Study On The Carbon Emission Effect Of Land Use Change In Lanzhou City From 2002 To 2012

With the continuous development of industrialization and urbanization,the emission of greenhouse gas was increasingly,and thus caused the global climate change,especially the global warming---a serious challenge mankind facing today.The human activity is the main cause of various kinds of environmental problems,among which the way of land use change behind fuel combustion is a major factor leading to a sharp rising of global atmospheric CO2 content and influencing terrestrial ecosystem carbon cycle.Therefore,the study on carbon emissions of land use change can provide reference for the development of carbon emission reduction measures and low-carbon economy,thereby further improving the quality of ecological environment and human living environment.This paper selected Lanzhou city as the research object which has rapid economic development and weak ecological environment quality in recent years.The area data of six major land use types,such as cultivated land,grassland,woodland,water area,construction land,and unused land of Lanzhou in 2002,2005,2008 and 2012,were obtained by means of remote sensing.And then,the amount of carbon absorption,carbon emission and net carbon emission were acquired with the carbon accounting model by use of energy consumption statistics for Lanzhou city.Furthermore,the effects of carbon emissions in Lanzhou city during 2002 and 2012,and the correlation and regression analysis among the land use change,the amount of carbon absorption and carbon emission were analyzed more detailly.The research results show that:(1)The imbalance between carbon absorption and emission for Lanzhou city was a constant state from 2002 to 2012,and the total amount of net carbon emission was continued increasing,the maximum was 12073.33 kt,and It totally increases 7575.86 kt in eleven years.(2)The land of forest,as the main carrier of carbon sequestration,had an average annual carbon uptake amount of 4712.65 kt from 2002 to 2012.The construction land was the main source of carbon emission,producing a relative larger amount of carbon emission,13496.68 kt per year,which was much higher than the annual carbon uptake amount of the forest.(3)Certain correlations were existed among the land use change,the carbon emission,and the carbon absorption.The significant correlation was between the aera of woodland and the carbon uptake,the correlation coefficient reached 1.000,and the lowest correlation(0.273)was between that of grassland and the carbon uptake;while a highest correlation coefficient(0.98)was between that of construction land and carbon emission.(4)The fitting degree of regression analysis between the aera of forest land and the total amount of carbon absorption was the highest(R2 1.000),and then was that of construction land(R2 0.959),followed by unused land(R2 0.955),cultivated land(R20.896),and water area(R2 0.829),and the lowest was that of the grassland(R2 0.105).Finally,the suggestions and measures were proposed so as to reduce the amount of carbon emission from land use,and develop the low carbon economy and ecological city in Lanzhou.