In Press, 2015
Deng, Yu, and Sumeeta Srinivasan. In Press, 2015. “Urban Land Use Change and Regional Access: A Case Study in Beijing, China.” Habitat International.Abstract
In the recent past Beijing has experienced rapid development. This growth has been accompanied by many problems including traffic congestion and air pollution. Understanding what stimulates urban growth is important for sustainable development in the coming years. In this paper, we first estimate a binary auto-logistic model of land use change, using physical and socioeconomic characteristics of the location and its access to major centers within the city as predictors. We find that variables determining regional access, like time distance to the city center, the Central Business District (CBD), industrial centers, employment centers, and the transportation system, significantly impact urban land conversion. By using measures of access to predict land use change we believe that we can better understand the planning implications of urban growth not only in Beijing but other rapidly developing cities.
Guo, Meiyu, Xi Lu, Chris P Nielsen, Michael B McElroy, Wenrui Shi, Yuntian Chen, and Xuan Yu. Submitted. “Prospects for Shale Gas Production in China: Implications for Water Demand.” Renewable & Sustainable Energy Reviews.
Zhang, Ning, Xi Lu, Chris P Nielsen, Michael B McElroy, Xinyu Chen, Yu Deng, and Chongqing Kang. Submitted. “Reducing Curtailment of Wind Electricity in China by Employing Electric Boilers for Heat and Pumped Hydro for Energy Storage.” Applied Energy.Abstract
Accommodating variable wind power poses a critical challenge for electric power systems that are heavily dependent on combined heat and power (CHP) plants, as is the case for north China. An improved unit-commitment model is applied to evaluate potential benefits from pumped hydro storage (PHS) and electric boilers (EBs) in West Inner Mongolia (WIM), where CHP capacity is projected to increase to 33.8 GW by 2020. A business-as-usual (BAU) reference case assumes deployment of 20 GW of wind capacity. Compared to BAU, expanding wind capacity to 40 GW would allow for a reduction in CO2 emissions of 33.9 million tons, but at a relatively high cost of US$25.3/ton, reflecting primarily high associated curtailment of wind electricity (20.4%). A number of scenarios adding PHS and/or EBs combined with higher levels of wind capacity are evaluated. The best case indicates that a combination of PHS (3.6 GW) and EBs (6.2 GW) together with 40 GW of wind capacity would reduce CO2 emissions by 43.5 million tons compared to BAU, and at a lower cost of US$16.0/ton. Achieving this outcome will require a price-incentive policy designed to ensure the profitability of both PHS and EB facilities.
Zhao, Yu, Hui Zhong, Jie Zhang, and Chris P Nielsen. 2015. “Evaluating the Effects of China's Pollution Control on Inter-Annual Trends and Uncertainties of Atmospheric Mercury Emissions.” Atmospheric Chemistry and Physics 15: 4317–4337. Publisher's VersionAbstract
China's atmospheric mercury (Hg) emissions of anthropogenic origin have been effectively restrained through the national policy of air pollution control. Improved methods based on available field measurements are developed to quantify the benefits of Hg abatement through various emission control measures. Those measures include increased use of flue gas desulfurization (FGD) and selective catalyst reduction (SCR) systems for power sector, precalciners with fabric filter (FF) for cement production, machinery coking with electrostatic precipitator (ESP) for iron and steel production, and advanced manufacturing technologies for nonferrous metal smelting. Declining trends in emissions factors for those sources are revealed, leading to a much slower growth of national total Hg emissions than that of energy and economy, from 679 in 2005 to 750 metric tons (t) in 2012. In particular, nearly half of emissions from the above-mentioned four types of sources are expected to be reduced in 2012, attributed to expansion of technologies with high energy efficiencies and air pollutant removal rates after 2005. The speciation of Hg emissions keeps stable for recent years, with the mass fractions of around 55, 39 and 6% for Hg0, Hg2+ and Hgp, respectively. The lower estimate of Hg emissions than previous inventories is supported by limited chemistry simulation work, but middle-to-long term observation on ambient Hg levels is further needed to justify the inter-annual trends of estimated Hg emissions. With improved implementation of emission controls and energy saving, 23% reduction in annual Hg emissions for the most optimistic case in 2030 is expected compared to 2012, with total emissions below 600 t. While Hg emissions are evaluated to be gradually constrained, increased uncertainties are quantified with Monte-Carlo simulation for recent years, particularly for power and certain industrial sources. The uncertainty of Hg emissions from coal-fired power plants, as an example, increased from −48 ~ +73% in 2005 to −50 ~ +89% in 2012 (expressed as 95% confidence interval). This is attributed mainly to swiftly increased penetration of advanced manufacturing and pollutant control technologies. The unclear operation status or relatively small sample size of field measurements on those technologies results in lower but highly varied emission factors. To further confirm the benefits of pollution control polices with reduced uncertainty, therefore, systematic investigations are recommended specific for Hg pollution sources, and the variability of temporal trends and spatial distributions of Hg emissions need to be better tracked for the country under dramatic changes in economy, energy and air pollution status.
Huang, Junling, and Michael B McElroy. 2015. “Thermodynamic Disequilibrium of the Atmosphere in the Context of Global Warming.” Climate Dynamics, no. (March). Publisher's VersionAbstract
The atmosphere is an example of a non-equilibrium system. This study explores the relationship among temperature, energy and entropy of the atmosphere, introducing two variables that serve to quantify the thermodynamic disequilibrium of the atmosphere. The maximum work, Wmax, that the atmosphere can perform is defined as the work developed through a thermally reversible and adiabatic approach to thermodynamic equilibrium with global entropy conserved. The maximum entropy increase, (ΔS)max, is defined as the increase in global entropy achieved through a thermally irreversible transition to thermodynamic equilibrium without performing work. Wmax is identified as an approximately linear function of (ΔS)max. Large values of Wmax or (ΔS)max correspond to states of high thermodynamic disequilibrium. The seasonality and long-term historical variation of Wmax and (ΔS)max are computed, indicating highest disequilibrium in July, lowest disequilibrium in January with no statistically significant trend over the past 32 years. The analysis provides a perspective on the interconnections of temperature, energy and entropy for the atmosphere and allows for a quantitative investigation of the deviation of the atmosphere from thermodynamic equilibrium. 
Zhang, Yanxia, Haikun Wang, Sai Liang, Ming Xu, Qiang Zhang, Hongyan Zhao, and Jun Bi. 2015. “A Dual Strategy for Controlling Energy Consumption and Air Pollution in China's Metropolis of Beijing.” Energy 81 (1 March): 294-303. Publisher's VersionAbstract
  It is critical to alleviate problems of energy and air pollutant emissions in a metropolis because these areas serve as economic engines and have large and dense populations. Drivers of fossil fuel use and air pollutants emissions were analyzed in the metropolis of Beijing during 1997-2010. The analyses were conducted from both a bottom-up and a top-down perspective based on the sectoral inventories and structural decomposition analysis (SDA). From a bottom-up perspective, the key energy-intensive industrial sectors directly caused the variations in Beijing's air pollution by means of a series of energy and economic policies. From a top-down perspective, variations in production structures caused increases in most materials during 2000-2010, but there were decreases in PM10 and PM2.5 emissions during 2005-2010. Population growth was found to be the largest driver of energy consumption and air pollutant emissions during 1997-2010. This finding suggests that avoiding rapid population growth in Beijing could simultaneously control energy consumption and air pollutant emissions. Mitigation policies should consider not only the key industrial sectors but also socioeconomic drivers to co-reduce energy consumption and air pollution in China's metropolis.
Huang, Junling, and Michael B McElroy. 2015. “A 32-Year Perspective on the Origin of Wind Energy in a Warming Climate.” Renewable Energy 77 (May): 482-492. Publisher's VersionAbstract
Based on assimilated meteorological data for the period January 1979 to December 2010, the origin of wind energy is investigated from both mechanical and thermodynamic perspectives, with special focus on the spatial distribution of sources, historical long term variations and the efficiency for kinetic energy production. The dry air component of the atmosphere acts as a thermal engine, absorbing heat at higher temperatures, approximately 256 K, releasing heat at lower temperatures, approximately 252 K. The process is responsible for production of wind kinetic energy at a rate of 2.46 W/m2  sustaining thus the circulation of the atmosphere against frictional dissipation. The results indicate an upward trend in kinetic energy production over the past 32 years, indicating that wind energy resources may be varying in the current warming climate. This analysis provides an analytical framework that can be adopted for future studies addressing the ultimate wind energy potential and the possible perturbations to the atmospheric circulation that could arise as a result of significant exploitation of wind energy.    
Cui, Hongfei, Pan Mao, Yu Zhao, Chris P Nielsen, and Jie Zhang. 2015. “Patterns in Atmospheric Carbonaceous Aerosols in China: Emission Estimates and Observed Concentrations.” Atmospheric Chemistry and Physics 15: 8657–8678. Publisher's VersionAbstract
China is experiencing severe carbonaceous aerosol pollution driven mainly by large emissions from intensive use of solid fuels. To gain a better understanding of the levels and trends of carbonaceous aerosol emissions and the resulting ambient concentrations at the national scale, we update an emission inventory of anthropogenic organic carbon (OC) and elemental carbon (EC), and employ existing observational studies to analyze characteristics of these aerosols including temporal, spatial, and size distributions, and the levels and contributions of secondary organic carbon (SOC) to total OC. We further use ground observations to test the levels and inter-annual trends of the calculated national and provincial emissions of carbonaceous aerosols, and propose possible improvements in emission estimation for the future. The national OC emissions are estimated to have increased 29% from 2000 (2127 Gg) to 2012 (2749 Gg) and EC by 37% (from 1356 to 1857 Gg). The residential, industrial, and transportation sectors contributed an estimated 76±2%, 19±2% and 5±1% of the total emissions of OC, respectively, and 52±3%, 32±2% and 16±2% of EC. Updated emission factors based on the most recent local field measurements, particularly for biofuel stoves, lead to considerably lower emissions of OC compared to previous inventories. Compiling observational data across the country, higher concentrations of OC and EC are found in northern and inland cities, while larger OC/EC and SOC/OC ratios are found in southern cities, due to the joint effects of primary emissions and meteorology. Higher SOC/OC ratios are estimated at rural and background sites compared to urban ones, attributed to more emissions of OC from biofuel use, more biogenic emissions of volatile organic compound (VOC) precursors to SOC, and/or transport of aged aerosols. For most sites, higher concentrations of OC, EC, and SOC are observed in colder seasons, while SOC/OC is reduced, particularly at regional sites, attributed partly to weaker atmospheric oxidation and SOC formation compared to summer. Enhanced SOC formation from oxidization and anthropogenic activities like biomass combustion is judged to have crucial effects on severe haze events characterized by high particle concentrations. Several observational studies indicate an increasing trend in ambient OC/EC (but not in OC or EC individually) from 2000 to 2010, confirming increased atmospheric oxidation of OC across the country. Combining the results of emission estimation and observations, the improvement over prior emission inventories is indicated by inter-annual comparisons and correlation analysis. It is also indicated, however, that the estimated growth in emissions might be faster than observed growth, and that some sources with high primary OC/EC like burning of biomass are still underestimated. Further studies to determine changing emission factors over time in the residential sector and to compare to other measurements such as satellite observations are thus suggested to improve understanding of the levels and trends of primary carbonaceous aerosol emissions in China.
Deng, Yu, Shenghe Liu, Jianming Cai, Xi Lu, and Chris P Nielsen. 2015. “Spatial Pattern and Evolution of Chinese Provincial Population: Methods and Empirical Study.” Journal of Geographical Sciences 25: 1-14.
Wang, Haikun, Yanxia Zhang, Xi Lu, Chris P Nielsen, and Jun Bi. 2015. “Understanding China's Carbon Dioxide Emissions from Both Production and Consumption Perspectives.” Renewable and Sustainable Energy Reviews 52: 189-200. Publisher's VersionAbstract
China is now the largest emitter of CO2 in the world, having contributed nearly half of the global increase in carbon emissions between 1980 and 2010. The existing literature on China’s carbon emissions has focused on two dimensions: the amount of CO2 emitted within China’s geographical boundaries (a production-based perspective), and the drivers of, and responsibility for, these emissions (a consumption-based perspective). The current study begins with a comprehensive review of China’s CO2 emissions, and then analyzes their driving forces from both consumption and production perspectives, at both national and provincial levels. It is concluded that China’s aggregate national CO2 emissions from fossil fuel consumption and cement production maintained high growth rates during 2000-2010. National emissions reached 6.8–7.3 billion tons in 2007, nearly 25% of which were caused by net exports (i.e., exports minus imports) to other countries. However, emission characteristics varied significantly among different regions and provinces, and considerable emission leakage from the developed eastern regions to inland and western areas of the country was found. The objectives of China’s policies should therefore be broadened from continued improvement of energy efficiency to accelerating regional technology transfer and preventing mere relocation of carbon-intensive economic activities from developed coastal regions to less developed, inland provinces. To rapidly and effectively cut down China’s carbon emissions, moreover, its energy supply should be aggressively decarbonized by promoting renewable and low carbon energy sources.
Zhao, Y, LP Qiu, RY Xu, FJ Xie, Q Zhang, YY Yu, CP Nielsen, et al.. 2015. “Advantages of City-Scale Emission Inventory for Urban Air Quality Research and Policy: The Case of Nanjing, a Typical Industrial City in the Yangtze River Delta, China.” Atmospheric Chemistry and Physics Discussions 15: 18691-18746. Publisher's VersionAbstract
With most eastern Chinese cities facing major air quality challenges, there is a strong need for city-scale emission inventories for use in both chemical transport modeling and the development of pollution control policies. In this paper, a high-resolution emission inventory of air pollutants and CO2 for Nanjing, a typical large city in the Yangtze River Delta, is developed incorporating the best available information on local sources. Emission factors and activity data at the unit or facility level are collected and compiled using a thorough onsite survey of major sources. Over 900 individual plants, which account for 97% of the city's total coal consumption, are identified as point sources, and all of the emission-related parameters including combustion technology, fuel quality, and removal efficiency of air pollution control devices (APCD) are analyzed. New data-collection approaches including continuous emission monitoring systems and real-time monitoring of traffic flows are employed to improve spatiotemporal distribution of emissions. Despite fast growth of energy consumption between 2010 and 2012, relatively small inter-annual changes in emissions are found for most air pollutants during this period, attributed mainly to benefits of growing APCD deployment and the comparatively strong and improving regulatory oversight of the large point sources that dominate the levels and spatial distributions of Nanjing emissions overall. The improvement of this city-level emission inventory is indicated by comparisons with observations and other inventories at larger spatial scale. Relatively good spatial correlations are found for SO2, NOX, and CO between the city-scale emission estimates and concentrations at 9 state-opertated monitoring sites (R = 0.58, 0.46, and 0.61, respectively). The emission ratios of specific pollutants including BC to CO, OC to EC, and CO2 to CO compare well to top-down constraints from ground observations. The inter-annual variability and spatial distribution of NOX emissions are consistent with NO2 vertical column density measured by the Ozone Monitoring Instrument (OMI). In particular, the Nanjing city-scale emission inventory correlates better with satellite observations than the downscaled Multi-resolution Emission Inventory for China (MEIC) does when emissions from power plants are excluded. This indicates improvement in emission estimation for sectors other than power generation, notably industry and transportation. High-resolution emission inventory may also provide a basis to consider the quality of instrumental observations. To further improve emission estimation and evaluation, more measurements of both emission factors and ambient levels of given pollutants are suggested; the uncertainties of emission inventories at city scale should also be fully quantified and compared with those at national scale. 

Lu, Xi, Michael B McElroy, Xinyu Chen, and Chongqing Kang. 2014. “Opportunity for Offshore Wind to Reduce Future Demand for Coal-Fired Power Plants in China with Consequent Savings in Emissions of Co2.” Environmental Science & Technology 48 (24): 14764–14771. Publisher's VersionAbstract
Although capacity credits for wind power have been embodied in power systems in the U.S. and Europe, the current planning framework for electricity in China continues to treat wind power as a non-dispatchable source with zero contribution to firm capacity. This study adopts a rigorous reliability model for the electric power system evaluating capacity credits that should be recognized for offshore wind resources supplying power demands for Jiangsu, China. Jiangsu is an economic hub located in the Yangtze River delta accounting for 10% of the total electricity consumed in China. Demand for electricity in Jiangsu is projected to increase from 331 TWh in 2009 to 800 TWh by 2030. Given a wind penetration level of 60% for the future additional Jiangsu power supply, wind resources distributed along the offshore region of five coastal provinces in China (Shandong, Jiangsu, Shanghai, Zhejiang and Fujian) should merit a capacity credit of 12.9%, the fraction of installed wind capacity that should be recognized to displace coal-fired systems without violating the reliability standard. In the high-coal-price scenario, with 60% wind penetration, reductions in CO2 emissions relative to a business as usual reference could be as large as 200.2 million tons of CO2 or 51.8% of the potential addition, with a cost for emissions avoided of $29.0 per ton.
Song, Tao, Jian-ming Cai, Teresa Chahine, Hui Xu, and Fang-qu Niu. 2014. “Modeling Urban Metabolism of Beijing City, China, with Coupled System Dynamics: Emergy Model.” Stochastic Environmental Research and Risk Assessment 28 (6): 1511-1524. Publisher's VersionAbstract
Chinese cities are plagued by the rise in resource and energy input and output over the last decade. At the same time, the scale and pace of economic development sweeping across Chinese cities have revived the debate about urban metabolisms, which could be simply seen as the ratio of output to resource and energy input in urban systems. In this study, an emergy (meaning the equivalent solar energy) accounting, sustainable indices of urban metabolisms, and an urban metabolic system dynamics model, are developed in support of the research task on Chinese cities ‘metabolisms and their related policies. The dynamic simulation model used in the paper is capable of synthesizing component-level knowledge into system behavior simulation at an integrated level, which is directly useful for simulating and evaluating a variety of decision actions and their dynamic consequences. For the study case, interactions among a number of Beijing’s urban emergy components within a time frame of 20 years (from 2010 to 2030) are examined dynamically. Six alternative policy scenarios are implemented into the system simulation. Our results indicate that Beijing’s current model of urban metabolism—tertiary industry oriented development mode—would deliver prosperity to the city. However, the analysis also shows that this mode of urban metabolism would weaken urban self-support capacity due primarily to the large share of imported and exported emergy in the urban metabolic system. The keys of improving the efficiency of urban metabolism include the priority on the renewable resource and energy, increase in environmental investment and encouragement on innovative technologies of resource and energy utilization, et al.
Huang, Junling. 2014. “A Climate-Friendly Energy Future: Prospects for Wind.” School of Engineering and Applied Sciences, Harvard University.
Wang, Long, Shuxiao Wang, Lei Zheng, Yuxuan Wang, Yanxu Zheng, Chris P Nielsen, Michael B McElroy, and Jiming Hao. 2014. “

Source Apportionment of Atmospheric Mercury Pollution in China Using the Geos-Chem Model

.” Environmental Pollution 190 (July): 166-175. Publisher's VersionAbstract
China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. In this study, China's Hg emission inventory is updated to 2007 and applied in the GEOS-Chem model to simulate the Hg concentrations and depositions in China. Results indicate that simulations agree well with observed background Hg concentrations. The anthropogenic sources contributed 35–50% of THg concentration and 50–70% of total deposition in polluted regions. Sensitivity analysis was performed to assess the impacts of mercury emissions from power plants, non-ferrous metal smelters and cement plants. It is found that power plants are the most important emission sources in the North China, the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) while the contribution of non-ferrous metal smelters is most significant in the Southwest China. The impacts of cement plants are significant in the YRD, PRD and Central China.
Wang, SX, B Zhao, SY Cai, Z Klimont, CP Nielsen, T Morikawa, JH Woo, et al.. 2014. “

Emission Trends and Mitigation Options for Air Pollutants in East Asia

.” Atmospheric Chemistry and Physics 14: 6571-6603. Publisher's VersionAbstract
Emissions of air pollutants in East Asia play an important role in the regional and global atmospheric environment. In this study we evaluated the recent emission trends of sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter (PM), and non-methane volatile organic compounds (NMVOC) in East Asia, and projected their future emissions up until 2030 with six emission scenarios. The results will provide future emission projections for the modeling community of the model inter-comparison program for Asia (MICS-Asia). During 2005–2010, the emissions of SO2 and PM2.5 in East Asia decreased by 15 and 12%, respectively, mainly attributable to the large-scale deployment of flue gas desulfurization (FGD) at China's power plants, and the promotion of highly efficient PM removal technologies in China's power plants and cement industry. During this period, the emissions of NOx and NMVOC increased by 25 and 15%, driven by rapid increase in the emissions from China due to inadequate control strategies. In contrast, the NOx and NMVOC emissions in East Asia except China decreased by 13–17%, mainly due to the implementation of stringent vehicle emission standards in Japan and South Korea. Under current regulations and current levels of implementation, NOx, SO2, and NMVOC emissions in East Asia are projected to increase by about one-quarter over 2010 levels by 2030, while PM2.5 emissions are expected to decrease by 7%. Assuming enforcement of new energy-saving policies, emissions of NOx, SO2, PM2.5 and NMVOC in East Asia are expected to decrease by 28, 36, 28, and 15%, respectively, compared with the baseline case. The implementation of "progressive" end-of-pipe control measures would lead to another one-third reduction of the baseline emissions of NOx, and about one-quarter reduction of SO2, PM2.5, and NMVOC. Assuming the full application of technically feasible energy-saving policies and end-of-pipe control technologies, the emissions of NOx, SO2, and PM2.5 in East Asia would account for only about one-quarter, and NMVOC for one-third, of the levels of the baseline projection. Compared with previous projections, this study projects larger reductions in NOx and SO2 emissions by considering aggressive governmental plans and standards scheduled to be implemented in the next decade, and quantifies the significant effects of detailed progressive control measures on NMVOC emissions up until 2030.
Zhao, Yu, Jie Zhang, and Chris P Nielsen. 2014. “The Effects of Energy Paths and Emission Controls and Standards on Future Trends in China's Emissions of Primary Air Pollutants.” Atmospheric Chemistry and Physics 14: 8849-8868. Publisher's VersionAbstract
To examine the efficacy of China's actions to control atmospheric pollution, three levels of growth of energy consumption and three levels of implementation of emission controls are estimated, generating a total of nine combined activity-emission control scenarios that are then used to estimate trends of national emissions of primary air pollutants through 2030. The emission control strategies are expected to have more effects than the energy paths on the future emission trends for all the concerned pollutants. As recently promulgated national action plans of air pollution prevention and control (NAPAPPC) are implemented, China's anthropogenic pollutant emissions should decline. For example, the emissions of SO2, NOx, total suspended particles (TSP), PM10, and PM2.5 are estimated to decline 7, 20, 41, 34, and 31% from 2010 to 2030, respectively, in the "best guess" scenario that includes national commitment of energy saving policy and implementation of NAPAPPC. Should the issued/proposed emission standards be fully achieved, a less likely scenario, annual emissions would be further reduced, ranging from 17 (for primary PM2.5) to 29% (for NOx) declines in 2015, and the analogue numbers would be 12 and 24% in 2030. The uncertainties of emission projections result mainly from the uncertain operational conditions of swiftly proliferating air pollutant control devices and lack of detailed information about emission control plans by region. The predicted emission trends by sector and chemical species raise concerns about current pollution control strategies: the potential for emissions abatement in key sectors may be declining due to the near saturation of emission control devices use; risks of ecosystem acidification could rise because emissions of alkaline base cations may be declining faster than those of SO2; and radiative forcing could rise because emissions of positive-forcing carbonaceous aerosols may decline more slowly than those of SO2 emissions and thereby concentrations of negative-forcing sulfate particles. Expanded control of emissions of fine particles and carbonaceous aerosols from small industrial and residential sources is recommended, and a more comprehensive emission control strategy targeting a wider range of pollutants (volatile organic compounds, NH3 and CO, etc.) and taking account of more diverse environmental impacts is also urgently needed.
Huang, Junling, and Michael B McElroy. 2014. “

Contributions of the Hadley and Ferrel Circulations to the Energetics of the Atmosphere over the Past 32 Years

.” Journal of Climate 27 (7): 2656–2666. Publisher's VersionAbstract
The Hadley system provides an example of a thermally direct circulation; the Ferrel system in contrast provides an example of a thermally indirect circulation. In this study, the authors develop an approach to investigate the key thermodynamic properties of the Hadley and Ferrel systems, quantifying them using assimilated meteorological data covering the period January 1979–December 2010. This analysis offers a fresh perspective on the conversion of energy in the atmosphere from diabatic heating to the production of atmospheric kinetic energy. The results indicate that the thermodynamic efficiency of the Hadley system, considered as a heat engine, has been relatively constant over the 32-yr period covered by the analysis, averaging 2.6%. Over the same interval, the power generated by the Hadley regime has risen at an average rate of about 0.54 TW yr−1; this reflects an increase in energy input to the system consistent with the observed trend in the tropical sea surface temperatures. The Ferrel system acts as a heat pump with a coefficient of performance of 12.1, consuming kinetic energy at an approximate rate of 275 TW and exceeding the power production rate of the Hadley system by 77 TW.
Zhang, Yanxia, Haikun Wang, Sai Liang, Ming Xu, Weidong Liu, Shalang Li, Rongrong Zhang, Chris P Nielsen, and Jun Bi. 2014. “

Temporal and Spatial Variations in Consumption-Based Carbon Dioxide Emissions in China

.” Renewable & Sustainable Energy Reviews 40: 60-68. Publisher's VersionAbstract
China’s CO2 emissions have sharply increased in recent years with soaring economic development and urbanization. Consumption-based accounting of CO2 emissions could provide new insights for allocating regional mitigation responsibility and curbing the emissions. A multi-regional input–output model is used to study the trends and disparities of consumption-based emissions from Chinese provinces during the period 2002–2007. Results show that China’s consumption-based CO2 emissions grew from 3549 Mt in 2002 to 5403 Mt in 2007 with an annual average growth rate of 8.8%. The annual growth rate in the richer eastern region was over 10% because of a rapid increase in capital investment and the growth of urban consumption. Consumption-based CO2 emissions embodied in interprovincial trades contributed only 10% (351 Mt) to the national total of such emissions in 2002, but 16% (864 Mt) in 2007. Given low per capita emissions currently, China’s consumption-based emissions have much room to grow because of further development of urbanization and stimulation of domestic demand. The government should pay greater attention to controlling CO2 emissions from a consumption-based perspective.
Chen, Xinyu, Xi Lu, Michael B McElroy, Chris P Nielsen, and Chongqing Kang. 2014. “

Synergies of Wind Power and Electrified Space Heating: A Case Study for Beijing

.” Environmental Science & Technology 48 (3): 2016–2024. Publisher's VersionAbstract
Demands for electricity and energy to supply heat are expected to expand by 71% and 47%, respectively, for Beijing in 2020 relative to 2009. If the additional electricity and heat are supplied solely by coal as is the current situation, annual emissions of CO2 may be expected to increase by 59.6% or 99 million tons over this interval. Assessed against this business as usual (BAU) background, the present study indicates that significant reductions in emissions could be realized using wind-generated electricity to provide a source of heat, employed either with heat pumps or with electric thermal storage (ETS) devices. Relative to BAU, reductions in CO2 with heat pumps assuming 20% wind penetration could be as large as 48.5% and could be obtained at a cost for abatement of as little as $15.6 per ton of avoided CO2. Even greater reductions, 64.5%, could be realized at a wind penetration level of 40% but at a higher cost, $29.4 per ton. Costs for reduction of CO2 using ETS systems are significantly higher, reflecting the relatively low efficiency for conversion of coal to power to heat.