High Greenhouse Gas Research Articles

Spatial and temporal variability in summertime dissolved carbon dioxide and methane in temperate ponds and shallow lakes

AbstractSmall waterbodies have potentially high greenhouse gas emissions relative to their small footprint on the landscape, although there is high uncertainty in model estimates. Scaling their carbon dioxide (CO2) and methane (CH4) exchange with the atmosphere remains challenging due to an incomplete understanding and characterization of spatial and temporal variability in CO2 and CH4. Here, we measured partial pressures of CO2 (pCO2) and CH4 (pCH4) across 30 ponds and shallow lakes during summer in temperate regions of Europe and North America. We sampled each waterbody in three locations at three times during the growing season, and tested which physical, chemical, and biological characteristics related to the means and variability of pCO2 and pCH4 in space and time. Summer means of pCO2 and pCH4 were inversely related to waterbody size and positively related to floating vegetative cover; pCO2 was also positively related to dissolved phosphorus. Temporal variability in partial pressure in both gases weas greater than spatial variability. Although sampling on a single date was likely to misestimate mean seasonal pCO2 by up to 26%, mean seasonal pCH4 could be misestimated by up to 64.5%. Shallower systems displayed the most temporal variability in pCH4 and waterbodies with more vegetation cover had lower temporal variability. Inland waters remain one of the most uncertain components of the global carbon budget; understanding spatial and temporal variability will ultimately help us to constrain our estimates and inform research priorities.

Measuring and managing for environmental sustainability. An application of the Environmental Sustainability Gap (ESGAP) framework in New Caledonia

Environmental policymakers need to monitor the state of the environment to evaluate the effectiveness of their actions, prioritize policies, and thus establish their contribution to the conservation of natural capital. The Environmental Sustainability GAP (ESGAP) is a framework that introduces a synthetic dashboard to monitor the state of the environment from a strong sustainability perspective, adopting stringent criteria on the maintenance of critical natural capital. This article focuses on the implementation of the ESGAP framework in New Caledonia, a developing economy heavily dependent on natural capital. The results highlight sustainability issues that require policy attention and methodological challenges about the construction of sustainability indicators. The strong environmental sustainability index score obtained is 43/100. This value is mainly driven downwards by high greenhouse gas emissions, and the impact of fire on ecosystems in New Caledonia. Both are moving away from the strong environmental sustainability objectives over the years, indicating a worsening situation. The ESGAP provides a holistic view on sustainability that was previously lacking, thus informing environmental management and policies. This study also identifies gaps in environmental monitoring and needs in the setting of objectives, as well as the cost of reaching them.

Analysis of climate extremes indices in tropical South America through the RegCM4.7

AbstractIn recent decades, the frequency and intensity of extreme weather events induced by global warming have increased significantly, exerting serious impacts on the development of society and ecosystems. Based on low (RCP2.6) and high (RCP8.5) greenhouse gas emissions scenarios from the Intergovernmental Panel on Climate Change, we use the general circulation model HadGEM2‐ES that is part of the Coupled Model Intercomparison Project Phase 5 (CMIP5) to drive the regional climate model RegCM4.7. This study evaluated the ability of both models to simulate (1986–2005) and projection (2080–2099) spatio‐temporal features of extreme indices over tropical South America (TSA). Indices based on precipitation and daily maximum and minimum temperature follow the definitions of the Expert Team on Climate Change Detection and Indices (ETCCDI). In general, the RegCM4.7 reproduces accordingly the spatial distribution of the ETCCDI indices derived from precipitation and temperature on the TSA, in addition to added value to HadGEM2‐ES, especially over regions of complex topography. HadGEM2‐ES performs poorly along the west coast, due to the topography and altitude of the Andes. On the other hand, it demonstrates better performance in the Amazon Basin compared to RegCM4.7. The projection results showed that climate extreme indices based on precipitation and temperature indicate that drought events may advance to the end of the century, showing a spatial pattern that precipitation will be gradually reduced in the Amazon Basin and Northeast region of Brazil. Despite some discrepancies between the models, studies like this one help us to understand how climate change can affect regional planning and development.

Municipal Solid Waste Management towards Climate Neutrality

In line with the European Union’s move and the Green Deal initiative, Latvia needs to reduce CO2 emissions by 2030 and reach their complete elimination by 2050. Since waste management sector is associated with high greenhouse gas emissions, the sector will experience changes in the near future, and its sustainable development is linked to overcoming technical, economic and environmental challenges. The work aims to find solutions to the development of the waste sector in an environmentally sound manner, ensuring that the sector is closer to climate neutrality in 2050. Waste management is at the forefront of major changes and challenges in achieving regulatory objectives. In view of the changes expected and taking place in the sector, it is essential to carry out studies on resource and material recovery optimization options and potential for waste streams to be recycled and the energy recovery potential for non-recyclable streams. Acquiring knowledge and raising awareness of the role of changing management practices in saving CO2 emissions – avoided emissions – will allow the sector to move towards climate neutrality. This article analyses biodegradable waste management options and proposes the optimal solution for biodegradable waste management towards climate neutrality.

Carbon sink and greenhouse gas emission of dryland vegetation cover in tourism villages in Flores Island, East Nusa Tenggara, Indonesia

Abstract. Lestari F, Tua IN, Muzanni A, Nugroho DF, Wibowo AA, Wartono T, Widanarko B, Saepullah A, Modjo R, Farida M, Erwandi D, Aryani DD, Kadir A, Widiatmoko AI, Hendra, Herwanto ZJ, Tejamaya M, Hamid RA, Fatmah, Gunawan EL, Setyowati DL, Hafids MF, Yuliani R. 2023. Carbon sink and greenhouse gas emission of dryland vegetation cover in tourism villages in Flores Island, East Nusa Tenggara, Indonesia. Biodiversitas 24: 1998-2005. Due to its natural features and scenery, the dryland ecosystem has recently become a tourist destination. One of the growing dryland ecosystems for village tourism is Flores Island, East Nusa Tenggara, Indonesia. Those tourism villages have the potential to promote carbon sequestration through the preservation of natural resources and, at the same time, can release Green-House Gases (GHG). Despite growing research on carbon stock, there is little information on the carbon budget of a dryland tourism village, which includes the values of carbon stock sequestered from the atmosphere and greenhouse gas emissions. This research aimed to measure the carbon stock and GHG emissions in three villages containing paddy fields, savanna, and forest covers. The measured gases, including CO2, CH4, and N2O, were collected using the gas chamber method and analyzed using gas chromatography. The result shows that forest land covers have the highest carbon stock, with average values of 97.44 Mg ha-1 within the 57.34-117.5 Mg ha-1. A low average carbon stock of 17.39 Mg ha-1 was observed in paddy fields. The GHG was in the order of CO2 > CH4 > N2O. The paddy field has higher GHG than other land covers, with average CO2, CH4, and N2O values of 292.45 ppm, 1.35 ppm, and 1.09 ppm. While CO2, CH4, and N2O values for the forest were 281.05 ppm, 1.30 ppm, 1.05 ppm, 272.83 ppm, 1.26 ppm, and 1.02 ppm for savanna covers.

Contribution of anthropogenic pollutant sources to greenhouse gas emissions: a case study from a developing country.

Anthropogenic greenhouse gas (GHG) emissions are the primary cause of climate change, one of the biggest challenges for humankind. To tackle this problem, the international community is looking for ways to reduce GHG emissions. To create reduction strategies in a city/province/country, there is a need for an inventory that provides emission amounts from different sectors. This study aimed to develop a GHG emission inventory for Karaj, a megacity in Iran, using international guidelines such as AP-42 and ICAO, and IVE software. The emissions of mobile sources were accurately calculated by a bottom-up method. The results showed that power plant with 47% of the total emissions is the primary GHG contributor in Karaj. Residential and commercial units with 27% and mobile sources with 24% of the total emissions play a critical role in emitting GHGs in Karaj. On the other hand, the industrial units and the airport have negligible (2%) contribution to the total emissions. Subsequent estimates showed that GHG emissions per capita and per GDP of Karaj were 6.03 t per person and 0.47 t per thousand US dollars, respectively. These amounts are higher than the global averages (4.97 t per person and 0.3 t per thousand US dollars). The relatively high GHG emissions in Karaj are due to the sole reliance on the consumption of fossil fuels. To reduce emissions, mitigation strategies such as developing renewable energy sources, switching to low-emission transportation, and raising public awareness should be implemented.

An examination of how climate change could affect the future spread of Fusarium spp. around the world, using correlative models to model the changes

Climate change is predicted to have a significant impact on the geographic distribution of various flora, fauna, and insect species by expanding, contracting, or shifting their suitable climate environment. The plant pathogenic fungus Fusarium is known for causing crop diseases like blight, root and stem rots, and wilts, making it the most significant mycotoxigenic genus in weeds and food across various climatic zones worldwide. In this study, we hypothesize that crop diseases caused by Fusarium spp. will increase across all four corners of the world by 2050 and 2070 in response to future climate conditions. A series of correlative species distribution models (SDMs), including a generalized linear model (GLM), maximum entropy (MaxEnt), generalized boosting model (GBM), and surface range envelope, were employed to project and compare how the niche of Fusarium spp. will change from the present time to 2050 and 2070 under two Climate Change Representative Concentration Pathways (RCPs) of 8.5 and 4.5 (scenarios of high and low greenhouse gas emissions, respectively). Our approach (the ensemble predictions of 4 SDMs) minimizes the uncertainty (differences) of the projection results from each one of the models. The findings of this study have global implications because Fusarium spp. are associated with host species that are present on major continents such as Asia, Europe, Australia, and North and South America. The information gathered could be beneficial to farmers and planners when creating strategies to prevent the proliferation of Fusarium spp. as well as calculating the expenses associated with using pesticides to minimize contamination and increase yields.

Mortality, metabolic rate, and oviposition of Gryllus (Gryllus) assimilis (Fabricius, 1775) (Orthoptera: Gryllidae) females under constant and fluctuating warm temperatures

The global average temperature will increase by up to 5.7 °C, under high greenhouse gas emissions, consequently increasing the frequency of heatwaves, according to recent IPCC forecasts. These especially impacts ectotherms, such as insects, which are the most susceptible animals to changes in environmental temperature, affecting their physiology and reproduction. Thus, we investigated the effects of a 96-h exposure to constant temperatures (CT: 27, 30.5, 34, 39, 41, or 43 °C) and fluctuating temperatures (FT: 27/34 °C, 12/12 h) on the survival, metabolic rate, and oviposition of the female cricket Gryllus (Gryllus) assimilis (Orthoptera: Gryllidae). Mortality, body mass and water content of females and males were quantified and compared. It was found that CT27, CT34 and FT27/34 do not cause mortality in females of G. (G.) assimilis. CT30.5 (average temperature between 27 and 34), despite causing mortality of 5.0 ± 3.5%, do not differ from CT27, CT34 or FT27/34. CT39 causes a mortality of 8.3 ± 5.5%. Estimated lethal temperature for 50% of the population of females (LT50Temp) is 40 °C, and 43 °C promotes 100% mortality in 96 h. Comparing mortality between sexes, females present higher LT50Temp and thermotolerance than males. In addition, FT27/34 and CT34 do not differ in the metabolic rate, but both have higher values than CT27. CT34 strongly reduces oviposition in females, however FT27/34 does not. We suggest that CT34 reduces oviposition in females in two ways: by affecting the endocrine system related to egg production, or by causing behavioral egg retention, as a strategy to survive thermal stress. Moreover, females had a higher wet body mass and present a lower average weight loss than males. In conclusion, despite females present a higher mortality at temperatures above 39 °C, they are more thermotolerant than males. Furthermore, CT34 is detrimental to the oviposition of G. (G.) assimilis.

Changing perioperative practice in the time of climate crisis

BackgroundTo reduce the healthcare sector's contribution to carbon emissions, many hospitals have advocated avoiding inhaled anesthetic agents with high greenhouse gas potential, such as desflurane and nitrous oxide; using low gas flows; and adopting alternative anesthetic techniques. However, limited evidence is available on how to implement these changes, which require both organizational and individual adjustment. We engaged our healthcare workers on the topic of climate change, and reviewed any change in their knowledge and attitudes towards environment-friendly use of inhaled anesthetic agents. MethodsWe sent out a survey via email to our anesthetic staff to assess their baseline knowledge and opinions regarding inhaled anesthetic agents and climate change. We then provided an online education session, followed by a debate on whether to remove desflurane from use. The session was recorded and emailed to all staff. The impact of the intervention was subsequently assessed by repeating the knowledge and attitude survey. ResultsOf the 101 anesthetic staff members, 76 completed the initial survey and 54 completed the post-intervention survey. Using a pre-determined generated code, we matched 44 pairs of datasets for analysis (response rate 44%). We demonstrated an overall improvement in knowledge on the topic, and showed a positive attitude towards reducing the use of nitrous oxide. There was minimal attitude change on desflurane use, a considerable concern about risk shifting and limited support for total intravenous anesthesia as the default technique. ConclusionsAs an initial step of a practice change process, this study raised climate change awareness and enabled our staff with differing opinions to feel involved and prepared for change. However, additional strategies may be required before initiating organizational changes, with the aim to provide environmentally sustainable practice while maintaining safe and high-quality perioperative patient care.

An integrated approach for sustainable food waste management towards renewable resource production and GHG reduction

There has been an increasing interest in diverting food waste from landfills to enhance renewable resource production due to high greenhouse gas emissions. Sustainable processing of food waste to generate renewable energy represents a significant, though underutilized, opportunity for producing energy. This study proposes an integrated model to simultaneously boost food waste valorization and reduce GHG emissions using geospatial analyses, a clustering algorithm, and a mixed-integer linear optimization program. We maximized net present value by optimizing network and configuration designs in the Illinois food waste system, using stand-alone anaerobic digestion and co-digestion at wastewater treatment plants. We identified the influences of techno-economic factors like prices and logistics parameters on the model objective, electricity production, digestate sales, and system configuration. Results show that installing anaerobic co-digesters at wastewater treatment plants with a total annual capacity of 9.3 million metric tons (Mg) could generate an 8.3% return on investment while reducing CO2 equivalent by approximately one million Mg annually. Tipping price, capital investment, operational cost, and food waste availability were the most significant factors to the net present value of the system. Anaerobic co-digesters were more economically competitive than stand-alone digesters which were only recommended when the tipping price of sludge was lower than food waste. Expanding digestate marketability is crucial to food waste valorization profitability using both stand-alone anaerobic and co-digestion. The minimum tipping prices to operate the anaerobic digestion system were 40 USD/Mg for food waste and 20 USD/Mg for sludge. Depending on the system size and tipping prices, anaerobic digestion and co-digestion could reduce CO2 equivalent between 29 kMg/y and one MMg/y. Expanding the current framework with advanced regional food waste prediction and other bioprocessing techniques will be essential for improving the profitability of food waste valorization and the circular bioeconomy in agriculture.

Mapping and evaluating sustainable and unsustainable urban areas for ecological management towards achieving low-carbon city: an empirical study of Asir Region, Saudi Arabia

Urbanisation can cause a variety of environmental and health issues, which has prompted experts to evaluate degraded areas and develop management strategies aimed at promoting urban sustainability and reducing carbon emissions. In low-carbon cities, sustainable urban areas have low carbon emission and prioritised carbon reduction by implementing sustainable transportation, green infrastructure, and energy-efficient buildings. On the other hand, unsustainable urban areas tend to lack these priorities and rely heavily on non-renewable energy sources and have high carbon emission. Therefore, this study aims to identify the most sustainable and unsustainable regions in the Abha-Khamis Mushayet Twin City region of Saudi Arabia in respect to urbanisation and carbon emission during the period between 1990 and 2020. To do so, we used Landsat datasets to create land use land cover (LULC) maps and then calculated carbon storage, emission, and absorption using InVest software. Additionally, the study examined micro-climatic conditions by calculating the urban heat island (UHI) effect, which allowed determining sustainable and unsustainable regions by comparing the UHI model and carbon similarity and mismatch model using coupling coordination degree model (CCDM). The study found that during the last three decades, the LULC pattern of the region underwent significant alterations, resulting in a substantial decline in carbon storage from 710,425 Mg C/hm2 in 1990 to approximately 527,012.9 Mg C/hm2 in 2020. Conversely, carbon emissions were observed to be very high in areas with high built-up density, with emission levels exceeding 20 tons per annum. Whilst the areas of excess carbon have decreased significantly, the areas of excess carbon emission have increased over time, resulting in the UHI effect due to high greenhouse gases. By comparing the UHI and carbon similarity and mismatch model, the researchers found that over 280 km2 of the study area is unsustainable and has increased since 1990. In contrast, only about 410 km2 of the study area is currently sustainable. To promote sustainability, the study recommends several strategies such as carbon capture, utilisation, and storage; green infrastructure; and the use of renewable energy to manage carbon emissions.

Walkability under Climate Pressure: Application to Three UNESCO World Heritage Cities in Central Spain

Walkability is a modern concept that has become important in recent years due to the doubtless effects it has on aspects such as health and wellbeing, sustainable development, climate change, and tourism. It is necessary, therefore, that urban development strategies aim to achieve walkable cities. The main objective of this study is to define a methodology to calculate the walkability index in tourist cities and to predict the effects of climate change on this index, which is applied to three World Heritage cities in central Spain: Salamanca, Ávila, and Segovia. The methodology is developed in three phases. Phase I focus on the calculation of walkability, considering the following factors: facilities and services, accessibility, sidewalk width, population density, green areas, and urban trees. In Phase II, walkability in 2020, climate-related variables were added to the previous result: temperatures, solar radiation, and shadows. Finally, the third phase, walkability under climate change pressure in 2030, 2050, and 2100, establish predictions for different climate scenarios. The results show excellent walkability indices (higher) in city centers and newly built neighborhoods and low values in the rest of the peripheral areas, industrial estates, and neighborhoods. Climate predictions showed a generalized decrease in walkability over time, even higher in the scenario with high greenhouse gas emissions. Likewise, the models can be an excellent tool for the tourist management of cities since they show the most walkable areas and, therefore, the most suitable for tourist routes.

Research Progress and Development Trends of Greenhouse Gas Emissions from Cereal–Legume Intercropping Systems

High yields and low carbon emissions are new challenges for modern crop production. Balancing the crop yield and reducing greenhouse gas (GHG) emissions has become a new field of agronomic technology innovation. Cereal–legume intercropping is a typical diversification planting system, which has been expected to achieve the dual goals of high production and low GHG emissions. However, the synergistic effect of integrating various technologies in an intercropping system on GHG emissions and whether it will achieve the high yield and low emissions goal remains to be determined. Therefore, bibliometric analysis has investigated the worldwide development trend of cereal–legume intercropping designs. The literature on the GHG emissions of the cereal–legume intercropping system was summarized. Additionally, the effects and mechanisms of different agricultural management methods regarding soil nitrous oxide and carbon dioxide emissions in the cereal–legume intercropping system were summarized. The research on GHG emissions of cereal–legume intercropping systems in non-growing seasons must be revised. In situ observations of GHG emissions from intercropping systems in different regions should be strengthened. This work is valuable in supporting and evaluating the potential of GHG reduction in a cereal–legume intercropping system in various farming areas.

Greener theatre, greener surgery - environmental sustainability in a rural surgical setup.

Greener theatre, greener surgery - environmental sustainability in a rural surgical setup.

Development of Heavy-Weight Hematite-Based Geopolymers for Oil and Gas Well Cementing.

In the petroleum industry, ordinary Portland cement (OPC) is utilized for different cementing applications. Yet, there are some technical and environmental issues for the usage of OPC in well cementing. The technical problems include gas invasion while setting, instability at corrosive environments, cement failure while perforation and fracturing due to high stiffness and brittleness, and strength reduction and thermal instability at elevated temperatures. Moreover, OPC production consumes massive energy and generates high greenhouse gas emissions. This study introduced the first hematite-based class F fly ash geopolymer formulation that can be used in oil and gas well cementing. Different properties of the designed slurry and hardened samples such as rheology, thickening time, strength, and elastic and petrophysical properties were evaluated. Moreover, mixability and pumpability challenges of heavy-weight geopolymer slurries were investigated. Unlike most of the studies in the literature, this work used 4 M NaOH solution only as an activator that can reduce the overall cost. The results showed that increasing the hematite percentage significantly decreased the thickening time. The developed formulation fell within the recommended fluid loss ranges for some cementing applications without using a fluid loss control additive. A proposed mixture of retarder and superplasticizer was introduced to enhance the thickening time by almost 5 times. The compressive strength increased by 49% and the tensile strength was enhanced by 27.4% by increasing the curing time from 1 to 7 days. The improvement in both compressive and tensile strength with curing time indicated that the geopolymerization reaction continued for extended time but with a smaller rate. The developed slurry acted more like a power law fluid at low temperatures and more like a Bingham plastic fluid at high temperatures. The elastic properties of the developed geopolymer samples proved that they are more flexible than some cement systems.

Projected effects of climate change on marine ecosystems in Southeast Asian seas

The seas of Southeast Asia are home to some of the world’s most diverse ecosystems and resources that support the livelihoods of millions of people. Climate change will bring temperature changes, acidification and other environmental change, with uncertain consequences for human and natural systems, but there has been little regional-scale climate modelling of the marine ecosystem. We present initial dynamically downscaled projections using a biogeochemical model suitable for coastal and shelf seas. A coupled physical-biogeochemical model with a resolution of 0.1° (approximately 11 km) was used to create projections of future environmental conditions under moderate (RCP4.5) and high (RCP8.5) greenhouse gas scenarios. Changes for different parts of the region are presented, including four sensitive coastal sites of key importance for biodiversity and sustainable development: UNESCO Biosphere Reserves at Cu Lao Cham-Hoi An in Vietnam, Palawan in the Philippines and Taka Bonerate-Kepulauan Selayar in Indonesia, and coastal waters of Sabah, Malaysia, which include several marine parks. The projections show a sea that is warming by 1.1 to 2.9°C through the 21st century, with dissolved oxygen decreasing by 5 to 13 mmol m-3 and changes in many other environmental variables. The changes reach all parts of the water column and many places are projected to experience conditions well outside the range seen at the start of the century. The resulting damage to coral reefs and altered species distribution would have consequences for biodiversity, the livelihoods of small-scale fishers and the food security of coastal communities. Further work using a range of global models and regional models with different biogeochemical components is needed to provide confidence levels, and we suggest some ways forward. Projections of this type serve as a key tool for communities and policymakers as they plan how they will adapt to the challenge of climate change.

Electrification of Oil and Gas Platforms by Wind Energy

In this paper, we address the problem of high greenhouse gas emissions from oil and gas platforms in Norway. We look at the potential of integrating an energy system composed of wind turbines and battery systems to unload the electrical power generated by gas turbines being the main source of emissions today. We propose a simulation model of the energy system, the power demand, the available wind speed, and different control strategies. By putting the models together, we evaluate the performance of various compositions of the system and determine their impact on emissions and battery lifetime. The numerical results show that changing today’s practices has great potential to reduce greenhouse gases, with amounts varying between 30% and 80% compared with today’s level.

Assessment of the Future Changes in the Socio-Economic Vulnerability of China’s Coastal Areas

China’s coastal areas are under serious threat of continued sea-level rise, and sustainable coastal development is closely linked to changes in socio-economic vulnerability. To this end, based on the Intergovernmental Panel on Climate Change framework of shared socio-economic pathways (SSPs), this study constructed a system of indicators to assess the socio-economic vulnerability of China’s coastal areas in 2030, 2050, and 2100 under low, medium, and high greenhouse gas emission scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5, respectively). The results showed the following: (1) the vulnerability of China’s coastal provinces, cities, and counties shows an upward trend (ranked SSP5-8.5 > SSP2-4.5 > SSP1-2.6), which is mainly attributed to a continued increase in the exposure of socio-economic systems to sea-level rise and differences in the age structure of the population within the study regions; and (2) areas with higher vulnerability are concentrated in economically developed coastal areas, such as the Bohai Bay Rim and the Yangtze River Delta, Jiangsu, and Pearl River Delta regions, owing to their high proportions of low-lying land, long coastlines, and dense residential areas associated with economic development. Based on these results, climate-resilient solutions are needed to improve socio-economic adaptations for ongoing climate change in China’s coastal areas.

Greenhouse gas emissions and future development trends of primary aluminum in China

Primary aluminum is widely used because of its excellent performance, and world primary aluminum production has increased 2.73 times in the past 20 years, with China increasing up to 13.9 times. China's primary aluminum industry (CPAI) is a high greenhouse gas (GHG) emitting industry and is facing a grim situation to reduce emissions. Therefore, quantifying the GHG emissions of CPAI and exploring future development trends are beneficial to the sustainable development of CPAI. In this study, the emission factor method was used to calculate the GHG emissions of CPAI from 2000 to 2020. The result shows that GHG emissions increased dramatically from 65.85 Mt CO2-eq in 2000 to 460.32 Mt CO2-eq in 2020, a seven-fold increase. GHG emissions from aluminum smelting were 363.62 Mt CO2-eq in 2020, which was the largest sub-process of emissions in CPAI, with a high share of 79%. Electricity emissions were the largest source of GHG emissions, accounting for more than 60%, with a maximum of 70.5%. The intrinsic drivers of GHG emissions were explored by the Log-Mean Divisia Index (LMDI) method, and the results showed that primary aluminum production was the largest driver of GHG emissions promotion, while energy intensity was the most important driver of GHG emissions suppression in the last decade. In this study, a modified “S" shaped mathematical model was used to predict the primary aluminum production, which laid the foundation for the subsequent analysis of emission reduction potential. On this basis, five types of scenarios were set based on the results of the driving force analysis. Finally, based on the results of our analysis, we propose strategies for low-carbon development in the primary aluminum industry, including the use of clean energy, and the development of new low-carbon technologies.

Life cycle assessment of stone buildings in the Taihang mountains of Hebei province: Evolution towards cleaner production and operation

The building sector has gained significant attention due to its remarkably high energy consumption and greenhouse gas emissions. In China's rural areas, stone is a popular building material, but there are unprecedented demands to improve the life-cycle performance of stone buildings. It is essential to preserve the original architectural features while evolving towards a cleaner production and operation. This study implements a field survey in the Taihang Mountains of Hebei province. The improvement of stone extraction methods and the evolution of three stone wall styles are collected and developed. Thermal transmittances of three stone walls are measured and modeled. A cradle-to-grave life cycle assessment is conducted, and the results are compared to show their environmental performance in the embodiment and operation phases. Their life cycle inventories, including stone extraction, are developed. One representative building style sample is developed for the cooling and heating energy requirement simulation in the DesignBuilder. Based on the inventories, conducting life cycle impact assessment shows various environmental profiles in their whole life cycles. From the outcomes, the stone cladding wall (SCW) outperforms the other stone walls in both the embodiment and operation phases. However, its relatively high cost is a challenge for an individual house owner. This study proves the SCW is more sustainable, providing a basis for the choice of stone wall style in the future construction.