基于PCA-BP神经网络的用地碳排放预测研究

量化和预测用地的碳排放是实现规划控碳的前提和基础。基于城镇建设用地分类体系,从城市用地建筑能源消费的碳排放核算视角,提出以"用地"作为碳排放的核算终端和核算单元,基于PCA-BP神经网络建立规划用地碳排放预测模型来预测用地碳排放。将调研获得的样本地块的碳排放数据作为因变量,以其用地特征指标(包括:容积率、建筑单体数量、用地面积、建筑密度、建筑高度、用地类型、用地兼容性、人口密度)作为自变量,建立用地碳排放预测模型。以长兴县老城区为实例,应用该模型预测用地碳排放,从模型预测结果来看,该方法能较准确地预测用地的碳排放,为城市的低碳规划和碳排放管控提供了量化依据。

中国夜间灯光与建设用地碳排放关系实证分析

为厘清建设用地碳排放与夜间灯光之间的关系,利用静态面板回归以及EKC模型,对1995年到2015年全国30个省级行政单位的建设用地碳排放量与灯光指数ANLI的关系进行实证,并基于城市化的视角对结果进行分析。研究发现:(1)城市化与建设用地碳排放在全国与西部存在双向因果关系,在东中部存在城市化对建设用地碳排放的单向因果关系,说明东中部的城市化质量高于全国整体以及西部;(2)全国以及东中西部的ANLI指数与建设用地碳排放都存在着倒U型曲线的关系,说明城市化对建设用地碳排放具有驱动与制动的双重作用;(3)城市化对建设用地碳排放的贡献具有区域性,按大小排序为:东部>中部>全国>西部。研究结果可为夜间灯光数据估算碳排放提供一定的理论支持,未来应因地制宜地制定减排政策,积极构建环境友好型社会。

基于STIRPAT模型的辽宁省工业用地碳排放影响因素分析

探究工业用地碳排放影响因素作用程度及变动规律,为工业用地低碳高效利用提供依据。利用STIRPAT模型、Tapio脱钩分析模型研究,发现辽宁省2006—2020年间工业用地碳排放的主要驱动因素为工业发展水平,主要抑制因素为科研投入水平;15 a间工业用地碳排放和工业发展水平距离强脱钩状态还有一定的差距。研究结论:现期辽宁省工业用地利用效率总体不高、产出水平偏低,工业经济的快速发展还是以牺牲环境为代价,加大科研投入力度并提高科研投入的产出效率将显著降低工业用地碳排放。建议从扎实推进工业经济高质量发展、加大科研投入力度和产出效率、加强政府工业用地调控管理等层面考虑工业用地低碳高效利用,助力辽宁省“双碳”目标实现和新时代东北老工业基地振兴。

双碳目标下农用地碳排放研究进展及热点分析

为揭示我国农用地碳排放的研究现状与未来发展趋势,基于CNKI数据库提取样本文献,从年发文量、作者分布、期刊来源和关键词进行文献计量统计,采用UCINET社会网络分析技术绘制关键词网络图谱进行可视化分析。研究发现:2008-2019年期间农用地碳排放的发文量呈快速上升趋势;李波、张俊飚和田云为排名前三的高产作者。农地利用、碳效应、时空特征关键词为农地碳研究热点,而碳补偿、农业生产效率和碳核算是未来农用碳研究的可拓展空间。

碳排放约束下广西城市建设用地利用效率特征分析

土地利用/覆被变化是影响碳排放、碳吸收量变化的主要原因。本文通过碳排放系数间接估算法、HicksMoorsteen生产率指数分析广西2011年-2020年城镇建设用地利用效率动态变化,结果发现:(1)广西建设用地碳排放总量的变化趋势可分为“先升后降再升”三个阶段,地均碳排放总量整体呈“先降后升”的趋势,万元GDP碳排放量的变化呈平稳下降趋势;(2)广西全区HM指数呈现年平均4.87%的上升趋势,受综合利用效率(Δ_(E))和技术进步(Δ_(tech))共同驱动,各市城镇建设用地利用效率都出现微小波动的上升趋势,呈现出区域的非均衡性。广西应综合考虑各市城镇建设用地利用效率存在的问题,因地制宜实施产业转型、能源结构优化以及节能环保等政策。

碳排放峰值控制下的建设用地扩展规模研究

建设用地作为最大的碳源用地类型,碳排放贡献率显著,因此,低碳调控是实现建设用地减量化的有效手段。已有研究多是通过优化土地利用结构、控制建设用地扩展来实现碳减排效果,而当中国政府做出2030年左右达到CO2排放峰值的承诺后,首先需要解决的是碳排放的达峰问题。因此,本文通过构建与修正Kaya恒等式、回归拟合、灰色预测等方法,在合肥市建设用地碳排放峰值预测的基础上,对该峰值管控下的建设用地扩展进行研究。得到以下结论:①提出了碳排放峰值对建设用地管控的研究思路与框架,认为基于碳排放峰值的科学预测,可以有效地控制建设用地扩展,并引导土地利用结构调整。②GDP、人口与建设用地、碳排放的关系密切,按照人均GDP高、中、低值三种情景的设定,认为中值情景更符合合肥市“十二五”以来的发展状况,即合肥市将在2030年达到CO2排放峰值1862.54万t,此后开始逐渐降低。③建设用地扩展与碳排放之间具有强相关性,根据中值情景下合肥市的CO2排放峰值预测结果,合肥市建设用地将在2030年达到最高值10.81万hm^2,此后开始逐渐减少。最后,提出两点讨论:①对于模型构建、因素分解等方面可进一步深入研究,从而为决策、规划提供更全面的依据。②展望未来,“退建还耕”应当是中国城市精明增长的路径之一,城市周边建设用地复垦将是城镇建设用地整治的重要工作内容。

碳排放权交易政策的有效性及作用机制研究——基于建设用地碳排放强度省际差异视角

碳排放权交易政策是当前我国实现低碳经济转型的重要举措。以中国30个省级单位2007～2016年的面板数据为研究对象,从建设用地碳排放强度省际差异视角出发,运用双重差分法探究碳排放权交易政策有效性,并对该政策的作用机制进行分析。结果表明:(1)试点区与非试点区建设用地碳排放强度均值有相同的变化趋势,但试点区的碳排放强度值总体呈下降趋势,非试点区则略有上升,说明碳排放权交易政策的实施效果优于强制性减排政策;(2)双重差分法结果证实在控制其他变量的情况下,碳排放权交易政策显著降低了建设用地碳排放强度,且地均GDP、能源强度和工业结构等控制变量对建设用地碳排放强度有显著的促进作用;(3)进一步对碳排放权交易政策的作用机制检验发现,碳排放权交易政策通过对能源强度的相对下降,最终起到抑制建设用地碳排放强度的作用。

Carbon Emission of Regional Land Use and Its Decomposition Analysis: Case Study of Nanjing City, China

Through the matching relationship between land use types and carbon emission items, this paper estimated carbon emissions of different land use types in Nanjing City, China and analyzed the influencing factors of carbon emissions by Logarithmic Mean Divisia Index（LMDI） model. The main conclusions are as follows： 1） Total anthropogenic carbon emission of Nanjing increased from 1.22928 ×10^7 t in 2000 to 3.06939 × 10^7 t in 2009, in which the carbon emission of Inhabitation, mining ＆ manufacturing land accounted for 93% of the total. 2） The average land use carbon emission intensity of Nanjing in 2009 was 46.63 t/ha, in which carbon emission intensity of Inhabitation, mining ＆ manufacturing land was the highest（200.52 t/ha）, which was much higher than that of other land use types. 3） The average carbon source intensity in Nanjing was 16 times of the average carbon sink intensity（2.83 t/ha） in 2009, indicating that Nanjing was confronted with serious carbon deficit and huge carbon cycle pressure. 4） Land use area per unit GDP was an inhibitory factor for the increase of carbon emissions, while the other factors were all contributing factors. 5） Carbon emission effect evaluation should be introduced into land use activities to formulate low-carbon land use strategies in regional development.

Forest and Soil Carbon Stocks, Pools and Dynamics and Potential Climate Change Mitigation in Nepal

The degradation of forest and soil contribute significantly to carbon emission to the atmosphere leading to the build-up of carbon dioxide in atmosphere and contributing to global warming. Consequences of climate change are not only the rise in global temperatures, but also changes in the precipitation patterns, which could affect agricultural production, food security, human health and long-term ecosystem properties balance. The deforestation and land degradation are major sources of GHG （greenhouse gas） emissions. International negotiations and dialogues on REDD＋ mechanism are held for both national and local level mitigation policies formulation for the reduction of carbon emission from land use, land use change and forestry sector. The reduction of emissions from fossil fuel combustion and avoidance of deforestation and forest/land degradation constitute lasting and long-term solutions for mitigating climate change. There is an urgent need of relevant and efficient methods of measuring forest and soil carbon through application of the latest geospatial technologies, i.e., GIS （geographic information system）, Remote Sensing and LiDAR （Light Detection and Ranging）. These technologies can support the precise measurement of carbon stocks, as well as, offer cost effective and interoperable data generation methods. The REDD＋ mechanism is being promoted worldwide mainly to reduce the diminishing of forest in developing countries. Such an approach must consider use rights, sustainable management of forests, ensuring and safe-guarding the benefit sharing mechanism and good governance, along with the legal framework and local livelihood concerns.

Apply of Low-Carbon Technology in Building Energy Conservation in Hot Summer and Cold Winter Area

Building energy conservation is the basis for carbon emission reduction, through elaborating the relationship between low carbon and energy efficient building. It points out that the construction of energy-saving emission reduction is an effective means to solve the problems of high energy consumption of the building, and it is also an important measure for China＇s carbon emission reduction. According to the climate characteristics in hot summer and cold winter area, low carbon technology suitable for the construction of energy-efficient hot summer and cold winter area is proposed which is based on the analysis of the current main building energy-saving technical measures.

The Measurement of Carbon Emission Effect of Construction Land Changes in Anhui Province Based on the Extended LMDI Model

In the context of ＂two-wheel drive＂ development mode, China＇s construction land shows significant expansion characteristics. The carbon emission effect of construction land changes is an important factor for the increase of carbon emissions in the atmosphere. In this study, the drivers of carbon emissions in Anhui Province from 1997 to 2011 were quantitatively measured using the improved Kaya identity and Logarithmic Mean Divisia Index. The results show that： economic growth, expansion of construction land and changes in population density have incremental effects on carbon emissions. The average contribution rate of economic growth as the first driver is 266.32 percent. The construction land expansion is an important driving factor with annual mean carbon effect of 6.4057 million tons and annual mean contribution rate of 187.30 percent. But the change in population density has little impact on carbon emission driving. Energy structure changes and energy intensity reduction have inhibitory effects on carbon emissions, of which the annual mean contribution rate is -212.06 percent and -158.115 percent respectively. The targeted policy approaches of carbon emission reduction were put forward based on the decomposition of carbon emission factors, laying a scientific basis to rationally use the land for the Government, which is conducive to build an ecological province for Anhui and achieve the purpose of emission reduction, providing a reference for the research on carbon emission effect of changes in provincial-scale construction land.