Anthropogenic Carbon Dioxide Emissions Research Articles

Modelling of Joule-Thomson cooling effect using a modified shift-DeepONet method for predicting hydrate onset during CO2 sequestration

Carbon Storage in underground depleted oil and gas reservoirs play a key role in reducing anthropogenic Carbon Dioxide (CO2) emissions around the world. Injection of CO2 at high pressure into a low pressure depleted gas formations containing methane (CH4) leads to Joule-Thompson (J-T) cooling, possibly resulting in injection blocking precipitation of CO2 or CH4 hydrates. Here, we present a deep neural operator-based approach to model the J-T effects during CO2 injection in depleted reservoirs to demonstrate the effectiveness of Deep Operator Networks (DeepONets) in modelling piece-wise functions with sharp changes in gradient for cases of varying permeabilities. We propose a modified version of the shift-DeepONet model using non-linear constructors in the neural network architecture to accurately model temperature and pressure profiles in space and time. The modified shift-DeepONet model achieves a higher accuracy in modelling temperature for permeability in the range of 1.01mD to 101mD with three to up to ten times improvement in reducing Relative L2 (RL2) norm and with a testing RL2 norm of 3.8 × 10-4 compared to 2.97 × 10-3 for the Vanilla DeepONet. Using the temperature and pressure profiles, estimates are made for hydrate onset in space and time. The proposed modified shift-DeepONet method achieves high accuracy in hydrate classification with precision values > 0.99, recall values > 0.86 and F1 scores > 0.92 in classification of CO2 or CH4 hydrate onset during CO2 injection into depleted gas reservoirs.

Recent Advances in Alloy Catalysts for CO2 Hydrogenation to Methanol

AbstractThe increasing anthropogenic carbon dioxide emissions (CO2) have a huge environmental impact, and CO2 emission reduction is already a common view in our society. Recently, selective hydrogenation of CO2 to methanol has attracted much attention because the process can effectively mitigate CO2 emissions and simultaneously produce high‐value‐added chemicals and fuels. The catalysts play a very important role in achieving high efficiency of CO2 to methanol. As one promising alternative, the alloy catalysts have demonstrated high performance in CO2 hydrogenation to methanol due to their unique geometry and electronic properties. Herein, we review the recent advances in alloy catalysts, including solid solution alloys and intermetallic compounds (mainly Cu‐based, In‐based, Ga‐based, and other alloy catalysts) for heterogeneous catalysis of CO2 hydrogenation to methanol. Moreover, the research ideas and development prospects of alloy catalysts for CO2 hydrogenation to methanol are overviewed to provide the ideas and references for the subsequent research on alloy catalysts for CO2 hydrogenation.

Contribution to Comparison Different Countries Regarding Carbon Dioxide Emissions

The paper discusses the problem of objectively comparing different countries in terms of their carbon dioxide emissions, in the light of climate and environmental justice. Applied methodology represents the combination of analytical method and comparative method. Two traditional and two untraditional indicators are considered. The indicators are applied to a selected group of countries that includes part of the BRICS countries and the G7 countries. The ratio of the share of carbon dioxide emissions of a country in the global emission and the share of its population in the global population gives the same distribution of countries from the selected group as the ratio of the carbon dioxide emissions of a country and its population. On the other hand, the observation of carbon dioxide emissions together with carbon dioxide absorption by the forests in relation to the country’s population shows a different distribution of the observed countries. The paper also reviews the possibilities of further improvement in the definition of appropriate indicators for an advanced comparison of different countries in terms of their carbon dioxide emissions. Complex indicators that comprise anthropogenic carbon dioxide emissions, forest absorption capacity and population can contribute to objective comparison of different countries regarding their carbon dioxide emissions, from the climate and environmental justice point of view.

Review of natural and anthropogenic emissions of carbon dioxide into the earth’s atmosphere

Review of natural and anthropogenic emissions of carbon dioxide into the earth’s atmosphere

Techno-economic implications of three phase fluidized bed absorption column applied to power generation for an intensified carbon capture process

This study addresses the pressing need to mitigate anthropogenic carbon dioxide emissions from energy-intensive industrial sectors to achieve climate neutrality goals. The focus of this paper is on evaluating the industrial feasibility of a novel three-phase gas-solid-liquid fluidized bed absorption column using mono-ethanol-amine for carbon capture and comparing it with conventional packed-bed technology. The findings show that the fluidized bed configuration reduces capital costs of the absorber by 40 % and of the carbon capture unit by 15 % compared to the packed-bed technology, leading to decreased electricity costs when used as additional unit for a 1000 MW power plant. The proposed mathematical model incorporates key factors such as hydrodynamics, mass transfer, and chemical reactions, accurately describing the intensified carbon dioxide absorption process. This intensified system enhances the transferred carbon dioxide flowrate between phases, increasing overall decarbonization capacity while reducing capital and operational costs, offering a promising solution for industrial carbon capture.

Bomb radiocarbon evidence for strong global carbon uptake and turnover in terrestrial vegetation.

Vegetation and soils are taking up approximately 30% of anthropogenic carbon dioxide emissions because of small imbalances in large gross carbon exchanges from productivity and turnover that are poorly constrained. We combined a new budget of radiocarbon produced by nuclear bomb testing in the 1960s with model simulations to evaluate carbon cycling in terrestrial vegetation. We found that most state-of-the-art vegetation models used in the Coupled Model Intercomparison Project underestimated the radiocarbon accumulation in vegetation biomass. Our findings, combined with constraints on vegetation carbon stocks and productivity trends, imply that net primary productivity is likely at least 80 petagrams of carbon per year presently, compared with the 43 to 76 petagrams per year predicted by current models. Storage of anthropogenic carbon in terrestrial vegetation is likely more short-lived and vulnerable than previously predicted.

Valorization of Biomass and Industrial Wastes as Alternative Fuels for Sustainable Cement Production

The cement industry contributes around 7% of global anthropogenic carbon dioxide emissions, mainly from the combustion of fuels and limestone decomposition during clinker production. Using alternative fuels derived from wastes is a key strategy to reduce these emissions. However, alternative fuels vary in composition and heating value, so selecting appropriate ones is crucial to maintain clinker quality and manufacturing processes while minimizing environmental impact. This study evaluated various biomass and industrial wastes as potential alternative fuels, characterizing them based on proximate analysis, elemental and oxide composition, lower heating value, and bulk density. Sawdust, pecan nutshell, industrial hose waste, and plastic waste emerged as viable options as they met the suggested thresholds for heating value, chloride, moisture, and ash content. Industrial hose waste and plastic waste were most favorable with the highest heating values while meeting all the criteria. Conversely, wind blade waste, tire-derived fuel, and automotive shredder residue did not meet all the recommended criteria. Therefore, blending them with alternative and fossil fuels is necessary to preserve clinker quality and facilitate combustion. The findings of this research will serve as the basis for developing a computational model to optimize the blending of alternative fuels with fossil fuels for cement production.

Forest-floor respiration, N2O fluxes, and CH4 fluxes in a subalpine spruce forest: drivers and annual budgets

Abstract. Forest ecosystems play an important role in the global carbon (C) budget by sequestering a large fraction of anthropogenic carbon dioxide (CO2) emissions and by acting as important methane (CH4) sinks. The forest-floor greenhouse gas (GHG; CO2, CH4, and nitrous oxide (N2O)) flux, i.e., from soil and understory vegetation, is one of the major components to consider when determining the C or GHG budget of forests. Although winter fluxes are essential to determine the annual C budget, only very few studies have examined long-term, year-round forest-floor GHG fluxes. Thus, we aimed to (i) quantify seasonal and annual variations of forest-floor GHG fluxes; (ii) evaluate their drivers, including the effects of snow cover, timing, and amount of snowmelt; and (iii) calculate annual budgets of forest-floor GHG fluxes for a subalpine spruce forest in Switzerland. We measured GHG fluxes year-round during 4 years with four automatic large chambers at the ICOS Class 1 Ecosystem station Davos (CH-Dav). We applied random forest models to investigate environmental drivers and to gap-fill the flux time series. The forest floor emitted 2336 g CO2 m−2 yr−1 (average over 4 years). Annual and seasonal forest-floor respiration responded most strongly to soil temperature and snow depth. No response of forest-floor respiration to leaf area index or photosynthetic photon flux density was observed, suggesting a strong direct control of soil environmental factors and a weak, or even lacking, indirect control of canopy biology. Furthermore, the forest floor was a consistent CH4 sink (−0.71 g CH4 m−2 yr−1), with annual fluxes driven mainly by snow depth. Winter CO2 fluxes were less important for the CO2 budget (6.0 %–7.3 %), while winter CH4 fluxes contributed substantially to the annual CH4 budget (14.4 %–18.4 %). N2O fluxes were very low (0.007 g N2O m−2 yr−1), negligible for the forest-floor GHG budget at our site. In 2022, the warmest year on record with below-average precipitation at the Davos site, we observed a substantial increase in forest-floor respiration compared with other years. The mean forest-floor GHG budget indicated emissions of 2319 ± 200 g CO2 eq. m−2 yr−1 (mean ± standard deviation (SD) over all years), with respiration fluxes dominating and CH4 offsetting a very small proportion (0.8 %) of the CO2 emissions. Due to the relevance of snow cover, we recommend year-round measurements of GHG fluxes with high temporal resolution. In a future with increasing temperatures and less snow cover due to climate change, we expect increased forest-floor respiration at this subalpine site modulating the carbon sink of the forest ecosystem.

Electricity climate-compatibility index: Measuring global progress towards decarbonising the power sector

This paper proposes a novel index, ECI (Electricity Climate-Compatibility Index), to measure global fossil fuel electricity generation alignment with climate targets. Net anthropogenic carbon dioxide emissions (CO2) must approach zero by mid-century to stabilise the mean temperature to well below 2°C. Pursuing carbon neutrality will require immediate action if we are to avoid the economic risks associated with a delayed, more abrupt energy transition. This paper reviewed the existing literature and found insufficient indicators for country-level climate targets in electricity generation. Therefore, the paper proposes a novel electricity climate-compatibility index (ECI) to address the gap. The index computes climate compatibility or incompatibility as the difference between fossil fuel electricity generation permitted in the Integrated Assessment Model (IAM) country-level climate scenarios and that which is generated from operational, under-construction and planned power generation assets. The ECI correlates positively in specific instances with relatable metrics such as Energy Transition Index (ETI) and Climate Change Performance Index (CCPI) but provides a better understanding of the climate-incompatible generation of fossil fuel plants for a decarbonised power sector.

Impact of anthropogenic emissions of carbon dioxide and related temperature rise on wildlife population: A modeling study

Climate change is driven by the increase in greenhouse gases in Earth’s atmosphere, especially carbon dioxide (CO2), leading to a rise in the global average temperature. This temperature rise unleash far-reaching and profound consequences on various living organisms. In this research work, we formulate a nonlinear mathematical model to perceive the impact of rising temperature on wildlife species. In formulating the model, we take into account that the escalating CO2 concentration contributes to a rise in the global average temperature, thereby impacting the growth rate of wildlife population. We pinpoint the sufficient conditions for all the dynamic variables to reach their simultaneous equilibrium levels. The model analysis reveals a spectrum of bifurcations, including transcritical, Hopf, saddle–node, and Bogdanov–Takens bifurcations. Further, the examination of transcritical bifurcation led to the identification of a critical reduction rate of wildlife species due to human activities above which the wildlife population may teeter on the brink of extinction under the considered stressor of temperature rise. This extinction of wildlife species can be avoided by increasing the carrying capacity of forest biomass. Also, we have shown that for a specific set of parameter values, there exists a bistability between the forest-wildlife free equilibrium and the coexisting equilibrium.

Efficient Selective Carbon Dioxide Separation via Task-Specific Ionic Liquids Incorporated in ZIF-8.

Owing to the rapid increase in anthropogenic emission of carbon dioxide (CO2) in the atmosphere, which has resulted in a number of global climate challenges, a decrease in CO2 emissions is urgently needed in the current scenario. This study focuses on the development and characterization of composites for carbon dioxide (CO2) separation. The composites consist of two task-specific ionic liquids (TSILs), namely, tetramethylgunidinium imidazole [TMGHIM] and tetramethylgunidinium phenol [TMGHPhO], impregnated in ZIF-8. The performance of CO2 separation, including sorption capacity and selectivity, was evaluated for pristine ZIF-8 and composites of TMGHIM@ZIF-8 and TMGHPhO@ZIF-8. To demonstrate the thermal stability of the material, thermogravimetric analysis (TGA) was performed. Additionally, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to showcase the crystal structures and morphology. Fourier transform infrared spectroscopy (FTIR) and BET were also utilized to confirm the successful incorporation of TSILs into ZIF-8. The composite synthesized with TMGHIM@ZIF-8 demonstrated superior CO2 sorption performance as compared with TMGHPhO@ZIF-8. This is attributed to its strong attraction toward CO2, resulting in a higher CO2/CH4 selectivity of 110 while pristine MOFs showed 12 that is 9 times higher than that of the pristine ZIF-8. These TSILs@ZIF-8 composites have significant potential in designing sorbent materials for efficient acid gas separation applications.

The Influence of Ozone Depletion Potential Weighted Anthropogenic Emissions of Nitrous Oxide

The effects of anthropogenic emissions of nitrous oxide (N2O), carbon dioxide (CO2), methane (CH4), and halocarbons on stratospheric ozone (O3) over the twentieth and twenty-first centuries are divided using a chemical model of the stratosphere. As halocarbon levels revert to pre-industrial levels, N2O and CO2 will likely play the primary roles in the evolution of ozone in the future. It is unable to distinguish clearly between these gases’ effects on ozone due to nonlinear interactions between them. The work was conducted using the monthly and annual data of the gases in the stratospheric layer to determine the overlap between N2O and O3 for the Iraq station and for the period (2003-2016). The strength of the association between gases was determined using the Spearman rho test (rs). It was found that there is a very high positive relationship between the N2O and O3 in Nasriyah station, which is 0.807 which indicates a strong association. This is because meteorological conditions, climatic fluctuations, and atmospheric location all affect correlation. The ozone layer is destroyed by nitrous oxide at high concentrations through the stratosphere layer and the tropospheric layer, the concentration of ozone increases with an increase in the concentration of nitrogen dioxide.

Trends of Satellite-Derived Thermal Fronts in the Southeast and Southwest of Australia Between 1993 and 2019

Oceanic fronts play a significant role in marine ecosystems by enhancing vertical exchange, promoting the aggregation of plankton, and drawdown of organic carbon. Anthropogenic emission of carbon dioxide and other greenhouse gases in the twentieth century has driven global warming, leading to rising ocean temperatures. Specific regions warming faster than the global average—known as ‘ocean warming hotspots’—have been identified, impacting geophysical and biogeochemical dynamics of local ecosystems. Here, we aim to characterize the variability of sea surface temperature (SST) fronts in the southeast and southwest Australia hotspots. Using a histogram frontal detection method, we derived fronts from AVHRR-only and Multi-sensor 6-day SST composites on a 0.02 × 0.02 grid between January 1993 and December 2019. Our results indicate that frontal frequency and frontal density have increased in both regions in the past three decades, by around 0.2–0.3%. In addition, both regions exhibit higher frequency and density of fronts in austral winter and fewer in austral summer. Our calculations show that changes in frontal frequency/density show some relationship to El Niño-Southern Oscillation and Indian Ocean Dipole. Changes in frontal activity could strongly impact local ocean biogeochemistry and marine ecosystems. A better understanding changing fronts in hotspots will help predict and manage future changes in regional oceans to warming.

Potential of wind turbines on the alteration of carbon dioxide concentration

Anthropogenic carbondioxide (CO2) emissions are a major factor in global warming, requiring significant cuts to combat climate change. A crucial technology to reduce global CO2 concentration is direct air capture (DAC) of CO2. However, existing DAC techniques are expensive because of low CO2 concentrations, and they frequently rely on fossil fuel-based energy. In this article, we investigate how wind turbines can influence local CO2 levels and potentially collaborate with DAC and other technologies. To explore this idea, we performed large-eddy simulations using two 5 MW commercial-scale wind turbines. We incorporated realistic CO2 profiles collected from 13 different global locations across different seasons. The simulations were performed under neutral atmospheric boundary layer conditions. The results demonstrate that the wake recovery mechanism of a wind turbine promotes rapid mixing of CO2 both above and below the turbine blade tips in the wind turbine wake. In cases where the initial concentrations of CO2 were elevated above the turbine, downward entrainment of CO2 occurred. Conversely, when high concentrations of CO2 were present in the lower atmosphere, wind turbines facilitated a decrease in concentration at that layer by up to 138 kg/m within the intermediate wake (within 7 diameters) of the second turbine, T2. These discoveries inspire further investigation into the potential synergies between wind turbines and DAC devices or local CO2 pollutant diverters, depending on the prevailing CO2 profile. Consequently, this article marks the initial showcase of wind turbines' capability to influence CO2 levels by creating an entrainment and removal effect.

Optimisasi Budidaya Rumput Laut sebagai Benteng Alami untuk Mengurangi Asidifikasi Laut

Anthropogenic carbon dioxide emissions are propelling a concerning rise in ocean acidity, posing severe threats to marine ecosystems, especially calcifying organisms like corals and mollusks. In response to this global challenge, seaweed farming has emerged as a promising remedy. Leveraging their remarkable growth rates and carbon sequestration abilities, seaweeds offer a viable solution to counteract the acidifying effects of elevated carbon dioxide levels in the oceans. Through photosynthesis, seaweeds actively absorb carbon dioxide from seawater, thereby mitigating acidity and fostering improved water quality. The potential of seaweed farms extends beyond mere carbon sequestration. These farms play a pivotal role in habitat creation, absorb nitrogen and phosphorus nutrients, and contribute to enhanced biodiversity. The cultivation of seaweed not only addresses the immediate concern of ocean acidification but also provides a holistic ecological approach with far-reaching benefits. As a sustainable and scalable strategy, seaweed farming exemplifies an innovative and multifaceted solution to the complex challenges posed by anthropogenic impacts on the oceans, underlining the importance of nature-based interventions in preserving the health and balance of marine ecosystems.

Industrial by-products-derived binders for in-situ remediation of high Pb content pyrite ash: Synergistic use of ground granulated blast furnace slag and steel slag to achieve efficient Pb retention and CO2 mitigation

Ordinary Portland cement (OPC) is a cost-effective and conventional binder that is widely adopted in brownfield site remediation and redevelopment. However, the substantial carbon dioxide emission during OPC production and the concerns about its undesirable retention capacity for potentially toxic elements strain this strategy. To tackle this objective, we herein tailored four alternative binders (calcium aluminate cement, OPC-activated ground-granulated blast-furnace slag (GGBFS), white-steel-slag activated GGBFS, and alkaline-activated GGBFS) for facilitating immobilization of high Pb content pyrite ash, with the perspectives of enhancing Pb retention and mitigating anthropogenic carbon dioxide emissions. The characterizations revealed that the incorporation of white steel slag efficiently benefits the activity of GGBFS, herein facilitating the hydration products (mainly ettringite and calcium silicate hydrates) precipitation and Pb immobilization. Further, we quantified the cradle-to-gate carbon footprint and cost analysis attributed to each binder-Pb contaminants system, finding that the application of these alternative binders could be pivotal in the envisaged carbon-neutral world if the growth of the OPC-free roadmap continues. The findings suggest that the synergistic use of recycled white steel slag and GGBFS can be proposed as a profitable and sustainable OPC-free candidate to facilitate the management of lead-contaminated brownfield sites. The overall results underscore the potential immobilization mechanisms of Pb in multiple OPC-free/substitution binder systems and highlight the urgent need to bridge the zero-emission insights to sustainable in-situ solidification/stabilization technologies.

A decade of marine inorganic carbon chemistry observations in the northern Gulf of Alaska – insights into an environment in transition

Abstract. As elsewhere in the global ocean, the Gulf of Alaska is experiencing the rapid onset of ocean acidification (OA) driven by oceanic absorption of anthropogenic emissions of carbon dioxide from the atmosphere. In support of OA research and monitoring, we present here a data product of marine inorganic carbon chemistry parameters measured from seawater samples taken during biannual cruises between 2008 and 2017 in the northern Gulf of Alaska. Samples were collected each May and September over the 10 year period using a conductivity, temperature, depth (CTD) profiler coupled with a Niskin bottle rosette at stations including a long-term hydrographic survey transect known as the Gulf of Alaska (GAK) Line. This dataset includes discrete seawater measurements such as dissolved inorganic carbon and total alkalinity, which allows the calculation of other marine carbon parameters, including carbonate mineral saturation states, carbon dioxide (CO2), and pH. Cumulative daily Bakun upwelling indices illustrate the pattern of downwelling in the northern Gulf of Alaska, with a period of relaxation spanning between the May and September cruises. The observed time and space variability impart challenges for disentangling the OA signal despite this dataset spanning a decade. However, this data product greatly enhances our understanding of seasonal and interannual variability in the marine inorganic carbon system parameters. The product can also aid in the ground truthing of biogeochemical models, refining estimates of sea–air CO2 exchange, and determining appropriate CO2 parameter ranges for experiments targeting potentially vulnerable species. Data are available at https://doi.org/10.25921/x9sg-9b08 (Monacci et al., 2023).

Satellite derived trends and variability of CO2 concentrations in the Middle East during 2014–2023

The Middle East has major sources of anthropogenic carbon dioxide (CO2) emissions, but a dearth of ground-based measurements precludes an investigation of its regional and temporal variability. This is achieved in this work with satellite-derived estimates from the Orbiting Carbon Observatory-2 (OCO-2) and OCO-3 missions from September 2014 to February 2023. The annual maximum and minimum column (XCO2) concentrations are generally reached in spring and autumn, respectively, with a typical seasonal cycle amplitude of 3–8 ± 0.5 ppmv in the Arabian Peninsula rising to 8–10 ± 1 ppmv in the mid-latitudes. A comparison of the seasonal-mean XCO2 values with the CO2 emissions estimated using the divergence method stresses the role played by the sources and transport of CO2 in the spatial distribution of XCO2, with anthropogenic emissions prevailing in arid and semi-arid regions that lack persistent vegetation. In the 8-year period 2015–2022, the XCO2 concentration in the United Arab Emirates (UAE) increased at a rate of about 2.50 ± 0.04 ppmv/year, with the trend empirical orthogonal function technique revealing a hotspot over northeastern UAE and southern Iran in the summer where anthropogenic emissions peak and accumulate aided by low-level wind convergence. A comparison of the satellite-derived CO2 concentration with that used to drive climate change models for different emission scenarios in the 8-year period revealed that the concentrations used in the latter is overestimated, with maximum differences exceeding 10 ppmv by 2022. This excess in the amount of CO2 can lead to an over-prediction of the projected increase in temperature in the region, an aspect that needs to be investigated further. This work stresses the need for a ground-based observational network of greenhouse gas concentrations in the Middle East to better understand its spatial and temporal variability and for the evaluation of remote sensing observations as well as climate models.

Designing organic bridging linkers of metal–organic frameworks for enhanced carbon dioxide adsorption

The global rate of anthropogenic carbon dioxide (CO2) emission is rising, which urges the development of efficient carbon capture and storage (CCS) technologies.

Valorization of bio-oil distillation residue through co-pyrolysis with moso bamboo to prepare biochar: Optimization study on effects of blend ratio, pyrolysis temperature, and residence time

In view of the high energy consumption and pollutant emissions in the cement production industry, biomass as the renewable carbon-neutrality energy is promisingly conducive to remitting cement carbon dioxide emissions and simultaneously realizing waste-to-energy initiatives. In this study, bio-oil distillation residue (DR), with high carbon content and heat value, is co-pyrolyzed with moso bamboo (MB) to optimize the bulk and combustion properties of biochar, aiming at yielding bio-fuel as an alternative fuel to replace coals for energy and heat supply in cement industry. The impacts of three primary process parameters on the carbonization reaction were investigated, while the parametric interactions were further estimated by using response surface methodology (RSM) to optimize the ultimate, proximate and fuel characteristics of biochars. The results showed the co-pyrolysis synergies between bio-oil distillation residue and moso bamboo endowed the maximum biochar yield of 44.62% and the maximum difference biochar yield of 7.56%. Meanwhile, the experimental carbon content, fixed carbon content and high heat value (HHV) were regulated through coupling parametric distribution and further increased by 1.96%, 2.59% and 1.23 MJ/kg, respectively. The parametric responses on combustion characteristics of biochar based on thermogravimetric analysis were predicted, and the optimal carbonization conditions for biochar production were also summarized. This study would offer an optimal biochar production scheme to adaptively yield coal-like biochar for reducing anthropogenic carbon dioxide emissions in cement industry.