A Study On The Temporal Characteristics And Influential Factors Of Land-use Carbon Emission In Beijing-Tianjin-Hebei Region

By the 1930s,annual carbon emissions from land use change had been significantly higher than those from fossil fuels,maintaining slight but persistent disturbances in the global carbon cycle.Therefore,clarifying the coupling relationship between change of land use and carbon emission has practical guiding significance for efficiency improvement and the regulation of land use carbon reduction.Based on the six phases land use raster data of Beijing-Tianjin-Hebei region from 1990 to 2015,this paper uses carbon emission model to measure carbon emissions,carbon sequestrations and the net carbon emissions of different land types in different regions.The key drivers of carbon emissions as well as its intensity and direction are identified using LMDI model.Meanwhile,the spatial differences in land use carbon emissions are clarified as well.According to the research results,the paper innovatively carried out researches on differentiated carbon emission strategy,based on the function orientation of different regions,and the optimization path of land use structure.The main conclusions are as follows:(1)The total amount of carbon emission was increasing in Beijing-Tianj in-Hebei region from 1990 to 2015.The distribution of total carbon emission shows a trend of decreasing from southeast to northwest and the provincial capitals are the regions where the carbon emissions problem is most prominent.The trend of total carbon sequestration presents a highly consistency in each land use type of different districts,showing a slowly decreasing overall.The spatial distribution showed an increasing trend from southeast to northwest.The high carbon sequestration areas are concentrated in the Bashang Plateau,the northern Hebei Mountains and the Tai-hang Mountains,while the low carbon sequestration areas are mainly distributed in the low-lying North China Plain.(2)The function of carbon source/sink varies between different land use types.Built-up areas and cultivated land are the major carbon sources,while the main contribution of carbon sequestration come from woodland and grassland.The contribution to carbon source form built-up areas increases year by year,mainly due to the large amount of energy consumed by industrial production,household use and transportation.On the contrary,cultivated land contributes less to carbon emissions and declines volatility over time,mainly due to a significant carbon emission reduction benefited by technological innovation and increasing technology investment.(3)The carbon effect of land use change in Beijing-Tianjin-Hebei region is represented as carbon emissions,and the spatial trends of net carbon emissions are similar to carbon emissions.The net carbon sink region is located near the northeast woodland and the southwest Tai-hang Mountains,which owns the richest forest and grassland resources in BTH region and mainly used for eco-tourism development;however,the net carbon source region is located in North China Plain,in which Beijing,Tianjin,Shijiazhuang,and Tangshan become the largest carbon sources and account for 58.2%of the total.(4)Based on the LMDI model,the study on key driving factors,intensity and direction of carbon emissions show that the land use structure,per capita GDP and population size have positive effects on the increase of net carbon emissions during the study period.The population size plays the main role among those three factors,followed by per capita GDP and land use structure.However,the intensity of carbon emissions per unit of land and the intensity of land per unit of GDP have a depressing effect on carbon emissions.