International Emission Trading and the Cost of Greenhouse Gas Emissions Mitigation and Sequestration

The deployment of carbon capture and sequestration (CC&S) technologies is greatly affected by the marginal cost of controlling carbon emissions (also the value of carbon, when emissions permits are traded). Both the severity and timing of emissions limitations and the degree to which emissions limitation obligations can be traded will affect the value of carbon and thereby the timing and magnitude of CC&S technology deployment. Emissions limits that are more stringent in the near term imply higher near-term carbon values and therefore encourage the local development and deployment of CC&S technologies.Trade in emissions obligations lowers the cost of meeting any regional or global emissions limit and so affects the rate of penetration of CC&S technologies. Trade lowers the marginal value of carbon and CC&S penetration in high cost regions and raises the marginal value of carbon and CC&S penetration in low cost regions. The net impact on the world CC&Stechnologies depends on whether their increased use in low-cost regions exceeds the reduced use in high-cost regions.In the long term, CC&S technologies must not only remove carbon but permanently sequester it. If reservoirs are not permanent, then the emissions and costs of control are merely displaced into the future. The paper presents quantitative estimates for the impacts of trade in emissions limitation obligations on the timing, magnitude, and geographic distribution of CC&S technologies and the marginal and total costs of carbon control.     

A Model for Estimating Future Emissions of Sulfur Hexafluoride and Perfluorocarbons

Sulfur hexafluoride (SF₆), perfluoromethane (CF₄) and perfluoroethane (C₂F₆) are strong greenhouse gases with long (>1000 year) atmospheric residence times. We derive emission factors for the major anthropogenic sources and project future emissions for 5 regions and the world. Although firms in many industrialized countries are already limiting emissions, without further policy intervention global emissions will rise 150% (CF₄ and C₂F₆) and 210% (SF₆) between 1990 and 2050; radiative forcing will increase 0.026 W m^-2. Full application of available low-cost and costless policies in industrialized nations would cut that radiative forcing by one-quarter. Increased forcing due to these gases is small (<2%) relative to other gases but permanent on the timescale of human civilization. We also quantify plausible manipulations to governmental data that will be used to determine compliance with the 1997 Kyoto Protocol, which includes commitments for industrialized countries to regulate these and other greenhouse gases. More complete and transparent data are urgently needed. West European nations, for example, can cut their emissions of these gases by half by 2010 simply by manipulating emission factors within the current bounds of uncertainty.     

Future impacts of global warming and reforestation on drought patterns over West Africa

This study investigates how a large-scale reforestation in Savanna (8–12°N, 20°W–20°E) could affect drought patterns over West Africa in the future (2031–2060) under the RCP4.5 scenario. Simulations from two regional climate models (RegCM4 and WRF) were analyzed for the study. The study first evaluated the performance of both RCMs in simulating the present-day climate and then applied the models to investigate the future impacts of global warming and reforestation on the drought patterns. The simulated and observed droughts were characterized with the Standardized Precipitation and Evapotranspiration Index (SPEI), and the drought patterns were classified using a Self-organizing Map (SOM) technique. The models capture essential features in the seasonal rainfall and temperature fields (including the Saharan Heat Low), but struggle to reproduce the onset and retreat of the West African Monsoon as observed. Both RCMs project a warmer climate (about 1–2 °C) over West Africa in the future. They do not reach a consensus on future change in rainfall, but they agree on a future increase in frequency of severe droughts (by about 2 to 9 events per decade) over the region. They show that reforestation over the Savanna could reduce the future warming by 0.1 to 0.8 °C and increase the precipitation by 0.8 to 1.2 mm per day. However, the impact of reforestation on the frequency of severe droughts is twofold. While reforestation decreases the droughts frequency (by about 1–2 events per decade) over the Savanna and Guinea coast, it increases droughts frequency (by 1 event per decade) over the Sahel, especially in July to September. The results of this study have application in using reforestation to mitigate impacts of climate change in West Africa.     

"两岸温室气体减排政策及其经济问题分析"学术研讨会在京召开

2006年8月19日,由中国社会科学院城市发展与环境研究中心主办的“两岸温室气体减排政策及其经济问题分析”学术研讨会在北京召开。来自台湾地区的清华大学、台湾大学、台湾中原大学、台北大学、台湾中央大学、台湾综合研究院、台湾经济研究院、台湾绿色生产力基金的专家和来自大陆的中国社会科学院、中国科学院、清华     

Impacts of Future NOx and CO Emissions on Regional Chemistry and Climate over Eastern China

A coupled chemical/dynamical model (SOCOL-SOlar Climate Ozone Links) isapplied to study the impacts of future enhanced CO and NOx emissionsover eastern China on regional chemistry and climate. The result shows thatthe increase of CO and NOx emissions has significant effects onregional chemistry, including NOx, CO, O₃, and OH concentrations.During winter, the CO concentration is uniformly increased in the northernhemisphere by about 10 ppbv. During summer, the increase of CO has aregional distribution. The change in O₃, concentrations near easternChina has both strong seasonal and spatial variations. During winter, thesurface O₃, concentrations decrease by about 2 ppbv, while during summerthey increase by about 2 ppbv in eastern China. The changes of CO, NOx,and O₃, induce important impacts on OH concentrations. The changes inchemistry, especially O₃, induce important effects on regional climate.The analysis suggests that during winter, the surface temperature decreasesand air pressure increases in central-eastern China. The changes oftemperature and pressure produce decreases in vertical velocity. We shouldmention that the model resolution is coarse, and the calculatedconcentrations are generally underestimated when they are compared tomeasured results. However, because this model is a coupleddynamical/chemical model, it can provide some useful insights regarding theclimate impacts due to changes in air pollutant emissions.     

21世纪新疆区域气候暖湿化趋势预估分析

新疆未来暖湿化的预估分析可为区域气候变化减缓和适应提供重要的科学基础。国际耦合模式比较计划第六阶段（CMIP6）全球气候模式在三种共享社会经济路径（SSPs）下的结果显示,新疆地区未来2021~2100年总体呈现气温升高、降水增加的“暖湿化”现象,但这种变化的具体数值和空间分布存在一定差异。其中SSP2-4.5情景下,相对于1995~2014年,预估2021~2040年新疆地区年平均气温将升高1.2℃左右,年平均降水将增加6.8%。对极端事件的预估结果表明,新疆地区未来暖事件将增加,冷事件将减少;极端强降水事件将增多,且高排放情景下的增加更为显著。新疆地区的未来预估分析,将有助于对新疆地区灾害风险时空变化格局的认识,对未来农业方面等风险防范也有重要的指示作用。     

The Present, Past, and Future Contributions to Global Warming of CO2 Emissions from Fuels

The objective of this paper is to emphasize theresponsibility of developed countries to implement the Climate Convention, as well as the role ofdeveloping countries in CO₂ emissions controlwhile sustaining their rights to increase energyconsumption per capita during the development process. Itis shown that the growth in CO₂$ emissions fromfossil fuel consumption in North America, excludingMexico, from 1990 to 1996 was 3.7 times higherthan that of Latin America in absolute terms. Thecumulative contribution to global warming, expressedas the mass of the gas multiplied by time (GtCy), can becalculated as the integration of the atmosphericconcentration of the emitted gas along time, witha weight function in the integrand to simulate theclimate response. To simulate climate response,we used the superposition of exponential decay functions with different decay constants. Thehistorical contributions of the OECD countries,the Eastern European countries and theex-Soviet Union, and from all developingcountries are considered. The future contributionsare computed in three scenarios. All of them showthat emissions from Non-Annex I countrieswill become higher than those of Annex I countriessoon after 2010, while the curves of atmosphericconcentration will cross one another later, not muchbefore 2050, and the respective contributions toglobal temperature increase will cross about 2090.     

气候变化减缓技术：国际现状与发展趋势

介绍了当前国际主要气候变化减缓技术,并以国际能源署（IEA）、世界自然基金会（WWF）、全球能源技术战略计划（GTSP）、世界资源研究所（WRI）和欧盟（EU）、美国等国际组织、机构与国家发布或拟议中的有关气候变化减缓技术的报告为框架,对全球的气候变化减缓技术部署进行了概述。在此基础上,分析了主要的气候变化减缓技术对减缓气候变化的预期贡献。最后,对减排技术的效果、安全性、对环境的影响以及公众的认可程度等进行了讨论。     

Emissions trading and competitiveness: lessons from Germany

Germany's National Allocation Plans (NAP I and NAP II) for implementing the EU Emissions Trading Scheme (EU ETS) are critically analysed. Emissions trading has created a new scarcity, and grandfathering constitutes a subsidy that is used to reach additional policy goals related to energy and distribution policy. With respect to energy policy, the objective was to protect the German coal industry; but in terms of distribution policy the hidden agenda was to allocate as many emissions allowances as possible to the industries involved. The whole discussion is based on the false premise that a generous, or at least ‘needs-based’, allocation of costless emissions allowances increases an industry's competitiveness. As a consequence, NAP I is overburdened with several complex special rules and exemptions which distort the incentive effect of emissions trading, thus making climate change mitigation in Germany more costly than necessary. The attempted continuation of this policy, in particular with regard to new installations and an over-generous cap, has led to the European Commission's rejection of these rules in the German NAP II in November 2006. Despite significant improvements since then, some important shortfalls remain. Unfortunately, the economic literature available on this topic refers to highly stylized models of allocation rules and neglects the concrete details of the German NAP II. This article tries to close this gap in the literature by analysing the most distorting rules as well as the most important and arguments of the misguided debate on competitiveness.     

Dynamical greenhouse-plus feedback and polar warming amplification. Part II: meridional and vertical asymmetries of the global warming

This paper examines several prominent thermodynamic and dynamic factors responsible for the meridional and vertical warming asymmetries using a moist coupled atmosphere–surface radiative transportive four-box climate model. A coupled atmosphere–surface feedback analysis is formulated to isolate the direct response to an anthropogenic greenhouse gas forcing from individual local feedbacks (water vapor, evaporation, surface sensible heat flux, and ice-albedo), and from the non-local dynamical feedback. Both the direct response and response to water vapor feedback are stronger in low latitudes. The joint effect of the ice-albedo and dynamical greenhouse-plus feedbacks acts to amplify the high latitude surface warming whereas both the evaporation and dynamical greenhouse-minus feedbacks cause a reduction of the surface warming in low latitudes. The enhancement (reduction) of local feedbacks in high (low) latitudes in response to the non-local dynamic feedback further strengthens the polar amplification of the surface warming. Both the direct response and response to water vapor feedback lead to an increase of lapse rate in both low and high latitudes. The stronger total dynamic heating in the mean state in high latitudes is responsible for a larger increase of lapse rate in high latitudes in the direct response and response to water vapor feedback. The local evaporation and surface sensible heat flux feedbacks reduce the lapse rate both in low and high latitudes through cooling the surface and warming the atmosphere. The much stronger evaporation feedback leads to a final warming in low latitudes that is stronger in the atmosphere than the surface.     

Relationship between Droplet pH and Aerosol Dissolution Kinetics: Effect of Incorporated Aerosol Particles on Droplet pH during Cloud Processing

The effect of incorporated aerosols on droplet pH was investigated by dissolution experiments on various particle types. These experiments conducted in an open-flow system show that the pH changes induced by aerosol solubilisation last up to 30 min, in the range of a typical droplet lifetime. These pH changes depend upon the initial pH of the experiment, i.e., the pH at cloud condensation. In the pH range between 3 and 5, the pH varies the most when it is high, since the base agents leached from the particles are neutralised by the protons present in the aqueous phase. A relationship between the neutralising capacity of the aerosol (NCA), i.e., the amount of uncompensated base species, and the pH after neutralisation has been found. Other experiments show that the NCA is related to the aerosol composition: silicates present more or less pronounced NCA, whereas C graphite presents a negative NCA, i.e., an acidifying capacity. The aerosol composition can be modified during cloud evapocondensation, notably by the addition of sulphate or sulphuric acid to the aerosol surface. NCA modification with cloud processing is observed when the amount of dissolved acid is larger than the neutralising capacity of the aerosol, i.e., when the droplet pH is less than a compensation pH characteristic of the aerosol type.     

英国温室气体排放贸易制度的实践与评价

温室气体排放贸易作为一种经济激励型的环境管理手段,对企业减少温室气体排放有成本效率作用。详细介绍了英国温室气体排放贸易制度框架,并对其政策的效果及存在的问题进行了评价。     

气溶胶对亚洲季风的强迫及影响：认识与挑战

亚洲是世界上人口密度最大、也是近几十年来经济发展最快的地区。从广大民众到各级政府都深刻感受到这种巨大的变化所带来的各种影响。从事相关研究的科学家最关心的是各种变化的因果关系、影响机理并对未来变化进行客观预测。该地区日益严重的空气污染,尤其是由颗粒污染物造成的雾、霾发生频率和强度的增加,不仅影响人们的日常生活和健康,而且进一步影响了在过去几十年已经发生了巨大变化的季风气候。本文提出了一些研究气溶胶与季风相互作用的新视角、新途径、新挑战。东亚和南亚是全球气溶胶主要源地。气溶胶对季风的一个显著影响体现在南亚和东亚大范围的暗化现象,即到达地面的太阳辐射的整体减少。气溶胶对东亚和南亚夏季风的强迫机理存在差异。中国灰霾天增加除了污染排放也与东亚季风气候变化息息相关。在实际大气季风气候系统的准静力平衡态的演变中,动力反馈过程可能扮演着至关重要的作用,而这种作用会受到人类污染和自然源气溶胶的强迫作用。对气溶胶-季风相互作用进行研究,需要把各种尺度的观测和模拟开展起来。更好地了解气溶胶与亚洲季风气候的联系,对于制定和实施科学的可持续发展政策,造福世界上过半人口,起着至关重要的作用。     

Aerosol, clouds and rainfall: inter-annual and regional variations over India

Inter-annual and regional variations in aerosol and cloud characteristics, water vapor and rainfall over six homogeneous rainfall zones in India during the core monsoon month of July from 2000 to 2010, and their correlations are analyzed. Aerosol optical depth (AOD) and aerosol absorbing index (AAI) in July 2002, a drought year are higher over India when compared to normal monsoon years. The drier conditions that existed due to deficient rainfall in July 2002 could be responsible for raising more dust and smoke resulting in higher AODs over India. In addition, over India precipitation is not uniform and large-scale interruptions occur during the monsoon season. During these interruptions aerosols can build up over a region and contribute to an increase in AODs. This finding is supported by the occurrence of higher anomalies in AOD, AAI and rainfall over India in July 2002. Aerosol characteristics and rainfall exhibit large regional variations. Cloud effective radius (CER), cloud optical thickness and columnar water vapor over India are the lowest in July 2002. CER decreases as AOD and AAI increase, providing an observational evidence for the indirect effect of aerosols. Eighty percent of CER in northwest India, and 30% of CER over All India in July 2002 are <14 μm, the precipitation threshold critical cloud effective radius. Northeast India shows contrasting features of correlation among aerosols, clouds and rainfall when compared to other regions. These results will be important while examining the inter-annual variation in aerosols, cloud characteristics, rainfall and their trends.     

North Atlantic warming: patterns of long-term trend and multidecadal variability

Climate fluctuations in the North Atlantic Ocean have wide-spread implications for Europe, Africa, and the Americas. This study assesses the relative contribution of the long-term trend and variability of North Atlantic warming using EOF analysis of deep-ocean and near-surface observations. Our analysis demonstrates that the recent warming over the North Atlantic is linked to both long-term (including anthropogenic and natural) climate change and multidecadal variability (MDV, ~50–80 years). Our results suggest a general warming trend of 0.031 ± 0.006°C/decade in the upper 2,000 m North Atlantic over the last 80 years of the twentieth century, although during this time there are periods in which short-term trends were strongly amplified by MDV. For example, MDV accounts for ~60% of North Atlantic warming since 1970. The single-sign basin-scale pattern of MDV with prolonged periods of warming (cooling) in the upper ocean layer and opposite tendency in the lower layer is evident from observations. This pattern is associated with a slowdown (enhancement) of the North Atlantic thermohaline overturning circulation during negative (positive) MDV phases. In contrast, the long-term trend exhibits warming in tropical and mid-latitude North Atlantic and a pattern of cooling in regions associated with major northward heat transports, consistent with a slowdown of the North Atlantic circulation as evident from observations and confirmed by selected modeling results. This localized cooling has been masked in recent decades by warming during the positive phase of MDV. Finally, since the North Atlantic Ocean plays a crucial role in establishing and regulating the global thermohaline circulation, the multidecadal fluctuations discussed here should be considered when assessing long-term climate change and variability, both in the North Atlantic and at global scales.     

The Paris warming targets: emissions requirements and sea level consequences

The Paris Agreement states that, relative to pre-industrial times, the increase in global average temperature should be kept to well below 2 °C and efforts should be made to limit the temperature increase to 1.5 °C. Emissions scenarios consistent with these targets are derived. For an eventual 2 °C warming target, this could be achieved even if CO₂ emissions remained positive. For a 1.5 °C target, CO₂ emissions could remain positive, but only if a substantial and long-lasting temperature overshoot is accepted. In both cases, a warming overshoot of 0.2 to 0.4 °C appears unavoidable. If the allowable (or unavoidable) overshoot is small, then negative emissions are almost certainly required for the 1.5 °C target, peaking at negative 1.3 GtC/year. In this scenario, temperature stabilization occurs, but cumulative emissions continue to increase, contrary to a common belief regarding the relationship between temperature and cumulative emissions. Changes to the Paris Agreement to accommodate the overshoot possibility are suggested. For sea level rise, tipping points that might lead to inevitable collapse of Antarctic ice sheets or shelves might be avoided for the 2 °C target (for major ice shelves) or for the 1.5 °C target for the West Antarctic Ice Sheet. Even with the 1.5 °C target, however, sea level will continue to rise at a substantial rate for centuries.     

The MJO and global warming: a study in CCSM4

The change in Madden–Julian oscillation (MJO) amplitude and variance in response to anthropogenic climate change is assessed in the 1° nominal resolution community climate system model, version 4 (CCSM4), which has a reasonable representation of the MJO characteristics both dynamically and statistically. The twentieth century CCSM4 run is compared with the warmest twenty-first century projection (representative concentration pathway 8.5, or RCP8.5). The last 20 years of each simulation are compared in their MJO characteristics, including spatial variance distributions of winds, precipitation and outgoing longwave radiation, histograms of event amplitude, phase and duration, and composite maps of phases. The RCP8.5 run exhibits increased variance in intraseasonal precipitation, larger-amplitude MJO events, stronger MJO rainfall in the central and eastern tropical Pacific, and a greater frequency of MJO occurrence for phases corresponding to enhanced rainfall in the Indian Ocean sector. These features are consistent with the concept of an increased magnitude for the hydrological cycle under greenhouse warming conditions. Conversely, the number of active MJO days decreases and fewer weak MJO events occur in the future climate state. These results motivate further study of these changes since tropical rainfall variability plays such an important role in the region’s socio-economic well being.