Increase In Carbon Emissions Research Articles

Carbon metabolism modelling and regulation in Beijing

Land use and cover change leads to significant increases in urban carbon emissions. Considering the insufficiency of spatially fine-grained management in previous carbon emission studies, this study integrated top-down and bottom-up methods to simulate urban carbon metabolism. Metabolic actors were allocated to grids based on land use and POI data and then attributed to districts. Results indicated that from 2000 to 2018, Beijing's Carbon Imbalance Index increased by 55.81% in 2010 and declined by 12.46%. Carbon emission dominated the changes in the Carbon Imbalance Index, with the Production and Supply of Electric Power actors consistently accounting for over 25.96%, while the contribution of Urban and Transportation actors reached 20.11% and 27.74% in 2018, respectively. The metabolic actors exhibited a gradient distribution pattern from southeast to northwest. Artificial actors' carbon emissions decreased from the center to the periphery and spread along the road network, with the High-High cluster in the southeast mainly contributed by Manufacturing (22.33%) and the Production and Supply of Electric Power (20.16%) actors. Spatial distribution changes of Natural actors mainly occurred in Daxing and Chaoyang districts, whose absorption area extended by 45% and 37.26%, respectively, contributing to an increase in carbon absorption by 2.47 and 0.15 times. The Semi-natural actor exhibited net carbon emissions, with the High-High cluster in the southeast zone contributing 60.96% of emissions in 2000. We also categorized Beijing into four Areas based on the relationship between carbon emission and absorption. Targeted policy recommendations were formulated for different districts and metabolic actors.

Globalization’s effects on South Asia’s carbon emissions, 1996–2019: a multidimensional panel data perspective via FGLS

Researchers and policymakers hold diverse opinions about the impact of globalization on environmental degradation. Over the past three decades, increased economic, social, and political interconnections have fueled this debate. However, prior studies have largely overlooked these facets of globalization concerning environmental implications, particularly carbon emissions in developing countries. We contribute to this discourse by examining how various aspects of globalization (economic, social, and political) and two specific measures, de facto and de jure trade, influenced carbon emissions in four selected South Asian countries from 1996 to 2019. The results obtained through feasible generalized least squares (FGLS) reveal that economic globalization increases carbon emissions while social and political globalization reduces them. These results further confirm that, in South Asia, the pollution haven hypothesis is associated only with economic globalization. In contrast, social and political globalization support the world polity theory, indicating potential for positive change. The results also show that both de facto and de jure measures of disaggregated globalization equally influence carbon emissions, suggesting a significant impact from policy interventions. For future environmental sustainability, the governments of these nations should intensify their efforts to strengthen social and political globalization. Meanwhile, the adverse effects of economic globalization can be mitigated by reducing reliance on fossil fuels and providing financial assistance to businesses to encourage the use of renewable energy and modern technology in production.

Reshaping water distribution topology from the carbon emission reduction perspective: An exploratory analysis of water distribution reliability

As urban economies continue to evolve, the water distribution networks (WDNs) are expanding in scale and becoming more interconnected, leading to increased carbon emissions from operations and maintenance. Consequently, enhancing the stability and safety of WDNs while saving energy has emerged as a primary research focus. This study abandoned the original use of high economic costs for post-maintenance of WDNs. Instead, it reshaped the traditional water distribution topology to form a dynamic, storable, energy-efficient "WDN self-help" model. Drawing inspiration from the "deep tunnel" project in drainage systems, the proposal was to leverage underground spaces to create a deep aqueduct (DA) complementing the traditional WDN, forming a three-dimensional (3D) WDN. Hydraulic and water quality analyses of varying scales of the 3D WDN model demonstrated its superior ability to equalize node pressures, reduce pipeline head losses, and maintain water quality for end-users. Reliability assessments of the 3D WDN revealed enhanced system robustness for medium-to large-scale distributions, while energy consumption analyses indicated a significant increase in water supply energy utilization and significant long-term reductions in carbon footprint. A practical case study was presented to validate the effectiveness of the 3D WDN concept, confirming its ability to reliably distribute water even in the event of a failure. Finally, an estimate of the retrofit cost and the static payback period of the 3D WDN was conducted. This study aims to provide a theoretical reference for the renovation of water supply projects or the optimal design of new WDNs in the context of carbon neutrality.

Spatial and Temporal Evolution Characteristics of Carbon Emission from Land Use and Influencing Factors in Gansu Province

Land ecosystems are the largest carbon sink in the world, and land use change is one of the main factors leading to regional carbon emissions. By studying the spatiotemporal evolution characteristics and influencing factors of land use carbon emissions in Gansu Province from 2000 to 2020, this research aimed to provide a scientific basis and reference for promoting low-carbon land use and low-carbon economic development in Gansu Province. Using land use data and the greenhouse gas emission coefficient method, the study analyzed the growth trend of land use carbon emissions at the city-regional scale in Gansu Province, and the spatiotemporal evolution characteristics at the provincial scale, and identified the controlling factors through principal component analysis. The results showed that： ① From 2000 to 2020, land use carbon emissions in Gansu Province showed an overall increasing trend, from 24.289 3 million tons to 57.739 6 million tons. The first stage from 2000 to 2014 was a significant increase period, whereas the second stage from 2014 to 2020 was a stable and slightly decreasing period. Construction land was the main carbon source, and the carbon intensity continued to increase. ② Spatially, there was an "east high, west low" pattern, with carbon emissions in the eastern part of the province significantly higher than those in the western part. ③ Based on emission characteristics, Gansu Province could be divided into five types of carbon emission zones： slow growth, relatively slow growth, moderate growth, relatively fast growth, and rapid growth. ④ The main reasons for the continuous increase in land use carbon emissions in Gansu Province were economic development level, degree of land use, and energy consumption.

Analysis of Spatiotemporal Differences and Influencing Factors of Land Use Carbon Emissions in Ningxia

Analyzing the spatiotemporal differences in land use carbon emissions systematically and exploring their influencing factors for the rational allocation of land resources is of great importance and promoting collaborative emission reduction in this region. Based on the calculation of land use carbon emissions in Ningxia and its prefecture-level cities from 2000 to 2021, the regional differences in carbon emissions, economic efficiency, and carbon sink capacity were reflected through the difference index, carbon emission intensity, economic contribution rate, and carbon sink ecological carrying capacity. The results were as follows： ① From 2000 to 2021, the land use carbon emissions in Ningxia showed a significant increase by 110 919 400 t. Construction land was the main carbon source land, accounting for 99.57% of the total carbon emissions in 2021, and forest land was the main type of carbon absorption, accounting for 79.22% of the total carbon absorption in 2021. ② During the research period, the carbon emission difference among prefecture-level cities showed a trend of first rising and then slightly falling, with the gap reaching the maximum in 2016. ③ Although the overall difference in carbon emission intensity among prefecture-level cities showed a trend of narrowing and convergence, the economic contribution coefficient and carbon sink ecological carrying coefficient had significant differences, and the economic contribution rate and carbon emission contribution rate were both in a relatively unbalanced state, with obvious regional differences. ④ Land use carbon emission intensity, land use structure, economic development level, and population all played a promoting role in land use carbon emission, with contribution rates of 56.48%, 41.27%, 85.20%, and 9.29%, respectively. The contribution value of land use carbon intensity per unit GDP was negative, which inhibited the increase of land use carbon emission.

Assessing Carbon Capture and Carbonation in Recycled Concrete Aggregates: A Holistic Life Cycle Assessment Perspective with Simulation at Industrial Scale

This work explores a life cycle assessment (LCA) concerning carbon capture and carbonation of recycled concrete aggregates (RCA), addressing the growing challenges posed by increased carbon emissions in power generation and ecological concerns tied to construction waste. We propose an integrated solution involving the capture of low-concentration carbon dioxide (CO2) from natural gas combined cycle (NGCC) power plants through aqueous ammonia absorption and sequestration by mineralization of RCA. The cradle-to-gate LCA focuses on an industrial-scale scenario for capturing 200 kilotonnes of CO2 annually, with functional unit per tonne of carbonated RCA output. The findings reveal a net positive carbon abatement of 21.42 kg CO2 eq., with heat production and electricity consumption being the major contributors to global warming potential (GWP). Within the spectrum of environmental impact categories under study, Marine Aquatic Ecotoxicity Potential (MAETP) exhibits a significant impact, primarily influenced by sulfur production. Human Toxicity Potential (HTP) follows as the second-worst contributor, with 96.80% of its impact attributed to heat and sulfur production. Subsequently, Acidification Potential (AP) follows, arising from sulfur and sulfuric acid production. Sensitivity analysis and Monte Carlo simulation introduce a ±20% standard deviation to electricity and thermal energy consumption. Scenario analysis demonstrates a net carbon-positive abatement potential of 286.66 kg CO2 eq. per tonne of CO2 input. Employing carbon mineralization for CO2 capture not only reduces emissions but also repurposes waste materials, providing a comprehensive and sustainable solution for effective CO2 management, contributing to reduced sand mining, and offering cost advantages through the production of carbonated RCA.

High-speed railways reduces carbon emissions: mediating effects of green innovation and the resilience of environmental investment

High-speed rails (HSRs) are a sustainable approach in many cities. Although some studies recognize that introducing HSR is negatively related to carbon emissions, explorations of the mechanisms underlying this relationship remain scarce. The main purpose of this study is to investigate whether introducing HSR reduces carbon emissions through increasing green innovation (GI) and the resilience of environmental investment (REI). Employing signal theory and fault tolerance theory, among others, we propose models that illuminate how inaugurating HSRs reduces carbon emissions through GI and REI. Our proposed central hypothesis is that GI and REI mediate carbon emission reduction by introducing HSR. In this study, we used the data from 284 China’s cities during 2000-2021 and examined our hypothesis via a difference-in-differences (DID) model. The results show that introducing HSR reduces carbon emissions through GI and REI. On the basis of the current status of China’s economic and social development, we further analyze several critical moderating effects, such as the digital economy, the urban‒rural gap, and whether it is a resource-based city. In 2023, China’s Central Economic Work Conference (CEWC) explicitly proposed “developing the digital economy.” We find that the digital economy strengthens the negative relationship between introducing HSRs and carbon emissions. The digital economy also strengthens the positive correlation between the introduction of HSR and GI. Additionally, this strengthens the positive correlation between HSRs and REI. In addition, the urban‒rural disparity is a manifestation of China’s uneven development. We find that the urban‒rural disparity weakens the relationship between HSRs and carbon emissions. In addition, China’s resource-based cities lag behind other cities. Our findings suggest that, in contrast to other cities, high-speed rails increase carbon emissions in resource-based cities.

Mechanical, freeze-thaw resistance and heavy metals leaching properties of alkali-activated recycled concrete powder solidified sludge

Solidified sludge was an efficient method to consume the large amount of sludge, which can be used as the subgrade filler in road engineering. However, the traditional solidified materials, such as cement and lime, consumed a large amount of natural resources and increased carbon emissions. This study used the alkali-activated recycled concrete powder (ARCP) to solidify sludge, which could be used as a potential subgrade stabilization filler. The optimal factors of ARCP were firstly determined by orthogonal test according to the compressive strength. Then the influences of different ARCP dosage, sludge moisture content and curing method on the mechanical properties, freeze-thaw resistance and heavy metals immobilization of the ARCP solidified sludge (ARCPS) were investigated. At last, microstructures of ARCPS were analyzed by SEM, XRD and TG-DTG tests. The experimental results demonstrated that the optimal mixture for ARCP: the silicate modulus of 1, liquid-solid ratio of 0.48 and calcium hydroxide content of 3 %. The solidified process by ARCP improved the mechanical properties and freeze-thaw resistance of ARCPS greatly. The 7 d unconfined compressive strength of ARCPS could reach 1305–2033 kPa when the sludge moisture content was 15 %, which meet the requirement of 500 kPa from the Chinese standard. The frost heaving rates of ARCPS were between non-frost heaving and mild frost heaving. The sludge moisture content was the most important factor affecting the freeze-thaw resistance of ARCPS. The properties of ARCPS were further improved after carbonation curing. The leaching mass concentration of heavy metals decreased significantly after the solidification of sludge. After 5 freeze-thaw cycles, the heavy metal leaching concentration increased but was still met the requirement of standards. SEM results showed that the surface of carbonated ARCPS was covered by dense scale-like carbonation products, which further enhanced the strength and freeze-thaw resistance of ARCPS. The results can be used to guide the application of sludge and ARCP in construction.

Research and analysis of urban-rural residential carbon emissions in China

Residential carbon emissions are an important component of anthropogenic carbon emissions. a significant increase in residential carbon emissions has become a reality under the global urbanization process. In this context, this paper built a feature combination value model based on NPP-VIIRS nighttime light remote sensing data, and divided urban-rural areas through breakpoint analysis method and reference comparison method. Then, explored the characteristics and differences of residential carbon emissions and per capita residential carbon emissions in nine different levels of cities in 2019 from the perspective of urban-rural areas. The results indicate that the residential carbon emissions and per capita residential carbon emissions shows the spatial distribution characteristics of first tier cities>second tier cities>third tier cities. Among them, the residential carbon emissions in Beijing, Guangzhou, Nanjing, Taiyuan show a distribution pattern of urban>urban-rural fringe>rural. The residential carbon emissions in Shijiazhuang, Wuxi, Xiangyang, Zunyi, Huai’an show a distribution pattern of rural>urban-rural fringe>urban. The per capita residential carbon emissions of urban areas are relatively low, while the per capita residential carbon emissions of rural areas are relatively high, show a distribution pattern of rural>urban-rural fringe >urban. The results can help the Chinese government balance the needs of urban-rural development in different levels of cities, so as to formulate targeted carbon emission reduction policies and achieve low-carbon goals.

Can the Development of Renewable Energy Improve Total-Factor Carbon Emissions Efficiency? Evidence from 30 Provinces in China

Abstract The global temperature is exceeding 1.5°C above pre-industrial levels due to the increasing carbon emissions, and developing renewable energy is expected to be one of the most effective solutions. However, whether the development of renewable energy contributes to curbing the carbon emissions while maintaining economic development is still under investigation. Using the total-factor carbon emission efficiency (TFCEE), this paper first measures the carbon emission abatement and economic development of 30 provinces in China from 2005 to 2019. Then, based on the super-efficiency slacks-based measure (SE-SBM) model, the panel threshold models and spatial Durbin models are established to comprehensively investigate the impact of RED on TFCEE. The findings reveal that: (1) RED significantly improves TFCEE. For every 1% increase in RED, TFCEE experiences a rise ranging from 0.020% to 0.035%. (2) The beneficial effect of RED on TFCEE increases with economic restructuring and technological progress. (3) The indirect impact of RED on TFCEE through spatial spillover is significantly greater than its direct effect. Potential transmission mechanisms for this spatial spillover effect are the cross-regional mobilization of renewable electricity and the diffusion and absorption of low-carbon knowledge and technologies. The above conclusions provide empirical evidence for China and other developing countries to formulate appropriate energy transformation strategies. Keywords: Renewable energy development; Total-factor carbon emissions efficiency; Transmission mechanism; Spatial spillover effect; Nonlinear effect.

Green investment and its transformative impact on energy use in agriculture: A holistic approach towards carbon dioxide emissions

The extensive use of non-renewable energy sources in agriculture and associated unsustainable practices have contributed greatly to climate change issues. Africa's lack of green initiatives has exacerbated environmental pollution in the last decade. In that regard, this study investigates the transformative impact of green investment on carbon emissions in agriculture fueled by dependency on non-renewable energy use in the sector. It utilizes advanced econometric techniques, including dynamic ordinary least squares, fully modified ordinary least squares, and the causality tests to conduct a rigorous analysis. The findings reveal a concerning rise in agricultural pollution via crop and livestock production. However, green investment is found to have a positive impact on carbon dioxide emissions, hence a potent tool for significantly reducing carbon emissions. The causality analysis unveils a bidirectional causal relationship between green investment and agricultural pollution and a unidirectional causality between green investment and carbon emissions, shedding light on the complex interplay between these variables. Also, non-renewable energy is found to increase carbon emissions in the region. The outcomes of this research contribute valuable insights and lay a foundation for future research and policymakers to enhance the future of agricultural research and sustainability. It also offers a roadmap for developing effective policies that balance the immediate needs of the agricultural sector with the imperative of long-term environmental sustainability. Finally, it has a global significance on the relevance of green initiatives to boost sustainable agriculture and reduce pollution.

Analytical Study on Reducing the Heating Effects of Daylight and Improving Natural Lighting Performance at Erzincan Train Station in the Context of Climate Change

Climate change is an environmental issue that is rapidly escalating due to the effects of global warming. The increase in carbon emissions, along with various human activities such as industrial processes, land use changes, and the reckless consumption of natural resources, are among the primary causes of global warming. Various architectural interventions are being implemented in historical buildings to mitigate the impact of global warming and its consequence, climate change. The study aims to protect the historical building from the harmful effects of climate change by reducing the heating effects of direct sunlight during the summer and enhancing the efficiency of natural lighting throughout the day. In this context, the Erzincan Train Station is located in Erzincan in Eastern Anatolia. Erzincan is one of the most affected by the climate change crisis has been selected for the study. The plans of the Erzincan Train Station were digitized using AutoCAD software and subsequently modeled in three dimensions using Revit software. Daylight analysis was conducted on the created model using the Insight plugin in Revit software. The analysis determined that recommendations should be made for the building's south facade. Based on the climate data of Erzincan province and the conducted analyses, the light shelf system was designed and implemented due to its applicability, shading, and lighting advantages among daylighting systems. The effects of the proposed system were examined using spatial daylight autonomy (sDA) and annual sunlight exposure (ASE) daylight metrics according to LEED v4 EQc7 standards. The study found that the light shelf system resulted in a 5% reduction in ASE values building-wide and a 6% reduction in the average values of specific areas while increasing sDA values. In this context, it has been observed that areas experiencing a decrease in direct sunlight exposure (ASE values) also show an increase in sufficient daylight exposure (sDA values), which could contribute to improving the building's energy performance.

A distribution network carbon metering method and user carbon emission characterization method considering the influence of harmonics

Abstract This paper presents a novel carbon metering method for distribution grids that fully considers the impact of harmonics on the grid. Harmonics are sinusoidal waves with frequencies that are integer multiples of the fundamental frequency, and the presence of harmonics can lead to power losses, damage to equipment and degradation of power quality, thus increasing carbon emissions from the grid. Currently available carbon measurement methods often do not take this into account, so a more accurate method is needed to assess the carbon emissions of distribution grids. This new method, based on the carbon flow theory of trending power distribution, combines harmonic energy correction and node carbon potential correction, and is able to accurately calculate the carbon emissions as well as the harmonic carbon correction for each node and branch in the distribution network. In order to evaluate the carbon behavior characteristics of users more comprehensively, the study also adopts the DTW-K-Means clustering technique to group distribution network users. This innovative approach provides an effective technical means and theoretical basis for the monitoring, assessment and management of distribution network carbon emissions. This innovative method provides effective technical means and theoretical basis for distribution network carbon emission monitoring, assessment and management, not only considering the impact of harmonics on power metering, but also more accurately portraying the carbon behavior of users, which is expected to provide strong support for the reduction of grid carbon emissions.

How does enterprise digitalization affect corporate carbon emission in China: A firm-level study

This paper develops a theoretical framework to examine the influence of enterprise digitalization on corporate carbon emissions. Then it empirically measures the extent of digitalization in Chinese enterprises through their share of intermediate inputs to their value added from information and communication technologies. Data from the China Enterprise Tax Surveys and Inter-Country Input-Output Tables from 2007 to 2016 are used for the empirical analysis. It is noted that digitalization in enterprise manufacturing leads to an increase in corporate carbon emissions (CCE). The impact from the service sector, however, is not significant. The exacerbation of CCE is observed primarily among low-leverage enterprises, downstream industries, and firms located in relatively lower-income regions. In accordance with the theoretical model, it is observed that enterprise digitalization intensifies CCE by crowding out investment in environmentally friendly green production and by altering production patterns towards mass production. However, an efficient market mechanism effectively mitigates this exacerbation effect. The findings reveal the misalignment of enterprise digitalization transformation modes with long-term “low carbon” objectives, thereby exposing the need for appropriate policy interventions.

Geo-political risks, uncertainty, financial development, renewable energy, and carbon intensity: Empirical evidence from countries at high geo-political risks

Geopolitical risks and uncertainty negatively affect the economy and environmental quality. High geopolitical risks and high uncertainty increase carbon emission intensity by increasing dependence on fossil fuels. However, research in this area is still in its infancy and more empirical evidence is needed to justify the causal link. This research examines the causal mechanism linking geopolitical risk, uncertainty, financial development, renewable energy, and carbon intensity in a sample of eighteen countries with high geopolitical risk between 1985 and 2021. The selected countries have a high intensity of geopolitical risks due to internal and external conflicts that have worsened in recent years. We employ cointegration techniques from Hatemi-J [1] and Maki [2] in the presence of structural breaks, fully modified ordinary least squares (FMOLS), canonical cointegration regression (CCR) models, and static time-variant Granger causality (1969) test. We find robust empirical evidence that geopolitical risk, financial development, renewable energy, uncertainty, and carbon intensity have a cointegrating relationship in the presence of structural breaks. Results from FMOLS and CCR models indicate that carbon intensity responds differently to changes in geopolitical risk, renewable energy, uncertainty, and financial development. Environmental and energy policymakers should mitigate carbon intensity through long-run rather than short-run mechanisms to achieve SDG12 and SDG13.

Exploring the diffusion of low-carbon power generation and energy storage technologies under electricity market reform in China: An agent-based modeling framework for power sector

Promoting the widespread adoption of multi-complementary low carbon power generation technologies is a fundamental strategy for attaining carbon neutrality within the electricity sector. In the context of electricity market reform, this study develops an agent-based modeling framework integrated simulation with optimization. The model uses agent-based simulation to analyze annual market dynamics and low-carbon technology diffusion, with a two-stage optimization for energy storage and spot market simulation. The research findings indicate: (1) For different power generation technologies, the spot market can establish differentiated average prices, making the market price of carbon-captured coal power higher than that of conventional coal power, which are advantageous in reducing the subsidies required to promote the diffusion of carbon capture technology. (2) Expanding the spot market scale and implementing differentiated capacity compensation mechanisms both promote carbon capture technology diffusion. Nevertheless, with the marginal clearing mechanism, thermal power holds a average price advantage than renewable energy. Failing to control the growth of thermal power capacity will result in increased carbon emissions. (3) After 2030, energy storage's role in balancing supply and demand grows. Storage capacity should align with renewable energy scale and the regional characteristics of wind and solar resources to prevent overbuilding and stranded assets.

Exploring carbon storage and sequestration as affected by land use/land cover changes toward achieving sustainable development goals

Understanding the impact of changes in land use/land cover (LULC) on carbon sequestration (Cseq) and emission leads to achieving sustainable development goals (SDGs). For this, Business-As-Usual (BAU) and Sustainable Development (SD) scenarios were examined in Azarshar city, Iran which is faced with urban intensification. The spatiotemporal dynamics of the carbon cycle and influences of various urban growth indicators are still unclear even under climate change, rapid urbanization, and ecological deterioration. In this research, total carbon storage (Cts) and Cseq were determined at four carbon pools i.e., aboveground carbon (AGC), belowground carbon (BGC), dead organic carbon (DeOC), and soil organic carbon (SOC). This research revealed a successful implementation of integrated CA-Markov and InVEST models in delineating LULC changes between 2013 and 2033. It was concluded that land resources management play a crucial role in decreasing Cseq along with increasing carbon emission across the study area. The modelling results showed a significant shifting from barren and cropland to developed land uses. This research goes beyond providing supporting evidence that urban expansion is a key factor driving the aforementioned changes, but also illustrates the importance of remote sensing in ecological modelling, especially where information is sparse.

Dynamic evolution of particulate and gaseous emissions for typical residential coal combustion

Residential coal combustion still accounts for half of the heating energy consumption in many developing countries. The dynamic variation during the combustion process importantly determines the combustion facility design and appropriate air quality assessment, which was omitted in conventional studies. This study investigated the emissions of particulate and gaseous pollutants during the combustion process for typical coal types using online monitoring. During the first pyrolysis stage with temperature climbing, the organic aerosols (OA) and gases reached peak concentration. The second fierce combustion stage had the highest temperature and produced the highest cumulative emissions, particularly a substantial amount of black carbon for coals with higher volatile content. Using higher-quality coals will undoubtedly reduce PM emissions, by a factor of 10 from bituminous to anthracite coal. However, more ultrafine particles (d < 0.1 μm) from cleaner coal may pose additional health risks. Anthracite and honeycomb coal had approximately twice the energy content and emitted more CO2 per unit mass of fuel and had more persistent SO2 emissions throughout the burnout stage. The oxygenation of OA and organic gases remained increased during combustion, suggesting the pyrolysis products underwent oxidation before being emitted. The investigation of the coal combustion process suggests the importance of reducing volatiles to control PM emissions, but the potential negative synergistic effects between PM reduction and increased carbon emissions should also be considered.

Towards sustainable building landscapes: a spatially explicit life-cycle analysis of carbon emissions and mitigation strategies

ContextThe urban landscape plays a crucial role in achieving sustainability goals and aspiring to a zero-emission future. Effective carbon mitigation strategies need a spatially explicit and life-cycle analysis of building emissions, detailed mapping highlights the geographical distribution and specific characteristics of buildings, enabling precise identification and targeted management of emission sources.ObjectivesThis study aims to create a framework that reveals the spatial and temporal dimensions of building carbon emissions at each stage of their life cycle.MethodsWe developed a comprehensive approach for carbon accounting in buildings. This framework captures spatiotemporal carbon emission patterns across various building types, considering material, energy, and waste flows. It also identifies potential mitigation strategies within the urban building landscape.ResultsApplying this framework to a case study in Shenzhen, we observed a fluctuating increase in total carbon emissions, peaking at 201.5 Mt in 2016 and subsequently declining. Embodied emissions dominated before the twenty-first century, while operational emissions became significant afterward. Spatially, emissions hotspots concentrated in central urban districts, expanding outward, with residential buildings contributing the most. Scenario analysis revealed that extending building lifetimes is a key strategy for mitigating embodied carbon, while improving energy efficiency and adopting clean energy work well together to reduce operational carbon.ConclusionsMapping the spatiotemporal patterns of carbon emissions throughout a building’s lifespan can assist urban planners and policymakers in formulating targeted strategies for carbon reduction, thereby enhancing urban sustainability.

When green transportation backfires: High-speed rail's impact on transport-sector carbon emissions from 315 Chinese cities

High-speed rail is often viewed as a green transportation mode, substituting for carbon-intensive vehicular and aviation trips. However, its potential to induce additional travel demand and transport-sector carbon emissions has been largely overlooked. Here, we empirically examine the impacts of high-speed rail accessibility, the ease with which one city can reach other cities via the high-speed rail network, on transport-sector carbon emissions across 315 Chinese cities between 2010 and 2020, using a two-stage least squares model. Contrary to the anticipated emission-reduction effect, our analysis suggests a net positive impact of high-speed rail on transport-sector carbon emissions. Specifically, a 1% increase in high-speed rail accessibility leads to a 0.18% increase in transport-sector carbon emissions in the long run, as carbon emissions generated from induced travel demand have outweighed the carbon savings from substitution for carbon-intensive inter-city trips. This high-speed rail-induced increase in carbon emissions is observed in the road transport subsector, while the aviation subsector exhibits a compensatory reduction. Moreover, we find that integrating the high-speed rail network into local subway systems can curb the emission-intensifying effect, highlighting the importance of joint public transit planning. This study reveals an unexpected environmental impact of high-speed rail, conveying valuable insights into transport-sector decarbonization.