Low Emission Levels Research Articles

Higher Carbon Tax Rates More Effective in Reducing Emissions in G20 Countries?

This study investigates the impact of carbon tax policies on carbon emission reductions in G20 countries to support the achievement of the Net Zero Emissions target by 2060. As the G20 collectively accounts for a significant share of global greenhouse gas emissions, effective policy interventions in these nations are pivotal to addressing the climate crisis. The research employs the Pearson correlation test to quantify the statistical relationship between carbon tax rates and emission levels, alongside a content analysis of sustainability reports from G20 countries to evaluate policy implementation and outcomes. The results reveal a moderate yet statistically significant negative correlation (r = −0.30, p < 0.05), indicating that higher carbon taxes are associated with lower emission levels. Content analysis further demonstrates that countries with high and consistently enforced carbon taxes, such as Japan and South Korea, achieve more substantial emissions reductions compared to nations with lower tax rates or inconsistent policy implementation. The findings emphasize that while carbon taxes serve as an effective instrument to internalize the social costs of carbon pollution, their impact is maximized when integrated with broader strategies, including investments in renewable energy, advancements in energy efficiency, and technological innovation. This research contributes to the understanding of carbon tax effectiveness and offers policy recommendations to strengthen fiscal measures as part of comprehensive climate action strategies toward achieving global sustainability targets.

Western Blot Characterization of Human Serum Prestin, an Outer Hair Cell Biomarker.

Western blot analysis of human prestin in the blood reveals multiple bands, rather than a single band. Previously, using the ELISA method, prestin was shown to be a good biomarker of outer hair cell (OHC) health and sensorineural hearing loss that could be measured in the blood. Recently, we found that a Western blot approach in an experimental model demonstrated three prestin bands providing greater insights into prestin in the blood and its origins. This approach has not yet been explored in humans. Serum samples from 25 healthy human subjects were analyzed. An automated Western blot for each sample was generated, and bands were analyzed and compared with transient evoked otoacoustic emission levels (TEOAE). There were five bands at ~32, ~50, ~94, ~139, and ~171 kDa, respectively. Notably, the ~50-kDa band consistently was the most prominent. When the subjects were divided based on TEOAE level, those with high emission levels had a significantly larger ~94-kDa band than those with low emission levels. Western blot characterization of OHC biomarker prestin in humans shows that the band closest to the previously estimated molecular weight of prestin (81 kDa) is related to a functional measure of OHCs. This finding increases confidence in the value of serum prestin as a biomarker. The Western blot method appears to offer higher-resolution information on serum prestin. Future work will be carried out under pathological conditions to inform on the application of this quantitative method in clinical settings.

Utilization of High-Salinity Crude Glycerol Byproduct from Biodiesel Production for Biosynthesis of γ-Aminobutyric Acid in Engineered Halomonas elongata

As the development of renewable energy has become imperative, biodiesel fuel (BDF) has been used as renewable biofuel with the advantage of having lower levels of greenhouse gas emissions. However, the transesterification reaction that produces BDF generates a high-salinity crude glycerol (CG) byproduct, which is difficult to recycle. Halomonas elongata is a moderately halophilic bacterium being used as a cell factory due to its ability to assimilate varieties of substrates for growth in high-salinity conditions. Previously, we engineered a recombinant H. elongata GOP-Gad to biosynthesize and accumulate γ-aminobutyric acid (GABA) as a high-value product. Here, we tested the ability of H. elongata GOP-Gad to use CG as a substrate for cell growth and GABA production. The CG byproduct was obtained from a BDF facility in Unzen City, Nagasaki, Japan, where geothermal energy catalyzed BDF production from waste cooking oil and biomethanol. Prior to use as the sole carbon (C) source in culture media, the CG byproduct was partially purified to remove soap substances and other impurities. Finally, we showed that H. elongata GOP-Gad could grow and accumulate GABA up to 28 μmol/g cell fresh weight in a minimal M63 medium containing 7% w/v NaCl with 4% w/v glycerol from the partially purified CG as a C source and 15 mM (NH4)2SO4 as a nitrogen (N) source. This result demonstrates a new circulatory bioprocess of C and N, in which H. elongata GOP-Gad can use partially purified CG and (NH4)2SO4 as the sole C and N sources for growth and GABA production.

Sex differences in fear expression and persistence in an animal model of Post-Traumatic Stress Disorder

Post-Traumatic Stress Disorder (PTSD) is a complex psychiatric condition arising from traumatic experiences, marked by abnormal fear memories. Despite women are twice as likely as men to develop PTSD, the biological mechanisms underlying this disparity remain inadequately explored, particularly in preclinical studies involving female subjects.Previous research shows that female rats exhibit active fear responses, while males display passive behaviors. Additionally, sex differences in ultrasonic vocalizations (USVs) during fear conditioning have been observed, indicating varying emotional responses.Here, we validated a traumatic stress model consisting of footshock exposure paired with social isolation − originally developed in male rats − on females for the first time, focusing on sex differences in fear memory expression, retention and extinction. Our findings reveal that only during trauma exposure, males predominantly exhibited passive responses, whereas females demonstrated more active responses, despite both sexes emitting similar numbers of alarm USVs. Females also showed lower levels of freezing and USV emissions throughout extinction sessions and displayed a higher extinction rate compared to males. Notably, only males displayed a conditioned fear response when triggered by a single mild stressor.These findings highlight sex differences in trauma responses and fear memory processes. The study emphasizes the importance of incorporating 22-kHz USV evaluations along with other behavioral metrics for a comprehensive understanding of fear memory. This research contributes to the existing literature on traumatic stress models as well as underscores the necessity of including female subjects in preclinical studies to better inform treatment and prevention strategies tailored to both sexes.

Carbon balance in Maize (Zea mays L.) with various combinations of organic and inorganic fertilizers

Fertilization in agricultural cultivation has an important role in the carbon cycle. This study aims to evaluate using organic fertilizers with inorganic fertilizers that can produce high carbon sequestration with low CO2 emission levels in maize (Zea mays L.) cultivation. There were seven combinations of NPK and organic fertilizers, namely ¼ NPK + 1 OF (C), ½ NPK + 1 OF (D), ¾ NPK + 1 OF (E), 1 NPK + 1 OF (F), ¾ NPK + ¼ OF (G), ¾ NPK + ½ OF (H), ¾ NPK + ¾ OF (I), and two controls, namely no fertilizer (A) and standard NPK (350 kg/ha, SP36 150 kg/ha, KCl 75 kg/ha) (B). Organic fertilizer was applied one week before planting, SP-36 and KCl fertilizer at planting, and urea fertilizer at 0, 14, and 28 HST. Maize was planted with a spacing of 20 x 70 cm. Parameters observed included CO2 emissions, soil pH, C-Organic, C-microbial, and plant growth parameters. The combined use of NPK and organic fertilizer significantly increased soil carbon stocks (33.25-64.04 Mg/ha) and carbon sequestration by plants (3.76-5.98 Mg/ha). Therefore, using organic and inorganic fertilizer can be considered more environmentally friendly and effective in managing carbon balance on farmland and has great potential to contribute to climate change mitigation through increased soil and plant carbon sequestration.

Steel solutions for a sustainable bridge infrastructure of today and tomorrow

AbstractResponsible for 70% of the global CO2 emissions, infrastructure has a significant impact on our climate and the related consequences. Bridges are a major keystone of the infrastructure and take a leading position in its decarbonization. In this framework, low‐carbon emission steels play an important role. Low‐carbon emission steels, like ArcelorMittal's XCarb® recycled and renewably produced steels, are already available on the market. Combining scrap and renewable electricity, it offers very low levels of CO2 emissions per ton of finished steel. The present paper describes how different steel solutions can be combined to lower the material input, to simplify the construction process and to reduce the maintenance efforts in bridge construction. The impact of efficient design has been assessed by a Life‐Cycle Assessment (LCA) for bridge solutions with small and medium spans of up to 40 m. The paper concludes with a summary of recently realized bridge projects in Poland.

The formation process of the gaseous pollutant emissions in pure ammonia fueled engines with pre-chamber jet ignition

Ammonia, as a carbon-free fuel, can serve as an alternative fuel for future engines, which is consistent with the requirements of national carbon reduction policies. However, the higher concentrations of NOx, unburned ammonia and hydrogen emissions of ammonia-fueled engines need to be controlled seriously to meet the increasingly stringent emission regulations. In this study, a pre-chamber jet ignition single-cylinder engine with port pure ammonia injection was carried. The formation process of gaseous pollutants during engine operation was investigated using CFD simulations in the equivalence ratio range of 0.8–1.3. And, the study also discusses different methods for reducing gaseous pollutant emissions. The results reveal that under lean burn conditions, the ITE can exceed 49%, and unburned ammonia and hydrogen emissions are extremely low. However, the NO emission concentration is relatively high, reaching above 1500 × 10−6, and primarily dominated by thermal NO. N2O is primarily distributed near the flame front, The low temperature at the cylinder walls decelerates the pyrolysis of N2O, coupled with the influence of secondary combustion, both leading to higher N2O emission concentrations, with maximum value reaching 78.6 × 10−6. NO2 emissions are primarily generated in the burned regions. Under rich burn conditions, the ITE significantly decreases, with an ITE of only 34.6% at an equivalence ratio of 1.3. The unburned ammonia emissions rise with an increase in the equivalence ratio, and hydrogen emissions are mainly generated through the pyrolysis of residual ammonia in the burned region, so that the elevated unburned ammonia emissions could lead to an increase in hydrogen emissions. Fuel NO is dominant in NO emissions, and the reduction reaction of unburned ammonia results in extremely low emission concentrations, and also leading to the low levels of N2O and NO2 emissions. According to a comprehensive evaluation of pollutant emissions and engine thermal efficiency, stoichiometric condition is deemed optimal for engine operation, as it can achieve a balance between ITE and gaseous pollutant emissions. Moreover, the adoption of water injection technology can further reduce NOx emissions. Furthermore, the EGR technology and direct liquid ammonia injection will also achieve lower NOx emissions. However, it is insufficient to meet the national emission regulations that only controlling gaseous pollutant emissions during the combustion, and development of the special aftertreatment systems for ammonia fueled engines should not be neglected.

Extreme weather exposure and corporate carbon emissions management: Evidence from forty countries

Utilizing survey data for firms from 40 countries, we explore the impact of extreme weather exposure on corporate carbon emissions management. Our findings indicate that firms manage their carbon emissions better if they have suffered losses due to extreme weather events. These results persist after considering endogeneity concerns, including placebo tests, the Heckman two-stage method, propensity score matching, the instrumental variables approach, and other robustness tests. Cross-sectional analyses reveal that this impact is more pronounced for firms located in developed countries and in countries with superior climate protection and lower levels of carbon emissions. Furthermore, the effect of extreme weather exposure is more significant for firms with foreign ownership and political connections and those subject to an energy tax. Finally, improved management of carbon emissions accompanied by extreme weather exposure can lead to increased corporate capacity utilization and reduced production costs.

Exploring the Influence of Extended High-Frequency Hearing on Cochlear Functioning at Lower Frequencies.

Diminished basal cochlear function, as indicated by elevated hearing thresholds in the extended high frequencies (EHFs), has been associated with lower levels of click-evoked and distortion-product otoacoustic emissions measured at lower frequencies. However, stimulus-frequency otoacoustic emissions (SFOAEs) at low-probe levels are reflection-source emissions that do not share the same generation mechanism as distortion-source emissions. The primary objective of the present study was to examine the influence of hearing thresholds in the EHFs on SFOAEs measured at lower frequencies. SFOAEs were recorded from both ears in 45 individuals with normal hearing thresholds in the conventional audiometric frequencies (0.25-8 kHz). Hearing thresholds were also measured at EHFs (10, 12.5, and 16 kHz). SFOAE magnitudes and signal-to-noise ratios (SNRs) were averaged across 1, 2, and 4 kHz probe frequencies and also averaged for high-probe frequencies (2 and 4 kHz). SFOAE magnitudes and SNRs were significantly higher for ears with better EHF hearing relative to poorer EHF hearing, categorized based on the median split. In addition, hearing in the EHFs significantly contributed to the variance in all SFOAE measures, except for the high-frequency SFOAE magnitudes model. However, hearing thresholds at the probe frequencies did not significantly contribute to the variance in SFOAEs. The study findings suggest that alterations in the basal cochlea, as revealed by EHF hearing thresholds, could be associated with diminished cochlear functioning in relatively apical regions, shown by SFOAEs at lower frequencies, in individuals with normal audiograms. These findings underscore the significance of considering EHF thresholds in audiological evaluations, as alterations in these frequencies may reflect broader cochlear health status.

Reducing sectoral hard-to-abate emissions to limit reliance on carbon dioxide removal

To reach net-zero greenhouse gas targets, carbon dioxide removal (CDR) technologies are required to compensate for residual emissions in the hard-to-abate sectors. However, dependencies on CDR technologies involve environmental, technical and social risks, particularly related to increased land requirements for afforestation and bioenergy crops. Here, using scenarios consistent with the 1.5 °C target, we show that demand and technological interventions can substantially lower emission levels in four hard-to-abate sectors (industry, agriculture, buildings and transport) and reduce reliance on the use of bioenergy with carbon capture and storage. Specifically, demand measures and technology-oriented measures could limit peak annual bioenergy with carbon capture and storage use to 0.5–2.2 GtCO2e per year and 1.9–7.0 GtCO2e per year, respectively, compared with 10.3 GtCO2e per year in the default 1.5 °C scenario. Dietary change plays a critical role in the demand measures given its large share in residual agricultural emissions.

Carbon Emissions and Intensity of Land Use: A Rural Setting Analysis in Ningde City, China

Carbon emissions and land use intensity serve as crucial indicators of land management. This paper proposes a methodological framework to elucidate the sustainability of carbon emissions in rural areas via a coordination model, scrutinizes the correlation with land use intensity, and investigates the significance of influential factors. The study focuses on village-level units within Ningde City, and finds the pronounced spatial heterogeneity characterizing the distribution of carbon emissions across different villages: (1) Villages exhibiting high levels of carbon emissions are predominantly concentrated in the southeast region, whereas those with low carbon emission levels are primarily clustered in the northwest region. The majority of the villages serve as net carbon emission sources. (2) Spatial disparities exist in the impact of land use intensity on economic benefits from carbon sources, ecological benefits from carbon sinks, and carbon emission sustainability. (3) Significant variations exist in the influence of factors affecting land use intensity, economic benefits of carbon sources, ecological benefits of carbon sinks, and the sustainability of carbon emissions in rural areas. These findings could guide governments in implementing distinct land use control policies and provide a framework for assessing carbon emission sustainability within land management strategies.

Effect of non-axisymmetric endwall contouring and swirling inlet flow on film cooling performance of turbine endwall

Non-axisymmetric endwall contouring (NEC) is one of the verified approaches to suppress secondary flows and improve aerodynamic performance. However, the design of NEC brings significant challenges to the design of endwall cooling structures. Herein, a pressure-sensitive paint experimental approach was used to obtain the film cooling effectiveness of the NEC endwall with a purge slot in this study. Three NEC types were adopted: NEC (COS), NEC (SIN), and NEC (−SIN). In addition, lean premixed combustion technology was used to achieve lower levels of NOx emissions. The turbine inlet was characterized by high turbulence and strong swirling. The effects of different swirling angles (±10, ±20, and ±30°) and densities were further explored. Due to the NEC profiling changing the secondary flow near the endwall area, coolant from the purge slot was better attached to the slot exit position, leading to a significant increase in the size of the high-cooling-efficiency region. With the mass flow ratio (MFR) varying from 0.5 to 2%, the film cooling effectiveness of the flat and NEC endwalls had similar variation characteristics. When the MFR = 0.5%, the area-averaged cooling efficiencies of the NEC (COS), NEC (SIN), and NEC (−SIN) endwalls could be improved by 2, 12.5, and 20%, respectively. Positive swirling and smaller negative swirling inflow could improve the film cooling effectiveness inside the channel. The case of SA = +20° had the best improvement, where the film cooling effectiveness of the NEC (COS), NEC (SIN), and NEC (−SIN) endwalls could reach up to 29, 35, 36, and 34%, respectively. The NEC (−SIN) endwall was less sensitive to the effects of the swirling inflow.

Experimental investigation of the effect of variable valve lift on combustion stability and exhaust emissions in a diesel/methane CRDI engine

Diesel/methane combustion still encounters challenges in terms of lower combustion stability and elevated levels of HC and CO emissions. The valve lift (VL) technique is a method that contributes to increased in-cylinder volumetric efficiency, thereby improving engine performance and reducing emissions. Hence, the application of VL in diesel/methane operations would be highly significant. Therefore, an experimental study on the VL for reducing HC and CO emissions and enhancing combustion stability in a diesel/methane CRDI engine was performed at varying methane fractions and torques. In the study, three different cam profiles were used with VL extrapolated using Fourier series and designed: the original VL of 4.46 mm, as well as two different VLs of 4.0 mm and 4.9 mm. The methane in the total fuel energy was initially increased to 20 % and later further increased to 40 %. The experimental findings demonstrated that the augmented VL mitigated the prolonged ignition delay caused by the increase of methane fraction, thereby ensuring enhanced combustion stability across all torques. On the other hand, in diesel/methane operation, increasing the VL resulted in maximum reductions of approximately 17 % in HC, 6 % in CO emissions, and 75 % in smoke opacity.

Advancements and challenges in BaTiO3-Based materials for enhanced energy storage

Numerous researchers worldwide have been motivated to develop highly effective, environmentally acceptable green energy sources as a result of the recent sharp increase in energy use and the need for low emission levels. The energy generated from various renewable sources can be stored efficiently with a system that has a high energy density and high energy efficiency. Due to their enhanced dielectric, ferroelectric, and breakdown strength characteristics, BaTiO3 based dielectric/ferroelectric ceramic materials have received a lot of interest for energy storage applications in the past tw decades. In the present work, a thorough analysis of recent advancements in composites and single-phase BaTiO3 materials with enhanced energy storage performance. This review's main focus is on the crucial tactics and theoretical frameworks for improving the energy efficiency and recovered energy storage density of various BaTiO3-based materials. A thorough summary has been provided with the most recent developments in BaTiO3 based materials for multi-layered ceramic capacitors (MLCCs), pulse power capacitors, piezoelectric transducers, energy harvesting, electric vehicle batteries, and high-power electronic devices in order to confirm the commercial applications of BaTiO3 based single phase as well as multi-phase layered structures and composites.

Application of semi-direct fuel injection system to free piston engine generator for better performance: Simulation approach with validation results

This paper explores methods to improve the fuel economy of a two-stroke free piston engine generator (FPEG) with no additional cost. In order to solve the problem of low fuel capture and poor fuel economy of two-stroke FPEG using port fuel injection (PFI), the fuel injection method is optimised in this paper. This fuel injection system is semi-direct injection (SDI). In contrast to PFI, SDI also uses a low-pressure injector, which introduces fuel directly into the ports of the engine. This study explores the feasibility of SDI on a free-piston engine generator through numerical simulation. The results show that SDI can effectively avoid short-circuit losses and improve the fuel capture rate by more than 60 % relative to PFI. Meanwhile, the ISFC is reduced by 42.3 %, and the lowest fuel consumption rate is 259.7 g/(kW·h). The combustion efficiency of SDI is maintained at over 95 % under warm-up conditions. Compared with PFI, the stagnation period is shortened by up to 10.9 % and the centre of gravity of combustion is advanced by up to 16.7 %. SDI effectively reduces HC emissions and has a lower NOx emission level than PFI. At the same time, SDI produces more CO due to stratified combustion.

Investigations on the effects of injection parameters and EGR in a glow plug assisted methanol fueled Hot Surface Ignition (HSI) Engine

Methanol can be produced from renewable sources and is also clean burning. Hence it is an ideal alternative fuel for transportation applications. However, its low cetane number prevents its direct application in compression ignition (CI) engines. One of the promising but not widely explored methods is to use a hot surface for its ignition in CI engines at normal compression ratios. In this work a turbocharged automotive common rail diesel engine was modified to operate in the hot surface ignition (HSI) mode with methanol as the sole fuel with 3% by mass of lubricity and corrosion inhibiting additive. Initially, a single pulse injection (SPI) strategy was employed at different injection timings at a BMEP of 8 bar. Subsequently a double pulse injection (DPI) strategy was employed and the effects of gap between the injection pulses, injection timing and injection pulse width share among the two pulses were studied. The HSI mode of neat methanol performed with comparable brake thermal efficiency (BTE), reduced combustion rates and hence low NOx emission levels with respect to diesel operation when the DPI mode was employed with almost equal pulse width share. Engine performance was better at rail pressures of around 800 bar. Hot EGR of up to 8% was beneficial as it reduced the engine-out NOx without affecting the BTE. The engine was operated at different BMEPs in the range of 4–10 bar and compared with the baseline diesel operation. The BTE was similar to the baseline diesel engine at all loads. Engine-out NOx was lower than diesel operation by 23.6%–61.5% while near zero smoke levels and similar CO and THC emissions (after the DOC) were observed. Though slipped methanol and formaldehyde were the significant unregulated emissions, they were reduced to very low levels after the DOC.

The impact of trans-provincial watershed eco-compensation policy on carbon emissions: Evidence from China

To manage transboundary pollution, China has promoted trans-provincial watershed eco-compensation (WEC), which is a market-oriented policy that adjusts ecological and economic interests between upstream and downstream areas and promotes regional green and low-carbon transformation. Hence, a reasonable evaluation of the carbon emission reduction effect of WEC is of great value for achieving green transformation. Using data from Chinese counties between 2003 and 2020, we consider 11 trans-provincial WEC agreements and evaluate their influence on carbon emissions. We find that trans-provincial WEC policies reduce water pollution emissions and significantly lower carbon emission levels. Mechanism tests show that the policy reduces carbon emissions by limiting polluting industrial development and stimulating low-carbon technological innovations. Moreover, this policy improves regional low-carbon economic development, and there are significant heterogeneity effects of the WEC in different regions and compensation modes. This research provides new insights for transitional countries to design green transformation policies.

Performance Evaluation of Low-Concentration Methane Combustion in a Four-Layer Gradually-Varied Porous Burner

ABSTRACT Porous media combustion (PMC) has made a comeback as a practical technology for the utilization of low-concentration methane (LCM) from coal mining. However, the conventional direct-fired PM burner still suffers from the rampart of flame stability and combustion efficiency not addressing industrial demands. Herein, a four-layer gradually-varied porous burner was innovatively developed for LCM combustion to investigate combustion performance under lean combustion conditions (CH4 volume fraction below 5%). The methane conversion, pollutant emissions, and flue gas temperature were also evaluated in detail. The results indicated that the burner offered a favorable combustion resistance due to the gradually-varied PM arrangement to heighten combustion stability with subtle temperature fluctuation and flame migration. The flammability limit of LCM was extended to the lowest equivalence ratio of 0.43 with stationary combustion at 240°C for 120 min. The energy efficiencies of the LCM combustion under lean combustion conditions were greatly boosted with the highest combustion and thermal efficiencies attained at 99.52% and 70.05%, respectively. The maximum 99.93% CH4 conversion was acquired at an equivalence ratio of 0.45 and a flow rate of 80 L/min. LCM combustion in the burner achieved extremely low pollutant emission levels and the overall CO and NOx emissions were 58.04 ppm and below 23 ppm respectively under the experimental conditions. In addition, the high-quality flue gas with an average temperature of more than 516°C was detected in the operating process, which allowed the available heat utilization at the coal mine scenes or in other industries.

Does culture matter for household carbon emissions? Evidence from “confucian” households in China

ABSTRACT Exploring cultural factors in household carbon emissions is of positive significance in promoting low carbon life. This research uses China Household Financial Survey 2015 (CHFS 2015) to investigate how Confucian culture impacts carbon emission of Chinese household. We found that Confucian households have significant lower level of carbon emissions due to the ‘inhibited’ consumption level and the service-oriented consumption structure; Specifically speaking, larger household sizes, stronger propensity to save, and stronger housing preferences lead to Confucian households’ lower consumption level, and an expenditure arrangement favouring education and medical care shapes a service-oriented consumption structure, which is also a low-carbon emissions consumption structure. Furthermore, Confucian ecological ethics did not notably enhance households’ subjective environmental attitudes, but strengthen adaptive behaviours in response to ecological deterioration, thereby reducing household carbon emission levels. Our research contributes fresh evidence and findings to the study of the environmental implications of Confucian culture.

TRANSITION TO A GREEN ECONOMY: THE LINK BETWEEN POLITICAL UNCERTAINTY AND CARBON EMISSIONS

This paper investigates the environmental consequences of political uncertainty due to terrorism using a panel dataset of 158 economies from 1995 to 2020. The empirical findings show that terrorist activities lead to lower levels of carbon dioxide emissions, with severe terrorist activities having quantitatively larger impacts. This paper further analyzes the heterogeneity of impact across economies from two distinct perspectives, involving disaggregation by the level of democracy and by the political stability of economies. Results suggest that economies with a low democracy level and fragile situation are characterized by a significant impact of terrorism on carbon emissions. However, the impact on democratic and politically stable economies is insignificant.