中国农业碳排放拐点变动及时空分异研究

与基于总量或人均指标衡量经济增长与环境质量相比,以播种面积作为测算指标揭示农业经济增长与农业环境质量之间的关系,既便于年度间纵向对比,又消除了复种指数影响,使得研究更具操作性和公平性。以农业碳排放强度作为碳排放指标、以农业经济强度作为经济增长指标,对中国农业碳排放进行EKC检验,在此基础上对农业碳排放拐点变动及时空分异进行实证分析。结果表明:1从长期来看,中国农业碳排放强度与农业经济强度之间存在"倒N型"EKC关系且存在双拐点,其临界值分别为15 167元/hm2和27 647元/hm2。2012年,我国农业经济强度为28 725元/hm2,已超出高拐点临界值(27 647元/hm2),这意味着伴随我国农业经济的进一步发展,农业碳排放强度将呈现下降趋势。2从空间分布来看,有18个省(区、市)农业经济强度超过高拐点值,包括北京、福建、海南、浙江、广东、上海、天津、江苏、辽宁、山东、陕西、河北、新疆、湖南、湖北、四川、广西、河南等,主要为东部沿海省份以及中西部部分农业较为发达的省份。这18个省(区、市)农业碳排放量将随其农业经济的发展而逐渐下降。其余13个省(区、市)则低于拐点值,均分布于我国中西部地区。3从时间路径来看,对于未抵达拐点的13个省(区、市)而言,各自农业碳排放EKC拐点存在明显差异,甘肃、重庆、吉林、青海在未来5年内可达到EKC拐点;宁夏、安徽、黑龙江、陕西在未来6-10年内可达到EKC拐点;西藏、内蒙古、江西、云南、贵州则分别需要12年、14年、21年、23年、32年才有可能抵达EKC拐点。     

区域间供给驱动的碳排放溢出与反馈效应

减缓区域间的碳排放溢出-反馈效应对中国协调区域发展和实现绿色发展意义重大。本文基于供给多区域投入产出模型建立了供给视角下三区域碳排放溢出-反馈效应的分析方法,继而测算了2002-2010年中国东、中、西部之间的碳排放溢出-反馈乘数和实际效应。研究发现,在整个研究时期内东、中部对西部以及东、中部之间的溢出乘数有所下降,但西部对东、中部的溢出乘数有所上升。同时,三大地区的反馈乘数则都有所上升。不过,由于各个地区的经济总量都显著上升,因而各区域各种实际的碳排放效应在整个研究时期内都显著上升。东部对中、西部地区的溢出乘数明显小于中、西部对东部地区的溢出乘数,且东部地区的反馈乘数也几乎一直小于中部和西部。不过,由于东部地区的经济总量远远大于中、西部,因而东部地区各种实际的碳排放效应在整个研究时期内都显著大于中、西部地区相应的实际碳排放效应。三大地区碳排放溢出及反馈乘数效应较大的部门很相似,它们都以采掘业及相关下游重工业为主,如煤炭开采和洗选业。碳排放溢出及反馈乘数效应较小的部门则主要包括通信设备、计算机及其他电子设备制造业、建筑业以及服务业。为减缓区域间供给驱动的碳排放溢出-反馈效应,地区间应当加强在碳减排领域的合作,以此提升区域间供应链的碳排放效率;促进节能减排技术的推广应用以提高各部门特别是碳排放密集型产业的能源利用效率;同时应大力发展清洁型战略新兴产业并严格控制碳密集型产业的扩张,从而优化产业结构。     

我国碳排放区域差异性分析

在对我国各地区的碳排放总量、人均碳排放和碳排放强度进行计算的基础上,运用Theil系数等方法对我国碳排放区域差异性进行分析。Theil系数分析结果表明我国碳排放强度呈现区域差异性,区域内差异是总体差异的主要原因,而东部和中部地区内部差异是导致区域内差异的主要原因;变异系数分析结果表明：碳排放总量东部地区差异最大、中部最小,人均碳排放西部地区差异最大、东部最小,碳排放强度中部地区差异最大、东部最小;基尼系数分析结果表明：西部地区碳排放差异最大,中部次之,东部最小;运用聚类分析将全国各省碳排放现状分为优、良、中、差四大类。针对研究结果,提出了转化经济发展方式、优化产业结构等节能减排建议     

外商直接投资地区差距对碳排放的影响北大核心CSSCI

本文根据1999-2010年相关数据,利用变异系数和广义最小二乘法对中国东、中、西和东北四大地区外商直接投资地区差距对地区碳排放差距的影响进行了研究,认为四大地区碳排放绝对差距呈逐年上升趋势,无论是碳排放的绝对差距和相对差距均表现为东部最大,中部次之,西部和东北地区最少;四大地区外商直接投资绝对差距逐年上升,且东部最大、东北次之、中部第三、西部最少;外商直接投资相对差距的大小依次为西、东、东北和中部;实证研究的结果表明,外商直接投资地区差距对地区碳排放差距的影响为负;人均总产值地区差距对碳排放地区差距的影响为负;地区开放程度差距对碳排放地区差距的影响为正;从外商直接投资地区差距对不同能源碳排放地区差距的影响来看,外商直接投资地区差距对煤和石油两种能源碳排放地区差距的影响为负,对天然气碳排放地区差距的影响为正,最后在此基础上提出了对策建议。     

空间依赖、碳排放与人均收入的空间计量研究

本文采用较为前沿的空间计量方法研究我国29个省区2000-2008年间人均碳排放与人均收入之间的关系。研究结果表明:①我国人均碳排放和人均收入均表现出明显的空间集群特征,特别是人均收入的空间依赖性表现出加强的趋势。②人均碳排放与人均收入呈"倒U"型曲线关系,拐点为人均收入16 953元。并进一步计算了我国各省区的人均碳排放拐点,发现各地区人均碳排放拐点在时间路径上存在明显差异性,东部地区的多数省区较早地到达拐点,而中西部地区则要经历较长时间。③城市化水平、就业人员比重和技术进步是导致我国人均碳排放量增长的重要因素。④对外贸易程度在一定程度上减少了人均碳排放。因此,提出了大力倡导低碳生活方式、优化产业结构、积极开发低碳技术、转变贸易结构以及将地区的空间依赖性纳入到碳排放的政策制定中等政策建议。     

长江经济带碳减排潜力与低碳发展策略

为长江经济带低碳发展需要,借助长江经济带11省市2005～2014年间相关数据,对长江经济带及区域间的碳排放、能源强度、碳吸收进行测算,并探讨长江经济带未来低碳发展策略,分析 “高碳情景”与“低碳情景”下2030年各区域的碳减排潜力。研究发现：长江经济带碳排放聚集度较高且整体增速趋缓。东部区域碳排放均值最大,西部区域最小。中部区域碳排放增速最快,东部区域最慢。西部区域能源强度最高,东部区域最低;但中部区域能源强度降幅最大,东部区域降幅最小。西部区域碳汇能力最强,东部区域最弱。基于以上发现,从碳减排责任划分、低碳消费、清洁能源替代、高耗能产业优化以及区域生态质量提升等方面提出相关策略,力图实现碳源面的直接碳减排与碳汇面的相对碳减排。最后,经预测可知：2030年,长江经济带“低碳情景”比“高碳情景”减少碳排放约12亿t,中部区域将成为碳排放主要来源地     

中国农业碳排放强度动态演进及碳补偿潜力

农业已成为中国碳排放主要源头之一,研究农业碳排放强度动态演进及碳补偿潜力,可以为农业碳达峰和碳中和提供指导。基于2001—2018年中国省级面板数据,首先采用基尼系数、核密度分析中国农业碳排放强度动态演进,再利用空间相关性检验和绝对β收敛性检验中国农业碳补偿率的"追赶效应",最后选取参数对比法测算中国农业碳补偿潜力区域差异。结果表明:(1)中国农业碳排放强度基尼系数均值为0.039,整体差异变化呈现"U"型态势,这说明中国农业碳排放强度整体相对差异具有明显的波动演进趋势。各省份农业碳排放强度都出现下降的趋势,但不同地区其下降速度并不一致,东部和中部农业碳排放强度下降速度较快,全国和西部下降速度次之。(2)2001—2018年中国农业碳补偿率的Moran’s I整体为正,Geary’s C整体小于1,LISA集聚分布呈现高-高、低-低集聚态势。这些结果均表明中国农业碳补偿率存在显著的空间正相关,高(低)相邻省份相对集聚,呈现出比较强的空间集聚模式。(3)绝对β收敛性结果显示全国层面和三大区域层面的农业碳补偿率都存在"追赶效应"。趋同理论下的参数对比法表明中国农业碳补偿潜力区域差异明显,西部地区碳补偿潜力最大,平均碳补偿潜力为42.72%,明显高于东部平均碳补偿潜力(27.05%)和中部平均碳补偿潜力(29.40%)。就区域内部而言,东、中、西部地区碳补偿潜力最高的省份分别为福建(59.23%)、湖北(47.63%)和甘肃(64.85%)。因此,着力推进农业提质增效并加强区域间协调合作能早日实现中国农业碳达峰和碳中和目标。     

城市生活垃圾与经济增长的非线性关系——基于环境库兹涅茨曲线的实证分析北大核心CSCDCSSCI

良好的环境是人类赖以生存和发展的基础,随着中国经济的快速发展和城镇化水平的不断提高,城市生活垃圾成为影响居民健康和城市可持续发展的重要因素。城市生活垃圾是否会随着经济发展一直持续增长下去?还是会存在着拐点?文章基于环境库兹涅茨曲线,选取2005—2019年中国30个省、自治区、市的面板数据,实证研究城市生活垃圾与经济增长之间的关系,并在不同经济发展水平下检验区域异质性。研究结果表明:(1)中国整体城市生活垃圾与经济增长呈倒“S”型,两个拐点大约在人均GDP为36 890元和107 450元。(2)北京、上海等沿海经济发达的地区大都已越过或接近第二个拐点,未来城市生活垃圾将随着经济增长呈下降趋势。(3)内陆地区除甘肃外,其余地区均已越过第一个拐点,但尚未越过第二个拐点,未来城市生活垃圾将随着经济增长呈上升趋势。(4)区域异质性检验发现,东部地区城市生活垃圾与经济增长呈倒“U”型;拐点大约在人均GDP为75 720元,中部地区城市生活垃圾与经济增长呈“U”型,拐点大约在人均GDP为34 500元;西部地区城市生活垃圾与经济增长呈倒“U”型,拐点大约在人均GDP为181 795元。总体来看,东部经济发达的地区企业和居民环保意识较强,政府对城市生活垃圾治理效果较好;中部和西部地区企业和居民环保意识还有待提高,政府应加强对城市生活垃圾的治理以及提高企业和居民的环保意识,特别是西部地区环保意识还很薄弱。由此,为实现环境保护与经济增长的协调发展,基于实证结果提出以下政策建议:(1)改变垃圾计费方式,有助于加速WKC曲线“拐点”的来临。(2)对不同地区应实行差异化环境规制政策。(3)应加大对“绿色”技术创新的投入。     

江苏省13城市1996～2008年碳排放时空变异分析

运用秩相关系数、变差系数、曲线拟合等方法,以市域为基本单元,以人均碳排放量、碳排放强度、脱钩指数等为指标,对江苏省1996～2008年的碳排放时空变异特征进行分析,研究得出：(1)近13 a来,江苏省碳排放量不断增加,年均增长率高达13%,2008年已达20 000万t;经济较发达城市人均碳排放量较大,但碳排放强度相对不大;经济落后城市人均碳排放量小,但碳排放强度增加较快。(2)江苏省13城市人均碳排放、碳排放强度差异在不断缩小。(3)从人均碳排放看,江苏省及各市人均碳排放都随人均GDP呈线性增加关系,而南京、苏州、扬州、徐州作为各个区域发展较好的中心城市,人均碳排放随人均GDP增加最快。(4)从碳排放强度看,江苏省碳排放强度与人均GDP呈倒U型曲线关系,其拐点在人均GDP 25万元左右;但是各个城市碳排放强度与人均GDP呈波浪型曲线关系。(5)从脱钩指数看,脱钩水平受经济政策、产业结构、清洁技术水平的影响较大     

我国东、中、西部地区经济发展与碳排放的关联分析及比较

随着我国社会经济的迅速发展，能源消耗和环境问题日益严重，特别是由于碳排放带来的温室效应已经成为全世界关注的焦点问题。全球气候变暖已经对人类社会的可持续发展带来了严峻的挑战，深度触及了农业和粮食安全、水资源安全、生态安全和公共卫生安全。为此。在测算我国东部、中部以及西部三大地区的碳排放总量的基础上。分析三大地区碳排放的特征和差异。结果表明我国东部地区的碳排放量最大、中部地区次之、西部最少。并且从碳排放的增长速度上看．东部地区增速最快，中部最慢；采用灰色关联度方法分析三大地区生产总值与碳排放之间的关系，进而解释它们之间碳排放存在差异的原因，并针对上述的研究结论提出减少我国碳排放的政策建议。以为我国发展低碳经济服务。     

Present status of Rn in groundwater in Extremadura

Radon-222 was measured in groundwater sources of Extremadura (Spain), analyzing 350 samples from private and public springs, wells, and spas by liquid scintillation counting (LSC) and gamma spectrometry. The ²²²Rn activity concentrations ranged from 0.24 to 1168 Bq L⁻¹. The statistical analysis showed a log-normal distribution with a mean of (111 ± 7) Bq L⁻¹ and a median of (36 ± 3) Bq L⁻¹. A hydrogeological study revealed correlations between the activity concentration and the aquifer material's characteristics. A map of ²²²Rn in groundwater was elaborated and compared with the natural gamma radiation map for this region. About 35% of the samples showed ²²²Rn activity concentrations above the Euratom recommended limit of 100 Bq L⁻¹. Three uranium series radionuclides (²³⁸U, ²³⁴U, and ²²⁶Ra) were also assayed by alpha-particle spectrometry, estimating the annual effective dose due to the presence of these natural radionuclides in drinking water.     

我国南方地区50 a冬季降水和相对湿度特征分析

根据中国地面气候日值数据集资料,利用气候趋势系数、气候倾向率等方法,研究了我国南方地区冬季50 a降水和湿度的时空变化特征,并运用基尼系数对降水均匀性的空间分布进行了分析。结果表明：降水和相对湿度分布皆自西北向东南递增,最大中心位于长江以南附近内陆区域,最小值基本位于高原。降水强度整体呈现增加趋势,在沿长江附近区域以及云南部分地区增强明显,最大气候倾向率为1.0 mm/d/10 a左右,有明显的突变时间,为1979年;降水量呈微弱的增加趋势,其中云贵和川渝局部区域降水量呈减少趋势,为-3 mm/10 a左右,没有明显的突变时间;降水日数在长江以南局部区域及云贵区域显著减少,其中云南的西南地区为最小气候倾向率-10 d/10 a,明显突变时间为1980年;相对湿度表现出一定的局地增减趋势,长江以北（南）主要呈微弱增加（减少）趋势,云南南部减小趋势显著;相对湿度和降水呈明显的正相关,其中与降水量和降水日数相关系数高达0.784、0.753。降水量基尼系数的空间分布与降水分布相似,只是降水分布的大（小）值中心为基尼系数小（大）值中心,不同年代及冬季不同月份的降水量基尼系数大（小）值区域范围有所增减。总的来看,我国南方冬季中部和东部大部分区域为降水均匀区,西南高原区域为不均匀区。 关键词： 南方地区;冬季;降水;相对湿度     

Kinetics of dissolution of Chernobyl fuel particles in soil in natural conditions

Kinetic of fuel particles dissolution under natural environmental conditions has been investigated using the data on (90)Sr speciation in soils collected from 1995 to 1997 within the Chernobyl nuclear power plant 50 km zone. The dependency of fuel particles dissolution constants on the soil acidity (pH = 4-7) has been obtained on the basis of large and statistically reliable experimental data. Results show that between 2 and 21% of (90)Sr activity is associated with weathering resistant fuel particles. Therefore, these particles would not influence the radiological situation in the near future. The map of the main agrochemical characteristics and the map of the fuel particles dissolution constants have been created for the 30-km zone territory. According to the prognosis of dynamics of fuel particles dissolution in the investigated zone, a radiological situation along the fuel paths of radioactive fallout in present time reached a stable state. An increasing in absolute contents of (90)Sr mobile forms in neutral soils will be observed in the next 10-20 yr. However, the difference between the maximum level of mobile forms contents and their existing contents will not exceed 20%.     

Concentration and characterization of plutonium in soils of Hubei in central China

To study the Pu concentration and isotope ratio distributions present in China, the ^239+240Pu total activities and ²⁴⁰Pu/²³⁹Pu atom ratios in core soil samples from Hubei Province in central China were investigated using Accelerator Mass Spectrometry (AMS). The activities ranged from 0.019 to 0.502 mBq g⁻¹ and the ^239+240Pu inventories of 45 and ∼55 Bq m⁻² agree well with that expected from global fallout. The ²⁴⁰Pu/²³⁹Pu atom ratios in the soil ranged from 0.172 to 0.220. The ratios are similar to typical global fallout values. Hence, any close-in fallout contribution from the Chinese nuclear weapons tests, mainly conducted in the 1970s, must have either been negligible or had a similar ²⁴⁰Pu/²³⁹Pu ratio to that of global fallout. The top 10 cm layer of the soil contributes ∼90% of the total inventory and the maximum concentrations appeared in the 2-4 cm or 4-6 cm layers. It is suggested that climatic conditions and organic content are the two main factors that affect the vertical migration of plutonium in soil.     

Diffusion of Lead-free Soldering in Electronics Industry in China

The EU directives on e-waste management (WEEE and RoHS) have drawn the attention of electronics producers around the world to the environmental benign technologies in recent years. One of the technological challenges to the electronics manufacturers is the adoption of the lead-free soldering system. This article studies the diffusion of lead-free soldering technology among the electronics producers in China, and finds out the relevance of clusters for the diffusion of environmental benign technological innovation among firms. Four agents, as key promoters, were identified within the production network –leading global brand-name companies, the OEM companies who provide integrated manufacturing service, the suppliers of lead-free components, and specialized consultant companies. The conclusion is that industrial cluster facilitates communications among all agents for the diffusion of innovation, whereas, the incentives for firms within the cluster, to collaborate for innovation, comes from outside.     

Predictions of in situ solid/liquid distribution of radiocaesium in soils

Previous work has demonstrated that plant uptake of radiocaesium (RCs) is related to the activity concentration of RCs in soil solution, which is linked to the soil/soil solution distribution coefficient, K(D). The solid-liquid distribution of RCs is generally studied in soil suspensions in the laboratory and there are few reported measurements for in situ soil solutions. From a data set of 53 different soils (contaminated with either 134CsCl or 137CsCl) used in pot trials to investigate grass uptake of RCs, we analysed the variation of in situ K(D) with measured soil properties. The soils differed widely in % clay (0.5-58%), organic matter content (1.9-96%) and pH (2.4-7.0, CaCl2). The K(D) varied between 29 and 375,000 L kg-' (median 1460 L kg(-1)). Stepwise multiple regression analysis showed a significant correlation between the log K(D) and pH (p < 0.001), log %clay (p < 0.01) and log exchangeable K (p < 0.001) (overall R2 = 0.70). The in situ K(D) values were further compared to K(D)S predicted using an existing model, which assumes that RCs sorption occurs on specific sites and regular ion-exchange sites on the soil solid phase. Sorption of RCs on specific sites was quantified from the radiocaesium interception potential (RIP) measured for each soil and the soil solution concentrations of K+ and NH4+. The in situ log K(D) correlated well with the predicted K(D) (R2 = 0.85 before plant growth, R2 = 0.83 after plant growth). However, the observations were fivefold to eightfold higher than the predictions, particularly for the mineral soils. We attribute the under-prediction to the long contact times (minimum 4 weeks) between the RCs tracers and our experimental soils relative to the short (24 h) contact times used in RIP measurements. We conclude that our data confirmed the model but that ageing of RCs in soil is a factor that needs to be considered to better predict in situ KD values.     

Evaluation of Urban Sustainability in Specific Sectors in Latvia

In Latvia, the concept of sustainability is only slowly gaining recognition. An analysis of Development Plans prepared by the four largest cities of Latvia indicates that sustainability is presented as one of the guiding principles. However, a comparison of Development Plan policies against the urban sustainability issues reveals a great deal of ambiguity and contradiction.At the municipal level, planners and politicians lack indicators to gauge whether the long-term goals of Development Plans and the principles of sustainable development are being achieved. As a consequence, the broad public is deprived of the opportunity to assess for itself the process of development in relation to Development Plan policies, thus limiting accountability in development decision-making. Relevant statistical data collected on a regular basis are required to create sustainability indicators reflecting sustainability issues, to supplement and replace existing statistical compilations pertaining almost exclusively to economic growth and consumption. Development and utilisation of sustainability indicators can be an effective instrument for promoting the values of sustainable development amongst politicians, planners and the broad public and for enhancing accountability in decision-making.     

Reuse of mining wastewater in agricultural activities in Jordan

A pilot study was completed in the Al-Abyad area near phosphate mining activity in Jordan. Six plots of 50 m² each were planted with two types of plant species (Zea mays spp. and Medicago lupulina spp.) and irrigated using three types of water (fresh groundwater, mine wastewater, and hydride water consisting of 50% fresh and 50% mine wastewater) to investigate the suitability of utilizing mine wastewater for food production in the area. Water, soil and plant sampling was completed for each plot over different time intervals and analyzed for heavy metal (Cr⁺⁶, Ni⁺², Zn⁺² and Pb⁺²) in addition to major ionic composition of the water used for irrigation. Crop yield was estimated at the end of the experiment. Plots irrigated with mine wastewater showed slightly higher heavy metals concentrations and soil salinity during the experiment period was higher for plots irrigated with mine wastewater compared to plots irrigated with fresh water, and it was uniform through the upper 45 cm of the soil profile due to the high amount of irrigation water used during the experiment. Crop yield was inversely proportional to salinity as an increase of salinity by 2-folds resulted in reducing yield by almost 50%. However, no risk of heavy metals contamination was found in plants and soil. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Seasonal changes in radon concentrations in buildings in the region of northeastern Poland

In this study, seasonal observations of radon concentration changes inside buildings carried out in the northeastern region of Poland is presented. One-year measurements of radon concentrations were performed in chosen buildings. The integral method of Cr-39 trace detectors in diffusive chambers was used. Mean values of radon concentrations were determined in monthly, 2-, 3-, 6-month, and annual observations. The fraction of a mean annual concentration of the value obtained in a shorter observation was calculated. Monthly concentration values were from about 0.2 to 14.9 of the annual mean. All buildings revealed seasonal fluctuation of radon concentration. Negative correlation of indoor radon concentration in the buildings and the mean temperature outside was observed in most examined buildings. The lowest coefficient range, determining which part of the annual mean value would be obtained in the 6-month observation, was gained for exposure begun in April or October.