The Research On Carbon Emission Effects Of Land Use Change

Climate change has become severe challenge which the mankind face, especially the global warming, it is a global environmental problem that generally acknowledged by international community. The main cause of global warming is the increasing of greenhouse gas in atmospheric resulted from fossil energy consumption and land use change. Land is the basis of human activity. Human activities, such as energy consumption, industrial distribution, economic construction, etc, have close relation with land utilization. The relation caused or reflected by conversion of land use types, adjusting land-use structure, etc. In the background of developing low-carbon economy, reasearch on how to converse land-use types, adjust land-use structure and innovate land-use technology to realize energy-saving and emission-reduction are significant.At present, the research on energy consumption carbon emission is about the relationship between carbon emission and economic growth, influencing factors of carbon emission, dynamic change of carbon emission, etc. The research on carbon emission effect of land-use change mainly concentrates on two aspects:on the one hand, it's to adopt relevant models to analyze and predict the carbon emission effect caused by conversion of land use types, such as cultivated land, forest land, meadow, construction land, etc; on the other hand it's to test the carbon emission effect through longtime location observation on land-use management practices. Above research mostly concentrates on a certain respect about carbon emission caused by land use change, so there is lacking a analytical framework in system to explore the carbon emission effect caused by land use change in different levels.This research will analyze the carbon emission effect caused by land use change based on the exist literature, provide reference for reducing carbon emission intensity, changing land-use types, adjusting land-use structure, and popularizing land-use technology. The major analytical procedure guiding the whole thesis is "theoretical analytical framework-empirical analysis-conclusion and policy suggestions". First of all, buiding theoretical framework on macro, meso and micro levels, namely carbon emission influenced by conversing land-use types, adjusting land-use structure, and changing land-use technology, respectively; then using relevant models to carry on empirical analysis; at last summarizing the research conclusion and proposing the corresponding policy suggestions.In macro level, the thesis analyzed the effect caused by land use types conversion from energy consumption perspective. First of all, the thesis analyzed the temporal-spatial characteristic of carbon emission, carbon intensity and carbon footprint; Then examined the relationship between carbon emission and economic growth through co-integration theory; and analyzed the contribution of different effects of economic growth to carbon emission using logarithmic mean divisia index method. The results show that:(1) 2002-2008, the amount of carbon emission increased 0.5 Gt, the emission amount caused by the residential area, industrial and mining land accounted for 85.36% of the total amount; the emission amount caused by transpotation land increased the fastest, and average annual growth rate was 13.09%. Land conversion caused carbon intensity showed a increasing tendency overall, among three land-use types, transpotation land carbon intensity was the highest, the average value reached 37.51 t/hm2. From terminal fossil energy consumption view, the carbon emission amount caused by land conversion has not resulted in the ecological deficit, however the ecological surplus quantity has been reduced constantly, the pressure faced has been strengthened constantly. There was obviously different in carbon emission, carbon intensity among different provinces, but the overall trend was gradually reducing from eastern coastal area to west; According to carbon footprint, the ecological deficit of east district in our country was relatively large, but in the western region it appeared the ecological surplus. (2) In the long-term, land use carbon emission and economic growth has co-integration relation; in the short-term, land use carbon emission was Granger reason to economic growth, but unfitable on the contrary, so there is one-way causality between two variables. It was a positive effect that energy structure, land benefit and land scale cumulative effect to carbon emission respectly, and energy intensity, industrial structure cumulative effect presented negative effect; the effect in order according to absolute value of cumulative contribution rate was land production, energy intensity, industrial structure, energy structure, land scale. The mainly influencing effect types were different for different land use types. The energy intensity cumulative effect was the main contribution effect to agricultural land, and land benefit cumulative effect was the main contribution effect to the residential area, industrial and mining land, transpotation land. Different effects'function direction to different land types was not all identical. Energy structure effect presented negative effect to transpotation land, positive or negative effect to agricultural land and residential land; the land scale effect presented negative effect to the agricultural land, and positive effect to the two kinds of construction land; energy intensity effect and land production effect presented negative effect and positive effect to the three land use types, respectively.In meso level, the thesis analyzed the carbon emission effect caused by adjusting land structure, including adjusting industry structure of construction land and planting structure of farming land. First of all, the thesis took Beijing, Hubei and Guizhou as example, which takes different industry development strategy, through adopting logarithmic mean divisia index method again to analyze the contribution to construction land carbon intensity from adjusting industry structure; Then through adopting carbon uptake and emission estmating models, the center of gravity model and C-D production function to analyze the temporal-spatial characteristic of net carbon uptake from adjusting planting structure in our country. The results show that:(1) The industrial structure effect presented negative effect on the carbon intensity of Beijing and Hubei, but positive effect on Guizhou. As to Beijing this kind of area, which implements industry shift strategy, and the industrial structure is relative optimization, the contribution of industrial structure adjusting to reduce carbon intensity is smaller than the carbon intensity of the secondary industry; As to Hubei this kind of area, which undertakes industrial transfer strategy, but the industrial structure optimization space is slow, the industrial structure adjusting contribution to reduce carbon intensity is not enough to offset the increase effect caused by the secondary industry; As to Guizhou this kind of area, which undertakes industrial transfer strategy too, but the industrial structure shows a fluctuating state, industrial structure adjusting contribution is smaller than industry intensity, but can't be neglected. (2) The net carbon uptake of farmland ecosystem in our country showed a fluctuated increase tendency, grain crop net carbon uptake amount taked primary proportion; In terms of the proportion of total net carbon uptake, Southeast China declined the most, while Mongolia-Xinjiang Region increased the most. Southwest China has gradually become a major contributor to the national net carbon uptake. The gravity center of net carbon uptake offset the geometric centre; In terms of the geographical location, the center of gravity of net carbon uptake showed a trend of moving towards northwest. The planting structural adjustment exerted a great impact on net carbon uptake, and had different contribution rate and direction to different regional net carbon uptake. Except for Northeast and Middle-lower reaches of Yangtze River districts, the planting structural adjustment influenced more prominently to the net carbon uptake of six other areas. Although the drop proportion of grain crop resulted in a more prominent negative effect to net carbon uptake, but at present, in the most region of our country, the negative effect to net carbon uptake is still not enough to offset the positive effect resulted from conventional input, such as chemical fertilizer.In micro level, the thesis analyzed the carbon emission effect caused by different land use technology. This thesis took rice production in Taihu Basin as example, through life cycle assessment method to assess the effect from greenhouse gas emission to environment by different fertilization technology, namely conventional fertilization technology and formula fertilization by soil testing. The results show that:Compared to conventional fertilization technology, applying formula fertilization by soil testing could reduce fertilization input about 40.38 kg/hm2, and producing 1ton rice could make energy consumption reduce 227.74 MJ, the global warming potential (GWP) reduces 40.48 kg CO2-eq; The reduction input of nitrogen could make environmental acidification potentiality reduce 3.76 kg SO2-eq at the same time, eutrophication potentiality reduce 0.71 kgPO43--eq. The formula fertilization by soil testing technology can make the greenhouse effect index produced in the process of rice production reduce by 6.32%. Though the decrease extent is not much, this new technology has played a certain role in slowing down the greenhouse effect, as well adopting the new technology can promote the energy-saving and emission-reduction.Based on the above research results, the policy implications are as follows:(1) Control the land conversion quantity rationally, improve the energy efficiency effectively. Under the premise of not impeding economic growth, through enhancing the technical effect and optimizing structure effect, in the certain extent it may slow down the carbon emission increasing. Through reforming the price of energy to internalize environmental cost and resource rare cost; Through setting up transparent price forming mechanism to guide the rational consumption of the energy, and improve the energy efficiency. (2) Optimize the land use structure, reduce the carbon source, increase carbon sink. In the process of implementing the strategy of "shifting from labor-intensive industry to service economy", the fact that different areas carry different role decides different emphasis points. The regions of industry shift should lay particular emphasis on reducing industry carbon intensity, especially the carbon intensity of the secondary industry; The regions of industry undertake should lay particular emphasis on improving industry entry threshold, eliminating the backward industry which high energy-consumption, high pollution and high emission, improve the clean production of the industry to a certain extent. On the premise of food security, through raising the economic crop planting proportion to improve agricultural income, it is feasible to a certain extent from the net carbon uptake pespective of farmland ecosystem; In the agricultural production region where farmland rare, through improving the agricultural production technology and management level to increase the carbon uptake amount is feasiable, for example, agroforestry planting pattern, non or reduce cultivation, etc. (3) Improve the land use technology, mitigate the greenhouse effect. The new agricultural production technology help to realize agricultural energy-saving and carbon-reduction, so from administrative management aspect, we can make agricultural energy-saving and carbon-reduction goal, set up the assessment system to advance agricultural energy-saving and emission reduction progressively; From policy guidance aspect, we can make economic policy to fomulate motivation mechanism, promote the fast development of agricultural energy-saving and emission-reduction; The government should strengthen the support for the new agricultural production technology, in order to expand the space of agricultural energy-saving and emission-reduction.