Urban Construction Land Expansion Boundary Research Based On Carbon Emission Peak

In recent years,the impact of climate change on human increasingly intensified.IPCC Fifth Assessment Report pointed out that climate change is more serious than the original understanding,with more than 95 percent certainty that the change is caused by the human behavior.As more and more climate change is awareness,global warming has become a serious challenge facing human development,the common will of the international community to address climate change have become stronger.China,the world’s largest developing country,the total amount of its carbon emissions has become the first place in the world,which will become an important issue in international competition and negotiations for China to face directly.At the end of 2014 on the APEC meeting,China and the US issued a joint statement,the Chinese government proposed to reach carbon peak in 2030,and will strive for this purpose as soon as possible.Land use change is one of the principle human activities which resulting in greenhouse gases,especially CO2 concentrations in atmospheric increased.It is not only influences terrestrial ecosystem carbon cycle by changing surface land cover or land use,but also carries all human carbon emissions activities.The cities are the areas affected by human activities most intensely.China is in the period of rapid urbanization.The growth of urban construction land within the coming period of land use change is inevitable.The city is the most violent region by human activities affect in the Earth’s surface.As a result,the rapid expansion of urban construction land would not only change the landscape pattern of urban space,but also has a tremendous impact on the ecological environment system,especially on considering the source of carbon emission,construction land carries a large number of high energy consumption,high carbon discharge of human activities.Its expansion will definitely affect the global greenhouse gas emissions,especially carbon cycle and climate change.Therefore,this dissertation takes Hefei city,the core of Wanjiang City Belt as an example,bases on the study of land use carbon emissions accounting and effects analysis,deeply explores the relation of construction land carbon emissions and construction land expansion under carbon peak.This dissertation also predicts and simulates the urban construction land expansion boundary,has important theoretical and practical value in exploring in reducing energy consumption intensity in newly urbanization,protecting the environment,adjusting land use structure and achieving a low-carbon development.Using land use change data,statistical data,empirical data as the foundation,through the decoupling theory,Kuznets theory,Kaya identity theory,statistical methods,cellular automata space simulation and other methods,this paper conducted a full accounting of carbon emissions on six projects including terrestrial ecosystems,energy consumption,industrial production,waste treatment,respiration and food consumption in Hefei,from 1995 to 2012.The thesis established the relationship of carbon emissions of various projects and land use type,and analysised the carbon intensity of land use,contribution rates,and changes in carbon sinks resulting from land-use changes.Based on construction land expansion and the carbon emissions it carried,this dissertation analyzed the decoupled state and coordination between them,as well as the existence of "inverted U" curve relationship,then predicted the construction land carbon peak and the construction land expansion under the control carbon peak in Hefei.Finally,using cellular automata model,the dissertation simulates city boundary extension of Hefei.The main conclusions are as follows:(1)The carbon sink capacity is weakening while the carbon capacity is increasing in Hefei,which needs timely control.Terrestrial ecosystems play a role in carbon sequestration,remained at the level of two million tons of carbon,farm system is the most important carbon sink;in the type of anthropogenic sources of carbon emissions,energy consumption is the largest source of carbon emissions,followed by respiration emissions,industrial production,food consumption and waste disposal,in the order from more to less.From the proportion of carbon source discharge point of view,only the proportion of carbon emissions generated by energy consumption is growing year by year,the proportion of carbon emissions in industrial production remained virtually unchanged,while the proportion of other carbon emissions accounting items are in decline.In general,during the 18 years from 1995 to 2012,the total carbon emissions in Hefei increased year by year.From 4,462,100 tons to 17,458,600 tons,there is an increase of 2.91 times and the average annual growth rate of 8.36%.2003 is an exception with a disaster led to terrestrial ecosystems carbon sink capacity decreased,so that the net carbon emissions increased,and the city was also found increased year by year trend in net carbon emissions in the 18-year period from 2,755,400 tons to 15,373,300 tons,with an increase of 4.58 times and the average annual a growth rate of 10.64%.(2)Strict control of construction land,especially in urban industrial land expansion in Hefei for inhibiting carbon emissions is particularly critical.Through the establishment of the relevant relationship between different land use types and their carbon emissions accounting detailed project,the dissertation analyzes the land-use emissions effects in Hefei,1995—2012.In terms of strength,garden,lawn carbon sink strength remains unchanged,carbon intensity of arable land,forest land slightly increased,carbon sink strength of waters slightly decreased;and carbon source intensity in urban industrial land is much higher than transportation land and rural residential Land.For the contribution rate,farmland,urban industrial land,transportation land and rural residential land show significant effects,in which are negative contribution rate of farmland,and positive contribution rate of urban industrial land,transportation land and rural residential land.On the topic carbon sink change accounting,the loss of carbon sink from farmland change into construction land,contributes about 80%of the total loss of carbon sink from carbon sink land change into carbon source land.Carbon sink land is most likely turns into urban construction land,in which the largest proportion is from farmland turns into urban industrial land and the percent of carbon sink loss is about 90%.(3)In Hefei,there was a weak decoupling state between carbon emission of construction land and construction land expansion and trended toward an ideal state,but still difficult to reach the peak in the natural growth.Unlike economic growth,the expectations of carbon emissions is a decline,and therefore on the decoupling or recoupling relationship between carbon emissions and construction land expansion,strong decoupling<weak decoupling<recessive decoupling<strong recoupling<weak recoupling<expansive recoupling.The ideal trend of development is toward expansive recoupling.Due to natural disasters in 2003,some of the index value in2003 and 2004 are abnormal,beside of which the construction land carbon emission and construction land expansion in Hefei from 1995 to 2012 represent a state of weak decoupling.The result of coordination evaluation shows that after 2010 the coordination of both is developing toward a positive trend.However,Kuznets curve relationship between the two is not clear,therefore,in the absence of external interference such as policy factors,carbon emissions intensity of construction land is difficult to reach the peak.(4)Carbon emissions of construction land in Hefei will reach peak around 2030.Based on the idea of Kaya identity,this dissertation builds a construction land carbon peak prediction model,sets multiple model control factors including,carbon emissions per unit of energy consumption,energy consumption per unit GDP(energy intensity),per capita GDP and technological progress correction factor.This dissertation sets three kind of per capita GDP in different scenarios,including high growth,median growth and low growth.Forecasts show that in the low per capita GDP growth scenarios,the city of Hefei’s construction land carbon emissions will peak 17,346,400 tons in 2025;in median growth scenarios,the construction carbon emissions would peak 18,625,400 ton in 2030;in high value growth scenario,the city’s construction land carbon emissions will peak 20,471,600 tons in 2035.According to the analysis,the construction land carbon emissions in Hefei will not peak before 2025,and will peak around 2030.(5)The partition synchronization constraints of cellular automata model can simulate urban expansion under low carbon target.This dissertation built a partition synchronization constraint of CA model.Through the accuracy test,the dissertation found that the simulation test result has the features of higher point accuracy and more compact overall spatial pattern,etc.,which can be effectively applied to urban expansion process simulation.Thus,based on the prediction of urban construction land under the constriction of carbon peak,this dissertation application of the model in the urban construction land simulation of Hefei in 2025,2030 and 2035.The simulation results showed that the major construction land propagation directions in the main city of Hefei would be south and west.After the carbon emissions peak in 2030,the urban construction land area would begin to decrease,might obviously appear in the west and southeast of Hefei.There were two mian innovations in the thesis.On the one hand,this paper primarily put forward the control of urban construction land expansion boundary based on carbon emissions peak.On the other hand,this paper explored to bring the carbon constraint factor into the partition synchronization constraints of CA model.