Study On The Spatial And Temporal Differences Of Land Use Carbon Emissions In Kunming And The Influencing Factors

Global warming is becoming more serious today,and the root cause cannot be traced back to the rapid growth of CO₂emissions brought about by economic development,among which the carbon emissions brought about by land use changes are second only to those generated by energy consumption,and research shows that effective control of carbon emissions can be achieved through scientific and reasonable land use.In this context,exploring how land use carbon emissions evolve and clarifying how the influencing factors play a role can provide theoretical support and decision-making reference for the implementation of the regional"double carbon"target and the construction of low carbon cities.As the capital city of Yunnan Province,Kunming is one of the important central cities in southwest China and an important highland in the national"Belt and Road"economic corridor,and with the official release of the"Work Plan for Accelerating the Establishment of a Sound Green,Low-Carbon and Circular Economic System in Kunming City"in 2022,it is especially difficult to achieve the"double carbon"goal while maintaining high-quality socio-economic development.In view of this,this paper takes Kunming city as an example,based on land use,population,energy and economic data of Kunming city from 2000 to 2020,and uses the carbon emission factor method to account for carbon emissions in Kunming city as a whole as well as in each district and county,and analyses spatial and temporal changes based on trend analysis of land use change;the LMDI decomposition model is used to explain the mechanism of Kunming’s land use carbon impact,and the Tapio decoupling model is used to further analyse Kunming’s carbon emissions change and growth decoupling;Optimize the land use structure of Kunming City using linear planning method,determine the quantitative structure of each land use type,and make recommendations for energy conservation and emission reduction.The study was conducted with the aim of providing theoretical support and decision making for the realization of low carbon,green and high quality development in Kunming,the main findings of the study are as follows:（1）From the viewpoint of land use change,this paper analyzes three perspectives:land use quantity change characteristics,land use dynamic attitude and land use transfer matrix.From the characteristics of land use quantity change,the land use type in Kunming is mainly forest land,and the land area accounts for more than45%of the city’s land area.The area of water,construction land and unused land in Kunming increased during the study period,and the area of arable land,forest land and grassland decreased,among which the area of construction land increased the most,by 605.23 km²,with an average annual increase of 6.24%,and the area of arable land decreased The largest decrease was 227.53 km²,with an average annual decrease of 0.27%;In terms of land use dynamics,the fastest deceleration in terms of area by category during the study period was for cropland,with an average annual deceleration of 0.27%,and the fastest growth rate was for construction land,with an average annual growth rate of 4.57%;from the land use transfer matrix,the transfer out of arable land accounts for the largest share of the total land transfer in Kunming during the study period,with 306.7 km²transferred to construction land,11.32 km²transferred to forest land,and 1.29 km²transferred to water;the transfer in of construction land accounts for the largest share of the total land transfer,with 306.7km²transferred to arable land,97.37 km²transferred to forest land,and 187.95 km²transferred to grassland.（2）In terms of land use carbon emission accounting and spatial and temporal differences,net carbon emissions in Kunming during the study period reached its maximum in 2010,showing a fluctuating trend of rapid growth followed by a slight decline,but the overall net carbon emissions increased by a total of 11,154,444 tons.The carbon source is mainly construction land,which accounts for 97%of the total carbon emissions,followed by arable land.The carbon sink is mainly forest land,which accounts for nearly 96%of the total carbon uptake,followed by grassland,water and unused land.There is no obvious change in the total carbon sink during the study period,which has no obvious influence on the change of net carbon emissions from land use,the total carbon source is much higher than the total carbon sink,and the change trend of net carbon emissions from land use is basically consistent with the change trend of carbon source;the spatial distribution pattern of net carbon emissions has obvious heterogeneity,and the high carbon emission areas are mainly concentrated in Wuhua District,Panlong District,Guandu District,Xishan District and Anning City,and Chenggong District after 2010 The carbon emission increase is the largest,and the low-carbon emission area is mainly concentrated in Yiliang County,Luquan County and Xundian County,and the land use carbon emission is relatively stable,with small changes.（3）From the viewpoint of the factors influencing land use carbon emission,overall land use carbon emission intensity and land use efficiency play the role of suppressing land use carbon emission in Kunming,while land use structure effect,economic development level and population scale play the role of promoting land use carbon emission in Kunming.Land use efficiency is the biggest inhibitor of carbon emission increase,and the cumulative decrease of land use carbon emission is10,503.2157 million tons;economic development level is the biggest promoter of carbon emission increase,and the cumulative increase of land use carbon emission is86,444.566 million tons;land use structure effect and population size promote the cumulative increase of land use carbon emission by 27,865.371 million tons and18,586.679 million tons,respectively.million tons and 18.5867.91 million tons respectively;the intensity of land use carbon emissions transformed from the promoting effect before 2010 to the suppressing effect after 2010,and the overall cumulative suppression of land use carbon emissions decreased by 16.702.113 million tons.（4）From the relationship between land use carbon emission and economic development,the decoupling index for 2000-2005 is 1.18,showing an expansionary negative decoupling;the decoupling index for 2005-2010 is 0.38,showing a weak decoupling;the decoupling index for 2010-2015 is-0.15,showing a strong decoupling;the decoupling index for 2015-2020 is-0.82,showing a strong decoupling.-0.82,showing a strong decoupling state.Overall,the decoupling index keeps decreasing and the level of sustainable socio-economic development has improved.（5）In terms of land use structure optimization,the optimization model is constructed with the objectives of minimizing carbon emissions and maximizing ecological benefits,and the results obtained are that in 2025,the arable land area decreases by 8446 hm²,the forest land area decreases by 3878 hm²,the grassland area decreases by 15853 hm²,the water area increases by 1094 hm²,the area of construction land increased by 27,200 hm²and the area of unused land decreased by60 hm².The carbon emissions generated by the land use area under the optimized scenario decreased by 682.0305 million tons compared to 2020.In view of the carbon emissions from land use in Kunming,the following suggestions are made:adjust the land use structure and improve the efficiency of land use;optimize the energy consumption pattern and improve the energy The following recommendations are made with regard to the land use carbon emission situation in Kunming:adjust the land use structure and improve land use efficiency;optimize the energy consumption pattern and improve energy use efficiency;promote high-quality economic development and coordinate regional development;reasonably control the population size and establish the concept of low-carbon living.