CO2 Equivalent Research Articles

Carbon footprint of a laser unit: a study of two centres in the UK.

Climate change has serious consequences for our wellbeing. Healthcare systems themselves contribute significantly to our total carbon footprint, of which emissions from surgical practice are a major component. The primary sources of emissions identified are anaesthetic gases, disposal of single-use equipment, energy usage, and travel to and from clinical areas. We sought to quantify the waste generated by laser surgery which, to our knowledge, has not been previously reported. The carbon footprint of two laser centres operating within the United Kingdom were measured. The internationally recognised Greenhouse Gas Protocol was used as a guiding framework to classify sources of waste and conversion factors issued by the UK government were used to quantify emissions. The total carbon footprints per day at each unit were 299.181 carbon dioxide equivalents (kgCo2eq) and 121.512 kgCO2eq, respectively. We found the carbon footprint of individual laser treatments to be approximately 15 kgCO2eq per procedure. The biggest overall contributor to the carbon footprint was found to be the emissions generated from staff, patient and visitor travel. This was followed by electricity usage, and indirect emissions from physical waste and laundry. The carbon footprint of laser procedures was considerably less than the average surgical operation in the UK. This initial study measures the carbon footprint of a laser center in a clinical setting and allows us to identify where improvements can be made to eventually achieve a net carbon zero health care system.

Monitoring loss and degradation of forests and shrubs in the North of Chile using Landsat time series data sets from 1998 to 2018

Deforestation and degradation are among the main sources of climate-change-inducing greenhouse gas emissions. Implementing sustainable forest management and conservation programs, such as Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD+), requires a forest monitoring system and carbon inventory to define reference emissions. Most REDD+ projects focus on dense forests, with limited studies conducted in arid and semi-arid regions where shrubs dominate. Despite diverse vegetation formations, these areas are often overlooked for their carbon sequestration potential. This study estimated gross and net deforestation and degradation of forest formation and from devegetation and degradation of shrub formation in Norte Grande (Far North), Chile, from 1998 to 2018 using remote sensing satellite imagery and projected out to 2118. The carbon equivalent (Ce) content of forest and shrub formations and their associated processes’ CO2 equivalent (CO2-e) emissions were also estimated. The results showed that the total Ce content in shrubs was higher than in forests because of the larger area. Although deforestation/devegetation and degradation tended to decrease across the study period, they will continue to affect forests and shrubs in the future, reaching a deforestation rate of 21.82 and 393.28 ha y−1 by 2118, respectively, and an annual degradation rate of 9535.31 and 255,850.65 kg m−2, respectively. Therefore, arid and semi-arid zones and shrub formations should be integrated into REDD+ strategies to promote their protection, given their potential to increase carbon reserves.

Carbon Pricing Policy to Support Net Zero Emission: A Comparative Study of Indonesia, Finland and Sweden

The Nationally Determined Contribution (NDC) of Indonesia in the Paris Agreement targeted emission reductions of 29% on its own and 41% with international cooperation in 2030, followed by Net Zero Emissions (NZE) in 2060. To achieve NZE, Indonesia enacted a carbon tax policy on April 1, 2022. The 2022–2024 carbon tax is limited to Steam Power Plants and will be imposed on other sectors by 2030. This research examines the ratio legis of carbon cost policies in Indonesia and compares the core of carbon tax policies in Indonesia with Sweden and Finland. Indonesia is starting to implement a Carbon Pricing policy under the ‘Cap-and-Tax’ scheme. The Cap scheme will be a means to force changes in the business culture in Indonesia, so the companies will pay attention to and reduce the carbon emission produced to avoid paying penalties for carbon exceeding the limits. Meanwhile, the Carbon Tax will provide economic resources to Indonesia to develop environmentally friendly technologies, fund research on renewable energy, and provide incentives for environmentally friendly businesses during the transition process to a carbon culture in Indonesia. Referring to the results of the comparison of carbon pricing policies in Finland and Sweden, Indonesia can gradually increase the cost of carbon taxes starting from Rp30,000/US$2 per ton CO2 equivalent to US$10 per ton CO2 equivalent. Meanwhile, for the imposition of high carbon tax rates, such as in Finland (US$73.02 per ton CO2 equivalent) and Sweden (US$137 per ton CO2 equivalent), Indonesia must carry out tax reforms, so the applied carbon tax is able to reduce carbon emissions without causing adverse impacts for the Indonesian economy.

Carbon carrying capacity in primary forests shows potential for mitigation achieving the European Green Deal 2030 target

Carbon accounting in the land sector requires a reference level from which to calculate past losses of carbon and potential for gains using a stock-based target. Carbon carrying capacity represented by the carbon stock in primary forests is an ecologically-based reference level that allows estimation of the mitigation potential derived from protecting and restoring forests to increase their carbon stocks. Here we measured and collated tree inventory data at primary forest sites including from research studies, literature and forest inventories (7982 sites, 288,262 trees, 27 countries) across boreal, temperate, and subtropical Global Ecological Zones within Europe. We calculated total biomass carbon stock per hectare (above- and below-ground, dead biomass) and found it was 1.6 times larger on average than modelled global maps for primary forests and 2.3 times for all forests. Large trees (diameter greater than 60 cm) accounted for 50% of biomass and are important carbon reservoirs. Carbon stock foregone by harvesting of 12–52% demonstrated the mitigation potential. Estimated carbon gain by protecting, restoring and ongoing growth of existing forests equated to 309 megatons carbon dioxide equivalents per year, additional to, and higher than, the current forest sink, and comparable to the Green Deal 2030 target for carbon dioxide removals.

Pine needle gasification-based electricity production: Understanding the effect of supply chain.

Pine needles (pine tree leaves), found abundantly across continents such as North America, Asia, Europe, South America, Africa, and parts of the Southern Hemisphere, are a significant global concern due to their high susceptibility to catching fire, especially in dry and hot climates. The same issue persists in the Uttarakhand state of India, which boasts ample pine forests, yielding a substantial 1.67 × 109kg of pine needles annually. In the present study, the annual potential emissions from forest fires in Uttarakhand were estimated to be 58.37 × 109kg of CO2 equivalent. Therefore, the present research aims to unlock pine needles' potential via gasification for green electricity and biochar production, offering an alternative to coal-based plants while reducing forest fire frequencies. Nevertheless, obstacles hindering pine needle gasification include an unsteady supply chain, limited collection windows (100days), and plant expenses, including transportation and operational costs. The primary focus of the research is to design and assess the performance of a gasification-based supply chain for pine needles in the Almora District of Uttarakhand. Ten plant capacity scenarios were considered, ranging from 25 to 250kW. The study incorporated critical factors, encompassing diverse losses within the supply chain, selecting potential plant sites, minimizing transportation distance, and evaluating the supply chain's economic and environmental performance. The economic analysis revealed that the 250-kW plant scenario exhibited a minimum discounted payback period (DPP) of 3.93years, alongside an internal rate of return (IRR) of 19% and a net present value (NPV) of 653.32 million INR without government subsidies. With subsidies included, the DPP decreased to 1.30years, improving the IRR to 69% with an NPV of 916.17 million INR. The emission analysis indicated that gasification plant capacity scenarios could potentially reduce 44.63 × 106 to 46.16 × 106kg of CO2 equivalent emissions annually compared to grid electricity while meeting nearly 5.5% of the electricity demand of Almora district. The present study aligns with SDG-7 (Affordable and Clean Energy), SDG-13 (Climate Action), SDG-9 (Industry, Innovation, and Infrastructure), SDG-11 (Sustainable Cities and Communities), SDG-3 (Good Health and Well-being), and SDG-15 (Life on Land).

Tracing fossil-based plastics, chemicals and fertilizers production in China

Phasing down fossil fuels is crucial for climate mitigation. Even though 80–90% of fossil fuels are used to provide energy, their use as feedstock to produce plastics, fertilizers, and chemicals, is associated with substantial CO2 emissions. However, our understanding of hard-to-abate chemical production remains limited. Here we developed a chemical process-based material flow model to investigate the non-energy use of fossil fuels and CO2 emissions in China. Results show in 2017, the chemical industry used 0.18 Gt of coal, 88.8 Mt of crude oil, and 12.9 Mt of natural gas as feedstock, constituting 5%, 15%, and 7% of China’s respective total use. Coal-fed production of methanol, ammonia, and PVCs contributes to 0.27 Gt CO2 emissions ( ~ 3% of China’s emissions). As China seeks to balance high CO2 emissions of coal-fed production with import dependence on oil and gas, improving energy efficiency and coupling green hydrogen emerges as attractive alternatives for decarbonization.

Geographic Equity and Environmental Sustainability of Conference Models: Results of a Comparative Analysis.

We conducted a comparative analysis of in-person, virtual, and hybrid conferences on tuberculosis hosted by Keystone Symposia and examined the number of participants, their country of residence, carbon dioxide equivalents (CO2e) produced, and participant impressions regarding scientific quality. Data were available from three in-person meetings, one virtual meeting, and one hybrid. The virtual conference hosted 2.5-fold more participants compared with the in-person conferences (842 versus an average of 328) from more than double the number of countries (68 versus an average of 33). The virtual conference attracted 4.5-fold more participants from countries with a high burden of tuberculosis, compared with the average in-person conference (209 versus an average of 46). For in-person meetings, an average of 79% of participants were based in high-income countries. For the virtual meeting, 53% of participants were from high-income countries, and 47% from low- and middle-income countries. For the hybrid conference, there were 465 participants from 43 countries, of which 289 attended in person from a total of 20 countries, and 176 participated virtually from 34 countries. Of those who took part in person, 91% were from high-income countries. The average CO2e emissions from an in-person conference was 696 tons of CO2e, with 96.0% from air travel. The virtual meeting produced 0.48 ton of CO2e from electricity usage, a 1,450-fold decrease compared with in-person events. Virtual conferences scored a content quality rating of 87.3% to 90.8% compared with a range of 86.4% to 92.2% for in-person conferences.

Least-cost decarbonization pathways for electricity generation in Finland: A convex quantile regression approach

This study investigates the least-cost decarbonization pathways in the Finnish electricity generation industry in order to achieve the national carbon neutrality goal by 2035. Various abatement measures, such as downscaling production, capital investment, and increasing labor and intermediate inputs, are considered. The marginal abatement costs (MACs) of greenhouse gas emissions are estimated using the convex quantile regression method and applied to unique register-based firm-level greenhouse gas emission data merged with financial statement data. We adjust the MAC estimates for the sample selection bias caused by zero-emission firms by applying the two-stage Heckman correction. Our empirical findings reveal that the median MAC ranges from 0.1 to 3.5 euros per tonne of CO2 equivalent. The projected economic cost of a 90% reduction in emissions is 62 million euros, while the estimated cost of achieving zero emissions is 83 million euros.

Effect of aging on the mechanical properties of woven fabric-reinforced calcined diatomite substituted cement-based composites

The mechanical characteristics of polyester and flax woven fabric-reinforced, diatomite-substituted, cement-based composites have been examined at different ages within the scope of this study. The use of calcined diatomite in combination with a cement-based matrix aims to improve the mechanical performance within the composite as well as reduce carbon emissions. The consistency of cement-based and diatomite-substituted matrices with water-to-binder proportions of 0.28 and 0.45 was maintained at a fixed flow diameter of 235 mm with the adjusted use of a superplasticizer. The stress–strain graphs of the composites were obtained using an axial tensile testing machine and Linear Variable Differential Transformers (LVDT). The tensile strength, ductility, toughness development, and multi-crack performance of WFRC were obtained as a function of fabric type and aging. The effects of aging on tensile properties are discussed separately for each fabric type. Polyester woven fabric-reinforced composites were found to be superior to flax WFRC in terms of several mechanical properties at all ages. The substitution of diatomite further improved the tensile performance of the polyester woven fabric-reinforced composites. The fabric-matrix interface densification role of diatomite was determined by SEM/EDS line analysis. Evidence of a pozzolanic reaction between portlandite and diatomite was obtained through microstructure studies. Carbon emission analysis revealed that equivalent CO2 emissions could be reduced using diatomite in woven fabric reinforced composites. However, diatomite substitution caused a cost increasing effect.

Role of solar water heater refurbishment in student hostel building to achieve sustainability goals: A techno-economic study

Solar energy technologies are emerging as strong alternatives to their fossil fuel-based conventional counterparts for various applications. Solar water heating system (SWHS) is one of the most adopted technologies all over the world. Moreover, the building sector consumes significant energy from fossil fuels worldwide to meet hot water demand. This fossil fuel consumption can be reduced with the surplus economic and environmental benefits through the refurbishment of SWHSs in residential buildings. Additionally, the student hostels of academic institutes/Universities have great potential to save energy, environment, and money. In view of the same, the technical, economic, and environmental analyses of refurbishing SWHS in the student hostel are presented in the present paper. The analysis is carried out for the hostel named ‘Raman’ of DIT University, located in Dehradun, India. The energy-saving potentials of flat plate collector (FPC)-based and evacuated tube collector (ETC)-based SWHSs to accomplish the hot water demand of selected site are assessed in comparison with electric geyser. Moreover, the economic analysis is also reported in terms of net present value and benefit-to-cost analysis. Whereas the environmental benefit is presented in terms of reduction in equivalent CO2 emissions through implementing both types of considered SWHSs. It is found that the FPC-based and ETC-based SWHSs can fulfil 60.9 % and 67.6 % of the energy demand to heat the required water. Whereas, both of the systems are found economically as well as environmentally beneficial and ETC-based SWHS is recommended for the selected site. The present study may be useful for the energy planning and management of student hostels under academic institutes/Universities.

Patients’ views and behaviours in relation to asthma inhalers use and their impact on environmental sustainability: a cross-sectional survey study

Abstract Introduction Approximately 60 million inhalers are used annually in England, contributing 3% to the National Health Service (NHS) carbon footprint. Of these, 2 out of 3 are metered-dose inhalers (MDIs) containing greenhouse gas propellants.[1] The carbon footprint of an MDI device is around 500g CO2 equivalent, in contrast with the 20g CO2 equivalent of a dry powder inhaler (DPI).[2] The NHS Long Term Plan introduced measures on environmental sustainability, leading to the National Institute of Health Care and Excellence (NICE) launching a ‘shared decision aid’ to promote the discussion of options for inhaler devices. This landmark policy step could be more effective if received with patient support and informed behaviours of patients with regard to inhalers. Research is therefore needed to identify patients’ views and behaviours on this matter. Aim To identify patients’ views and behaviours related to environmental sustainability aspects of their use of inhalers for the management of asthma. Methods An anonymous self-completion paper-based questionnaire was administered to patients with a clinical diagnosis of asthma. These were recruited opportunistically via 10 community pharmacies in the South of England during the month of February 2020. They were provided information about the study and invited to participate by pharmacy staff when collecting prescriptions. Participants had to be prescribed at least one MDI inhaler and not to be using a DPI, and report on the use, disposal and views regarding their environmental impact. Responses to the questionnaire were coded and analysed using descriptive statistics. Results A total of 149 surveys were completed by patients, of which 47% (n=70) were male and 53% (n=79) were female. The age range of respondents varied with the majority 45.6% being 18-29 years old, followed by 21.5% in the 60-69 years category. Of these, 30.2% (n=48) were aware of MDI inhalers having an impact on carbon footprint, and 53% (n=79) on plastic pollution. A majority (81%) of patients stated that they were involved or partially involved in their inhaler choice. Only 62% (n=92) said they would be willing to switch their MDI to a more environmentally friendly inhaler with equal effectiveness, 15.4% (n=23) reported they would not be willing to do so and 22.1% (n=33) were not sure. Unwanted inhalers were returned by 43% (n=64) of participants for appropriate disposal, with 55% (n=82) of respondents being unaware of this option. A majority (91%, n=136) of participants said they would like further information about their inhalers and their impact on the environment. Conclusion There is scope for a more environmentally friendly management of asthma and the use of inhalers. Healthcare professionals are involving patients in decision making when prescribing, and pharmacists could contribute to this when dispensing. Patients would welcome information on the impact of inhalers on the environment and further research could identify more precisely on what aspects, alongside barriers preventing a switch to more environmentally friendly options. A small sample size and geographical area were limitations of this study, which could be overcome by further researching issues identified in this survey.

Environmental Impact Evaluation of Tofu Production using Life Cycle Assessment

Tofu is one of the products made from soybeans that a sizable portion of people in a larger society consume. There are several ways to make tofu, from conventional to modern. The conventional tofu production process generates a lot of waste. Many of the researchers have explored numerous strategies to handle tofu waste in a way that minimizes its harmful influence on the environment. However, in many cases, the environmental impact is simply transferred from one process to another during the treatment of tofu waste. As a result, the whole tofu-making process requires an evaluation of the effects. Among these approaches is life cycle assessment (LCA). The study discovered that energy use was the primary factor leading to environmental impacts. Burning firewood for energy resulted in 55.61 kg of carbon dioxide equivalent. The emission value has been reduced to 32 kg CO₂ eq and 28 kg CO₂ eq, respectively, according to the findings of simulations by utilizing biogas and natural gas as fuels.

Exploring the Environmental Impact of Telemedicine: A Life Cycle Assessment.

Telemedicine has emerged as a potential solution to mitigate the significant greenhouse gas emissions of the healthcare sector. A comprehensive evaluation is required to quantify the environmental benefits of its implementation. The study aims to compare the environmental sustainability of in-person and virtual examinations for heart failure patients. A standard life cycle assessment has been applied to quantify the equivalent CO2 of direct and indirect activities required to release a medical examination (virtual or physical) for a patient in an Italian hospital. Inputs of the analysis include electronic devices of hospital and patients, energy consumption, wastes, internet usage and patient travel. Depending on the type of visit (virtual or physical), inputs have been processed differently, considering actual consumption and utilization. Televisit reduces emissions from 9.77 kgCO2e to 0.41 kgCO2e. Transport and internet data use are key inputs for in-person (i.e., 98%) and telemedicine visits (i.e., 72%), respectively. Given the frequent car travels, telemedicine emerges as a tool to improve environmental benefits and reduce time for patients and caregivers.

Effects of extending dairy cow longevity by adjusted reproduction management decisions on partial net return and greenhouse gas emissions: A dynamic stochastic herd simulation study

Prolonging dairy cattle longevity is regarded as one of the options to contribute to more sustainable milk production. Because failure to conceive is one of the main reasons for culling, this study investigates how adjustments in reproduction management affect partial net return at herd level and greenhouse gas emissions per unit of milk, using a dynamic stochastic simulation model. The effects of reproduction decisions that extend cattle longevity on milk yield, calving interval and pregnancy rate were derived from actual performance of Dutch commercial dairy cows over multiple lactations. The model simulated lactations, calving, and health status events of individual cows for herds of 100 cows. Scenarios evaluated differed in the maximum number of consecutive AI attempts (4, 5, or 6 services), or the production threshold (20, 15, or 10 kg of milk/d) at which cows that failed to conceive are culled (reproductive culling). Annual partial net return was computed from revenues of sold milk, calves, and slaughtered cows, and the costs from feed consumption, rearing replacement heifers, AI services, and treatment for clinical mastitis and lameness. Greenhouse gas emissions were computed for feed production, enteric fermentation, and manure management, and were expressed as total CO2 equivalents (CO2-eq). Average age at culling increased with an increased maximum number of AI services. This increase was larger when going from a maximum of 4 to 5 AI attempts (108 d) than from a maximum of 5 to 6 attempts (47 d). Similarly, the average age at culling increased from 1,968 to 2,040 and 2,132 d when the threshold for reproductive culling decreased from 20, to 15 and 10 kg of milk/d, respectively. Average annual partial net return increased by 1.1% from €165,850 per 100 cows at a maximum of 4 AI to €167,670 per 100 cows at a maximum of 6 AI, and increased by 4.3% from €161,210 per 100 cows at a reproductive culling threshold of 10 kg/d to €168,190 per 100 cows at a threshold of 20 kg/d. Greenhouse gas emissions decreased by 1.2% from 0.926 to 0.915 kg CO2-eq per kg of fat- and protein-corrected milk (FPCM) with an increase in a maximum number of AI from 4 to 6 AI. Conversely, greenhouse gas emissions increased by 0.2% from 0.926 kg at a threshold of reproductive culling of 20 kg/d to 0.928 kg CO2-eq/kg FPCM at a threshold of 10 kg/d. Although lowering the threshold for reproductive culling has the potential to extend cattle longevity more than increasing the maximum number of AI services, only the increase in AI services benefits a farm's partial net return, while reducing greenhouse gas emissions.

Teleconsultation for Preoperative Anesthesia Evaluation: Identifying Environmental Potentials by Life Cycle Assessment.

Introduction: Teleconsultations for preoperative evaluation in anesthesiology proved to be feasible during the COVID-19 pandemic. However, widespread implementation of teleconsultations has not yet occurred. Besides time savings and economic benefits, teleconsultations in anesthesia may have the potential to reduce CO2 emissions. Methods: We conducted a life cycle assessment based on prospective surveys to assess the potential environmental benefits of preoperative anesthesia teleconsultations in comparison to the status-quo in-person consultations. Within 1 month, all patients presenting at the preoperative anesthesia clinic at RWTH Aachen University Hospital were asked about the distance traveled and mode of transportation to the hospital. The main outcome measure was the potential environmental benefit resulting from the implementation of teleconsultations. Results: In total, 821 out of 981 patients presenting at the anesthesia clinic participated in the survey. Most patients visited on an outpatient basis (62.9%) and traveled by car (81.7%). The median travel distance was 25 km [interquartile range 12-40]. If patients who came to the hospital solely for the anesthesia appointment had scheduled virtual appointments, the emissions of 3.03-ton CO2 equivalents (CO2-eq) could be avoided in the first month after implementation. The environmental impact associated with the production of teleconsultation equipment is outweighed by the reduction in patient travel. If all outpatient appointments were performed virtually, these savings would triple. Within 10 years, more than 1,300 tons CO2-eq could be avoided. Conclusion: Teleconsultations can mitigate the environmental impact of in-person anesthesia consultations. Further research is essential to leverage teleconsultations for preoperative evaluation also across other medical specialties.

Assessing the circularity status of waste management among manufacturing, waste management, and recycling companies in Kigali, Rwanda

A high quantity of waste is generated from industrial activities by manufacturers across metropolitan cities compared to smaller cities with fewer industrial activities. Adopting Circular Economy principles in waste management has the potential for sustainable waste management to reduce the quantity of waste at dumpsites and harmful emissions from wastes. The study was conducted to assess circularity status and challenges for attaining higher circularity by Kigali’s manufacturing, waste collection, and waste recycling companies using the 10-R framework. The study also sought to build estimates for industrial solid waste quantity and methane emissions for the next 10 years (2020–2030) in Rwanda. A mixed method approach was utilized where primary data was collected from manufacturing, waste collection, and waste recycling companies using a validated questionnaire and an in-depth interview guide. Thematic, descriptive analysis and First Order Decay methods were used to analyze the qualitative, quantitative, and secondary data. Results show that adopting the 10-R principles of circular economy was low and varies across manufacturing, waste collection and recycling companies. There were instances of high adoption of R3-Reuse and R8-Recycle with a mean score of 7.17 and 7.21 among manufacturing companies. R7-Repurpose (8.80) recorded a high adoption rate among waste collection companies and a medium level of adoption for R7-Repurpose (3.50) and R9-Recover (3.00) among recycling companies. The overall low adoption toward attaining circularity was attributed to various economic, institutional, infrastructural, operational, attitudinal, and technological challenges. In 2030, it is projected that 922 Gg of industrial waste will be deposited in solid waste disposal sites in Rwanda; with an estimated methane emission of 157 Gg Carbon dioxide equivalence. It was recommended among others, that human resource capacity development should be prioritized to drive the adoption of the 10-R principles across manufacturing, waste collection, and waste recycling companies in Kigali, which can reduce the quantity of wastes that ends at dumpsites and methane emissions that contribute significantly to global warming.

Global warming, a global energy resource

Global warming is a thermodynamics problem. When excess heat is added to the climate system, the land warms more quickly than the oceans due to the land’s reduced heat capacity. The oceans have a greater heat capacity because of its higher specific heat and the heat mixing in the upper layer of the ocean. Thermodynamic Geoengineering (TG) is a global cooling method which deployed at scale would generate 1.6 times the world’s current supply of primary energy and remove carbon dioxide (CO2) from the atmosphere. The cooling would mirror the ostensible 2008–2013 global warming hiatus. At scale 31,000 1-gigawatt (GW) ocean thermal energy conversion (OTEC) plants are estimated to be able to: a) displace about 0.8 watts per square meter (W/m2) of average global surface heat from the surface of the ocean to deep water that could be recycled in 226-year cycles, b) produce 31 terawatts (TW) (relative to 2019 global use of 19.2 TW and c) absorb about 4.3 Gt CO2 per year from the atmosphere by cooling the surface. The estimated cost of these plants is $2.1 trillion per year or 30 years to ramp up to 31,000 plants which are replaced as needed thereafter. Compared for example to the cost of world oil consumption that in 2019 was $2.3 trillion for 11.6 TW. The cost of the energy generated is estimated at $0.008/KWh.

Global warming, a global energy resource

Global warming is a thermodynamic problem. When excess heat is added to the climate system, the land warms more quickly than the oceans due to the land’s reduced heat capacity. The oceans have a greater heat capacity because of their higher specific heat and the heat mixing in the upper layer of the ocean. Thermodynamic Geoengineering (TG) is a global cooling method that, when deployed at scale, would generate 1.6 times the world’s current supply of primary energy and remove carbon dioxide (CO2) from the atmosphere. The cooling would mirror the ostensible 2008–2013 global warming hiatus. At scale, 31,000 1-gigawatt (GW) ocean thermal energy conversion (OTEC) plants are estimated to be able to: a) displace about 0.8 watts per square meter (W/m2) of average global surface heat from the surface of the ocean to deep water that could be recycled in 226-year cycles, b) produce 31 terawatts (TW) (relative to 2019 global use of 19.2 TW); c) absorb about 4.3 Gt CO2 per year from the atmosphere by cooling the surface. The estimated cost of these plants is $2.1 trillion per year, or 30 years to ramp up to 31,000 plants, which are replaced as needed thereafter. For example, the cost of world oil consumption in 2019 was $2.3 trillion for 11.6 TW. The cost of the energy generated is estimated at $0.008/KWh.

Development of a sustainable geopolymer using blast furnace slag and lithium hydroxide

Ground Granulated Blast furnace Slag (GGBS) is a promising alternative to ordinary Portland cement due to its potential to reduce CO2 emissions. However, the limited binding capability of pure GGBS necessitates the use of alkaline activators to enhance its hydration behaviour. The present work establishes the use of lithium hydroxide (LiOH), which can be synthesized by recycling lithium-ion batteries, as an effective alkaline activator for GGBS. Experimental results demonstrate that a 10 M LiOH solution enhances the hydration of GGBS 36 folds. LiOH activated GGBS exhibits the presence of hydration products such as lithium-alumino-silicate-hydrate and calcium-silicate-hydrate from day 1 of hydration, while GGBS mixed with DI water shows onset of hydration only after 28 days. Thermogravimetry results from long-term hydration studies indicate that LiOH activated GGBS forms a 73% higher quantity of hydration products as compared to cement paste samples. Additionally, LiOH activated GGBS demonstrates 42% and 46% higher compressive strength than GGBS activated with NaOH and Na2SiO3 at 7 and 28 days, respectively. Embodied energy analysis reveals that geopolymer prepared with GGBS and recycled LiOH leads to equivalent CO2 emissions reduction of 83% compared to NaOH based geopolymer and 85% compared to cement concrete.

Development of Regenerative Tea Cultivation Models through Dual Approach of Soil and Plant Health Management towards Crop Sustainability, Soil Quality Development, Pesticide Reduction and Climate Change Mitigation: A Case Study from Lakhipara Tea Estate,

Climate change is a reality and its impact on the tea plantations is apparent in the rise of pest intensity, higher agrochemical use, inconsistent crop yields, declining grand growth period, increased abiotic stress and various other challenges; that threaten long-term sustainability of the Indian tea sector. The urgency to adopt sustainable practices is increasing by the day but to gain time bound results a comprehensive focus encompassing soil and plant health development will be crucial. To deal with climate challenge head-on, the Indian tea industry is making changes at various levels of operations. The sustainable tea initiative at Lakhipara tea estate, was one such attempt by the Goodricke Group Limited in their Dooars tea growing region of West Bengal. The program was initiated in 2014 with an aim to reduce pesticide use, improve soil quality, and produce quality teas while sustaining crop yields, improving renewable energy use and lowering the carbon footprint. Adoption of Inhana Rational Farming (IRF) Technology and taking the essence from ‘Trophobiosis Theory’ of French Scientist F. Chaboussou, the program focused on management of soil and plant health. Three years evaluation of crop yields in respect of the budgeted crop, revealed on an average an excess of 78 kg/ha/year in the project area. In rest of the garden area a contrasting crop loss of 118 kg was recorded per ha during the same period. The higher crop performance positively correlated with the higher nutrient use efficiency which was 17.7 percent higher in the project area (NUENPK : 8.86) as compared to the general garden area (NUENPK : 7.53), which reflected the impact of plant health management towards enhanced nutrient uptake, assimilation and utilization. Assessment of pesticide usage, revealed up to 77% decrease in usage in the project area during 2014-16, as compared to the pre- project year. Comparison with pesticide usage of the Dooars tea growing region during this same period, indicated a 62% lower Crop Pesticide Pollution Index (CPPI) in the project area. The finding indicated a 52 to 77% reduction in the accumulated toxicity potential of the applied pesticides in the project area; thereby accrediting safer tea development under this program, when adjudged in terms of pesticide residue. Assessment of soil quality revealed an overall eight percent increment in Soil Fertility Index (FI) value, with significant improvement in soil microbial activity potential (MAP) values i.e., by almost four times. The finding pointed towards the favourable impact of soil health management primarily through Novcom composting towards enhancement of soil microbial interactions. Post three years of experimentation the overall Soil Quality Iindex (SQI) value increased by 6% in the project area. The finding corroborated a concurrent 6.72% increase in the soil organic carbon stock during the same period. Reduction in use of non- renewable inputs viz. chemical fertilizers and pesticides in the project area was indicated by approximately 40 percent enhancement in energy use efficiency and energy productivity post the assessment period. Carbon assessment in terms of kg CO2 equivalents/ kg made tea (using ACFA version 1.0) indicated approx. 65 to 70 % lower footprint in the project area, primarily due to 20 to 30 % reduction in chemical fertilizers and 60 to 70 % reduction in the use of synthetic pesticides. The results indicated that while integrated soil management is the pre-requisite criteria towards rejuvenation of soil health and for restoration of the habitat for predators, it does not play a direct role in reducing the pest pressure and simultaneously the requirement of pesticides. Physiologically activated plants/ bushes on the other hand; due to their higher nutrient assimilation capacity and efficient protein synthesis are always lesser susceptible to pest attack. Hence, focus on activation of plant physiology can reduce the plant- pest interaction leading to a natural reduction in the requirement for pesticides vis-à-vis the pesticide usage.