Validity of the Fossil Fuel Production Outlooks in the IPCC Emission Scenarios

Anthropogenic global warming caused by CO₂ emissions is strongly and fundamentally linked to future energy production. The Special Report on Emission Scenarios (SRES) from 2000 contains 40 scenarios for future fossil fuel production and is used by the IPCC to assess future climate change. Previous scenarios were withdrawn after exaggerating one or several trends. This study investigates underlying assumptions on resource availability and future production expectations to determine whether exaggerations can be found in the present set of emission scenarios as well. It is found that the SRES unnecessarily takes an overoptimistic stance and that future production expectations are leaning toward spectacular increases from present output levels. In summary, we can only encourage the IPCC to involve more resource experts and natural science in future emission scenarios. The current set, SRES, is biased toward exaggerated resource availability and unrealistic expectations on future production outputs from fossil fuels.     

An Analysis of Environmental and Economic Impacts of Fossil Fuel Production in the U.S. from 2001 to 2015

The production and burning of fossil fuels is the primary contributor to CO₂ emissions for the U.S. We assess the impact of producing coal, crude oil, and natural gas on the environment and economic well-being by analyzing state-level data from 2001 to 2015. Our findings show that coal production has led to more CO₂ emissions and no significant benefit to economic well-being. Crude oil production has a non-significant impact on CO₂ emissions but is related to a lower poverty rate, a higher median household income, and a higher employment rate. Natural gas withdrawals have a positive impact on median household income. We discuss these findings in the context of current U.S. energy policies and then provide directions for future research.     

黄河下游沿岸地市CO2排放的时空分异

地市级尺度的碳排放结构演变与区域差异分析对通过技术学习与知识流动短期内抑制 碳排放的快速增长具有重要意义。以地市级行政区作为基本空间单元, 对黄河下游沿岸区、 两大子区及21地市化石能源与水泥工业生产过程排放的CO₂ 进行科学核算, 发现CO₂ 排放量 变化于2000年的364.12～4426.95万t至2009年的1238.98～10411.91万t,呈现出典型的 “S型”增长特征, 但不同尺度区域排放结构的时空差异显着。2006年以来, 工业化进程较快 的区域水泥排碳比例有显着增长, 产业结构优化策略促使少数地市水泥排碳比例有所下降。 CO₂ 排放强度与人均排放量的变动符合碳排放EKC曲线关系, 但时空分异特征并不一致。排 放强度的全区总体差异较为合理, 而人均排放量的区域差异偏大, 从而为涓滴效应的加速作 用创造了空间。地区内差异分别为两指标全区总体差异变动的主导因素, 整体上, 中原区内 地市间差异对两指标全区差异变动的贡献更大。     

陆地生态系统碳循环研究进展

近年来,碳循环问题日益成为全球变化与地球科学研究领域的前沿与热点问题,其中陆地生态系统碳循环又是全球碳循环中最复杂、受人类活动影响最大的部分。本文结合IGBP和IPCC中有关碳循环的最新报告,介绍了全球碳循环中大气、海洋和陆地生态系统等几个主要碳库的大小及特点,并重点介绍了陆地生态系统碳循环及其基本过程。总结了当前陆地生态系统碳循环研究的四种主要方法:清单方法、反演模拟、涡度相关技术和陆地碳循环模式,介绍了它们的各自特点以及存在的问题,并对陆地碳过程中的不确定性进行了详细分析。此外,还简要叙述了当前碳循环研究中待解决的问题和今后的发展趋势。     

1991-2010年中国大陆化石能源消费的CO2排放研究（英文）

本文采用IPCC推荐的表观消费量法计算了中国大陆30省区1991到2010年化石能源消费产生的CO2排放,发现:(1)排放总量由 2293.01Mt 增长到 7467.77Mt;(2)煤炭消费的排放比重最高达到79.98%;(3)人均排放量由 1.98t 增长至 5.57t;(4)CO2排放强度显著降低,由6.66 kg USD-1降至1.07kg USD-1,近年来趋于稳定;(5)区域发展不平衡始终存在,根据省际数据,在一些落后地区经济增长过度依赖于化石能源消费。关于CO2高排放,中国已经做出承诺并采取了行动。基于对可持续发展和全球气候变化不确定性的综合考虑,健康的产业结构、化石能源集约利用,以及区域发展平衡应更加受到重视。     

Carbon Sequestration Potential of the Forest Ecosystems in the Western Ghats,a Global Biodiversity Hotspot

Global warming with the burgeoning anthropogenic greenhouse gas (GHG) emissions (400 parts per million from 280 ppm CO₂ emissions of pre-industrial era) has altered climate, eroding the ecosystem productivity and sustenance of water, affecting the livelihood of people. The anthropogenic activities such as burning fossil fuel, power generation, agriculture, industry, polluting water bodies and urban activities are responsible for increasing GHG footprint of which 72% constitute CO₂. GHG footprint needs to be in balance with sequestration of carbon to sustain ecosystem functions. Forests are the major carbon sinks (about 45%) that aid in mitigating global warming. The current research focusses on the carbon budgeting through quantification of emissions and sinks in the forest ecosystems and changes in climatic conditions of Western Ghats. This would help in evolving appropriate mitigation strategies toward sustainable management of forests and mitigate impacts of global warming. The land-use land-cover (LULC) dynamics are the prime driver of climate change due to the loss of carbon sequestration potential as well as emissions. The Western Ghats are one among 36 global biodiversity hotspots and forests in this region sequester atmospheric carbon, which aid in moderating the global climate and sustaining water to ensure water and food security in the peninsular India. Assessment of LULC dynamics using temporal remote sensing data shows the decline of evergreen forest by 5% with an increase in agriculture, plantations and built-up area. The interior or intact forests have declined by 10%, and they are now confined to protected areas. The simulation of likely changes indicates that the region will have only 10% evergreen cover and 17% agriculture, 40% plantations and 5% built-up. Quantification of carbon reveals that the WG forest ecosystem holds 1.23 MGg (million gigagrams or Gt) in vegetation and soils. The annual incremental carbon is about 37,507.3 Gg, (or 37.5 million tons, Mt) and the highest in the forests of Karnataka part of WG. Simulation of the likely changes in carbon content indicates the loss of 0.23 MGg (2018–2031) carbon sequestration potential under business as usual scenario. The conservation scenario depicts an increase in carbon sequestration potential of WG forests with the protection. Sequestered carbon in WG is about INR 100 billion ($1.4 billion) at carbon trading of INR 2142 ($30) per tonne. Large-scale land-cover changes leading to deforestation has contributed to an increase in mean temperature by 0.5°C and decline in rainy days, which necessitates evolving prudent landscape management strategies involving all stakeholders for conservation of ecologically fragile WG. This will enhance the ability of forests to sequester atmospheric carbon and climate moderation, with the sustenance of ecosystem goods and services.

     

Assessment of greenhouse gas emissions from agricultural sources in order to plan for needs of low carbon economy at local level in Poland

Agriculture is often not included in the baseline greenhouse gas (GHG) emission inventories created for local low carbon economy plans in Poland and other European countries. We therefore estimate the size of the carbon footprint from agricultural sources and indicate the share of agriculture in the total GHG emissions in selected Polish communes (LAU level 2). We propose a solution whereby local government units can estimate their carbon footprint independently and monitor the impact of actions taken to reduce emissions. The value of the carbon footprint from agriculture in the selected communes varies from .5 to 46.5 thousand Mg CO₂eq/year, with a mean value of 12.6 thousand Mg CO₂eq/year and a standard deviation of 11.4 thousand Mg CO₂eq/year. Per capita, these values range from 10 kg CO₂eq/year to 8.4 Mg CO₂eq/year, with a mean of 1.1 Mg CO₂eq/year and a standard deviation of 1.5 Mg CO₂eq/year. In all communes, the contribution of agriculture to total emissions is at an average of 14% (values range from .2 to 57.4%). The obtained results confirm the appropriateness of including emissions from the agricultural sector and other related sources in low carbon economy plans.     

Multi-scale integrated assessment of urban energy use and CO2 emissions

Accurate and detailed accounting of energy-induced carbon dioxide (CO₂) emissions is crucial to the evaluation of pressures on natural resources and the environment, as well as to the assignment of responsibility for emission reductions. However, previous emission inventories were usually production- or consumption-based accounting, and few studies have comprehensively documented the linkages among socio-economic activities and external transaction in urban areas. Therefore, we address this gap in proposing an analytical framework and accounting system with three dimensions of boundaries to comprehensively assess urban energy use and related CO₂ emissions. The analytical framework depicted the input, transformation, transfer and discharge process of the carbon-based (fossil) energy flows through the complex urban ecosystems, and defined the accounting scopes and boundaries on the strength of ‘carbon footprint’ and ‘urban metabolism’. The accounting system highlighted the assessment for the transfer and discharge of socio-economic subsystems with different spatial boundaries. Three kinds methods applied to Beijing City explicitly exhibited the accounting characteristics. Our research firstly suggests that urban carbon-based energy metabolism can be used to analyze the process and structure of urban energy consumption and CO₂ emissions. Secondly, three kinds of accounting methods use different benchmarks to estimate urban energy use and CO₂ emissions with their distinct strength and weakness. Thirdly, the empirical analysis in Beijing City demonstrate that the three kinds of methods are complementary and give different insights to discuss urban energy-induced CO₂ emissions reduction. We deduce a conclusion that carbon reductions responsibility can be assigned in the light of production, consumption and shared responsibility based principles. Overall, from perspective of the industrial and energy restructuring and the residential lifestyle changes, our results shed new light on the analysis on the evolutionary mechanism and pattern of urban energy-induced CO₂ emissions with the combination of three kinds of methods. And the spatial structure adjustment and technical progress provides further elements for consideration about the scenarios of change in urban energy use and CO₂ emissions.     

A GIS approach to modelling CO2 emissions associated with the pupil-school commute

Concerns have been raised in numerous countries over declining rates of active transport to school. In a UK context, the pupil-school commute is estimated to contribute around 658 kilotonnes of CO₂ per year; however, tackling this issue effectively requires an improved understanding of how emissions can be modelled and mapped over a variety of scales. This paper implements a new estimation technique for the modelling of CO₂ emissions linked with the school commute that integrates both transport network-level routing and geographically disaggregate vehicle emissions data. The model is then applied to a national cohort of pupils in England. Areas demonstrating the highest emissions were typically more rural and/or comprising more affluent resident populations. Emissions were also shown to increase with school year, with larger step changes between educational stages reflecting the different geography of school locations. Furthermore, where secondary school entry policies were selective or based on a religious domination, average emissions were typically higher than in non-selective schools.     

CO<Subscript>2</Subscript> emissions from cement industry in China: A bottom-up estimation from factory to regional and national levels

Much attention is being given to estimating cement-related CO₂ emissions in China. However, scant explicit and systematical exploration is being done on regional and national CO₂ emission volumes. The aim of this work is therefore to provide an improved bottom-up spatial-integration system, relevant to CO₂ emissions at factory level, to allow a more accurate estimation of the CO₂ emissions from cement production. Based on this system, the sampling data of cement production lines were integrated as regional- and national-level information. The integration results showed that each ton of clinker produced 883 kg CO₂, of which the process, fuel, and electricity emissions accounted for 58.70%, 35.97%, and 5.33%, respectively. The volume of CO₂ emissions from clinker and cement production reached 1202 Mt and 1284 Mt, respectively, in 2013. A discrepancy was identified between the clinker emission factors relevant to the two main production processes (i.e., the new suspension preheating and pre-calcining kiln (NSP) and the vertical shaft kiln (VSK)), probably relevant to the energy efficiency of the two technologies. An analysis of the spatial characteristics indicated that the spatial distribution of the clinker emission factors mainly corresponded to that of the NSP process. The discrepancy of spatial pattern largely complied with the economic and population distribution pattern of China. The study could fill the knowledge gaps and provide role players with a useful spatial integration system that should facilitate the accurate estimation of carbon and corresponding regional mitigation strategies in China.     

一次能源消费导致的二氧化碳排放量变化

从不同燃料和不同地区入手,分析了我国1995~2006年间一次能源消费导致的二氧化碳排放量变化情况。结果表明:1995~2006年间,我国一次能源消费导致的二氧化碳年总排放量呈现"先减少后增加"的发展态势,其拐点出现在2000年,而且2001年后各个省(区、市)的二氧化碳年排放量较前期均有大幅度的增加,总排放量由1995年的78678万t碳增长到2006年的146919万t碳,年均增长率5.84％,人均二氧化碳年排放量也由0.62t碳/人增加到1.12t碳/人;煤炭消费导致的二氧化碳排放量占全国二氧化碳年总排放量的79%~85％;我国七大区和大部分省(区、市)二氧化碳年排放量与全国总排放量有类似的发展态势,其中华北、华东地区二氧化碳排放量居全国首位,山西省的二氧化碳排放量位居全国第一。     

Urban Form,Air Pollution,and CO2 Emissions in Large U.S. Metropolitan Areas

In this article we explore the relationships between urban form and air pollution among 86 U.S. metropolitan areas. Urban form was quantified using preexisting sprawl indexes and spatial metrics applied to remotely sensed land cover data. Air pollution data included the nonpoint source emission of the ozone (O₃) precursors nitrogen oxides (NOx) and volatile organic compounds (VOCs), the concentration of O₃, the concentration and nonpoint source emission of fine particulate matter (PM2.5), and the emission of carbon dioxide (CO₂) from on-road sources. Metropolitan areas that exhibited higher levels of urban sprawl, or sprawl-like urban morphologies, generally exhibited higher concentrations and emissions of air pollution and CO₂ when controlling for population, land area, and climate.     

A New Model for the Lifetime of Fossil Fuel Resources

A critical examination of Hubbert’s model proves that it does not account for several factors that have significantly influenced the production of petroleum and other fossil fuels. The effect of these factors comes into the price of the fossil fuels, and the latter has a significant influence on the demand and rate of production of energy resources as well as on the long-term rate of production growth at both the regional and global levels. Based on several observations of historical production data, a simple mathematical model is constructed and presented in this paper for the lifetime of a fossil fuel resource. The recent data of global petroleum and natural gas production show that a very important period in the life of energy resources is a period when the demand of these resources increases almost linearly. The linear part of the production curve makes the entire lifetime production of the resource asymmetric. Information on the total available quantity of a resource at any time and of the average slope during this linear period yields an estimate of the timescale, T ₂, when peak production is reached and depletion follows. The total available quantity of the energy resource is laden with significant uncertainty, which propagates in the estimates of the timescale of the peak production in any resource model. The time asymmetry of the current model leads to a delay of the timescale, when the onset of the resource production commences (e.g., peak oil). However, the rate of the resource production decline is significantly higher than that predicted by other models that use a symmetrical curve-fitting method.     

Very high CO2 exchange fluxes at the peak of the rainy season in a West African grazed semi-arid savanna ecosystem

Africa is a sink of carbon, but there are large gaps in our knowledge regarding the CO₂ exchange fluxes for many African ecosystems. Here, we analyse multi-annual eddy covariance data of CO₂ exchange fluxes for a grazed Sahelian semi-arid savanna ecosystem in Senegal, West Africa. The aim of the study is to investigate the high CO₂ exchange fluxes measured at the peak of the rainy season at the Dahra field site: gross primary productivity and ecosystem respiration peaked at values up to ?48 μmol CO₂ m^?2 s^?1 and 20 μmol CO₂ m^?2 s^?1, respectively. Possible explanations for such high fluxes include a combination of moderately dense herbaceous C4 ground vegetation, high soil nutrient availability and a grazing pressure increasing the fluxes. Even though the peak net CO₂ uptake was high, the annual budget of ?229 ± 7 ± 49 g C m^?2 y^?1 (±random errors ± systematic errors) is comparable to that of other semi-arid savanna sites due the short length of the rainy season. An inter-comparison between the open-path and a closed-path infrared sensor indicated no systematic errors related to the instrumentation. An uncertainty analysis of long-term NEE budgets indicated that corrections for air density fluctuations were the largest error source (11.3% out of 24.3% uncertainty). Soil organic carbon data indicated a substantial increase in the soil organic carbon pool for the uppermost .20 m. These findings have large implications for the perception of the carbon sink/source of Sahelian ecosystems and its response to climate change.     

A First-Law Thermodynamic Analysis of the Corn-Ethanol Cycle

This paper analyzes energy efficiency of the industrial corn-ethanol cycle. In particular, it critically evaluates earlier publications by DOE, USDA, and UC Berkeley Energy Resources Group. It is demonstrated that most of the current First Law net-energy models of the industrial corn-ethanol cycle are based on nonphysical assumptions and should be viewed with caution. In particular, these models do not (i) define the system boundaries, (ii) conserve mass, and (iii) conserve energy. The energy cost of producing and refining carbon fuels in real time, for example, corn and ethanol, is high relative to that of fossil fuels deposited and concentrated over geological time. Proper mass and energy balances of corn fields and ethanol refineries that account for the photosynthetic energy, part of the environment restoration work, and the coproduct energy have been formulated. These balances show that energetically production of ethanol from corn is 2–4 times less favorable than production of gasoline from petroleum. From thermodynamics it also follows that ecological damage wrought by industrial biofuel production must be severe. With the DDGS coproduct energy credit, 3.9 gallons of ethanol displace on average the energy in 1 gallon of gasoline. Without the DDGS energy credit, this average number is 6.2 gallons of ethanol. Equivalent CO₂ emissions from corn ethanol are some 50% higher than those from gasoline, and become 100% higher if methane emissions from cows fed with DDGS are accounted for. From the mass balance of soil it follows that ethanol coproducts should be returned to the fields.

温度升高和CO2浓度增加对冬小麦生物量的影响和不确定性分析（英文）

Impacts of climatic change on agriculture and adaptation are of key concern of scientific research. However, vast uncertainties exist among global climates model output, emission scenarios, scale transformation and crop model parameterization. In order to reduce these uncertainties, we integrate output results of four IPCC emission scenarios of A1FI, A2, B1 and B2, and five global climatic patterns of HadCM3, PCM, CGCM2, CSIRO2 and ECHAM4 in this study. Based on 20 databases of future climatic change scenarios from the Climatic Research Unit (CRU) , the scenario data of the climatic daily median values are generated on research sites with the global mean temperature increase of 1 ℃(GMT+1D), 2 ℃ (GMT+2D) and 3 ℃(GMT+3D). The impact of CO2 fertilization effect on wheat biomass for GMT+1D, GMT+2D and GMT+3D in China’s wheat-producing areas is studied in the process model, CERES-Wheat and probabilistic forecasting method. The research results show the CO2 fertilization effect can compensate reduction of wheat biomass with warming temperature in a strong compensating effect. Under the CO2 fertilization effect, the rain-fed and irrigated wheat biomasses increase respectively, and the increment of biomass goes up with temperature rising. The rain-fed wheat biomass increase is greater than the irrigated wheat biomass. Without consideration of CO2 fertilization effect, both irrigated and rain-fed wheat biomasses reduce, and there is a higher probability for the irrigated wheat biomass than that of the rain-fed wheat biomass.     

中国钢铁产品国际贸易流与碳排放跨境转移

控制温室气体排放最终要落实到不同国家、不同行业之间的利益分配和责任分担,尤其是通过国际商品贸易转移的碳排放是在国家间分配排放配额时必须考虑的指标。基于中国钢铁产品国际贸易流的分析表明,中国在国际钢铁产品贸易中处于垂直产业内贸易的低端,中国具有比较优势的钢铁产品多为加工程度低、技术含量低、能源消耗强度大的初级产品。由于我国进出口钢铁产品在附加价值和能源消耗强度方面存在明显的差异,随着中国钢铁产品国际贸易规模的扩大,使大量CO₂排放责任向中国净转移。我国学者应以更加积极的姿态参与到国际谈判、国际规则的制订中,从产品生产者和消费者两个层面合理界定中国在全球温室气体减排中的责任,力争在气候变化国际谈判中确保中国的经济贸易利益。     

Black gold to green gold: regional energy policy and the rehabilitation of coal in response to climate change

Energy production has come under increasing scrutiny as concerns about energy security and climate change have risen. In the UK changes in government structure and privatisation of the electricity industry have led to the emergence of multi-level governance. This means that decisions on how to reduce carbon dioxide emissions from the electricity-generating sector should no longer be solely a national policy decision. Previous studies have sought to explore how renewable energy may develop under multi-level governance, but this paper pays attention to a traditional fossil fuel source, coal, which is still an important means of electricity generation. Coal is the most abundant fossil fuel and advocates argue that carbon capture and storage techniques could make coal 'clean', paving the way for a long-term, secure and low emission way to produce energy. This study focuses on the Yorkshire and Humber Region, which has had a long association with coal mining and looks at the implications of this as the region seeks to develop a climate change action plan and an energy strategy within the new regional governance structures. The paper argues that the regional networks developed to address climate change are influenced by existing social power structures and alliances. The region as a territorial structure becomes a useful device in promoting national priorities.     

基于EA-SD模型的生态农业系统模拟与优化调控——以平凉市崆峒区为例

以甘肃省平凉市崆峒区生态农业系统为例,基于农业产业链的物质、能量流动机理,运用Vensim软件建立生态农业系统动力学分析模型(EA-SD)。量化分析和模拟了生态农业发展的综合效益及其演变趋势。经模拟,按照现在的发展模式不变,系统不但存在牛粪尿污染等负效应,而且随着肉牛年屠宰量的快速上涨,未来崆峒区可能出现肉牛数量锐减,制沼产业、有机农业衰落,整个系统难以持续发展的情况。根据模拟结果,论文制定了系统优化调控政策,并模拟了优化后系统的发展情景。结果显示,优化能够消除系统缺陷和负效应,提升综合正效应,增强系统的可持续发展能力。本研究的模型及调控过程能够为类似的生态经济系统优化研究提供借鉴和参考。     

A 100-year record of changes in organic matter characteristics and productivity in Lake Bhimtal in the Kumaon Himalaya, NW India

Sediment variables total organic carbon (TOC), total nitrogen (TN), total sulfur (TS), as well as their accumulation rates and atomic ratios (C/N and C/S), were studied along with stable isotopes (δ¹³C, δ¹⁵N, and δ³⁴S), and specific biomarkers (n-alkanes and pigments) in a 35-cm-long sediment core from Lake Bhimtal, NW India. The average sedimentation rate is 3.6 mm year^?1, and the core represents a provisional record of ~100 years of sedimentation history. Bulk elemental records and their ratios indicate that sediment organic matter (OM) is derived primarily from algae. In-lake productivity increased sharply over the last two decades, consistent with paleoproductivity reconstructions from other lakes in the area. An up-core decrease in δ¹³C values, despite other evidence for an increase in lake productivity, implies that multiple biogeochemical processes (e.g. external input of sewage or uptake of isotopically depleted CO₂ as a result of fossil fuel burning) influence the C isotope record in the lake. The δ¹⁵N values (?0.2 to ?3.9 ‰) reflect the presence of N-fixing cyanobacteria, and an increase in lake productivity. The δ³⁴S profile shows enrichment of up to 5.6 ‰, and suggests that sulfate reduction occurred in these anoxic sediments. Increases in total n-alkane concentrations and their specific ratios, such as the Carbon Preference Index (CPI) and Terrestrial Aquatic Ratio (TAR), imply in-lake algal production. Likewise, pigments indicate an up-core increase in total concentration and dominance of cyanobacteria over other phytoplankton. Geochemical trends indicate a recent increase in the lake’s trophic state as a result of human-induced changes in the catchment. The study highlights the vulnerability of mountain lakes in the Himalayan region to both natural and anthropogenic processes, and the difficulties associated with reversing trophic state and ecological changes.