Spatial And Temporal Differentiation Of China’s Agricultural Carbon Productivity:Mechanism And Demonstraion

How to better adapt to and cope with climate change is a global environmental problem facing humanity since the 21st century.In this circumstance,countries generally seek a green and low-carbon development path.Although the industrial sector is the main sector of carbon emissions,agriculture also plays a vital role in global climate change.In order to promote the sustainable development,"climate smart" agriculture has emerged.Its aims are to continuously improve the production efficiency of agricultural systems and enhance the ability of agriculture to mitigate and adapt to climate change while reducing agricultural greenhouse gas emissions.Agricultural carbon productivity has the dual attributes of "guaranteeing growth" and "promoting emission reduction" ,which should be the core content of China’s climate smart agriculture development in the new period.So,what is the realistic level of China’s agricultural carbon productivity?And what is its historical evolution and development trend?How about the spatial distribution structure?Is there a certain change characteristic and law?What is the mechanism that leads to its spatial and temporal differentiation?Is there any spilover effect of agricultural carbon productivity in space?And which factors cause the spillover by spatial interaction?If there is a spillover feature,it means that the important role of spatial geographical factors cannot be ignored during the development of low-carbon agriculture.Meanwhile,how to balance the relationship between various agricultural sustainable development zones is also so important that can promote low-carbon transformation of agriculture and improve quality and efficiency with structural reforms on the supply side.Answers to the above questions can not only help to better grasp the basic facts and characteristics of China’s low-carbon agriculture development,but also find out the decision mechanism and key factors of agricultural carbon productivity growth and differentiation through the combination of theoretical analysis and empirical testing.Thus,more reasonable policy recommendations will lay the foundation for promoting the structural adjustment,spatial layout optimization and sustainable development of China’s agriculture.This study starts from the concept of "carbon productivity" ,takes "mechanism interpretation-productivity measurement-spatiotemporal analyzes-empirical test" as the logical main line,and systematically analyses the problem of China’s low-carbon agricultural development during the "relative emission reduction" stage.The research is analyzed as follows:the first part is the research origin,theoretical sources and analysis framework（Chapters 1,2,and 3）,aiming to introduce the domestic and international background and purpose,possible contributions,basic ideas,methods and possible innovativeness of this research.Then based on this,the core concepts of the research and its connotation are clarified,and the research trends in related fields are sorted out.Finally,the internal mechanism and determinants of the spatiotemporal differentiation of agricultural carbon productivity are explained based on the classical theory.The second part is mainly about characterizing and revealing the temporal evolution and spatial pattern of agricultural carbon productivity.That is to measure agricultural carbon productivity in a suitable way and its differentiation characteristics are analyzed from the two dimensions of time and space（Chapters 4,5,and 6）which is from the phase of "relative emission reduction" and basing on the content of the agricultural carbon emissions accounting list of the study.The third part is to empirically test the decision mechanism of agricultural carbon productivity growth from the perspective of spatial geography,and to deeply analyze the growth of agricultural carbon productivity in the changing agricultural industrial structure,after that,to examine the threshold structural effect of agricultural industrial agglomeration.Furthermore,policy recommendations on harmonious development relationships between agricultural industrial structure optimization,rural human capital investment,co-ordination of new industrialization,urbanization and agricultural modernization are put forward.（Chapters 7 and 8）.Through systematic and meticulous research,the main conclusions are as follows:（1）From 1993 to 2016,the total amount of agricultural carbon emissions in China increased significantly,while the growth rate slowed down.Specifically,in terms of various gases,CH₄ emissions>CO₂ emissions>N₂O emissions,of which the shares of CH₄ will continue to decline,while CO₂ ratio will increase significantly.In terms of regions,the priority development area>moderate development area>protection development area,also the emissions of protection development area decreased slightly.In the seven major agricultural areas,the middle and lower reaches of Yangtze River>Huanghua Hai>Southwest>Northwest>Northeast>South China>Qinghai Tibet.That is,different agricultural carbon emissions were structurally different.And animal husbandry was still the largest carbon source in agriculture.（2）China’s agricultural carbon productivity growth is generally faster,but the inter-provincial and inter-regional growth is uneven.There is no sign ofσconvergence in agricultural carbon productivity of the whole country and all the sustainable development areas.There are also signs of absoluteβconvergence and conditionalβconvergence in agricultural carbon productivity in China,priority development areas,the Huanghua Hai,the middle and lower reaches of Yangtze River.The basic pattern of China’s agricultural carbon productivity within the peripheral high-value areas of the eastern coastal provinces and the low-value areas in the western inland areas has basically taken shape.In the crop field,the carbon productivity presents the regional distribution characteristics of "high in west and north" and "low in east and south" .Animal husbandry carbon productivity showed a step-by-step distribution pattern of "east to west low" .According to the Theil index,the overall gap in agricultural carbon productivity in the country has been shrinking,while the northwest and south China regions are the root causes of the uneven development of agricultural carbon productivity among the provinces within the region.（3）There is spatial autocorrelation in provincial agricultural carbon productivity,but it is shranking.That is,although China’s agricultural carbon productivity has a clustering phenomenon,the differentiation of agricultural carbon productivity among provinces in local areas is more obvious,which is more consistent with the previous findings.Meanwhile,spatial spillover effect plays an important role in regional agricultural development,and the agricultural carbon productivity in a province is not only significantly affected by industrialization,technological progress,urbanization,agricultural industrial agglomeration,national financial support,planting structure and natural disasters,but also affected by the spillover effect of financial input,industrialization,agricultural openness and agricultural agglomeration in neighbouring countries.Agricultural industry agglomeration has a positive impact on agricultural carbon productivity,and it has a significant threshold effect between agricultural industrial structure and agricultural carbon productivity.In view of this,this paper proposes the following suggestions:First,each region should promote the low-carbon transformation of agriculture according to the characteristics of its own agriculture,its dominant industries and its functional status,and differentiated and focused.Second,how to further optimize the layout and spatial structure of agricultural production,adjust the structure of agricultural industry,strengthen the support of science and technology and talents,coordinate the relationship between agricultural modernization and new urbanization,maybe become to improve agricultural carbon productivity and solve agricultural structural contradictions.And it is also an effective path to promote sustainable low-carbon agriculture.Third,the adjustment and optimization of agricultural industrial structure is an important force affecting the low-carbon transformation of agriculture.However,the role of this kind of function will be different due to the difference in the concentration of agricultural industries.The scale of planting and animal husbandry should be promoted differently,Cluster development and its low carbon transformation.The possible innovations in this paper are as follows:First,the scope of the agricultural carbon accounting inventory is more comprehensive and scientific.The appropriateness and scientificity of agricultural carbon emission accounting content is directly related to the accuracy and objectivity of related research.Combining the agricultural carbon accounting system of China and the world’s authoritative institutions,using the field experiment data that is more in line with China’s actual conditions to measure China’s agricultural carbon emissions is a useful supplement and expansion of existing research.The second is the innovation of perspective.Explaining the issue of low-carbon development of agriculture from the perspective of agricultural carbon productivity is not only in line with the binding development goals of China’s socio-economic development carbon intensity reduction at the current stage,but also more suitable for agricultural emission reduction.At the same time,based on the new geoeconomics theory,this paper analyzes the mechanism of agricultural carbon productivity differentiation from the perspective of spatial geography,and uses the spatial econometric model to explore the determinants of agricultural carbon productivity.It is also an improvement of the spatial homogenization of previous research hypotheses.The third is the innovation of research methods.From the perspective of spatial geography,the spatial threshold effect model is used to explore the nonlinear relationship between agricultural industrial structure and agricultural industrial agglomeration and agricultural carbon productivity,and expands the understanding of the internal role of agricultural industrial structure in agricultural carbon productivity growth.