Spatio-temporal Evolution And Its Driving Factors Of Agricultural Carbon Emissions In Central Yunnan

The series of problems caused by global climate change are one of the biggest challenges facing mankind at present,and it also strengthens the global political consensus and major actions to deal with the climate crisis.In the face of continuous global warming,reducing greenhouse gas emissions in the process of human activities and increasing the carbon sink of terrestrial ecosystems are of great significance to mitigate the negative impact of climate change on human beings and achieve China’s goal of"carbon peak and carbon neutrality".Agricultural production is not only a major source of greenhouse gas emissions,but also a major carbon sink for terrestrial ecosystems,as well as a human activity with a large number of participants,a large range of activities and a prominent ecological environment.Therefore,the environmental effects of agricultural production are the main fields of research on human-land relations;Based on the theory of human-land relationship,the theory of regional differentiation,the theory of low-carbon economy and the three laws of geography,and on the basis of the measurement of industrial carbon emissions,farmland vegetation carbon sink,agricultural carbon sink surplus accounting,carbon decoupling and difference in central Yunnan,this paper takes the county as the basic spatial unit,comprehensively uses mathematical statistics,GIS spatial analysis,geographic detector methods to carry out research on spatial effect characteristics of agricultural carbon emissions in central Yunnan,such as spatial heterogeneity and spatial dependence,as well as spatial pattern evolution,equity evaluation and driving factors;Among them,agricultural carbon emission accounting mainly accounts for greenhouse gas emissions from planting,livestock and poultry breeding with high participation and frequency of human activities,and non-CO₂greenhouse gases such as CH4 and N2O are converted into CO₂equivalent according to the IPCC global warming potential（GWP）.From the above research,the basic conclusions reached are as follows:（1）Agricultural carbon emissions show a trend of rising first and then falling,carbon sinks continuing to rise,and carbon sink surpluses falling first and then rising.（1）In terms of agricultural carbon emissions,it increased from 10.5469 million tons in2000 to 18.5865 million tonsin 2016,and then dropped to 14.1355 million tons in2020,which will continue to decline slowly in the next few years;structurally,the proportion of carbon emissions from aquaculture has always been greater than that of planting,ranking the first source of carbon emissions from agricultural sources.（2）In terms of agricultural carbon sinks,agricultural carbon sinks in central Yunnan showed a four-stage change characteristic of"stable-rising-falling-rising"from 2000 to 2020;Structurally,agricultural carbon sinks are composed of carbon sinks of food crops and carbon sinks of cash crops,and the carbon sinks brought by food crops account for most of China’s total agricultural carbon collection,but their proportion is generally declining.（3）In terms of agricultural source carbon surplus,the agricultural source carbon surplus in central Yunnan showed a clear"stable-rising"trend from 2000 to2020,although the agricultural carbon sink surplus fluctuated,it generally showed an upward trend..（2）The spatial agglomeration effect of agricultural carbon emissions,carbon sinks and carbon sink surpluses is significant,showing the distribution characteristics of high in the east and low in the west.（1）In terms of agricultural carbon emissions,the spatial and temporal evolution of agricultural carbon emissions in central Yunnan from 2000 to 2020 was less different,and the spatial heterogeneity was enhanced,Kunming urban area and Yuxi City were"low-lying areas"of agricultural carbon emissions,and high-value emission areas were still concentrated in Qujing City;In terms of trend,the center of mass is located in Songming County,central Yunnan,showing the"northeast-southwest"transfer trajectory process.In terms of spatial autocorrelation,the global Moran’s I index showed a trend of continuous increase and tail decrease,and the spatial agglomeration continued to increase.（2）In terms of agricultural carbon sinks,the spatio-temporal evolution of agricultural carbon sinks in central Yunnan from 2000 to 2020 showed significant differences between the east and the west.The central Kunming and Yuxi urban areas were low-value agricultural carbon sinks,and the eastern part of Qujing was high-value agricultural carbon sinks;In terms of trend,the center of mass is located in the eastern part of Songming County,central Yunnan,showing a"northeast-southwest-southeast"transfer trajectory process.the global Moran’s I index has no significant inter-annual change,it is positive and shows an upward trend,and the spatial agglomeration trend is strengthened.（3）In terms of agricultural carbon sinks,the spatial and temporal evolution of difference agricultural carbon surplus in central Yunnan from 2000 to2020 was not obvious,and the total amount showed an increasing trend,with the smallest change in Kunming City and the largest change in Xuanwei City;In terms of trend,the center of mass is located in the western part of Malong County,showing a"southeast-southwest-northeast"transfer trajectory process.In terms of spatial autocorrelation,the global Moran’s I index is at a high level,with a mean value above0.4,and the overall spatial correlation is strong.（3）The decoupling elasticity of central Yunnan has been further improved,and the regional differences in carbon emission equity assessment are significant.（1）In terms of the elastic relationship of decoupling,the fluctuation period（2001-2010）showed three types of decoupling:strong negative decoupling,weak decoupling and extended negative decoupling.In the relatively stable period（2011-2016）,the growth rate of agricultural economy from 2011 to 2015 was faster than the growth rate of carbon emissions,and the elastic characteristics of carbon emissions were weakly decoupled,and the growth rate of carbon emission agricultural economy and carbon emissions in 2016 were consistent with negative decoupling of expansion.The ideal stable period（2017-2020）is all strong decoupling,and the decoupling effect is further improved.（2）In terms of difference evaluation,the type with high ecological bearing-high economic contribution（"high-high"）is mainly distributed in the south-central part of Yunnan,which is generally a developed county with good ecological and agricultural economy,they can be used as a demonstration area;the type with high ecological bearing-low economic contribution（"high-low"）is mainly concentrated in eastern Yunnan.it’s ecology is excellent and the agricultural economy is poor,so it is necessary to vigorously develop the agricultural economy;the type with high ecological bearing-low economic contribution（"high-low"）is mainly in the central region,with poor ecology and good agricultural economy,but the overall proportion is not high;the type with low ecological load-low economic contribution（"low-low"）is mainly distributed in northwest Yunnan,it’s ecological and economic conditions are very backward,and it needs the most attention.（4）From 2000 to 2020,agricultural carbon emissions in central Yunnan were formed in the interaction of multiple factors such as economy,population and society,but the differences between factors were relatively large.Agricultural input has the largest driving force on agricultural carbon emissions,followed by the level of economic development,then the population and natural factors.The production structure has the smallest driving force on agricultural carbon emissions.