Research On The Impact Of Land Use Recessive Transformation On Carbon Emissions In Urban Agglomeration In The Middle Reaches Of The Yangtze River

At present,the world is still facing a serious climate problem--global warming.The increasing carbon emission is an important factor of global warming.Land use change has become the second largest source of carbon emissions,second only to energy consumption.Scientific and reasonable land use can effectively control carbon emissions,so as to alleviate the severe situation of global warming.However,with the release of"The Construction of the Two-carbon Urban Agglomeration in the Middle reaches of the Yangtze River is a grand Strategy"in 2022,it is particularly difficult to achieve the goal of simultaneously promoting economic development and ecological environment.In view of this,this thesis takes the urban agglomeration in the middle reaches of the Yangtze River as an example,and selects four phases of land use data from 30 cities in 2010,2015,2018 and 2020 to explore the relationship between hidden land use transition and carbon emissions.Firstly,the index system of land use recessive form was established,the entropy method was used to determine the index weight,and the linear weighting method was used to calculate the recessive form index of land use in 2010,2015,2018 and 2020.Kernel density estimation and natural breakpoint method in GIS were used to describe the time series evolution and spatial pattern evolution of these indices.Based on the carbon emission coefficient method,this thesis analyzes the temporal and spatial changes of carbon sources,carbon sinks and net carbon emissions of urban agglomerations in the middle reaches of the Yangtze River,and explores the correlation between the hidden form of land use and carbon emissions by using the Moreland index.Finally,this thesis uses the geographical detector model to deeply analyze the mechanism of land use impact on carbon emissions of urban agglomerations in the middle reaches of the Yangtze River,and proposes feasible solutions.The main conclusions are as follows:(1)The kernel density estimation method was used to explore the spatio-temporal evolution characteristics of the recessive form of land use in urban agglomerations in the middle reaches of the Yangtze River.With the passage of time,the crest continued to decline,indicating that the difference between cities was increasing,from 0.46 in 2010 to 0.97 in 2020.By observing the left and right tail of the curve,it is found that the gap between the curves is slightly shortened,indicating that the proportion of regions with low level of land use recessive form in the middle reaches of the Yangtze River urban agglomeration has decreased,and the number of cities with low recessive index has decreased from 13 in 2010 to 2 in 2020.Obviously,the recessive form of land use in the middle reaches of the Yangtze River is improving and changing to a higher level.From the single dimension index of land use recessive form,the fastest growth of land input index is in Wuhan,Nanchang and other cities.The fastest growth of land output index is in Wuhan,Changsha and other cities.The fastest growth of land intensity index is in Wuhan,Huangshi and other cities.The fastest growing land property index is Wuhan,Nanchang and other cities.From the perspective of spatial change,the land use pattern of the urban agglomeration in the middle reaches of the Yangtze River has undergone great changes,from a three-core agglomeration pattern to a multi-core equilibrium pattern,with Wuhan City,Changsha City and Nanchang City as the center and spreading around,forming a unique spatial distribution pattern.Locally,the recessive results of land use in Wuhan City,Changsha City and Nanchang City have been in the leading position.It can be seen from the conclusion that the change of land use recessive transformation is not only reflected in time,but also shows certain convergence in space.(2)Land use dynamic analysis was used to calculate the land use change of the urban agglomeration in the middle reaches of the Yangtze River from 2010 to 2020.The results show that the construction land area has been increasing both in growth rate and increment,from 10,757 km~2in 2010 to 15,378km~2in 2020,followed by the water area,showing a trend of decreasing first and then increasing.The area of arable land is the fastest decreasing land type,having decreased from 128086km~2in 2010 to 125,197km~2in 2020,followed by unused land.In terms of the spatial distribution of land use area,the construction land of urban agglomeration in the middle reaches of the Yangtze River is mainly distributed in Wuhan,Jingzhou and other cities,the cultivated land is mainly distributed in Jingmen and Xiangyang and the water area is mainly distributed in Jingzhou and Yueyang.The unused land is mainly distributed in Nanchang,Jiujiang and other cities.Woodland is mainly distributed in Ji’an,Yichun and other cities,while woodland and grassland are concentrated in Ji’an,Jiujiang and other cities.(3)The temporal and spatial changes of urban agglomeration in the middle reaches of the Yangtze River were explored according to the carbon emission coefficient method and the natural breakpoint method of GIS.The results show that the net carbon emissions in the middle reaches of the Yangtze River change over time,and the total carbon emissions are on the rise.In terms of carbon sources,the total amount of carbon sources increased by2.770×10~7t,the growth rate reached 11.34%,and the annual growth rate also reached 0.134%.Construction land is the main carbon source and its carbon source is on the rise.In terms of carbon sink,the cumulative reduction of carbon sink is 6.390×10~4t,with a decrease of 0.15%.Forest land is the main carbon storage area,followed by water,grassland and unused land.However,forest and grassland carbon storage is decreasing,water carbon storage is increasing,and unused land carbon storage is stable.From the perspective of space,the spatial difference of net carbon emissions of land use in urban agglomerations in the middle reaches of the Yangtze River is gradually expanding,and the bifurcation becomes more obvious.Carbon emissions of Wuhan City and Yueyang City are the regions with heavy emissions.Low emission areas are mainly distributed in Yingtan,Xiantao and other cities.(4)The spatial autocorrelation and local autocorrelation of Moran index were used to study the relationship between the recessive form of land use and net carbon emissions of land use.From a global perspective,the intensity factor layer,property right and input of land use had the strongest positive correlation on carbon emissions,in which the intensity factor layer had the greatest influence,while the property right layer had a weak influence.Input level has less influence.From the perspective of local autocorrelation,the local spatial pattern can be divided into the following three categories:The high-high concentration area is Wuhan.The high-low concentration areas are Yichang,Jingmen and other cities.Low-low concentration areas are mainly located in the southern and western cities of the urban agglomeration in the middle reaches of the Yangtze River.(5)Use geographic detectors to explore the influence of recessive transition on carbon emissions.The results show that the hidden transformation of land use in urban agglomerations in the middle reaches of the Yangtze River has a significant impact on carbon emissions,among which the output value of the secondary industry,the output value of the tertiary industry and the power consumption of the average land have the most significant impact on carbon emissions during 2010-2020,and have a strong explanatory power.In addition to the above three leading factors,land urbanization has also become one of the main factors affecting carbon emissions.In 2020,land urbanization is the leading factor affecting carbon emissions,with q values ranking the first in that year.With the rapid development of the secondary industry,carbon emissions will increase accordingly.