Clearing the air: The costs and consequences of higher CAFE standards and increased gasoline taxes

Concerns about energy security and climate change have sparked legislators’ interest in reducing gasoline consumption by increasing corporate average fuel-economy (CAFE) standards. Using an empirically rich simulation model and cost estimates for anticipated fuel-economy technologies, we estimate annual costs of reducing long-run gasoline consumption by 10% via a 3.8 miles per gallon increase in the standards, and the potential cost savings from allowing manufacturers to buy and sell fuel-economy credits. Maximum gasoline savings would be realized only after all existing vehicles were replaced, or 14 years in our model. A gasoline tax would produce greater immediate savings by encouraging people to drive less, and eventually to choose more-fuel-efficient vehicles. We demonstrate the advantage of a tax by comparing the cost of the higher CAFE standards over the first 14 years against the cost of a gasoline tax that would save the same amount of gasoline over that time.     

沂河流域土地利用时空变化图谱特征分析

基于沂河流域1995年、2005年和2015年土地利用空间数据,运用地学信息图谱方法构建1995-2005年和2005-2015年两个时序单元的土地利用转移图谱和涨落势图谱,分析了沂河流域近20年来的土地利用时空变化规律及发展过程。结果表明：（1）1995-2015年,沂河流域土地利用结构以耕地和林地为主,其中耕地和草地减少,林地和建设用地增加是主要变化趋势。（2）土地利用转移图谱以耕地与林地、草地之间的相互转换以及建设用地占用耕地为主,林地、草地转变为耕地主要发生在费县和平邑县中部地势平缓的山前平原,耕地转变为林地、草地则主要分布于研究区北部和西南部土壤侵蚀较为严重的山区,耕地转变为建设用地主要集中在各县市城区周边经济相对发达的区域。两个时序单元中,发生变化的主要图谱单元类型及面积存在显著差异,2005-2015年土地利用发生转换的空间进一步扩张。（3）土地利用涨势图谱中新增耕地面积最大,占新增面积的比例为33.87%;落势图谱中耕地萎缩面积最大,占萎缩面积的比例为51.38%。两个时序单元中,各县市涨落势图谱变化存在明显差异。该研究可为沂河流域土地资源的可持续利用及生态建设提供科学依据。     

Effects of arsenic on seed germination and physiological activities in wheat seedlings

The effects of arsenic(As)were investigated on seed germination,root and shoot length and their biomass and some other factors to elucidate the toxicity of As.The results showed low concentrations of As(O-1 mg/kg)stimulated seed germination and the growth of root and shoot,however,these factors all decreased gradually at high concentrations of As(5-20 mg/kg).The contents Of O2-,MDA,soluble protein and peroxidase(POD)activity all increased with increasing As concentrations.Soluble sugar content,ascorbate peroxidase(APX),and superoxide dismutase(SOD)activities decreased at low concentrations of As,and increased at high concentrations of As.While acetylsalicylic acid(ASA)and chlorophyll contents,catalase(CAT)activity displayed increasing trend when the concentrations of As was lower than 1 mg/kg,and then decreasing trend.By polyacrylamide gel electrophoresis(PAGE).As induced the expression of POD isozymes of wheat seedlings.As induced the expression of CAT isozymes but inhibited the expression of SOD isozymes of wheat seedlings at concentrations lower than 1 mg/kg.However,As inhibited the expression of CAT isozymes but induced the expression of SOD isozymes at concentrations higher than 5 mg/kg.The results indicated As could exert harmfulness in the early development stage of wheat at inappropriate concentrations.     

改革开放以来我国国土整治历程回顾与新构想

改革开放40多年,国土整治随着资源、生态环境领域政治意愿和体制的变迁而变化,经历兴起、搁浅、整合的过程。在梳理改革开放40余年国土整治领域重要政策文件基础上,总结了国土整治历程中的发展经验、主要问题以及新趋势,并提出了新时代国土整治新构想。新时代国土整治目标将牢牢结合生态文明战略,以期实现空间、资源、生态环境优化,打造以人为本高品质国土空间。新时代国土整治是通过“承载力”“适宜性”评价机制,结合综合研判、归因分析划分“国土整治”功能分区开展重大工程,多措并举处置国土开发利用过程中“负外部性”问题,修复国土功能,以实现空间结构优化调整、资源高效利用、生态保护修复、灾害污染治理,以期提升国土空间承载力、适宜性、美丽度、安全性,提升国土可持续发展能力的综合治理活动。     

Why a 100-Year Time Horizon should be used for GlobalWarming Mitigation Calculations

Global warming mitigation calculationsrequire consistent procedures for handlingtime in order to compare `permanent' gainsfrom energy-sector mitigation options with`impermanent' gains from many forest-sectoroptions. A critical part of carbonaccounting methodologies such as thosebased on `ton-years' (the product of thenumber of tons of carbon times the numberof years that each ton is held out of theatmosphere) is definition of a timehorizon, or the time period over whichcarbon impacts and benefits are considered. Here a case is made for using a timehorizon of 100 years. This choice avoidsdistortions created by much longer timehorizons that would lead to decisionsinconsistent with societal behavior inother spheres; it also avoids a rapidincrease in the implied value of time ifhorizons shorter than 100 years are used.Selection of a time horizon affectsdecisions on financial mechanisms andcarbon credit. Simple adaptations canallow a time horizon to be specified andused to calculate mitigation benefits andat the same time reserve a given percentageof weight in decision making forgenerations beyond the end of the timehorizon. The choice of a time horizon willheavily influence whether mitigationoptions such as avoided deforestation areconsidered viable.     

呼和浩特市地表水水质变化趋势分析

对黄河(过境)、大黑河水系及浑河水系十年水质检测结果进行综合分析,揭示其变化趋势,并针对各河流污染断面提出急需解决的问题.     

Revisit ocean thermal energy conversion system

The earth, covered more than70.8% by the ocean, receives most of itsenergy from the sun. Solar energy istransmitted through the atmosphere andefficiently collected and stored in thesurface layer of the ocean, largely in thetropical zone. Some of the energy isre-emitted to the atmosphere to drive thehydrologic cycle and wind. The wind fieldreturns some of the energy to the ocean inthe form of waves and currents. Themajority of the absorbed solar energy isstored in vertical thermal gradients nearthe surface layer of the ocean, most ofwhich is in the tropical region. Thisthermal energy replenished each day by thesun in the tropical ocean represents atremendous pollution-free energy resourcefor human civilization. Ocean ThermalEnergy Conversion (OTEC) technology refersto a mechanical system that utilizes thenatural temperature gradient that exists inthe tropical ocean between the warm surfacewater and the deep cold water, to generateelectricity and produce other economicallyvaluable by-products. The science andengineering behind OTEC have been studiedin the US since the mid-seventies,supported early by the U.S. Government andlater by State and private industries.There are two general types of OTECdesigns: closed-cycle plants utilize theevaporation of a working fluid, such asammonia or propylene, to drive theturbine-generator, and open-cycle plantsuse steam from evaporated sea water to runthe turbine. Another commonly known design,hybrid plants, is a combination of the two.OTEC requires relatively low operation andmaintenance costs and no fossil fuelconsumption.OTEC system possesses a formidablepotential capacity for renewable energy andoffers a significant elimination ofgreenhouse gases in producing power. Inaddition to electricity and drinking water,an OTEC system can produce many valuableby-products and side-utilizations, such as:hydrogen, air-conditioning, ice,aquaculture, and agriculture, etc. Thepotential of these by-products, especiallydrinking water, aquaculture andmariculture, can easily translate intobillions of dollars in businessopportunities. The current status of theOTEC system definitely deserves to becarefully revisited. This paper willexamine recent major advancements intechnology, evaluate costs andeffectiveness, and assess the overallmarket environment of the OTEC system anddescribe its great renewable energypotential and overall benefits to thenations of the world.     

Bioenergy to mitigate for climate change and meet the needs of society,the economy and the environment

Changes towards environmental improvementsare becoming more politically acceptableglobally, especially in developedcountries. Society is slowly moving towardsseeking more sustainable productionmethods, waste minimisation, reduced airpollution from vehicles, distributed energygeneration, conservation of native forests,and reduction of greenhouse gas (GHG)emissions. Modern biomass, when used tosupply useful bioenergy services, has arole to play in each one of theseenvironmental drivers at both the large andsmall scales.This paper describes recent developments inbiomass supply and the technologies for itsconversion to bioenergy including biofuelsfor transport. It examines the economic,environmental and social benefits andidentifies barriers to bioenergy projectimplementation. Future opportunities forbiomass as a carbon (C) sink, a C offsetand a potential source of renewablehydrogen are discussed.Whether or not a bioenergy project iseconomically viable, as well as being trulyrenewable, sustainable and environmentallysound, is determined mainly by the sourceof biomass. The social benefits from usingbiomass are also valuable, though they areoften not clearly presented when proposingnew bioenergy projects or conductinganalyses of existing plants. Employmentrates per MWh or per GJ exceed those whenusing fossil fuel supplies to provide thesame energy service. `Ownership' bystakeholders and local communities at anearly stage in the development process isthe key to successful project developmentin order to share the benefits. Bioenergyhas a significant global role to play inthe mitigation of atmospheric GHG concentrations.     

Life on the Edge: Vulnerability and Adaptation of African Ecosystems to Global Climate Change

Donor countriesare providing financial and technicalsupport for global climate change countrystudies to help African nations meet theirreporting needs under the United NationsFramework Convention on Climate Change(UNFCCC). Technical assistance to completevulnerability and adaptation assessmentsincludes training of analysts, sharing ofcontemporary tools (e.g. simulationmodels), data and assessment techniques,information-sharing workshops and aninternational exchange programme foranalysts. This chapter summarizes 14African country studies (Botswana, Côted'Ivoire, Egypt, Ethiopia, the Gambia,Kenya, Malawi, Mauritius, Nigeria, SouthAfrica, Tanzania, Uganda, Zambia andZimbabwe) assessing vulnerabilities toglobal climate change and identifyingadaptation options. The analysis revealedthat the participating African countriesare vulnerable to global climate change inmore than one of the followingsocio-economic sectors: coastal resources,agriculture, grasslands and livestock,water resources, forests, wildlife, andhuman health. This vulnerability isexacerbated by widespread poverty,recurrent droughts, inequitable landdistribution, environmental degradation,natural resource mismanagement anddependence on rain-fed agriculture. Arange of practical adaptation options wereidentified in key socio-economic sectors ofthe African nations analysed. However,underdeveloped human and institutionalcapacity, as well as the absence ofadequate infrastructure, renders manytraditional coping strategies (rooted inpolitical and economic stability)ineffective or insufficient. FutureAfrican country studies should be moreclosely coordinated with development ofnational climate change action plans     

滇池富营养化发展趋势分析及其控制对策

1988～1999年滇池监测数据的统计分析表明,滇池水质在继续恶化,全湖水质超V类,富营养化程度呈上升趋势.近10年来,滇池主体外海TP浓度增加了一倍多,叶绿素a增长了十几倍,营养水平由富营养发展到严重富营养,增加了两个级别,发展趋势近年来尤为明显.P是近10年来滇池水体中增长最快的营养盐,水体中P浓度的持续增