Mitigate Global Warming Research Articles

Closed-Loop and Precipitation-Free CO2 Capture Process Enabled by Electrochemical pH Gradient.

Carbon dioxide (CO2) capture is a crucial negative-emission technology for the mitigation of climate change and global warming. The urgent need of combating climate change motivates the research and development of economical, effective and environmentally benign processes for CO2 capture. Herein, we design and report a flow cell for the CO2 capture from air or flue gas in a precipitate-free and closed-loop manner. No ion-exchange membrane is used in the electrolyser. The water electrolysis produces acidic solution near the anode and alkaline solution near the cathode, while generating valuable hydrogen and oxygen byproducts. The dilute CO2 in air or flue gas is captured by the alkaline solution, which is then mixed with the acidic solution to release the concentrated CO2. The process operates in a cyclic manner as driven by the water electrolysis and the mechanical pumping. No precipitation of calcium carbonate is involved for fixing CO2, which may simplify the separation process and minimizing the materials loss. The simple process enabled by electrochemical pH gradient shows promise for efficient CO2 capture on both small and large scales.

Accounting of weathering enhancement by mafic mineral spreading for CO 2 storage

The reduction of atmospheric CO 2 is an urgent global issue in the mitigation of global warming. Carbonate acts as a carbon sink in Earth's surface layer, and the weathering of terrestrial silicates and the deposition of oceanic calcium carbonate and organic matter mainly determine atmospheric and oceanic carbon dynamics on geological time scales. Various CO 2 reduction approaches have been evaluated, and the weathering acceleration method is expected to be a low-cost approach. This study attempts to estimate carbonate precipitation potential and dissolution rate from alkali leaching rates using weathering tests on mafic rocks. Based on Japan's annual average rainfall, the in situ carbonate precipitation potential obtained by spreading an olivine mineral or basalt rock powder at 40 ton-powder/ha was on the order of 10 -3 ton/year/ton-rock. This weathering rate could not be greatly accelerated under natural temperature conditions and fine granulation of the minerals.

Effective Utilisation of AI to Improve Global Warming Mitigation Strategies through Predictive Climate Modelling

Effective Utilisation of AI to Improve Global Warming Mitigation Strategies through Predictive Climate Modelling

Phosphorus limitation promotes soil carbon storage in a boreal forest exposed to long‐term nitrogen fertilization

AbstractForests play a crucial role in global carbon cycling by absorbing and storing significant amounts of atmospheric carbon dioxide. Although boreal forests contribute to approximately 45% of the total forest carbon sink, tree growth and soil carbon sequestration are constrained by nutrient availability. Here, we examine if long‐term nutrient input enhances tree productivity and whether this leads to carbon storage or whether stimulated microbial decomposition of organic matter limits soil carbon accumulation. Over six decades, nitrogen, phosphorus, and calcium were supplied to a Pinus sylvestris‐dominated boreal forest. We found that nitrogen fertilization alone or together with calcium and/or phosphorus increased tree biomass production by 50% and soil carbon sequestration by 65% compared to unfertilized plots. However, the nonlinear relationship observed between tree productivity and soil carbon stock across treatments suggests microbial regulation. When phosphorus was co‐applied with nitrogen, it acidified the soil, increased fungal biomass, altered microbial community composition, and enhanced biopolymer degradation capabilities. While no evidence of competition between ectomycorrhizal and saprotrophic fungi has been observed, key functional groups with the potential to reduce carbon stocks were identified. In contrast, when nitrogen was added without phosphorus, it increased soil carbon sequestration because microbial activity was likely limited by phosphorus availability. In conclusion, the addition of nitrogen to boreal forests may contribute to global warming mitigation, but this effect is context dependent.

Modelling carbon capture from power plants with low energy and water consumption using a novel cryogenic technology

Global warming mitigation requires modern energy generation technology to integrate low-cost carbon capture techniques. Despite volumes of research on the latter, the significantly high unit energy (MWh) of capture and high water consumption, do not enable any current carbon capture techniques to be adopted at a scale. To address this problem, we theoretically explore a novel low-cost carbon capture technology (NLCCT). In this paper, a detailed thermodynamic analysis of the effects of the operating conditions and parameters of NLCCT, such as the initial feed gas concentration, compressor intercooler temperature, number of compressor stages, efficiencies of the compressors, and turbines, ambient temperatures on the energy consumption for CO2 capture (ECC) is carried out with a view to obtain costs much lower than current techniques. The study identifies the inlet feed concentration, turbine and compressor efficiencies, and compressor intercooler temperatures (heat transfer effectiveness) as the significant parameters. For a drop of 20 % efficiency, the ECC was found to increase by 40 %, and for an increase in inlet CO2 feed concentration from 4 % to 10 %, the ECC was found to decrease by 31 %. Considering the effect of intercooler temperatures, the ECC increases by 25 % when the intercooler temperature is raised by 6 K. The effect of ambient conditions was also analyzed and observed that for an increase of 27C in the ambient temperature, the ECC would rise by 15 %.

Soil macroaggregate-occluded mineral-associated organic carbon drives the response of soil organic carbon to land use change

Understanding land use effects on carbon sequestration in various soil fractions is vital to mitigating climate change and restoring soil functions. The objective of this study was to explore the effects of land use on soil organic carbon (SOC) fractions in different soil types. For this purpose, we studied the effects of long-term (>20 years) land use including dryland pasture (DP), irrigated pasture (IP) and irrigated cropland (IC) on SOC in water-stable aggregates, particle-size fractions, and their coupling relations at the surface soils (0–7.5 cm) in the Canterbury Plains, New Zealand. For each land use, three typical soil types with contrasting drainage levels (i.e. well drained Lismore soil, LIS; imperfectly drained Templeton soil, TEM; and poorly drained Waterton/Temuka soil, WAT) were selected. Macroaggregate-occluded mineral-associated organic carbon (M-MAOC) contributed to the majority of the total SOC difference and drove the response of SOC to land use change. On average, M-MAOC followed an order of IP > DP > IC. The effects of land use change from DP to IP and IC on M-MAOC varied, and these variations were dependent on soil type. The relative gain in M-MAOC with change in land use from DP to IP was the greatest in the well drained LIS soil, while both the relative and absolute loss in M-MAOC following the land use change to IC was the greatest in the poorly drained WAT soil. The interactive effects of managements (e.g. irrigation and cultivation) and soil type (e.g. soil water condition) on aggregate size distribution and macroaggregate-associated C concentration were important in explaining the responses of M-MAOC to land use change. This study advances the mechanistic understanding of total SOC dynamics in response to land use (changes) in different soil types. It also highlights the potential of M-MAOC to serve as a diagnostic fraction to reflect changes in total SOC, which may have application to global warming mitigation.

Global Warming Mitigation Innovation Through Household Waste Management Becomes Eco-Enzyme: A Review

The dumping of fruit and vegetable waste into landfills contributes to an increase in methane gas that contributes to global warming. Waste materials in the form of fruits and vegetables can be used and processed into eco-enzymes. Fermented waste enzymes have a variety of benefits and add value to materials that have been tended to be wasted. This environmentally friendly enzyme has been utilized ranging from disinfectants, floor cleaners, dishwashers to liquid organic fertilizers. The production of eco-enzymes in addition to being able to reduce the volume of household waste, also contributes to the reduction of methane gas. During the fermentation process produces O3 (ozone) which is beneficial in maintaining ozone content in the atmosphere. This means that eco-enzyme production becomes an innovation in mitigating global warming from the household level. The manufacture of eco-enzymes is an effort to provide economic value to waste that has a positive impact on the environment and is a step to maximize the utilization of natural resources better known as circular economies. The advantages of eco-enzyme production in the short term are the ability to maximize raw materials and provide economic value and reduce the cost of handling household waste.

A mathematical modelling for solar irradiance reduction of sunshades and some near-future albedo modification approaches for mitigation of global warming

To address the global warming problem, one of the space-based geoengineering solutions suggests the construction of an occluding disc that can work as a solar curtain to mitigate solar irradiation penetration to the earth atmosphere. A widely discussed concept needs the construction of a large-scale sunshade system near the Sun–Earth L1 equilibrium point in order to control the average global temperature. However, to improve the accuracy of theoretical estimations, more consistent modeling of the Sun-Curtain-Earth system and solar irradiance reduction rate are required. This study revisits the mathematical modeling of the solar irradiance reduction system and considers the fundamentals of shading physics. Simplified mathematical modeling of solar irradiance reduction rate is derived based on the solar flux density. For the climate control, controllability of the reduction rate by using some physical parameters (e.g., flux reflection rate and angle of the curtain) is discussed. Based on the results of this model, the technical challenges and feasibility of constructing a sunshade system at L1 Lagrange point are evaluated. Some technologically feasible, near-future options for the warming problem are discussed briefly.

Optimizing CO2 hydrate storage: Dynamics and stability of hydrate caps in submarine sediments

Addressing the escalating impacts of climate change, this study explores the potential of CO2 storage in submarine sediments, presenting a promising strategy for sustainable global warming mitigation. We examine the dynamics and stability of CO2 hydrate caps using magnetic resonance imaging to investigate their spatial-temporal distribution under varying flowrates and storage pressures. Our findings indicate that hydrate caps predominantly expand along the flow direction, influenced significantly by the state of CO2 (liquid or gas) and operational parameters (storage pressure and CO2 flowrate). Notably, higher flowrates and pressures expedite hydrate formation, thereby mitigating the risks of injection well blockages and enhancing cap stability. However, excessively rapid formation may compromise cap thickness and effectiveness. The study delineates optimal conditions that sustain hydrate cap integrity, advocating for a minimum safety pressure of 9000 kPa to prevent failure. These insights significantly advance the development of efficient CO2 storage strategies in submarine environments, offering vital guidance for policy and industry practices aimed at achieving carbon neutrality. By highlighting the technological challenges and solutions associated with deep-sea CO2 storage, this research contributes to the broader discourse on innovative approaches to climate change mitigation.

Forecast modeling of the resource potential of forests in the volga river basin for the regulation of carbon cycle and mitigation of global warming

Forecast modeling of the resource potential of forests in the volga river basin for the regulation of carbon cycle and mitigation of global warming

What’s the difference between factors influencing household waste management and energy-saving behavior? A meta-analysis

PurposeThis study aims to identify the key factors that influence household pro-environmental behaviors (HPEBs) and explore the differences caused by the same influencing factors between household waste management behavior (HWM) and household energy-saving behavior (HES).Design/methodology/approachA meta-analysis was conducted on 90 articles about HPEBs published between 2009 and 2023 to find the key factors. HPEBs were further categorized into HWM and HES to investigate the difference influenced by the above factors on two behaviors. The correlation coefficient was used as the unified effect size, and the random-effect model was adopted to conduct both main effect and moderating effect tests.FindingsThe results showed that attitude, subjective norms, and perceived behavioral control all positively influenced intention and HPEBs, but their effects were stronger on intention than on HPEBs. Intention was found to be the strongest predictor of HPEBs. Subjective norms were found to have a more positive effect on HES compared to HWM, while habits had a more positive effect on HWM. Furthermore, household size was negatively correlated with HWM but positively correlated with HES.Originality/valueThe same variables have different influences on HWM and HES. These results can help develop targeted incentives to increase the adoption of HPEBs, ultimately reducing household energy consumption and greenhouse gas emissions and contributing to the mitigation of global warming.

Characterization of Several Pellets from Agroforestry Residues: A Comparative Analysis of Physical and Energy Efficiency

The use of agroforestry biomass provides several advantages, both from an environmental point of view, in terms of the mitigation of global warming, and in terms of a circular economy for agricultural or agroforestry companies that reuse pruning residues as a source of energy. However, even if the use of energy pellets resulting from the pruning residues of various agroforestry species has excellent potential for the valorization of agricultural by-products, the physicochemical characteristics of these pellets have been scarcely studied by the scientific community. In this context, this study aims to assess the valorization potential of various lignocellulosic material residues produced during agroforestry activities. The objectives of the study include evaluating the chemical and physical characteristics of pellets produced with different mixtures of agroforestry biomass (olive, citrus, black locust, poplar, paulownia, etc.) in order to determine the optimal pellet blend from an energy and physicochemical perspective. The results of this study demonstrate that this comprehensive analysis provides valuable information on the optimization of biomass mixtures for better energy valorization, addressing both compositional and combustion-related challenges. In fact, it is observed that the addition of citrus and olive biomass to the various mixtures increases their energy potential. Furthermore, all of the pellets analyzed are found to possess an adequate and useful durability index (PDI) for their handling during storage and transport operations. This study demonstrates that olive and citrus pruning residues can be used to improve biomasses that have poor suitability in energetic, physical, and chemical terms. Further studies could be useful to understand which specific interaction mechanisms have an influence on emissions in order to optimize mixtures using different biomass sources for sustainable energy production.

Potential of achieving sustainable development through integrated optimization of mariculture species based on the food-energy-water nexus in China

The sustainability of mariculture possesses substantial enormous potential in food security and the mitigation of global warming. Based on the food‑carbon-water nexus, this study assessed the carbon and water footprints of mariculture in China, identified key drivers, and constructed a multi-objective optimization model of mariculture structure. Results showed that the carbon and water footprints of mariculture in China increased continuously from 2008 to 2020, with the intensity of carbon footprint increasing from 0.08 to 0.14 t CO2/t and that of water footprint increasing from 5436.72 to 6169.01 m3/t. Shellfish showed lower intensity of footprints than fish and crustaceans. The carbon footprint intensity of mariculture was high in Tianjin and Hainan but resulted in negative carbon emissions in Shandong and Liaoning. Hainan, Hebei, and Liaoning provinces had the highest average annual water footprint intensity. Provincial population and total mariculture production significantly impacted the carbon and water footprints of mariculture. Optimizing mariculture species structure can reduce carbon and water footprints while increasing protein production. However, a large gap still exists between the current development and optimization scenarios for mariculture structure in China. A targeted increase in the production of mariculture species such as plaice in Tianjin, American redfish in Guangxi, oysters and scallops in Guangdong, wakame in Liaoning, and gracilaria in Fujian, can help promote low carbon and water-saving practices, thus achieving sustainable mariculture development. Therefore, China's mariculture should continuously optimize its structure and enhance carbon sink capacity in the future.

Remittance from migrants reinforces forest recovery for China's reforestation policy.

Forests play a key role in the mitigation of global warming and provide many other vital ecosystem goods and services. However, as forest continues to vanish at an alarming rate from the surface of the planet, the world desperately needs knowledge on what contributes to forest preservation and restoration. Migration, a hallmark of globalization, is widely recognized as a main driver of forest recovery and poverty alleviation. Here, we show that remittance from migrants reinforces forest recovery that would otherwise be unlikely with mere migration, realizing the additionality of payments for ecosystem services for China's largest reforestation policy, the Conversion of Cropland to Forest Program (CCFP). Guided by the framework that integrates telecoupling and coupled natural and human systems, we investigate forest-livelihood dynamics under the CCFP through the lens of rural out-migration and remittance using both satellite remote sensing imagery and household survey data in two representative sites of rural China. Results show that payments from the CCFP significantly increases the probability of sending remittance by out-migrants to their origin households. We observe substantial forest regeneration and greening surrounding households receiving remittance but forest decline and browning in proximity to households with migrants but not receiving remittance, as measured by forest coverage and the Enhanced Vegetation Index derived from space-borne remotely sensed data. The primary mechanism is that remittance reduces the reliance of households on natural capital from forests, particularly fuelwood, allowing forests near the households to recover. The shares of the estimated ecological and economic additionality induced by remittance are 2.0% (1.4%∼3.8%) and 9.7% (5.0%∼15.2%), respectively, to the baseline of the reforested areas enrolled in CCFP and the payments received by the participating households. Remittance-facilitated forest regeneration amounts to 12.7% (6.0%∼18.0%) of the total new forest gained during the 2003-2013 in China. Our results demonstrate that remittance constitutes a telecoupling mechanism between rural areas and cities over long distances, influencing the local social-ecological gains that the forest policy intended to stimulate. Thus, supporting remittance-sending migrants in cities can be an effective global warming mitigation strategy.

A hydrate-based post-combustion capture system integrated with cold energy: Thermodynamic analysis, process modeling and energy optimization

Carbon capture is a crucial part of global warming mitigation. Carbon capture via clathrate hydrate is an attractive approach due to its high capture capacity, high carbon dioxide purity, water-based benign process, ease of recycling, and robustness to contaminants. In this work, we propose a two-stage hydrate-based carbon dioxide separation system integrated with cold energy for carbon capture from flue gases. A thermodynamic cycle consisting of two sub-cycles was constructed to simulate the process. Operating conditions were optimized within the range of 274.15–282.15 K and 0.1–28.04 MPa, resulting in the lowest electricity consumption of 2.22 MJ/kg CO2 with 95.24 mol% CO2 purity and 65.97 % CO2 recovery. A higher CO2 recovery rate can be achieved by recycling the residual gas of Sub-cycle 2. Gas compression to the high operating pressure (16.01 MPa) is the major contributor to electricity consumption. By incorporating 100 % expansion work recovery from the high-pressure gases, the electricity consumption can be reduced to 0.43 MJ/kg CO2 (i.e., 0.119 kWh/kg CO2). A more realistic scenario assuming 80 % compression/pumping efficiency and 90 % expansion work recovery gives an electricity consumption of 1.16 MJ/kg CO2 (i.e., 0.322 kWh/kg CO2), representing an energy penalty of 33.1 % for a coal-fired power plant. Future direction for further improvement could be a paradigm shift to hydrate process with thermodynamic promoters, which can potentially reduce the operation pressure by over 90 % and thus cut down the energy consumption dramatically. This work established a framework to simulate the hydrate-based carbon capture process, evaluated its minimum energy consumption and examined how operating conditions affect the separation performance. The results could offer valuable guidelines for the design and optimization of real hydrate-based carbon capture systems.

Application of microbially induced calcium carbonate precipitation (MICP) process in concrete self-healing and environmental restoration to facilitate carbon neutrality: a critical review.

Soil contamination, land desertification and concrete cracking can have significant adverse impacts on sustainable human economic and societal development. Cost-effective and environmentally friendly approaches are recommended to resolve these issues. Microbially induced carbonate precipitation (MICP) is an innovative, attractive and cost-effective in situ biotechnology with high potential for remediation of polluted or desertified soils/lands and cracked concrete and has attracted widespread attention in recent years. Accordingly, the principles of MICP technology and its applications in the remediation of heavy metal-contaminated and desertified soils and self-healing of concrete were reviewed in this study. The production of carbonate mineral precipitates during the MICP process can effectively reduce the mobility of heavy metals in soils, improve the cohesion of dispersed sands and realize self-healing of cracks in concrete. Moreover, CO2 can be fixed during MICP, which can facilitate carbon neutrality and contribute to global warming mitigation. Overall, MICP technology exhibits great promise in environmental restoration and construction engineering applications, despite some challenges remaining in its large-scale implementation, such as the substantial impacts of fluctuating environmental factors on microbial activity and MICP efficacy. Several methods, such as the use of natural materials or wastes as nutrient and calcium sources and isolation of bacterial strains with strong resistance to harsh environmental conditions, are employed to improve the remediation performance of MICP. However, more studies on the efficiency enhancement, mechanism exploration and field-scale applications of MICP are needed.

Valorizing inherent resources from waste streams for in-situ CO2 capture and sequestration in the steel industry

The imperative need for decarbonization within the energy-intensive steel industry, a pivotal sector for meeting global warming mitigation targets, underscores the significance of deploying cost-effective CO2 capture and sequestration (CCS) measures. The substantial external costs and resource consumption associated with traditional CCS methods present practical challenges. Here, we proposed a pragmatic strategy to integrate CCS into the steel industry through recycling inherent resources from steelmaking waste streams for in-situ CCS (ICCS). The composites prepared from blast furnace slag (BFS) and steel slag (SS) demonstrated the capacity to capture a maximum of 2.77 mol/kg of CO2 from the simulated flowing flue gas at 75 °C, and the energy required could be sourced from steelmaking waste heat. Comprehensive characterizations revealed the evolution of phase compositions and pore structures in different BFS/SS-incorporated composites, providing insights into accelerating the carbonation by elevating temperatures and SS dosages. Notably, ICCS strategy was validated to offer significant potential in CO2 emission reduction (up to −570.0 kg CO2e/t) normalized by compressive strength of the conventional construction materials. Overall, ICCS strategy can minimize the external resource consumption and additional units for implementing collaborative waste recycling in the steel industry with significant environmental benefits.

Micro-layered film and foam alternating structures: A novel passive daytime radiative cooling material

This study investigates the confined foaming mechanisms and passive cooling performance of Micro-/Nano-Layered (MNL) film/foam alternating structures. These structures consist of solid poly(carbonate) (PC) film layers and foamed poly(methyl methacrylate) (PMMA) layers. We examine the impact of confinement effects, layer thicknesses, and foaming conditions on cell morphology, cell nucleation, growth, and bulk expansion behavior. Samples ranging from 1 to 513 layers were foamed at 20 MPa and temperatures between 70 and 150°C. We identified three distinct cell structures—multiple, double, or single row(s) of cells—in MNL film/foam structures. We observed that cell size decreases and cell nucleation density increases with increasing layer count. The highest cell nucleation density (1.1×1013 cells/cm3) and smallest cell size (400 nm) were achieved in a 513-layer sample foamed at 70°C and 20 MPa. MNL samples primarily expand vertically, with the apparent expansion ratio ranging from 2.3 to 11 times as layers increase. Samples with double or single row(s) of cells exhibited tensile strengths (∼30 MPa) comparable to their solid counterparts and thermal conductivities (29.7 mW/m·K) comparable to air. Our samples exhibited high solar radiation reflection (93.5 %) and strong infrared emissivity (91.2 %) in the atmospheric transparent window. Mid-day passive cooling experiments showed an average temperature of 17.7°C lower under our sample than ambient conditions. Given these combined properties and the cost-effective nature of the manufacturing method, our samples are readily applicable for building applications, offering significant energy savings and contributing to the mitigation of global warming.

Living emission abolish filters (LEAFs) for methane mitigation: design and operation

As one of the most potent greenhouse gases, methane is a critical target for the near-term mitigation of global warming. Efficient, scalable, easy-to-implement, and robust mitigation technologies are urgently needed to assist in reaching methane abolishment. The goal of this research was to test the applicability of active, extremophilic methanotrophic cells as a baseline concept for engineered systems aiming at methane capturing. The system, named living emission abolish filters (LEAFs), represents an array of immobilized biomaterials capable of capturing methane directly from vent streams. The biomaterials were made using cells of Methylotuvimicrobium alcaliphilum 20ZR, a robust halophilic methanotrophic bacterium with the ability to consume methane gas at low concentrations. Several critical parameters were tested, including (i) the composition of the matrix and optimal immobilization to increase catalyst load, (ii) the stability of methanotrophic cells, and (iii) the toxicity of trace gases (i.e. CO). We found that hydrogels coated with 2.3 mg cell dry weight/cm3 methanotrophic cells represent the best-performing biomaterials. The methane reduction potential of LEAFs fluctuated from 20% to 95% and depended on the methane concentration in the gas stream and the stream flow rates. The potential for commercial-scale deployment and emissions reductions was also evaluated. Total greenhouse gas emissions (combined using the global warming potential GWP100) from an example using a ventilation air methane source over a one-year period was shown to be reduced in two LEAF scenarios by 51% and 75%. Over longer time horizons, more significant reductions are possible as consistent methane consumption can be sustained. The study highlights the overall potential of the liquid-free bio-based composite methane mitigation system. Further improvements essential for system assembly and implementations should include (a) optimization of the cell immobilization protocols to improve cell load and the shelf-life of the system and (b) implementation of matrix moldings for cell immobilization to achieve optimal gas flow and increase the cell-gas interface.

Substantial cooling effect from aerosol-induced increase in tropical marine cloud cover

With global warming currently standing at approximately +1.2 °C since pre-industrial times, climate change is a pressing global issue. Marine cloud brightening is one proposed method to tackle warming through injecting aerosols into marine clouds to enhance their reflectivity and thereby planetary albedo. However, because it is unclear how aerosols influence clouds, especially cloud cover, both climate projections and the effectiveness of marine cloud brightening remain uncertain. Here we use satellite observations of volcanic eruptions in Hawaii to quantify the aerosol fingerprint on tropical marine clouds. We observe a large enhancement in reflected sunlight, mainly due to an aerosol-induced increase in cloud cover. This observed strong negative aerosol forcing suggests that the current level of global warming is driven by a weaker net radiative forcing than previously thought, arising from the competing effects of greenhouse gases and aerosols. This implies a greater sensitivity of Earth’s climate to radiative forcing and therefore a larger warming response to both rising greenhouse gas concentrations and reductions in atmospheric aerosols due to air quality measures. However, our findings also indicate that mitigation of global warming via marine cloud brightening is plausible and is most effective in humid and stable conditions in the tropics where solar radiation is strong.