Spatio-Temporal Distribution Of Carbon Source/Sink And Carbon Deficit Prediction In Northeast China

Climate warming is the result of the game between natural ecological evolution and human social development,and carbon circulation plays an important role in this process.Studying the dynamic changes of carbon sources / sinks,carbon emissions from social energy consumption and carbon profit and loss in terrestrial ecosystems is the entry point for analyzing the humanland relationship-carbon game process.The three provinces in Northeast China have an important forest reserve pool-northeast shelter forest.The vegetation structure and growth status in this area have a significant impact on China ’s climate change and natural carbon source/ sink.Since the founding of the People ’s Republic of China,the three northeastern provinces have long played an important role in social development.In the process of building heavy industrial bases,energy bases and commodity grain bases,the northeast region has faced greater pressure when facing the ’ double carbon ’ goal.Therefore,it is of great theoretical and practical significance to study the relationship between natural ecology and social carbon emissions in the three northeastern provinces.In this paper,multi-source data such as meteorology,remote sensing and statistical yearbook were collected,and the improved CASA(Carnegie Ames Stanford Approach,CASA)model and soil microbial respiration model were used to estimate the net ecosystem productive(NEP)of the three northeastern provinces from 2000 to 2020.The CA-Markov(Cellular Automata-Markov,CA-Markov)model is used to predict the future total carbon sinks in the three northeastern provinces;by increasing the constraints of real carbon emissions on the estimation process,the nighttime light remote sensing image and carbon emission fitting method are improved,and the historical carbon emissions of prefecture-level cities in each province are estimated.The ridge regression and STIRPAT(Stochastic Impacts by Regression on Population,Affluence and Technology,STIRPAT)methods were used to decompose the factors affecting carbon emissions in the three northeastern provinces,and the scenario analysis method was used to predict and discuss the future carbon emissions development path and scenario combination in the study area.On this basis,the spatial and temporal distribution and influencing factors of historical and future carbon profit and loss in the three northeastern provinces are explored,and the following main conclusions are drawn :(1)Historical evolution of natural carbon source / sink and future carbon sink capacity :From the perspective of time change,the interannual variation of NEP in the three northeastern provinces showed a fluctuating upward trend.From the analysis of monthly variation,the monthly mean of NEP showed a single peak trend.From the perspective of spatial distribution,the multi-year mean of NEP in Northeast China shows the distribution law of high mountain and low plain.Among the meteorological factors affecting NEP,precipitation has the greatest impact on NEP,followed by solar radiation,and finally temperature.In the past 21 years,the total amount of carbon sinks in the three northeastern provinces has shown a fluctuating upward trend.Among them,the total amount of carbon sinks in Heilongjiang Province is the highest,accounting for about 57.93 %-64.41 % of the total carbon sinks in the study area.The total amount of carbon sinks in Jilin Province is slightly lower,and the total amount of carbon sinks in Liaoning Province is the least.The prediction of future natural carbon sink capacity in the three provinces of Northeast China : The NEP of different vegetation types is quite different,showing the state of broadleaved forest > coniferous forest > cultivated land > grassland > desert and bare land.By calculation,the total carbon sink of the three northeastern provinces in 2025 is about 243.99-290.44 TgC / a;the total carbon sink in 2030 is about 243.02-289.33 TgC / a;the total carbon sink in 2035 is about 243.56-289.93 TgC / a.(2)Historical evolution and distribution characteristics of social carbon emissions : In the past 21 years,the carbon emissions of the three northeastern provinces have shown a trend of ’ rise-fall-rise ’,with the largest carbon emissions in Liaoning Province and the least carbon emissions in Jilin Province.Through the assistance of nighttime light remote sensing images,the peak carbon emissions of prefecture-level cities in each province over the years are estimated.Among them,Shenyang and Dalian in Liaoning Province,Changchun in Jilin Province,Harbin and Daqing in Heilongjiang Province have the most prominent carbon emission capacity.The total carbon emission capacity of the above five cities accounts for 44.8 %of the total annual carbon emissions of the three northeastern provinces.Prediction of future carbon emission potential in the three provinces of Northeast China :Using STIRPAT model to decompose the influencing factors of carbon emissions in the three provinces of Northeast China,it is found that population,energy structure and industrial structure are the main factors affecting carbon emissions in the three provinces of Northeast China.Using the scenario prediction method,the future carbon emission scenario trajectory of the three northeastern provinces is predicted.The most suitable basic development scenarios for Heilongjiang Province,Jilin Province and Liaoning Province are S2(benchmark development scenario),S4(technology development scenario)and S6(industrial structure optimization scenario).(3)Historical carbon profit and loss and future carbon profit and loss in the three northeastern provinces : The historical carbon profit and loss of the three northeastern provinces in the past 21 years has changed from a carbon surplus state to a carbon loss state,with a turning point around 2005.Heilongjiang Province has been in a state of carbon surplus for a long time,Liaoning Province has been in a state of carbon loss for a long time,and Jilin Province is hovering near the critical value of carbon surplus.The carbon profit and loss of the three provinces in Northeast China as a whole shows the spatial distribution law of southwest loss and northeast surplus.The carbon profit and loss of each province shows a stable positive correlation with natural factors,but the correlation with social factors is not the same.From the perspective of future carbon profit and loss results,the three northeastern provinces will still be dominated by carbon loss in the future,but the gap in carbon loss will gradually decrease.This shows that it is difficult to directly achieve carbon neutralization in the three northeastern provinces in the future by relying solely on terrestrial ecosystem carbon absorption and social emission reduction.It is necessary to seek carbon neutralization methods by developing carbon capture,carbon storage and other technologies,and cooperating with the development and application of clean energy.