Tons Of CO2-eq Research Articles

AMELIORATION OF CARBON FOOTPRINT SENSITIVITY WITHIN THE OIL PALM INDUSTRY: THE CHEMICAL ENGINEER’S PERSPECTIVE

High valued carbon stocks (HVCS) are established to nullify carbon emissions from the oil palm plantation (ENET,Y,PL,CPO) relative to crude palm oil (CPO) production (tonnes CO2eq per tonne CPO), estimated at an average of 13 tonnes CO2eq per tonne CPO. A yearly total of 19.5 tonnes biomass or 3.55 tonnes of HVCS is required per hectare to offset the emissions. The technological transition of energy generation by conventional diesel to sustainable biomass and biogas utilisation reduced emissions from 0.74 tonne CO2eq to 0.36 tonne CO2eq relative to each tonne of CPO in the palm oil mill. The emissions from the mill are discounted for its closed loop carbon cycle, with near net zero emissions (ENET) registered with respect to all sustainable technologies considered. The emission reduction is met with conditions of 25 years of plantation lifetime. The production of fresh fruit bunches must exceed 25 tonnes yearly per hectare with a minimum CPO production yield of 20 per cent. Furthermore, the use of HVCS shall not exceed 25 tonnes, with CPO and crude palm kernel oil (PKO) used as HVCS within the life cycle assessment (LCA) from the oil palm plantation to the palm oil mill gate. Net zero carbon emissions is approached upon consideration of emitted carbon dioxide returning to the oil palm plantation in the vicinity for assimilation. Keywords: Oil palm industry, palm oil mill, oil palm plantation, net zero emissions, life cycle assessment (LCA).

The Potential Role of Iceland in Northern Europe's Protein Self-Sufficiency: Feasibility Study of Large-Scale Production of Spirulina in a Novel Energy-Food System.

Europe is dependent on protein-rich crop imports to meet domestic food demand. This has moved the topic of sustainable protein self-sufficiency up the policy agenda. The current study assesses the feasibility of protein self-sufficiency in Iceland, and its capacity to meet Northern Europe's demand, based on industrial-scale cultivation of Spirulina in novel production units. Production units currently operating in Iceland, and laboratory-derived nutritional profile for the Spirulina cultivated, provide the basis for a theoretical protein self-sufficiency model. Integrating installed and potentially installed energy generation data, the model elaborates six production scale-up scenarios. Annual biomass produced is compared with recommended dietary allowance figures for protein and essential amino acids to determine whether Northern Europe's population demands can be met in 2030. Results show that Iceland could be protein self-sufficient under the most conservative scenario, with 20,925 tonnes of Spirulina produced using 15% of currently installed capacity. In a greater allocation of energy capacity used by heavy industry, Iceland could additionally meet the needs of Lithuania, or Latvia, Estonia, Jersey, Isle of Man, Guernsey, and Faroe Islands. Under the most ambitious scenario utilizing planned energy projects, Iceland could support itself plus Denmark, or Finland, or Norway, or Ireland with up to 242,366 tonnes of biomass. On a protein-per-protein basis, each kilogram of Spirulina consumed instead of beef could save 0.315 tonnes CO2-eq. Under the most ambitious scenario, this yields annual savings of 75.1 million tonnes CO2-eq or 7.3% of quarterly European greenhouse gas emissions. Finally, practicalities of production scale-up are discussed.

Decentralization of sustainable aviation fuel production in Brazil through Biomass-to-Liquids routes: A techno-economic and environmental evaluation

The present study evaluated the influence of three strategies to improve the economic feasibility of sustainable aviation fuel (SAF) production through gasification and Fischer-Tropsch synthesis (GFT) of lignocellulosic biomass feedstocks in Biomass-to-Liquids (BtL) plants. Apart from the integration with sugarcane ethanol production and the use of economic incentives by the carbon credits market, we evaluated the decentralization of the production chain with fast pyrolysis (FP) units to densify the biomass into bio-oil, aiming to reduce feedstock transportation costs for biofuel production. These analysis made use of process simulation coupled with techno-economic assessment (TEA) and life cycle assessment (LCA).Carbon credits commercialization alone is not enough to enable the standalone GFT scenario with current prices (up to 30 US$/tonne CO2 eq avoided). However, integration into a 1G mill can decrease SAF production costs to as low as 0.4–0.7 US$/L and achieve over 70 g of CO2 eq avoided/MJ of SAF. The addition of the FP process for decentralization is a better option than a centralized production only for distances above 1,000 km. This is due to expenses with feedstock bio-oil being from 2 to 5 times higher than with the direct use of solid biomass. In conclusion, the path to make SAF production feasible lies in the integration with more mature routes and by relying on incentives from environmental policies, while the decentralization could help markets with highly disperse biomass availability.

Municipal Solid Waste Collection and Haulage Modeling Design for Lahore, Pakistan: Transition toward Sustainability and Circular Economy

Municipal solid waste management (MSWM) is a critical administrative, environmental and financial issue in low-income countries, such as Pakistan, where waste collection efficiency is less than 75% in all urban areas, except Lahore. Therefore, it is pertinent to develop practical decision-making tools to enhance waste collection efficiency by local municipalities and waste management companies (WMCs). A tool/calculator, holistically measure analyze forecast honestly (HMAFH), is proposed for waste collection in urban areas based on the lessons learned. The tool was developed considering local conditions, i.e., business environment, socio-economic and cultural dynamics, city infrastructure and stakeholders’ desires. It is flexible to various proposed waste collection modes, with heterogeneous fleet choices, and it presents an opportunity to integrate collection with a material recovery facility (MRF) or direct haulage to the disposal site. The HMAFH was tested successfully in the Lahore district. Based on the proposed scenarios, the result shows a material recovery of up to 33% by defining dedicated waste collection streams with a 26% saving on fuel. The proposed interventions can prove to be a defining step toward building a circular economy (CE) that allows the integration of treatment options with economic potential to account for 35% of the current operating expenditures and a reduction in greenhouse gases (GHGs) emission, i.e., 1,604,019 tons of CO2-eq./annum.

Economic and Environmental Analysis of Incorporating Geothermal District Heating System Combined with Radiant Floor Heating for Building Heat Supply in Sarein, Iran Using Building Information Modeling (BIM)

Despite the considerable breakthrough in district heating systems (DHS) globally, there is not yet any policy on developing this technology in Iran. This country has a high range of energy demand, while renewable energies play a minor role in its energy supply chain. Furthermore, the world is going through a transition towards renewable resources, which currently consist of only 10% of the total energy mix. As the first contribution in this area, this paper aims to design a 100% renewable DHS integrated with radiant floor heating for a group of residential buildings in Sarein, Iran. Moreover, the literature proposes a novel approach for combining geothermal energy and Municipal Solid Waste (MSW) to achieve a 100% renewable energy system. Building Information Modeling (BIM) is used for thermal analysis by 3D designing the buildings in SketchUp and OpenStudio and simulating the heat load in EnergyPlus. Three scenarios are presented to better compare the DHS with the decentralized heating system regarding fuel consumption, as well as environmental and economic aspects. The town’s existing heating system that consumes natural gas for both space heating and hot water demand is referred to as the IHS-G scenario. The DHS-G scenario represents an 87% renewable DHS system, working with natural gas and geothermal energy, while the DHS-MSW scenario is a 100% renewable system, consuming both geothermal energy and Municipal Solid Waste (MSW). Finally, findings suggest that DHS-MSW and DHS-G scenarios reduce the annual energy consumption of buildings by about 595 and 33 toes, respectively. Hence, the greenhouse gas effect will alleviate by mitigating the emission of 1403 and 1339 tons of CO2-eq./year, respectively. Moreover, exporting the extra natural gas through both LNG and pipeline provides about 26 million and 28 million USD/year revenue in DHS-G and DHS-MSW scenarios.

Energy and Environmental Impact of the Promotion of Battery Electric Vehicles in the Context of Banning Gasoline Vehicle Sales

This study quantitively estimates the energy and environmental impacts of China’s promotion of battery electric vehicles (BEVs) in the context of banning the sale of gasoline vehicles (GVs). Combining the population ecological growth model and the life cycle assessment method, the potential of BEVs promotion in reducing fossil energy (FE) consumption and greenhouse gas (GHG) emissions under different timings of banning GV sales was dynamically simulated and analyzed. The results show that the current life cycle FE consumption and GHG emissions of BEVs are approximately 40.1% and 26.6% lower than those of GVs, respectively. Based on the development of automobile technology and the national energy plan, replacing GVs with BEVs can reduce GHG emissions and FE consumption by up to 43.61–55.81% and 46.33–55.45%, respectively. Compared with the scenario without BEV promotion, if sales of GVs in China are banned between 2040 and 2060, the point at which the carbon peak of the automobile market will be reached will be advanced by approximately two years, and the corresponding carbon peak value will be reduced by approximately 13.58–28.79 million tons of CO2-eq (MtCO2e). In addition, the annual FE savings and GHG emission reductions will reach approximately 2.99–6.35 million TJ and 276.54–488.77 MtCO2e by 2050. This research work will not only help authorities, managers, and the public to better understand the environmental and energy impacts of promoting new energy vehicles, but also provide a forward-looking reference for formulating comprehensive, systematic, and reasonable industrial planning to better promote a green and sustainable transformation of the automotive sector and solve the relevant energy and environmental problems.

Use of Biomass as Alternative Fuel in Magnesia Sector

The European Union has started a progressive decarbonization pathway with the aim to become carbon neutral by 2050. Energy-intensive industries (EEIs) are expected to play an important role in this transition as they represent 24% of the final energy consumption. To stay competitive as EEI, a clear and consistent long-term strategy is required. In the magnesia sector, an essential portion of CO2 emissions result from solid fossil fuels (MgCO3, pet coke) during the production process. This study concerns the partial substitution of fossil fuels with biomass to reduce carbon emissions. An experimental campaign is conducted by implementing a new low-NOx burner at the magnesia plant of Grecian Magnesite (GM). Life cycle assessment (LCA) is performed to quantify the carbon reduction potential of various biomass mixtures. The experimental analysis revealed that even with a 100% pet coke feed of the new NOx burner, NOx emissions are decreased by 41%, while the emissions of CO and SOx increase slightly. By applying a biomass/pet coke mixture as fuel input, where 50% of the required energy input results from biomass, a further 21% of NOx emission reduction is achieved. In this case, SOx and CO emissions are additionally reduced by 50% and 13%, respectively. LCA results confirmed the sustainable impact of applying biomass. Carbon emissions could be significantly decreased by 32.5% for CCM products to 1.51 ton of CO2eq and by 38.2% for DBM products to 1.64 ton of CO2eq per ton of MgO in a best case scenario. Since the calcination of MgCO3 releases an essential and unavoidable amount of CO2 naturally bound in the mineral, biomass usage as a fuel is a promising way to become sustainable and resilient against future increased CO2 prices.

Emissions of Greenhouse Gases from Municipal Solid Waste Management System in Ho Chi Minh City of Viet Nam

Accurate estimation of emissions of greenhouse gases (GHGs) is required for making effective climate change mitigation policies at the national level. Among major sources, municipal solid waste (MSW) is an important source of GHGs, such as methane (CH4), generated during the anaerobic decomposition of organic matter. In Viet Nam, the emissions of GHGs are not well quantified, in particular from the MSW management system. In this study, we estimated emissions of GHGs from the MSW management system of Ho Chi Minh City (HCMC), considering the current waste management practices. In HCMC, landfilling has been a common practice of solid waste management. About 85 percent of the total MSW generated in the city has been landfilled at two landfill sites. Our estimates show that landfilling was the significant source of GHGs in HCMC, with a net contribution of 781.05 kg CO2-equivalent (CO2-eq.) per tonne of MSW landfilled. From the whole MSW management system, the direct GHG emission was 768.61 (kg CO2-eq. per tonne of MSW) with avoided emissions of 72.47 (kg CO2-eq. per tonne of MSW) through composting and recycling of MSW. The net GHG emission from the MSW management system was 696.14 kg CO2-eq. per tonne of MSW (≈1.665 million tonnes of CO2-eq. per year). The GHG emission data of this study may be useful to policymakers for making effective climate change mitigation policies.

Dynamic LCA of the increased use of wood in buildings and its consequences: Integration of CO2 sequestration and material substitutions

Wood products can have a lower impact on climate change (CC) than other building materials, and their carbon content can transform buildings into temporary carbon sinks. However, the large-scale use of wood products in buildings requires a better understanding of their consequences to support CC policies. The consequential life cycle inventory of such products contains elementary flows with values sometimes greater sometimes less than zero. Therefore, their static assessment did not show the influence of carbon uptake and release, either during or after the temporal boundary of the system. The originality lies in the combination of the dynamic modeling of tree harvesting and growth, temporary carbon storage, end-of-life (EOL) strategies, material substitution, and characterization factors in a consequential life cycle assessment (LCA). This combination highlights the extent to which material substitution, EOL strategies, and carbon sequestration can be decisive. In addition, it addresses the static and dynamic measurements of radiative forcing (W.m−2) and the carbon dioxide (CO2) equivalent (CO2eq.). In this case study, material substitution contributed the most to result, followed by post-harvest CO2 sequestration. In terms of metrics, the conventional static LCA overestimates the long-term cumulative impact on CC (tonne CO2eq.) without providing information on the short-term impact of the case study. In addition, the assessment of such a dynamic consequential life cycle inventory (LCI) with a dynamic metric provides more specific information, regardless of the temporal boundary. However, the absolute dynamic metrics (W.m−2) should support the relative dynamic metric (tonne CO2eq.1st year) to avoid misleading conclusions.

A micro- and macro-scale look at the biochemical methanogenic potential of the organic fraction of municipal solid waste generated in a large city of a developing country

The management of municipal solid waste (MSW) is a complex and expensive task. This is especially the case in developing countries, where waste generation rates are continuously increasing and where current MSW management strategies are focused on inadequate practices, such as landfilling and incineration, which result in numerous health and environmental problems. The anaerobic digestion (AD) of MSW has been implemented worldwide as a solution to decrease the amount of waste ending up in landfills. This process allows for the recovery of energy from the organic fraction of MSW (OFMSW) in the form of biogas, which is largely composed of methane. Therefore, the goal of the present study was to evaluate the biochemical methane potential (BMP) of the OFMSW generated within different socioeconomic strata of the Metropolitan Area of Guadalajara (MAG), Mexico. From a microscale perspective, the microbial communities within the experimental AD system were analyzed using high-throughput sequencing of the 16S rRNA gene to assess the relationship between these communities and the biogas composition. This microbial identification revealed a typical AD composition consisting of the following six phyla: Actinobacteria, Bacteroidetes, Chloroflexi, Euryarchaeota, Firmicutes, and Proteobacteria. Furthermore, through the identification of Methanobacterium and Methanosaeta, two methanogenesis pathways (hydrogenotrophic and acetoclastic) were pinpointed. From a macroscale perspective, a multi-stage Gompertz kinetic model was used to describe cumulative biogas production. This model considered the complex nature of the OFMSW substrate in order to estimate the potential level of biogas production in the MAG using a weighted average that was based on the size of the population in each socioeconomic stratum evaluated (732.8 mL⋅g−1 VS). This novel contribution to the literature provides an estimation of the potential economic, energetic, and environmental benefits of treating the OFMSW produced in the MAG through AD. Through this approach, an estimated 8.5 MWh·year−1 of electrical power could be produced, translating into 1.13 million USD of yearly revenue and resulting in reduced GHG emissions (10,519 tonne CO2eq⋅year−1).

Assessment of methane emissions from a California landfill using concurrent experimental, inventory, and modeling approaches

Methane flux and emissions were obtained at a California landfill concurrently using field measurements, inventory analyses, and modeling. Measured fluxes ranged from −3.7 to 828 g/m2-day and generally decreased from daily to intermediate to final covers. Soil covers with high-plasticity clay had the lowest fluxes. Whole-site emissions ranged from 406 to 47,414 tonnes/year (11,368 to 1,327,592 tonnes CO2-eq./year), and were dominated by intermediate covers with high relative surface area. Emissions estimates from flux chamber tests and California Landfill Methane Inventory Model (CALMIM) with oxidation were similar and low, whereas emissions from aerial measurements and CALMIM without oxidation were similar and high. The inventory analyses provided intermediate emissions and a new Gaussian plume model based on ground cavity ring-down spectrometer measurements provided the highest emissions. The assumptions used and the inherent strengths and limitations of the different approaches resulted in the flux and emissions differences. With varied attributes (experimental/modeling; flux/emissions; whole-site/cover-specific, top-down/bottom-up), the approaches provide envelopes of methane emissions and can be used selectively for the two main purposes of landfill methane emissions analysis: to mechanistically determine the factors that control/limit surface emissions and to provide data for atmospheric methane analysis. To reduce emissions, progression from temporary to permanent cover areas can be accelerated and covers with coarser materials can be amended with plastic fines.

Estimating the cost efficiency and marginal cost of carbon reductions in the production of drinking water

Access to safe, reliable and affordable drinking water is a human right that should be achieved without neglecting Sustainable Development Goal 13 of the United Nations related to climate action. The production of drinking water involves using a non-negligible amount of energy, leading to relevant economic costs and greenhouse gas (GHG) emissions. Here, we employed a parametric method to assess the cost efficiency of a sample of drinking water treatment plants (DWTPs) and to estimate the marginal cost of reducing GHG emissions. The average cost efficiency was 0.386, indicating that the evaluated DWTPs had notable room (61.4%) to save costs. The average marginal cost was estimated at 30€ per ton of CO2eq. When comparing this value with the current carbon costs of carbon trading systems, reducing the GHG emissions of DWTPs might be cost-effective. The parametric approach enabled us to evaluate the influence of several environmental variables on the cost efficiency and marginal cost of reducing GHG emissions. Specifically, the size of the facility and source of raw water significantly influenced DWTP performance. In conclusion, this study provides a novel tool to obtain insights on the water-energy nexus for informed decisions towards a more sustainable urban water cycle.

Effect of reduced age at first calving and an increased weaning rate on CO2 equivalent emissions in a cow-calf system

The objective of this study was to evaluate the impact of using technology to reduce the age at first calving (AFC; from 48 to 24 months) and increase the weaning rate (WR; from 60% to 80%) in beef herds. The need for pasture area (hectares) and the CO2 equivalent emissions (CO2eq.) of animals present in the production system were analyzed. Data from a livestock breeding system were used to produce 400 male calves per year: System 1) using reproductive biotechnology (fixed-time artificial insemination [FTAI] and System 2) without the use of reproductive biotechnology (only natural mating). System 1, which used reproductive biotechnology (FTAI; composed of 1,540 AU of animals in 1,540 hectares), presented a lower AFC (24 months), a higher WR (80%), and lower CO2eq. emissions per year (2,311.3 tons). System 2, which did not employ reproductive technology (composed of 2,475 AU [450 kg of animals] on 2,475 hectares), had the highest AFC (48 months) and lowest WR (60%) and emitted 3,714.5 tons of CO2eq. per year. The reduction in CO2eq. emissions per year was 1,403.3 tons in the system that used reproductive biotechnology, corresponding to gains of US$ 135,920.42 (US$ 96.86 per ton of CO2eq.). It is estimated that the adoption of the FTAI increases the reproductive efficiency of a cow-calf operation system, which can produce the same number of male calves (400) on 935 fewer hectares of pasture (-37.3%) and with a reduction of 1,403.3 tons of CO2eq. produced per year.

Estimating smart energy inputs packages using hybrid optimisation technique to mitigate environmental emissions of commercial fish farms

The current study uses a hybrid optimization technique (ANN and DEA) to estimate smart energy input packages to reduce the environmental emissions of fish farms. In 2021, enumerators visited polyculture fish farms in Pakistan and interviewed 216 farmers using a well-structured questionnaire. The results showed that energy consumption and production were 1,11,493 and 54,62,643 MJ per farm, respectively. ANN determined that the emitted 8,323.57 tons of CO2eq per farm could be reduced to 6,403.39 tons of CO2eq. At a given level of farm output, nitrogen, diesel fuel, and electricity consumption were reduced by 31 %, 22 %, and 13 %, respectively. Using the smart energy input packages, the fish farm achieved a 23 % drop in environmental emissions and a 20 % improvement in energy use efficiency. A sensitivity analysis revealed that the energy production of fish farming increased significantly by 2.22, 0.83, 0.26, 0.09 and 1.14 units, respectively, with an increase of one-unit labor, juvenile fish, diesel fuel, electricity and green grass. While the energy output of carp was significantly decreased by 0.43, 1.64, and 0.13 units, with a 1 unit increase in the energy from mixed powder, animal manure, and nitrogen, respectively. Therefore, this study recommends using targeted energy inputs and substituting diesel fuel with green energy to reduce the environmental emissions of fish farms.

Household Food Waste to Biogas in Västerås, Sweden: A Comprehensive Case Study of Waste Valorization

Sustainable large-scale household food waste (HFW) reutilization is difficult worldwide. This study presents a systematic and in-depth analysis of the case of Västerås, Sweden, where biogas has been produced from HFW for years and utilized as renewable vehicle fuel. Various aspects are covered, including the logistic flow, energy recovery, environmental benefits, cost-benefit analysis, and social survey. In 2017, 8879 tons of food waste were collected from Västerås city, which could generate 590,000 Nm3 biomethane and support 21 biogas-powered buses. A reduction of 1052.9–1541.2 tons of CO2-eq was estimated by replacing fossil fuels in vehicles and centralized composting units for HFW. The actual operating profit of this process amounted to 6.604 million Swedish Krona (SEK), and the maximized environmental economic benefit was estimated to be 3.15–3.73 million SEK/year. The active participation of the residents to source-separate their HFW was crucial to the success of the project, and the driving factors were tentatively identified as value orientation and facility convenience. With information pooled from various sectors, this study constructs a comprehensive reference case for industrial, academic, and municipal entities that are interested in similar practices in the future.

Greenhouse Gas Mitigation Costs of Reduced Nitrogen Fertilizer

The reduction of nitrogen (N) fertilizer use is a possible greenhouse gas (GHG) mitigation option, whereas cost estimation highly depends on assumptions of the yield response function. This paper analyzes the potential and range of GHG mitigation costs with reduced N fertilizer application based on empirical yield response data for winter rye (Secale cereale L.) and rapeseed (Brassica napus L.) from field experiments from 2013 to 2020 in Brandenburg, Germany. The field experiments included four to five N rates as mineral fertilizer treatments. Three different functional forms (linear-plateau, quadratic, and quadratic-plateau) were estimated to model yield response as a function of N supply. Economic calculations were based on relevant price–cost ratios. The results indicate that the opportunity costs of applying less fertilizer and the resulting GHG mitigation thereof vary in a great range across the years and crops estimated by different yield response functions. The linear-plateau function predominantly results in lower GHG mitigation costs than the quadratic and the quadratic-plateau function. On average, over eight years, a moderate reduction of N fertilizer (up to 20 kg/ha) offers a cost-efficient option for mitigating GHG emissions below EUR 50 per ton of CO2eq, even resulting in net profit gain in some cases.

Negative emissions at negative cost-an opportunity for a scalable niche

In the face of the rapidly dwindling carbon budgets, negative emission technologies are widely suggested as required to stabilize the Earth’s climate. However, finding cost-effective, socially acceptable, and politically achievable means to enable such technologies remains a challenge. We propose solutions based on negative emission technologies to facilitate wealth creation for the stakeholders while helping to mitigate climate change. This paper comes up with suggestions and guidelines on significantly increasing carbon sequestration in coffee farms. A coffee and jackfruit agroforestry-based case study is presented along with an array of technical interventions, having a special focus on bioenergy and biochar, potentially leading to “negative emissions at negative cost.” The strategies for integrating food production with soil and water management, fuel production, adoption of renewable energy systems and timber management are outlined. The emphasis is on combining biological and engineering sciences to devise a practically viable niche that is easy to adopt, adapt and scale up for the communities and regions to achieve net negative emissions. The concerns expressed in the recent literature on the implementation of emission reduction and negative emission technologies are briefly presented. The novel opportunities to alleviate these concerns arising from our proposed interventions are then pointed out. Our analysis indicates that 1 ha coffee jackfruit-based agroforestry can additionally sequester around 10 tonnes of CO2-eq and lead to an income enhancement of up to 3,000–4,000 Euros in comparison to unshaded coffee. Finally, the global outlook for an easily adoptable nature-based approach is presented, suggesting an opportunity to implement revenue-generating negative emission technologies on a gigatonne scale. We anticipate that our approach presented in the paper results in increased attention to the development of practically viable science and technology-based interventions in order to support the speeding up of climate change mitigation efforts.

Assessing the carbon footprint of a Colombian University Campus using the UNE-ISO 14064–1 and WRI/WBCSD GHG Protocol Corporate Standard

Higher education institutions (HEIs) transfer skills and knowledge between industries, the government, and the public, playing a vital role at educating future leaders in creating a globally sustainable system. Therein, evaluating greenhouse gas emissions from an educational institute is the first step towards the proposed reduction targets at the local, national, and international levels. In this research, we report the first approximate carbon footprint calculation of emissions corresponding to scope 1, scope 2, and scope 3 emissions for the main urban campuses of Universidad Nacional de Colombia, Medellín, using the UNE-ISO 14064–1 and WRI/WBCSD GHG Protocol Corporate standard. The carbon footprint in 2019 was approximately 7250.52 tons CO2 eq, and 0.432 tons CO2 eq per person. Scope 1 emissions accounted for about 2.84% of the carbon footprint, while scope 2 and 3 emissions each contributed nearly 14% and 83%, respectively. The largest sources of greenhouse gas emissions were the transportation process (58.51%), the wastewater process (17.01%), followed by electricity consumption (14.03%), and the e-mails that are sent (6.51%). It is suggested some proposals and strategies for mitigating and reducing emissions. Colombian HEIs exhibit the lowest ton of CO2 eq. per person compared to the other HEIs. Several reasons explain this behavior across the document such as geographic location (climate and topography), cultural factors (consumption patterns and types of transportation), population size, typology (public or private), gross domestic product (GDP) of each country, and methodology implemented. Results cannot be extrapolated to the Colombian case for the differences in the local conditions; therefore, it is not possible to get solid conclusions on the CF behavior in the Colombian HEIs. In this research, we provide for the first time a carbon footprint calculation where the sociological, political, and geographic conditions not extrapolated representing a valuable contribution to the HEI’s of the country. This research can be a benchmark in the carbon footprint calculation and a methodological contribution to HEIs in the country.

Seasonal Variations in Grain Yield, Greenhouse Gas Emissions and Carbon Sequestration for Maize Cultivation in Bangladesh

Rationale: Greenhouse gas (GHG) emissions from crop agriculture are of great concern in the context of changing climatic conditions; however, in most cases, data based on lifecycle assessments are not available for grain yield variations or the carbon footprint of maize. The current study aimed to determine net carbon emissions and sequestration for maize grown in Bangladesh. Methods: The static closed-chamber technique was used to determine total GHG emissions using data on GHG emissions from maize fields and secondary sources for inputs. A secondary source for regional yield data was used in the current study. GHG emission intensity is defined as the ratio of total emissions to grain yield. The net GHG emission/carbon sequestration was determined by subtracting total GHG emissions (CO2 eq.) from net primary production (NPP). Results: Grain yields varied from 1590 to 9300 kg ha−1 in the wet season and from 680 to 11,820 kg ha−1 in the dry season. GHG emission intensities were 0.53–2.21 and 0.37–1.70 kg CO2 eq. kg−1 grain in the wet and dry seasons, respectively. In Bangladesh, the total estimated GHG emissions were 1.66–4.09 million tonnes (MT) CO2 eq. from 2015 to 2020, whereas the net total CO2 sequestration was 1.51–3.91 MT. The net CO2 sequestration rates were 984.3–5757.4 kg ha−1 in the wet season and 1188.62–5757.39 kg ha−1 in the dry season. This study observed spatial variations in carbon emissions and sequestration depending on growing seasons. In the rice–maize pattern, maize sequestered about 1.23 MT CO2 eq. per year−1, but rice emitted about 0.16 MT CO2 eq. per year−1. This study showed potential spatiotemporal variations in carbon footprints. Recommendation: Special care is needed to improve maize grain yields in the wet season. Fertiliser and water use efficiencies need to be improved to minimise GHG emissions under changing climatic conditions. Efforts to increase the area under cultivation with rice–maize or other non-rice crop-based cropping systems are needed to augment CO2 sequestration. The generation of a regional data bank on carbon footprints would be beneficial for combating the impact of climate change.

Investigation of provincial capacity to produce biogas from waste disposal sites in Turkey

The main aim of this study is to determine the theoretical capacities of waste disposal sites to produce biogas and electricity in Turkey in 81 provinces by using the First Order Decay (FOD) methodology. The population data of each province starting from 1950 to 2020 was used as time series to estimate the best fit model. The same model was also used for the future population estimations until the year 2080. The provinces have different characteristics. The big provinces in Turkey are best fitted with polynomial models. For 38 provinces the best fit models are “third order polynomials”, and for 10 provinces the “second order polynomials” are best fitted. The exponential and linear models are good for 15 and 13 provinces, respectively.Many statistical and “model performance studies” are done for increasing the accuracy level of this study. The results of this study have shown that the best fitted model is acceptable at province level although there are small differences between observed and fitted values.The CH4 emission potential of disposal sites are calculated as 273 thousand tonnes in 1950. This has increased and reached 1.2 million tonnes in 2020. It is projected that it will reach 3.1 million tonnes in 2080. The methane production capacity in Marmara and Central Anatolia regions is calculated as 46% of total capacity. In 2020 these two regions have 1.7 and 0.9 million kW-hr/year electricity production capacity, respectively. The highest provincial capacity of electricity production is observed in İstanbul, Ankara, İzmir, Bursa and Antalya with respective values of 1.02, 0.37, 0.29, 0.20 and 0.16 million kW-hr/year. These top five provinces constitute 37% of Turkey's total capacity.The results of this study have shown that approximately 4.8–7.4% of GHG emissions can be stopped by using CH4 produced in waste disposal sites in energy production. Further usage of methane instead of solid fuels or other non-renewable fuels will decrease the total GHG emissions an extra 2–3.5%. In 2020, 35 million tonnes of CO2 eq. emissions can be reduced in Turkey due to biogas production in waste disposal sites. This is very important from the Climate Change point of view.