Blame the exurbs, not the suburbs: Exploring the distribution of greenhouse gas emissions within a city region

SummaryThis research reports on a multivariate analysis that examined the relationship between direct greenhouse gas (GHG) emissions and socioeconomic and well‐being variables for 1,920 respondents living in Halifax Regional Municipality, Nova Scotia, Canada, using results from the Halifax Space‐Time Activity Research Project. The unique data set allows us to estimate direct GHG emissions with an unprecedented level of specificity based on household energy use survey data and geographic positioning system–verified personal travel data. Of the variables analyzed, household size, income, community zone, age, and marital status are all statistically significant predictors of direct GHG emissions. Birthplace, ethnicity, educational attainment, perceptions of health, life satisfaction, job satisfaction, happiness, volunteering, or community belonging did not seem to matter. In addition, we examined whether those reporting energy‐efficient behaviors had lower GHG emissions. No significant differences were discovered among the groups analyzed, supporting a growing body of research indicating a disconnect between environmental attitudes and behaviors and environmental impact. Among the predictor variables, those reporting to be married, young, low income, and living in households with more people have correspondingly lower direct GHG emissions than other categories in respective groupings. Our finding that respondents with lifestyles that generate higher GHG emissions did not report to be healthier, happier, or more connected to their communities suggest that individuals can experience similar degrees of well‐being regardless of the amount of GHG emissions associated with his or her respective lifestyle.

Carbon footprint of a conventional wastewater treatment plant: An analysis of water-energy nexus from life cycle perspective for emission reduction

Whole-farm systems modelling of greenhouse gas emissions from pastoral suckler beef cow production systems

Sewage treatment processes are considered an important source of greenhouse gas (GHG) emissions, particularly N2O and CH4. In rural sewage treatment processes, GHG emissions are often neglected owing to the small scale of treatment and dispersed distribution. In this study, the non-CO2 GHG emission quantity, spatiotemporal distribution characteristics, and influences factors were analyzed based on rural sewage from 2015 to 2020. Emissions from rural sewage treatment in 2020 reached 122.72 Gg (CO2-eq), comprising 69.81 Gg N2O and 52.91 Gg CH4, representing a 35.29% increase compared to 2015. There are large variations between province-level regions: more GHG was emitted from the eastern than the north-west of China. The treatment of rural domestic sewage can simultaneously purify water quality and decrease GHG emissions, and the improvement in the rate of treatment is beneficial to "carbon peak and carbon neutralization." GHG emissions from rural sewage treatment showed a positive correlation with both GDP and sewage discharge, and N2O was positively correlated with protein consumption per capita. This study would provide a theoretical basis for policy formulation, as it supplies basic data on carbon emissions for China's rural sewage treatment. SUMMARY: Rural sewage treatment (RST) plants contribute significantly to GHG emissions. N2O emission from rural sewage treatment in 2020 in China was 69.81 Gg. CH4 emission from rural sewage treatment in 2020 in China was 52.91 Gg. Large variations in GHG emissions were found between province-level regions. Domestic RST can simultaneously purify water quality and decrease GHG emissions.

This study focuses on evaluating the full distribution of greenhouse gas (GHG) emissions related to agricultural land-use change in Mato Grosso, Brazil, both from a farmer and policy perspective. By combining three simulation models as well as data from field experiments, we present a novel Integrated Assessment approach that evaluates a large set of production systems, management practices, technologies, climatic conditions, and soil types with very high spatial resolution. The main component of our application is a multi-agent mathematical programming simulator that links socio-economic and biophysical constraints at farm-level and, hence, simulates farmer decision-making and policy response. We estimate the GHG emissions related to the full range of farm production systems and sources, such as inputs, machinery production, diesel consumption, soil processes, land use change (soil organic carbon and carbon stock from vegetation) and enteric fermentation. The results of our simulations indicate that GHG emissions in Mato Grosso are very sensitive to alternative land use change scenarios. The largest source of GHG emissions from crop and eucalyptus production is the use of farming inputs, while for cattle production it is the emission from enteric fermentation. Final simulation results regarding farmer policy response will be presented at the ICAE conference. Acknowledgement : This research was financed by the CarBioCial project of the German Federal Ministry of Education and Research. We thankfully acknowledge the scholarships awarded by the Brazilian Coordination for the Improvement of Higher Education Personnel (CAPES) [grant number BEX-10421/14-9]. We are grateful to Embrapa Agrossilvipastoril and IMEA for the technical materials and knowledge provided. Special thanks to Eric B necke and Uwe Franko for their support on the parameterization of CANDY simulations. The simulation experiments were performed using the computational resources of bwUniCluster funded by the Ministry of Science, Research and the Arts and the Universities of the State of Baden-W rttemberg, Germany.

Highlights Direct greenhouse gas (GHG) emissions were measured in a decoupled aquaponics system. Solids concentration predicted methane emissions in the clarifier system. Lower pH in the plant system increased N2O emissions. Higher fish feeding rate increased CO2 and N2O emissions in the plant production system. Roughly half of direct GHG emissions were offset by carbon uptake during plant growth. Abstract. Agricultural production systems are known to be large contributors to global greenhouse gas (GHG) emissions and many studies have focused on the mitigation of GHG emissions from open-field and other traditional crop production practices. Little attention has been given to direct emissions from non-traditional production systems such as aquaponics. Here we determine direct GHG emissions (CO2, CH4, N2O) from a pilot-scale biofloc, decoupled aquaponics facility. We also determine how emissions from unit operations differ based on a set of environmental and operational parameters e.g. temperature, feeding rate, suspended solids, plant height, water flow rate, and nitrate levels. Major unit operations included a biofloc fish tank stocked with tilapia, a solids settling clarification system, and a climate-controlled greenhouse in which cucumber plants were grown in substrate culture. The study was separated into three seasons. In the summer of 2019, different pH treatments for cucumber irrigation water were tested. In the fall of 2019 and winter of 2020, emissions from perlite versus pine bark substrates were tested during cucumber production. Measurements indicated that aerial GHG emissions in intensively aerated areas of the fish tank were 4.7 to 46.8 times higher than those in areas with low-intensity aeration. High methane emissions (up to 44.8 g m-2 d-1) from the clarification system indicated anaerobic activity. Results from plant production showed a negative relationship between pH and N2O efflux (p=0.0001) while the choice of plant growth substrate had no significant effect on direct GHG emissions. Overall, carbon sequestration in plants could offset 40% to 62% of direct GHG emissions from the aquaponics system. This study provides insight into operational parameters that affect direct GHG emissions from aquaponics systems and provides data to support life cycle assessments. Keywords: Aquaculture, Carbon dioxide, Hydroponics, Methane, Nitrous oxide.

Municipal wastewater treatment plants (MWWTPs) are considered significant artificial sources of greenhouse gas (GHG) emissions, in the forms of methane (CH4) and nitrous oxide (N2O), during their normal operations. In this study, we used an emission factor method to determine the spatial and temporal distribution characteristics of GHG emissions from MWWTPs in China during the period 2005–2014; influencing factors and uncertainties were also analyzed. Our results show that total GHG emissions from Chinese MWWTPs increased from 326.54 to 1294.03 Gg CO2‐eq between 2005 and 2014, and that regional distribution was extremely variable. During this decade, the proportion of CH4 in the total GHG emissions decreased from 74.1 to 59.4% while that of N2O increased from 25.9 to 40.6%. The observed increase in N2O was probably due to the enhancement of wastewater discharge standards for nitrogen discharge, resulting in lower waterborne but higher atmospheric levels of nitrogen oxides. Our comparison of GHG emissions from wastewater discharging directly to the aquatic environment with that treated at MWWTPs in 2014 indicate that the latter disposal method resulted in an 18‐fold drop in GHG emissions. Regional economic development level and wastewater treatment capacity were the factors most closely related to GHG emissions from MWWTPs; the per‐capita protein supply was closely related to N2O emissions.

Identifying a sustainable rice-based cropping system via on-farm evaluation of grain yield, carbon sequestration capacity and carbon footprints in Central China

Sewage treatment processes are considered an important source of greenhouse gas (GHG) emissions, particularly N2O and CH4. In rural sewage treatment processes, GHG emissions are often neglected owing to the small scale of treatment and dispersed distribution. In this study the non-CO2 GHG emission quantity, spatiotemporal distribution characteristics, and influences factors were analyzed based on rural sewage from 2015 to 2020. Emissions from rural sewage treatment in 2020 were 122.72 Gg (CO2-eq), comprising 69.81 Gg N2O and 52.91 Gg CH4, an increase of 35.29%. There are large variations between province-level regions: more GHG was emitted from the eastern than the north-west of China. The treatment of rural domestic sewage can simultaneously purify water quality and decrease GHG emissions, and the improvement in the rate of treatment is beneficial to, ‘carbon peak and carbon neutralization’. GHG emissions from rural sewage treatment showed a positive correlation with both GDP and sewage discharge, and N2O was positively correlated with protein consumption per capita. This study would provide a theoretical basis for policy formulation, as it supplies basic data on carbon emissions for China's rural sewage treatment.

Greenhouse gas (GHG) emissions from unsustainable land-use practices around the world contribute significantly to anthropogenic climate change. Growing population pressure and low efficiency of agricultural production systems in Sub-Saharan Africa (SSA) trigger the expansion of agricultural land into natural ecosystems, which leads to deforestation and land degradation, and causes GHG emissions. At the same time, prolonged droughts and increasingly erratic weather patterns due to climate change jeopardise food security in SSA countries such as Kenya.

At present, urban greenhouse gas (GHG) emissions from different wastewater treatment stages are attracting increasing attention. Based on the Guidelines of the China Greenhouse Gas List Compilation (Trial) and the IPCC National Greenhouse Gas List Guidelines in 2006, this paper evaluated urban GHG emissions from wastewater treatment in China from 2011 to 2020. The contribution rates of GHG emissions to the total GHG emissions were calculated for the different wastewater treatment stages. The variations in annual GHG emissions and differences in GHG emissions among different regions and provinces were also analyzed. The total amount of equivalent CO2 emissions reaches 1478.51 million tons, and the annual average amount of equivalent CO2 emissions from 2011 to 2020 is 147.9 million tons, which shows a trend of decreasing first and then increasing. The distribution of GHG emissions from wastewater treatment is uneven among provinces and regions; Guangdong Province has the highest emission, while the Xizang autonomous Region has the lowest. The correlation and contribution rate analysis revealed that paper production and chemical and side food production could discharge a large amount of wastewater with a high COD content, which may have an important impact on GHG emissions during the wastewater treatment stages. According to the study results, CH4 accounts for the largest proportion (63.08%) of the total GHG emissions. The most important source of CH4 comes from the industrial wastewater treatment stage. The annual average CO2 emissions account for 22.24% of the total GHG emissions, which are mainly from the power and chemical consumption stage. The annual average N2O emissions account for 14.68% of the total GHG emissions and are mainly from the wastewater collection and discharge stage. Therefore, in the future, GHG emission reduction strategies should focus on CH4 emissions in the industrial wastewater treatment stage and develop CH4 recycling and utilization technologies.

The reliance on groundwater for irrigation is increasing in Australia and India, which is causing concerns to policy makers about energy consumption and greenhouse gas (GHG) emissions. Therefore, it is important to quantify the GHG emissions of all components of the groundwater‐based irrigation systems, over the entire life cycle to develop more environmentally friendly groundwater management strategies. This study identified and analysed energy use and GHG emissions associated with different components in the supply chain of groundwater‐based irrigation systems. An existing GHG emissions and energy‐accounting framework was adapted to enhance its capabilities by considering drilling techniques, water distribution and irrigation application methods. The results of this study highlighted that embodied and direct GHG emissions from drilling tube wells were higher in the Musi catchment, India, compared to South Australia. The study also highlighted that GHG emissions associated with water conveyance were higher for concrete and plastic‐lined channels than unlined channels. Drip irrigation systems in both countries were found to have more GHG emissions than gravity‐fed systems. Centre pivot systems were found to be emitting more than the drip systems in South Australia. We conclude that different components of the system have an impact on total GHG emissions and energy consumption for both countries. Any change in the most commonly used methods of drilling bore wells, water distribution in channels, and the irrigation methods, will have distinct impacts on energy consumption rates and GHG emissions. The developed conceptual framework provided a systematic complete analysis of the energy‐consuming and GHG‐emitting components associated with groundwater‐based irrigation systems. Policy makers and decision makers may use the developed framework to compare different system components to develop strategies that have minimal impact on the environment. Copyright © 2015 John Wiley & Sons, Ltd.

In the face of the global environmental problems of increasing energy consumption and increasing greenhouse gas emissions, China has taken the responsibility of emission reduction and formulated and promoted a series of policy measures to deal with climate change. Power industry is a key industry in greenhouse gas emissions, power grid enterprises as the core business of the power industry, will actively realize energy saving and emission reduction in the power industry and promote the development of low-carbon economy. Based on the characteristics of the power industry and the characteristics of the operation of the power grid enterprises, this paper identifies the greenhouse gas emission sources of the grid enterprises from three aspects: direct greenhouse gas emissions, indirect greenhouse gas emissions from electric power and other indirect greenhouse gas emissions. At the same time, the method of accounting for greenhouse gas emissions is put forward for each emission source.

China recently implemented a “Green Mine” policy focused on promoting the filling method, aiming to mitigate the environmental impacts of underground mining; nevertheless, quantitative inventories have rarely been provided to support or negate such promotion, especially from a life-cycle perspective. Accordingly, this paper proposes a bottom-up model for estimating life-cycle greenhouse gas (GHG) emissions from underground metal mines using either filling or caving methods. Two filling-based (Luohe and Longtangyan) and two caving-based (Maogong and Xiaowanggou) iron mines were studied; their direct GHG emissions were 0.576, 0.278, 2.130, and 1.425 tons of carbon dioxide equivalent per kiloton-extracted ore (t CO2 eq/kt), respectively. When indirect GHG emissions were considered, the results increased to 17.386, 15.211, 5.554, and 5.602 t CO2 eq/kt, respectively. In contrast to popular belief, such results demonstrate that promoting the filling method can potentially raise the overall GHG emissions. Although filling-based projects generate less direct GHG emissions, the emissions are transferred to upstream sectors, especially the cement and power sectors. The additional electricity consumption in the haulage and backfilling stages is primarily responsible for the greater GHG emissions occurring in filling-based projects. Some mitigation approaches are suggested, such as backfilling the subsidence pit, using industrial waste as cementing materials, employing energy-efficient pumps, and further developing hauling systems.

Analyzing greenhouse gas emissions from municipal wastewater treatment plants using pollutants parameter normalizing method：a case study of Beijing