Accounting And Predicting The Carbon Emission From Arable Land In Southern Jiangsu Province

Carbon emission has caused global climate and ecological environmental problems,which has brought serious impact on human life.Arable land is one of the important sources of carbon emission.Therefore,it is of great significance to study the carbon emission from arable land to achieve carbon emission reduction targets.The southern part of Jiangsu Province is the most developed area in Jiangsu Province.It has the characteristics of a typical developed urban belt in China,and the changes in arable land use are relatively intense.It is necessary to conduct in-depth research on the carbon emission from arable land use.This article takes the Southern Jiangsu Province(including Nanjing,Suzhou,Wuxi,Changzhou and Zhenjiang)as the research area,and select land use data from five time periods at six time points of 1990,1995,2000,2005,2010,and 2015,and use land use transfer matrix to obtain the area of farmland changes over five time periods.Establish a bookkeeping model suitable for use in this region to systematically calculate the amount of carbon emission from arable land.Then,based on the results of carbon accounting for arable land changes in southern Jiangsu during1990-2015,a grey GM(1,1)and BP neural network model were used to predict the carbon emission of this region in 2020-2025.Finally the countermeasures and suggestions of carbon emission reduction from the perspective of the use of arable land were putted forward.The results show:(1)In the changes of arable land in southern Jiangsu,construction land is the main source of farmland transfer-in,and the main direction of farmland transfer-out.The conversion area between water area and arable land is the second,and the conversion area between grassland and arable land is the least.The changes in arable land area were stable and the amount of the area changes are small from 1990 to 2000,and the changes from 2000 to 2010 increased rapidly,and the changes trend from 2010 to 2015 became gentle again.(2)During the study period,soil carbon emission from arable land transfer-out in southern Jiangsu > soil carbon emission from arable land transfer-in > vegetation carbon emission from arable land transfer-out > vegetation carbon emission from arable land transfer-in.The soil carbon emission from arable land transfer-out accounted for 97.97% of the total carbon emission from arable land changes,and it is the main source of carbon emission fromarable land changes.The vegetation carbon emission from arable land transfer-in accounted for only 0.04%.In regard to the carbon emission from arable land transfer-out,from the period of 1990 to 2015,the net carbon emission from the arable land transfer-out in the southern Jiangsu Province was 29.10 million tons.The net carbon emission from arable land during the 1990-2000 period was relatively small.The net carbon emission from the period 2000-2010 increased rapidly,and the average annual growth rate reached 6.09%.The net carbon emission from 2010 to 2015 increased slowly,the average annual growth rate was 1.78%.The amount of net carbon emission from arable land in Suzhou City was the largest,which reached 10.76 million tons,followed by Nanjing City,and Zhenjiang City had the least amount of net carbon emission.In the prediction of carbon emission from arable land changes in southern Jiangsu,the average absolute error(MAE),root mean square error(RMSE)and average relative error(MRE)predicted by BP neural network model are lower than those of grey GM(1,1).The BP neural network has a better fitting effect than the grey GM(1,1)model,and is selected to predict the future carbon emission from arable land in southern Jiangsu.The prediction results of BP neural network model show that the amount of carbon emission from arable land changes in southern Jiangsu show a trend of increasing year by year from 2020 to 2025,and effective measures should be taken to reduce the amount of carbon emission generated by changes in arable land.This study has achieved the accounting and forecasting of carbon emission from arable land use in southern Jiangsu.The results of the research can provide data supporting for the implementation of carbon emission reduction in southern Jiangsu,and also enrich the accounting and prediction research of carbon emission from arable land use in different types of areas in China.It provides reference for the study of carbon emission from arable land changes in other regions.