Climate change components such as increased in atmospheric carbon dioxide (CO2) and rising sea levels are likely to affect mangrove ecosystems. Healthy mature propagules of A. marina var. acutissima and B. parviflora were subjected to two tidal treatments; shallow and deep; for six months. Shallow treatment mimicked the current tidal fluctuations and deep treatment simulated future tidal conditions under rise in sea level. Deep treatment decreased Amax of both species and significant two way interactions between tidal treatments and species were observed. A400 was significantly reduced in the deep treatment in B. parviflora but not in A. marina. Carbon dioxide compensation point was not affected by the tidal treatments but varied significantly between both species. The ratio A400/Amax was significantly lower in the shallow treatment in B. parviflora indicating higher carbon sink potential at moderate tidal flooding whereas A400/Amax of A. marina was less variable between tidal treatments. Chlorophyll conductance was insensitive to tidal flooding but was significantly higher in B. parviflora than in A. marina. Carbon sequestration of B. parviflora was substantially reduced in the deep treatment while the difference between tidal treatments was much less in A. marina. These results indicated that these two species responded differently under tidal flooding where A. marina was less sensitive to tidal. Thus, A. marina is better adapted to the projected climate change than B. parviflora.
Haematococcus pluvialis is one of the most abundant sources of natural astaxanthin as compared to others microorganism. Therefore, it is important to understand the biorefinery of astaxanthin from H. pluvialis, starting from the cultivation stage to the downstream processing of astaxanthin. The present review begins with an introduction of cellular morphologies and life cycle of H. pluvialis from green vegetative motile stage to red non-motile haematocyst stage. Subsequently, the conventional biorefinery methods (e.g., mechanical disruption, solvent extraction, direct extraction using vegetable oils, and enhanced solvent extraction) and recent advanced biorefinery techniques (e.g., supercritical CO2 extraction, magnetic-assisted extraction, ionic liquids extraction, and supramolecular solvent extraction) were presented and evaluated. Moreover, future prospect and challenges were highlighted to provide a useful guide for future development of biorefinery of astaxanthin from H. pluvialis. The review aims to serve as a present knowledge for researchers dealing with the bioproduction of astaxanthin from H. pluvialis.
The increasing demands of natural gas pushes energy industries to explore the reservoirs contain high CO2 concentration
and impurities including heavy hydrocarbons. High efficiency of using membrane technology in CO2
-natural gas separation
has extended its potential application to offshore environment. Due to the limited studies related with the separation of
CO2
under offshore conditions, the present work has investigated the separation performance of a commercial membrane
in removing bulk CO2
from methane at elevated pressure condition. A wide range of offshore operating conditions
including pressure from 10 to 50 bar, CO2
concentration from 25 to 70% and temperature of 30o
C, 40o
C and 50o
C were
studied. High relative CO2 permeance and relative CO2
/CH4
selectivity were observed when the pressure and the CO2
concentration increased. This work, therefore substantial is to bridge the gap and facilitates the application of membrane
technology for offshore operating conditions.
The environment sustenance and preservation of global climate are known as the crucial issues of the world today. Currently, the crisis of global warming due to CO2 emission has turned into a paramount concern. To address such a concern, diverse CO2 capture and sequestration techniques (CCS) have been introduced so far. In line with this, Metal Organic Frameworks (MOFs) have been considered as the newest and most promising material for CO2 adsorption and separation. Due to their outstanding properties, this new class of porous materials a have exhibited a conspicuous potential for gas separation technologies especially for CO2 storage and separation. Thus, the present review paper is aimed to discuss the adsorption properties of CO2 on the MOFs based on the adsorption mechanisms and the design of the MOF structures. In addition, the main challenge associated with using this prominent porous material has been mentioned.
Overexploitation of natural resources to meet human needs has considerably impacted CO2 emissions, contributing to global warming and severe climatic change. This review furnishes an understanding of the sources, brutality, and effects of CO2 emissions and compelling requirements for metamorphosis from a linear to a circular bioeconomy. A detailed emphasis on microalgae, its types, properties, and cultivation are explained with significance in attaining a zero-carbon circular bioeconomy. Microalgal treatment of a variety of wastewaters with the conversion of generated biomass into value-added products such as bio-energy and pharmaceuticals, along with agricultural products is elaborated. Challenges encountered in large-scale implementation of microalgal technologies for low-carbon circular bioeconomy are discussed along with solutions and future perceptions. Emphasis on the suitability of microalgae in wastewater treatment and its conversion into alternate low-carbon footprint bio-energies and value-added products enforcing a zero-carbon circular bioeconomy is the major focus of this review.
Biogas consisting of carbon dioxide/methane (CO2/CH4) gas mixtures has emerged as an alternative renewable fuel to natural gas. The presence of CO2 can decrease the calorific value and generate greenhouse gas. Hence, separating CO2 from CH4 is a vital step in enhancing the use of biogas. Zeolite and zeolite-based mixed matrix membrane (MMM) is considered an auspicious candidate for CO2/CH4 separation due to thermal and chemical stability. This review initially addresses the development of zeolite and zeolite-based MMM for the CO2/CH4 separation. The highest performance in terms of CO2 permeance and CO2/CH4 selectivity was achieved using zeolite and zeolite-based MMM, which exhibited CO2 permeance in the range of 2.0 × 10- 7-7.0 × 10- 6 mol m- 2 s- 1 Pa- 1 with CO2/CH4 selectivity ranging from 3 to 300. Current trends directed toward improving CO2/CH4 selectivity via modification methods including post-treatment, ion-exchanged, amino silane-grafted, and ionic liquid encapsulated of zeolite-based MMM. Those modification methods improved the defect-free and interfacial adhesions between zeolite particulates and polymer matrices and subsequently enhanced the CO2/CH4 selectivity. The modifications via ionic liquid and silane methods more influenced the CO2/CH4 selectivity with 90 and 660, respectively. This review also focuses on the possible applications of zeolite-based MMM, which include the purification and treatment of water as well as biomedical applications. Lastly, future advances and opportunities for gas separation applications are also briefly discussed. This review aims to share knowledge regarding zeolite-based MMM and inspire new industrial applications.
This article projects the social cost of carbon (SCC) and other related consequences of climate change by using Malaysia's intended nationally determined contribution (INDC) and climate vision 2040 (CV2040) by 2050. It compares the projections derived from the Dynamic Integrated Model of the Climate and Economy (DICME) based on the respective INDC and CV2040 scenario. The results reveal that industrial emissions would incur a substantial increase every 5 years under the scenario CV2040, while Malaysia would experience lower industrial emissions in the coming years under the scenario INDC. Emission intensity in Malaysia will be 0.61 and 0.59 tons/capita in 2030 for scenario CV2040 and scenario INDC respectively. Malaysia would face climate damage of MYR456 billion and MYR 49 billion by 2050 under CV2040 and INDC scenario respectively. However, climate damage could be much lower if the INDC regime were adopted, as this scenario would decrease climatic impacts over time. The estimated SSC per ton of CO2 varies between MYR74 and MYR97 for scenario CV2040 and MYR44 and MYR62 for scenario INDC in 2030 and 2050 respectively. Considering different aspects, including industrial emissions, damage cost, and social cost of carbon, INDC is the best policy compared to CV2040. Thus, Malaysia could achieve its emissions reduction target by implementing INDC by 2050.
The Southeast Asian countries have experienced significant degrees of economic growth over the years but have not managed to safeguard their environmental attributes in tandem. As a result, the aggravation of the environmental indicators across this region casts a shadow of doubt on the sustainability of the economic growth achievements of the Southeast Asian countries. Against this milieu, this study specifically explores the influence of renewable electricity generation capacity, technological innovation, financial development, and economic growth on the ecological footprints in five Southeast Asian countries namely Indonesia, Malaysia, the Philippines, Thailand, and Vietnam during the period 1985-2016. One of the major novelties of this study is in terms of its approach to assess the renewable energy use-ecological footprint nexus using the renewable electricity generation capacity as an indicator of renewable energy use in the selected Southeast Asian nations. The econometric analysis involves methods that are robust to handling cross-sectional dependency and slope heterogeneity issues in the data. Accordingly, the recently developed Cross-sectional Augmented Autoregressive Distributed Lag estimator is used to predict the short- and long-run impacts on ecological footprints. The major findings suggest that higher renewable electricity generation capacity and technological innovation reduce ecological footprints, while higher financial development and economic growth increase the ecological footprints. Therefore, these findings imply that in forthcoming years, the selected Southeast Asian countries will need to tackle the environmental adversities by enhancing their renewable electricity generation capacities, increasing investment in technological development, greening the financial sector, and adopting environmentally-friendly growth policies. Hence, the implementation of relevant policies, in this regard, can be expected to ensure complementarity between economic growth and environmental welfare across Southeast Asia.
Green finance is inextricably linked to investment risk, particularly in emerging and developing economies (EMDE). This study uses the difference in differences (DID) method to evaluate the mean causal effects of a treatment on an outcome of the determinants of scaling up green financing and climate change mitigation in the N-11 countries from 2005 to 2019. After analyzing with a dummy for the treated countries, it was confirmed that the outcome covariates: rescon (renewable energy sources consumption), population, FDI, CO2, inflation, technical corporation grants, domestic credit to the private sector, and research and development are very significant in promoting green financing and climate change mitigation in the study countries. The probit regression results give a different outcome, as rescon, FID, CO2, Human Development Index (HDI), and investment in the energy sector by the private sector that will likely have an impact on the green financing and climate change mitigation of the study countries. Furthermore, after matching the analysis through the nearest neighbor matching, kernel matching, and radius matching, it produced mixed results for both the treated and the untreated countries. Either group experienced an improvement in green financing and climate change mitigation or a decrease. Overall, the DID showed no significant difference among the countries.
Economic integration in the form of Belt and Road Initiative project opens many opportunities and hazards, especially of the participating nations' environment. The current study attempted to empirically test the economic and energy usage (renewable and non-renewable) impact on some selected countries of belt and road projects. For this purpose, the panel data set of twenty-four emerging economies of belt and road projects was selected from 1995 to 2014. The autoregressive distributed lags technique of econometric applied to determine the effect of renewable and non-renewable energy, GDP and GDP2 for EKC, and gross fixed capital formation on carbon emission in the selected countries of Belt and Road Initiative project. The outcomes of this study confirm the existence of EKC in these underlined countries. Here, fossil fuel-based energy consumption is a source of environmental degradation, while renewable and clean energy usage can help sustain environmental conditions without affecting economic growth progress. Capital fixed formation in these economies can enhance economic growth and help to sustainable environmental conditions in the belt and road countries. Thus, based on these empirical outcomes, this study suggests economic and financial assistance in green renewable energy sources and clean technological innovation to enhance economic benefits of Belt and Road Initiative project without compromising the environmental conditions of the region.
This paper examines the effect of climate change and financial development on agricultural production in ASEAN-4, namely Indonesia, Malaysia, the Philippines, and Thailand from 1990 to 2016. Further, we explore the role of renewable energy, institutional quality, and human capital on agricultural production. Since the shocks in one country affect another country, we use second-generation modeling techniques to find out the relationship among the variables. The Westerlund (2007) cointegration tests confirm long-run relationship among the variables. The results from cross-sectionally augmented autoregressive distributed lag (CS-ARDL) model reveal that climate change negatively affects agricultural production; on the other hand, renewable energy, human capital, and institutional quality affect positively agricultural production. Moreover, renewable energy utilization, human capital, and intuitional quality moderates the effect of carbon emission on agricultural production. In addition, a U-shaped relationship exists between financial development and agricultural production, suggesting that financial development improves agricultural production only after reaching a certain threshold. Hence, this study suggests that ASEAN-4 countries must adopt flexible financial and agricultural policies so that farmers would be benefitted and agricultural production can be increased.
Since the inception of the twenty-first century, there has been a profound upsurge in economic policy uncertainty (EPU) with several economic and environmental impacts. Although there exists a growing body of literature that probes the economic effects of EPU, the EPU-energy nexus yet remains understudied. To fill this gap, the current study probes the impact of disaggregated EPU (i.e., monetary, fiscal, and trade policy uncertainty) on energy consumption (EC) in the USA covering the period 1990M1-2020M12. In particular, we use sectoral EC (i.e., energy consumed by the residential sector, the industrial sector, the transport sector, the electric power sector, and the commercial sector) in consort with total EC. The findings from the bootstrap ARDL approach document that monetary policy uncertainty (MP) plunges EC, whereas trade (TP) and fiscal policy uncertainty (FP) escalate EC in the long run. On the contrary, there is a heterogeneous impact of FP and MP across sectors in the short run, while TP does not affect EC. Keeping in view the findings, we propose policy recommendations to achieve numerous Sustainable Development Goals.
Replacing conventional fine aggregates with spent mushroom substrate (SMS) is aimed at developing a sustainable lightweight masonry mortar. It is also an alternative solution for the current improper mushroom waste disposals. Density, workability, compressive strength, specific strength, flexural strength, ultrasonic pulse velocity, water absorption, sorptivity, and equivalent CO2 emission in relation to sand reduction in mortars containing 2.5-15.0% (by volume) SMS passing through a 4.75-mm sieve were investigated. As the percentages of replacement increased from 2.5 to 15.0%, the density of the SMS mortar reduced up to 34.8%, with corresponding compressive strengths of 24.96 to 3.37 MPa. Mixes with up to 12.5% SMS met the minimum compressive and flexural strengths as stated in the ASTM C129 standard. In addition, the equivalent CO2 emission of the mixes reduced 15.09% as the SMS content increased while cost-effectiveness increases up to 98.15% until 7.5% SMS replacement. In conclusion, the use of SMS as fine aggregates up to 12.5% is a viable mix design strategy for producing sustainable lightweight mortar with a lower carbon emission.
Seaweed (macroalgae) has attracted attention globally given its potential for climate change mitigation. A topical and contentious question is: Can seaweeds' contribution to climate change mitigation be enhanced at globally meaningful scales? Here, we provide an overview of the pressing research needs surrounding the potential role of seaweed in climate change mitigation and current scientific consensus via eight key research challenges. There are four categories where seaweed has been suggested to be used for climate change mitigation: 1) protecting and restoring wild seaweed forests with potential climate change mitigation co-benefits; 2) expanding sustainable nearshore seaweed aquaculture with potential climate change mitigation co-benefits; 3) offsetting industrial CO2 emissions using seaweed products for emission abatement; and 4) sinking seaweed into the deep sea to sequester CO2. Uncertainties remain about quantification of the net impact of carbon export from seaweed restoration and seaweed farming sites on atmospheric CO2. Evidence suggests that nearshore seaweed farming contributes to carbon storage in sediments below farm sites, but how scalable is this process? Products from seaweed aquaculture, such as the livestock methane-reducing seaweed Asparagopsis or low carbon food resources show promise for climate change mitigation, yet the carbon footprint and emission abatement potential remains unquantified for most seaweed products. Similarly, purposely cultivating then sinking seaweed biomass in the open ocean raises ecological concerns and the climate change mitigation potential of this concept is poorly constrained. Improving the tracing of seaweed carbon export to ocean sinks is a critical step in seaweed carbon accounting. Despite carbon accounting uncertainties, seaweed provides many other ecosystem services that justify conservation and restoration and the uptake of seaweed aquaculture will contribute to the United Nations Sustainable Development Goals. However, we caution that verified seaweed carbon accounting and associated sustainability thresholds are needed before large-scale investment into climate change mitigation from seaweed projects.
Carbon dioxide is a major greenhouse gas that is responsible for global warming and renders harmful effects on the atmosphere. The unconstrained release of CO2 into the atmosphere should be prevented and various techniques have been developed in this regard to capture CO2 using different solvents and other compounds. Ionic liquids are a suitable candidate to capture CO2 due to their better solubility behaviour. In this work, two ionic liquids namely tetramethylammonium bromide (TMAB) and tetraethylammonium bromide (TEAB) are employed experimentally to capture CO2 and investigate their solubility behaviour. The study is performed at the temperature values of 303 K, 313 K, and 323 K and the pressure values of 5, 10, 15, and 20 bar equivalent to 0.5, 1.0, 1.5, and 2.0 MPa respectively. The concentrations of both ionic liquid solutions are 2.5 wt%, 5.0 wt%, and 10.0 wt%. The solubility results are considered in terms of mol fraction which is the ratio of moles of CO2 captured per moles of ionic liquid. The density and viscosity values are also determined for both compounds at respective conditions. COSMO-RS is used to generate the sigma profile, sigma surface, and Henry's constant of the ions involved in the study. CO2 is found to be soluble in both ionic liquids, but TEAB showed better solubility behaviour as compared to TMAB. The solubility of CO2 is found to be increasing with the increase in pressure while it decreases with the increase in temperature.
This study utilized panel data from 132 countries spanning from 1996 to 2019 to examine the effect of government efficiency on carbon emission intensity. Using a fixed effect model, the study found that stronger government efficiency is associated with a significant decrease in carbon emission intensity. Robustness tests were performed, the results of which consistently supported the main findings. Additionally, the study investigated the mechanisms underlying the linkage between government efficiency and carbon emission intensity, revealing that improved government efficiency can inhibit carbon emission intensity by fostering environmental innovation and promoting renewable energy consumption. Finally, the study examined the moderating effects of national income level, economic freedom, democracy, and ruling party ideology on the nexus of government efficiency and carbon emission intensity, and found empirical evidence supporting these moderating effects. These results provide new insights for governments seeking to reduce carbon emission intensity.
Carbon capture technologies are becoming increasingly crucial in addressing global climate change issues by lowering CO2 emissions from industrial and power generation activities. Post-combustion carbon capture, which uses membranes instead of adsorbents, has emerged as one of promising and environmentally friendly approaches among these technologies. The operation of membrane technology is based on the premise of selectively separating CO2 from flue gas emissions. This provides a number of different benefits, including improved energy efficiency and decreased costs of operation. Because of its adaptability to changing conditions and its low impact on the surrounding ecosystem, it is an appealing choice for a diverse array of uses. However, there are still issues to be resolved, such as those pertaining to establishing a high selectivity, membrane degradation, and the costs of the necessary materials. In this article, we evaluate and explore the prospective applications and roles of membrane technologies to control climate change by post-combustion carbon capturing. The primary proposition suggests that the utilization of membrane-based carbon capture has the potential to make a substantial impact in mitigating CO2 emissions originating from industrial and power production activities. This is due to its heightened ability to selectively absorb carbon, better efficiency in energy consumption, and its flexibility to various applications. The forthcoming challenges and potential associated with the application of membranes in post-carbon capture are also discussed.
A country's financing system is essential in addressing sustainable development requirements. National sources and international financial flows contribute to economic growth and environmental quality in many ways, and their impact can be critical. This paper applied panel data analysis using a comparative approach of Pooled Mean Group Auto Regressive Distribute Lags (PMG-ARDL) and Cross Sectionally ARDL (CS-ARDL) to estimate the effects of FDI, renewable energy, and remittance on environmental quality in the top remittance-receiving countries, during 2000-2021. The study emphasized the positive relationship between FDI and carbon emissions. Moreover, renewable energy and remittances revealed an inverted U-shaped relationship with carbon emissions. In the case of developing countries from the panel, remittance improves environmental quality after reaching the threshold. Moreover, for some of the developing countries included in the panel, we found that they do not achieve the desired carbon mitigation effect in their early stages of renewable energy implementation. However, renewable energy becomes a key factor for tackling environmental pollution after a certain threshold. The mixed results determined diverse policy recommendations for various stakeholders.
The rapid rise in climate and ecological challenges have allowed policymakers to introduce stringent environmental policies. In addition, financial limitations may pose challenges for countries looking to green energy investments as energy transition is associated with geopolitical risks that could create uncertainty and dissuade green energy investments. The current study uses PTR and PSTR as econometric strategy to investigate how geopolitical risks and financial development indicators influence energy transition in selected industrial economies. Our findings indicate a non-linear DCPB-RE relationship with a threshold equal to 39.361 in PTR model and 35.605 and 122.35 in PSTR model. Additionally, when the threshold was estimated above, financial development indicators and geopolitical risk positively impacts renewable energy. This confirms that these economies operate within a geopolitical context, with the objective of investing more in clean energy. We report novel policy suggestion to encourage policymakers promoting energy transition and advance the sustainable financing development and ecological sustainability.