The environmental Kuznets curve of CO2 emissions in the manufacturing and construction industries: A global empirical analysis

The manufacturing and construction industries have significantly contributed to the increase of carbon dioxide (CO₂) emissions. Environmental Kuznets curve (EKC) hypothesis is widely leveraged to analyze the peak of CO₂ emissions, which is considered as a pivotal step for the effective CO₂ emission reduction in previous studies. This study tests the EKC hypothesis using the data of CO₂ emissions of manufacturing and construction industries from 121 countries throughout 1960–2014, and turning points (TPs) are calculated for the countries where EKC hypothesis is validated. The results show that the EKC hypothesis was validated by 95 out of 121 countries, among which, 13 countries have not reached any of the three TPs, 11 countries have reached the first-step TP (TP_CI), 21 countries have reached the second-step TP (TP_PC), and 50 countries have reached the third-step TP (TP_TC). Moreover, the result of examination of the EKC existence at four income levels indicates the higher-income nations own a higher proportion of countries validates the EKC hypothesis and reach the TP. These findings help policy-makers analyze the TP status quo and generate step-wise strategies for national CO₂ emission reduction of manufacturing and construction industries.     

Electricity and emission-permits trade as a means of curbing CO2 emissions in the Nordic countries

The four Nordic countries Sweden, Denmark, Finland and Norway have fully integrated electricity grids, implying that electricity trade hitherto has accounted for a crucial part of each country’s power balance. Electricity trade also provides cost-efficient opportunities for the Nordic countries to either jointly or separately fulfil their CO₂ obligations. Assuming the targets that were agreed upon in (the aftermath of) the Kyoto negotiations in 1997, and establishing scenarios where CO₂-emission-permits trade among the Nordic countries is allowed, it is shown that the value of emission trading is somewhat larger than the corresponding value of electricity trade. Furthermore, if both electricity and emission permits can be traded on a common Nordic market this can lead to amplified economic benefits yielding a gain that exceeds the sum of the separate values of electricity and emission permits trade. It is also shown that the additional costs of fulfilling the Kyoto protocol are small compared to the total costs of the Nordic energy system. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of national-level spatial distribution of cities on national transport CO2 emissions

Most research regarding the relationship between cities and transportation carbon emission is focused on intra-city travel, and it has been found that compact patterns tend to emit less carbon. Yet, little is known about the impact of national-level spatial distribution of cities and inter-city transportation on transportation CO₂ emissions. Further, most studies regarding the impact of urbanization on CO₂ emission directly examine the relationship between urbanization rate and CO₂ emission with little consideration of the national spatial pattern of urbanization. This study hypothesizes that the national-level spatial distribution of cities – in a dispersed or polarized pattern – affects national transport CO₂ emissions due to the varying intensity of inter-city transportation. This study uses the Gridded Population of the World v3 and v4 from Socioeconomic Data and Applications Center (SEDAC) of NASA to examine the national-level spatial distribution of urban agglomerations. It applies the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model. The analysis shows that, among 60–90% of urbanized countries, spatially dispersed urbanized countries (e.g., countries with many medium-sized cities scattered over the territory) show a lower national transportation CO₂ emission than spatially polarized urbanized countries (e.g., there are only a few large cities). The urban system elasticity of transportation CO₂ emissions is 0.4 or 0.6. That is, if the degree of polarization decreases by 1%, national transportation CO₂ emissions decrease by approximately 0.4–0.6%. This effect is similar to the effect of GDP per capita of around 0.5%. Because it is particularly difficult to disperse people and economic activities across a country once spatial polarization is set, this study's findings have the most significant implications for urbanizing countries. If urbanizing countries adopt national urban policy and territorial plans to form dispersed cities, it could reduce transportation carbon emissions and promote sustainable development. For already urbanized countries, national urban policy development is recommended to promote spatially dispersed rather than polarized national urban systems.     

Identifying the European Fossil Fuel Plumes in the Atmosphere Over the Northeast Atlantic Region Through Isotopic Observations and Numerical Modelling

As part of the Danish NEAREX project the origin and variability of anthropogenic atmospheric CO₂ over the Northeast Atlantic Region (NEAR) has been studied. The project consisted of a combination of experimental and modelling activities. Local volunteers operated CO₂ sampling stations, built at University of Copenhagen, for ¹⁴C analysis at four locations (East Denmark, Shetland Isles, Faroe Isles and Iceland). The samples were only collected during winter periods of south-easterly winds in an attempt to trace air enriched in fossil-fuel derived CO₂ due to combustion of fossil fuels within European countries. In order to study the transport and concentration fields over the region in detail, a three-dimensional Eulerian hemispheric air pollution model has been extended to include the main anthropogenic sources for atmospheric CO₂. During the project period (1998–2001) only a few episodes of transport from Central Europe towards NEAR arose, which makes the data set for the evaluation of the method sparse. The analysed samples indicate that the signal for fossil CO₂, as expected, is largest (up to 3.7±0.4% fossil CO₂) at the Danish location closest to the European emissions areas and much weaker (up to ∼1.5±0.6% fossil CO₂) at the most remote location. As the anthropogenic signal is weak in the clean atmosphere over NEAR these numbers will, however, be very sensitive to the assumed background ¹⁴CO₂ activity and the precision of the measurements. The model simulations include the interplay between the driving processes from the emission into the boundary layer and the following horizontal/vertical mixing and atmospheric transport and are used to analyse the meteorological conditions leading to the observed events of high fossil CO₂ over NEAR. This information about the history of the air masses is essential if an observed signal is to be utilised for identifying and quantifying sources for fossil CO₂.     

中国水泥行业2011—2022年二氧化碳和大气污染物排放分析

2011—2021年,熟料产量呈波动上升趋势。水泥行业整体生产运行水平不断提高,熟料单条生产线平均规模由43.8万t/条提升至115.3万t/条,熟料单位产品综合能耗下降14.4%,熟料单位产品CO₂排放强度下降6.3%,但CO₂排放总量增加了13.8%,与氮氧化物减排趋势形成较大反差,碳污治理水平差距明显。熟料生产中石灰石分解和煤炭燃烧过程的CO₂排放合计占比为92.9%~93.8%,是CO₂排放的主要来源。由于熟料系数偏高、非碳酸盐原料替代不足、综合能耗仍然较高等原因,安徽等7个熟料产量大的省份的CO₂排放强度高于全国。建议实行碳酸盐熟料产量总量控制,逐步降低熟料应用比例,加快建材市场熟料产品和非碳酸盐原料替代,降低高标号水泥使用比例。应大力推广水泥行业节能降耗增效技术,加快熟料落后产能淘汰。对熟料产量大、碳排放强度高的地区,应结合当地碳排放特点,实行差别化降碳策略。各大气污染防治重点区域应因地施策推进水泥行业减污降碳工作。     

The Nexus Between CO2 Emissions and Genetically Modified Crops: a Perspective from Order Theory

Genetically modified crops (GMCs) and climate change have been two ecological issues intensely debated over the years. The search for global solutions to the effects of climate change on agriculture has led to the proposal of GMCs as a tool to reduce the environmental impact of agricultural practices and to improve their efficiency of production. At least 27 countries, all over the world, have cultivated GMCs. The purpose of the present paper is to provide insights about the possible linkages between the cultivated areas and the CO₂ emissions in these countries. In addition, the study intends to establish meaningful relationships between attributes related to the particular socio-economic situations and the environmental impacts of GMCs. Some examples are the connection between acreages of GMCs and the status of each country with respect to the Cartagena Protocol on Biosafety, as well as their classification according to the mean income per capita and their CO₂ emissions. In order to give the mathematical support to these links, the methodology known as Order Theory was employed. The results show that Paraguay, India, Burkina Faso, Brazil and Pakistan could be the best contributors to the mitigation of the climate change by the reduction of their CO₂ emission levels through GMCs.

     

Meta-Modeling to Assess the Possible Future of Paris Agreement

In the meta-modeling approach, one builds a numerically tractable dynamic optimization or game model in which the parameters are identified through statistical emulation of a detailed large scale numerical simulation model. In this paper, we show how this approach can be used to assess the economic impacts of possible climate policies compatible with the Paris Agreement. One indicates why it is appropriate to assume that an international carbon market, with emission rights given to different groups of countries will exist. One discusses the approach to evaluate correctly abatement costs and welfare losses incurred by different groups of countries when implementing climate policies. Finally, using a recently proposed meta-model of game with a coupled constraint on a cumulative CO₂ emissions budget, we assess several new scenarios for possible fair burden sharing in climate policies compatible with the Paris Agreement.     

An Oligopoly Game of CDR Strategy Deployment in a Steady-State Net-Zero Emission Climate Regime

In this paper, we propose a simple oligopoly game model to represent the interactions between coalitions of countries in deploying carbon dioxide removal (CDR) strategies in a steady-state net-zero emission climate regime that could take place by the end of the twenty-first century. The emission quotas and CDR activities obtained in the solution of this steady-state model could then be used as a target for end-of-period conditions in a dynamic integrated assessment analysis studying the transition to 2100. More precisely, we analyze a steady-state situation where m coalitions exist and behave as m players in a game of supplying emission rights on an international emission trading system. The quotas supplied by a coalition must correspond to the amount of CO₂ captured through CDR activities in the corresponding world region. We use an extension of the computable general equilibrium model GEMINI-E3 to calibrate the payoff functions and compute an equilibrium solution in the noncooperative game.

     

夏季上海城区大气中二氧化碳浓度特征及相关因素分析

利用连续自动监测仪器,获得CO2源区上海城区2010年夏季高时间分辨率的CO2连续监测数据.监测期间CO2平均浓度为414±16ppm,高于同期全球本底观测站约6%,与中国其他城市化地区的浓度水平基本相当或略低.CO2浓度日变化呈显著早晚双峰特征;周变化呈显著的波浪形,高值集中出现在工作日.除O3外,与其他污染物呈显著...     

Modelling of Materials Policies

This paper discusses the REAP1 model and its application for the analysis of CO₂ reduction and waste management policies for Japanese petrochemicals. The pros and cons of this modelling approach in comparison to other tools is elaborated. This is followed by a discussion of the model code and the modelling results. The results show that CO₂ policies can have significant impacts on waste flows and waste policies can have significant CO₂ benefits. As a consequence both effects must be considered in policy assessment. Pricing instruments are recommended instead of regulations because of the complex physical relations in the materials life cycle that extend beyond sector boundaries. A taxation approach is superior to a subsidy approach because rebound effects can be avoided.     

Energy forecasting and atmospheric CO2 perspectives: two worlds ignore each other

Macroeconomic models predict that the global primary energy demand will increase by a factor of 2–4 by the year 2050. In contrast, climate analyses made by the IPCC claim that CO₂ emissions in 2050 should not exceed the values of 1990 or even be 20% lower. By 2100 emissions should be reduced to one third of the present value. The common wisdom to deal with these opposing trends is the concept of de-carbonization, i.e., the continuous decrease of the carbon emission per unit energy utilization. De-carbonization rates needed to compensate for the growing demand while keeping the CO₂-emissions constant should at least be 2% per year compared to actual values of 0.3%. The potential of different de-carbonization rate measures is analyzed. It is argued that the goal can only be met if per capita energy utilization in the industrialized countries is significantly reduced from their typical level of 5000–10 000 W. As a realistic target we suggest 2000 Watt per capita, the present global average. This would leave expansion capacity for the developing countries which presently have per capita demand between 300 and 1000 W. Based on the example of Switzerland it is shown that the two key issues to attain this goal are the quality of buildings and the demand for mobility. It is concluded that the conversion of the present energy system into a 2000 W system is neither limited by technology nor by finances but by the acceptance of a new life style in which energy is used more efficiently and more intelligently than today. This revised version was published online in July 2006 with corrections to the Cover Date.     

CO2 Capture and Storage with Leakage in an Energy-Climate Model

Geological CO₂ capture and storage (CCS) is among the main near-term contenders for addressing the problem of global climate change. Even in a baseline scenario, with no comprehensive international climate policy, a moderate level of CCS technology is expected to be deployed, given the economic benefits associated with enhanced oil and gas recovery. With stringent climate change control, CCS technologies will probably be installed on an industrial scale. Geologically stored CO₂, however, may leak back to the atmosphere, which could render CCS ineffective as climate change reduction option. This article presents a long-term energy scenario study for Europe, in which we assess the significance for climate policy making of leakage of CO₂ artificially stored in underground geological formations. A detailed sensitivity analysis is performed for the CO₂ leakage rate with the bottom-up energy systems model MARKAL, enriched for this purpose with a large set of CO₂ capture technologies (in the power sector, industry, and for the production of hydrogen) and storage options (among which enhanced oil and gas recovery, enhanced coal bed methane recovery, depleted fossil fuel fields, and aquifers). Through a series of model runs, we confirm that a leakage rate of 0.1%/year seems acceptable for CCS to constitute a meaningful climate change mitigation option, whereas one of 1%/year is not. CCS is essentially no option to achieve CO₂ emission reductions when the leakage rate is as high as 1%/year, so more reductions need to be achieved through the use of renewables or nuclear power, or in sectors like industry and transport. We calculate that under strict climate control policy, the cumulative captured and geologically stored CO₂ by 2100 in the electricity sector, when the leakage rate is 0.1%/year, amounts to about 45,000 MtCO₂. Only a little over 10,000 MtCO₂ cumulative power-generation-related emissions are captured and stored underground by the end of the century when the leakage rate is 1%/year. Overall marginal CO₂ abatement costs increase from a few €/tCO₂ today to well over 150 €/tCO₂ in 2100, under an atmospheric CO₂ concentration constraint of 550 ppmv. Carbon costs in 2100 turn out to be about 40 €/tCO₂ higher when the annual leakage rate is 1%/year in comparison to when there is no CO₂ leakage. Irrespective of whether CCS deployment is affected by gradual CO₂ seepage, the annual welfare loss in Europe induced by the implementation of policies preventing “dangerous anthropogenic interference with the climate system” (under our assumption, implying a climate stabilisation target of 550 ppmv CO₂ concentration) remains below 0.5% of GDP during the entire century.

大气14CO2的加速器质谱分析技术研究进展

利用加速器质谱技术测定大气¹⁴CO₂以示踪大气化石源CO₂成为当前减污降碳工作的热点。该文从加速器质谱¹⁴C分析基础出发,系统介绍了加速器质谱的工作原理、大气样品的采集及纯化、石墨化样品的制备和测定,阐述了大气碳监测领域14 CO₂测试的研究进展。随着加速器质谱技术的不断发展,大气¹⁴CO₂的研究将会更加广泛和深入,有助于进一步认识大气化石源CO₂的来源,更有针对性地开展减污降碳工作。未来应统一制定¹⁴CO₂监测方法标准,规范操作流程和质控手段,完善实验仪器配套设施,加快提升监测能力和水平。     

Industrial point source CO<Subscript>2</Subscript> emission strength estimation with aircraft measurements and dispersion modelling

CO₂ remains the greenhouse gas that contributes most to anthropogenic global warming, and the evaluation of its emissions is of major interest to both research and regulatory purposes. Emission inventories generally provide quite reliable estimates of CO₂ emissions. However, because of intrinsic uncertainties associated with these estimates, it is of great importance to validate emission inventories against independent estimates. This paper describes an integrated approach combining aircraft measurements and a puff dispersion modelling framework by considering a CO₂ industrial point source, located in Biganos, France. CO₂ density measurements were obtained by applying the mass balance method, while CO₂ emission estimates were derived by implementing the CALMET/CALPUFF model chain. For the latter, three meteorological initializations were used: (i) WRF-modelled outputs initialized by ECMWF reanalyses; (ii) WRF-modelled outputs initialized by CFSR reanalyses and (iii) local in situ observations. Governmental inventorial data were used as reference for all applications. The strengths and weaknesses of the different approaches and how they affect emission estimation uncertainty were investigated. The mass balance based on aircraft measurements was quite succesful in capturing the point source emission strength (at worst with a 16% bias), while the accuracy of the dispersion modelling, markedly when using ECMWF initialization through the WRF model, was only slightly lower (estimation with an 18% bias). The analysis will help in highlighting some methodological best practices that can be used as guidelines for future experiments.     

Global warming implications of facade parameters: A life cycle assessment of residential buildings in Bahrain

On a global scale, the Gulf Corporation Council Countries (GCCC), including Bahrain, are amongst the top countries in terms of carbon dioxide emissions per capita. Building authority in Bahrain has set a target of 40% reduction of electricity consumption and associated CO₂ emissions to be achieved by using facade parameters. This work evaluates how the life cycle CO₂ emissions of buildings are affected by facade parameters. The main focus is placed on direct and indirect CO₂ emissions from three contributors, namely, chemical reactions during production processes (Pco₂), embodied energy (Eco₂) and operational energy (OPco₂). By means of the life cycle assessment (LCA) methodology, it has been possible to show that the greatest environmental impact occurs during the operational phase (80–90%). However, embodied CO₂ emissions are an important factor that needs to be brought into the systems used for appraisal of projects, and hence into the design decisions made in developing projects. The assessment shows that masonry blocks are responsible for 70–90% of the total CO₂ emissions of facade construction, mainly due to their physical characteristics. The highest Pco₂ emissions factors are those of window elements, particularly aluminium frames. However, their contribution of CO₂ emissions depends largely on the number and size of windows. Each square metre of glazing is able to increase the total CO₂ emissions by almost 30% when compared with the same areas of opaque walls. The use of autoclaved aerated concrete (AAC) walls reduces the total life cycle CO₂ emissions by almost 5.2% when compared with ordinary walls, while the use of thermal insulation with concrete wall reduces CO₂ emissions by 1.2%. The outcome of this work offers to the building industry a reliable indicator of the environmental impact of residential facade parameters.     

典型燃煤电厂机组二氧化碳排放测试及核算研究

为验证二氧化碳排放量的测试技术适用性及可行性,获取燃煤电厂机组碳排放特征,系统比较不同测试方法之间碳排放量的差异,对某典型火电机组二氧化碳排放开展测试,结果表明,不同测试原理及设备二氧化碳排放实测体积分数均较为接近。测试机组CO₂实测体积分数为11.28%～14.21%,与负荷变化呈一定的正相关关系,不同负荷下基准氧含量(体积分数6%)基本无变化。测试机组排放量与负荷正相关,使用了缺省值的指南排放量最高,与其他方法排放量相对偏差均值为31.6%;使用入炉煤实测数据的指南排放量差异不大,相对偏差为0.1%;使用入炉煤实测数据的2版指南排放量高于直接测量法,相对偏差均值为4.9%;直接测量各类方法间相对偏差均值为1.0%,其中在线法与手工法间相对偏差均值为1.2%。CO₂排放强度与负荷负相关,实验条件下,机组负荷越高,碳排放强度越低。     

Soil respiration,labile carbon pools,and enzyme activities as affected by tillage practices in a tropical rice–maize–cowpea cropping system

In order to identify the viable option of tillage practices in rice–maize–cowpea cropping system that could cut down soil carbon dioxide (CO₂) emission, sustain grain yield, and maintain better soil quality in tropical low land rice ecology soil respiration in terms of CO₂ emission, labile carbon (C) pools, water-stable aggregate C fractions, and enzymatic activities were investigated in a sandy clay loam soil. Soil respiration is the major pathway of gaseous C efflux from terrestrial systems and acts as an important index of ecosystem functioning. The CO₂–C emissions were quantified in between plants and rows throughout the year in rice–maize–cowpea cropping sequence both under conventional tillage (CT) and minimum tillage (MT) practices along with soil moisture and temperature. The CO₂–C emissions, as a whole, were 24 % higher in between plants than in rows, and were in the range of 23.4–78.1, 37.1–128.1, and 28.6–101.2 mg m^?2 h^?1 under CT and 10.7–60.3, 17.3–99.1, and 17.2–79.1 mg m^?2 h^?1 under MT in rice, maize, and cowpea, respectively. The CO₂–C emission was found highest under maize (44 %) followed by rice (33 %) and cowpea (23 %) irrespective of CT and MT practices. In CT system, the CO₂–C emission increased significantly by 37.1 % with respect to MT on cumulative annual basis including fallow. The CO₂–C emission per unit yield was at par in rice and cowpea signifying the beneficial effect of MT in maintaining soil quality and reduction of CO₂ emission. The microbial biomass C (MBC), readily mineralizable C (RMC), water-soluble C (WSC), and permanganate-oxidizable C (PMOC) were 19.4, 20.4, 39.5, and 15.1 % higher under MT than CT. The C contents in soil aggregate fraction were significantly higher in MT than CT. Soil enzymatic activities like, dehydrogenase, fluorescein diacetate, and β-glucosidase were significantly higher by 13.8, 15.4, and 27.4 % under MT compared to CT. The soil labile C pools, enzymatic activities, and heterotrophic microbial populations were in the order of maize?>?cowpea?>?rice, irrespective of the tillage treatments. Environmental sustainability point of view, minimum tillage practices in rice–maize–cowpea cropping system in tropical low land soil could be adopted to minimize CO₂–C emission, sustain yield, and maintain soil health.     

2022年春季南京臭氧污染特征及成因分析

2022年春季,受新一轮新冠疫情影响,长三角各城市采取了一系列管控措施,使得大气污染物排放水平降低。对2022年春季(3—5月)南京及长三角地区的六项污染物尤其是臭氧(O₃)的变化特征进行了分析,从气象因素和O₃前体物方面,同时利用基于观测的模型(OBM)对南京O₃污染变化原因进行了研究,并分析了南京挥发性有机物(VOCs)的关键活性组分和来源。结果表明:2022年春季,南京PM_2.5、PM₁₀、NO₂和CO均值浓度均同比下降,但O₃日最大8 h滑动平均质量浓度(O₃-8 h)同比上升19.8%,O₃-8 h超标时间同比增加9 d;长三角区域O₃-8 h同比上升17.9%,O₃-8 h超标天数为2021年同期的2.5倍。南京O₃浓度上升的原因:一方面是由于不利的气象条件,另一方面是由于南京O₃生成处于VOCs控制区,但氮氧化物(NO_x)降幅大于VOCs降幅,同时结合O₃前体物削减方案的分析结果发现,VOCs和NO_x不当的削减比例会导致O₃浓度不降反升。南京O₃生成的关键VOC活性物种依次为乙醛、丙烯、间/对二甲苯、丙烯醛和乙烯;正定矩阵因子分解(PMF)解析结果显示,机动车尾气是南京城区VOCs的主要来源,其次为液化石油气/天然气使用和石油化工。     

Institutional quality and environmental sustainability: The role of freedom of press in most freedom of press countries

Despite the fact that there are several attempts in the literature of environmental economics to identify the key determinants of environmental degradation particularly CO₂ emissions, little attention has been given to institutional factors, especially the influence of freedom of press has not been scrutinized. This study therefore is undertaking to close the gap and examine the impact of freedom of the press on CO₂ emissions. The study draws data from 10 countries indexed as the most freedom of press countries from 1993‐ to 2016 due to the availability of data on freedom of press and examines it using the technique of pooled mean group (PMG) belonging to the panel autoregressive distributed lag model. The study further applies the second generation techniques of cross-sectional dependence test, Westerlund cointegration-ECM test to account for cross-sectional dependence of the panel. The main finding of the study indicates that freedom of the press has the capacity to reduce CO₂ emissions in most freedom of press countries. In addition, the result confirms the existence of an inverted U-shaped curve between CO₂ emissions and per capita GDP, validating the environmental Kuznets curve (EKC) hypothesis. Energy use and foreign direct investment as control variables contribute to rising CO₂ emissions in most freedom of press countries. In this regards, the study recommends that freedom of the press should be improved upon through the channel of institutional quality, symmetry, efficiency and reputation effects in order to reduce the incidence of CO₂ emissions.     

Spatio-temporal variations of carbon dioxide and its gross emission regulated by artificial operation in a typical hydropower reservoir in China

Supersaturation and excess emission of greenhouse gases in freshwater reservoirs have received a great deal of attention in recent years. Although impoundment of reservoirs has been shown to contribute to the net emission of greenhouse gases, reservoir age, geographical distribution, submerged soil type and artificial regulation also have a great impact on their emissions. To examine how large scale reservoir operation impact the water column CO₂ and its air–water interface flux, a field study was conducted in 2010 to evaluate potential ecological processes that regulate the partial pressure of CO₂ (pCO₂) in the water column in the Pengxi River backwater area (PBA), a typical tributary in the Three Gorges Reservoir, China. Measurements of total alkalinity (TA), pH and water temperature were applied to compute the pCO₂. And this approach was also validated by calculation of pCO₂ from the dissolved inorganic carbon data of samples. Partial least squares (PLS) regression was used to determine how the dynamics of the water pCO₂ were related to the available variables. The estimated pCO₂ in our sample ranged from 26 to 4,087 μatm in the surface water. During low water operation from July to early September, there was an obvious pCO₂ stratification, and pCO₂ in the surface was almost unsaturated. This phenomenon was also observed in the spring bloom during discharge period. Conversely, there was no significant pCO₂ stratification and the entire water column was supersaturated during high water operation from November to the following February. Significant correlation was observed between the magnitude of pCO₂, DO and chlorophyll a, suggesting that phytoplankton dynamics regulate pCO₂ in the PBA. The average areal rate of CO₂ emissions from the Pengxi River ranged from 18.06 to 48.09 mmol m^?2 day^?1, with an estimated gross CO₂ emission from the water surface of 14–37 t day^?1 in this area in 2010. Photosynthesis and respiration rates by phytoplankton might be the dominant processes that regulated pCO₂ in the water column. We conclude that pCO₂ values in the surface water of Pengxi River could be regarded as potential sources of CO₂ to the atmosphere were smaller or similar to those that have been reported for many other reservoirs to date.