一定程度改变土地利用的碳源/汇格局,并引导区域经济社会的低碳发展。基于线性规划方法,该文建立了区域土地利用碳效应综合评估及优化调控的方法,并以南京市为例,提出了3种土地利用低碳优化方案,并对其碳减排潜力进行了对比分析及蒙特卡洛模拟,最后提出了低碳土地利用优化的政策建议。结果发现,2020年南京市土地利用总体规划方案使区域的总碳蓄积量有所提升,但预期碳排放远远大于碳蓄积的增加值,同时也将会导致生态系统碳汇能力的降低;在3种优化方案中,基于碳排放最小化的土地利用结构优化方案比2020年规划方案的碳排放减少了73.75万 t,碳减排潜力为8.50%,表明该方案起到了较好的预期减排效果;因此,该文建议将基于碳排放最小化的土地利用结构优化方案作为南京市未来土地结构调整和产业规划的参考,该方案不仅有助于实现碳减排的目标,而且对于控制建设用地的过快增长、增加生产性土地面积、引导农地整理和居民点用地整理等土地利用规划和开发活动都具有重要的现实意义。

Carbon effect evaluation and low-carbon optimization of regional land use

To explore the influences of human activities on the global carbon cycle, anthropogenic carbon emission has become one of the major concerns in academic circles. Regional land use is an important source of carbon emissions. As a direct embodiment of human activities and government policies, the alteration of land use structure will change the pattern and structure of human energy consumption, which will further influence natural and anthropogenic carbon emissions and regional carbon cycle efficiency. Therefore, the impact of human economic and energy activities on the regional carbon cycle was largely achieved by changing land use structure and pattern. Land use is an important driving factor of low-carbon economy and carbon emissions, and is an important tool for carbon emission regulation and control. Research on the carbon effect of land use and its regulation helps to promote the developing of a low-carbon economy through land use planning, industrial structure regulation and control and territorial development, renovation and management. First, this paper evaluated the carbon effect of the overall plan for land utilization in Nanjing through determining the parameters for carbon effect evaluation. Then, three schemes for land use low-carbon optimization were proposed and analyzed, and the policy suggestions were put forward finally. The main conclusions are as follows: 1) The carbon storage, carbon emission, and carbon sink under land use overall planning scheme of Nanjing in 2020 was 344.35?104, 1293.90?104, 3.40?104t higher than that in the land use structure in 2005 respectively. Generally, the land use planning scheme of Nanjing city in 2020 will increase regional carbon storage to some extent, but will decrease the carbon sink function of the terrestrial ecosystem, and will also promote the increase of carbon emission. 2) Carbon emission of the land use structure optimization scheme based on the lowest carbon emission will be 73.75?104t lower than that in the land use overall planning scheme in 2020, and the carbon emission reduction potential is 8.50%. If considering the carbon storage and carbon sink of Nanjing city under the land use structure optimization scheme base on the lowest carbon emission, the total carbon emission reduction and carbon sink increasing potential will reach 148?104t, which means that the land use structure optimization scheme base on lowest carbon emission scheme will be the best land optimization scheme to add carbon sink and reduce carbon emissions. Through Monte Carlo simulation, the carbon emission reduction potential of the land use structure optimization scheme based on the lowest carbon emission scheme was further confirmed. 3) In order to promote low-carbon economic development in Nanjing, we suggest that the land use structure optimization scheme based on the lowest carbon emission should be considered as an important reference in the future land use structure adjustment and industrial planning in Nanjing city. This scheme will not only help to realize the aim of carbon emission reduction during "the Twelfth-Five Planning" of Nanjing city, but will also have important practical significance for the controlling of constructive land expansion, adding of productive land use areas, guiding the land use planning and exploiting activities such as consolidation of agricultural land and rural residential areas. Furthermore, the carbon effect evaluation method should be introduced into the environmental impact assessment of land use activities to establish low-carbon land use patterns.