CO2 Increase Research Articles

Ocean acidification and its regulating factors in the East China Sea off the Yangtze River estuary.

This study examines the seasonal variations in carbonate system parameters in the East China Sea (ECS) off the Yangtze River estuary (YRE) and analyzes the contributions of anthropogenic CO₂ and eutrophication to acidification. Carbonate parameters data were collected during summer 2019 and combined winter 2011. During winter, acidification is primarily driven by rising atmospheric CO₂, with minimal impact from biological processes. In contrast, summer presents a different pattern: enhanced photosynthesis due to eutrophication in surface waters helps mitigate the acidification effects of atmospheric CO₂ increases, while in bottom waters, the combined pressures of atmospheric CO₂ and intensified aerobic respiration leads to more severe acidification. Notably, biological processes now contribute more to acidification than increasing atmospheric CO₂ in the bottom waters. Our projections indicate that the summer bottom waters will experience the most pronounced acidification, with average pH levels expected to decline from 8.04 to 7.82 and aragonite saturation state (Ωar) values decreasing from 2.24 to 1.38 between 2000 and 2100. Additionally, our study indicates that winter acidification trends are also concerning, with pH only slightly higher than in summer bottom waters. The buffering capacity and the DIC:TA ratio play significant roles in determining the rate of future pH and Ωar declines. The strong buffering capacity in summer surface waters mitigates the pH decline, while the low DIC:TA ratio results in a rapid drop in Ωar.

A new approach to off-gas analysis for shaken bioreactors showing high CTR and RQ accuracy

BackgroundShake flasks are essential tools in biotechnological development due to their cost efficiency and ease of use. However, a significant challenge is the miniaturization of process analytical tools to maximize information output from each cultivation. This study aimed to develop a respiration activity online measurement system via off-gas analysis, named “Transfer rate Online Measurement” (TOM), for determining the oxygen transfer rate (OTR), carbon dioxide transfer rate (CTR), and the respiration quotient (RQ) in surface-aerated bioreactors, primarily targeting shake flasks.ResultsSensors for off-gas analysis were placed in a bypass system that avoids the shaking of the electronics and sensors. An electrochemical oxygen sensor and an infrared CO2 sensor were used. The bypass system was combined with the established method of recurrent dynamic measurement phases, evaluating the decrease in oxygen and the increase in CO2 during stopped aeration. The newly developed measurement system showed high accuracy, precision and reproducibility among individual flasks, especially regarding CTR measurement. The system was compared with state-of-the-art RAMOS technology (Respiration Activity Monitoring System, see explanation below) and calibrated with a non-biological model system. The accuracy of RQ measurement was +-4% for the tested range (8% filling volume, OTR and CTR: 0–56 mmol/L/h), allowing for the determination of metabolic switches and quantitative analysis of metabolites. At ambient CO2 levels, a CTR resolution of less than 0.01 mmol/L/h was possible. The system was applied to the microbial model systems S. cerevisiae, G. oxydans, and E. coli. Physiological states, such as growth vs. protein production, could be revealed, and quantitative analysis of metabolites was performed, putting focus on RQ measurements.ConclusionsThe developed TOM system showcases a novel approach to measuring OTR, CTR, and RQ in shaken bioreactors. It offers a robust and accurate solution for respiration activity analysis. Due to its flexible design and tunable accuracy, it enables measurement in various applications and different shake flasks.

Molecular Understanding of CO2 Absorption by Choline Chloride/Urea Confined within Nanoslits.

Clarifying the potential relationship between the microstructure of nanoconfined choline chloride/urea (ChClU) and CO2 absorption performance is key to understanding the abnormal increase in CO2 under nanoconfinement. In this study, we used molecular dynamics simulations and grand canonical Monte Carlo (GCMC) to systematically study the mechanism underlying the absorption of CO2 by ChClU within nanoslits. According to the spatial distribution, ChClU can form two different laminar regions within nanoslits, namely, the interfacial region (region I) and beyond region I (region II). In region II, the interface induces rearrangement of ChClU, resulting in an increase in free volume and subsequent increase in CO2 solubility. In region I, changing the interface from hydrophobic to hydrophilic (e.g., S_I to S_IV) by setting the appropriate charge patterns, the urea molecules gradually change from "disordered" to "ordered standing" relative to the solid surface. The preferential orientation of the urea molecules causes competition between the ChClU's free volume and urea molecules, resulting in a non-monotonic change in CO2 solubility. Specifically, from S_I to S_III, the increase in urea molecules enhances the CO2 solubility. In S_IV, space for CO2 absorption is insufficient due to the accumulation of urea molecules, and thus CO2 solubility decreases.

Impact of carbonation on reinforced concrete structures, considering the increase of CO2 due to climate change in Brazil

Impact of carbonation on reinforced concrete structures, considering the increase of CO2 due to climate change in Brazil

A Climate Simulation Dataset From 11 Overriding Experiments for Analysing Cloud and Air–Sea Feedbacks

ABSTRACTUnder global warming, cloud change and its radiative feedback have often been considered to evolve from thermodynamic processes; however, cloud feedback may also force sea surface temperature to trigger such air–sea interactions. Due to complex cloud physics in air–sea coupling, this contributes to the surface warming pattern formation with significant uncertainty. Here we develop a novel overriding technique for climate projections that substitutes specific variables in control runs to isolate such feedback mechanisms, decoupling thermodynamic, dynamical and radiative responses of the surface ocean to the atmosphere. We apply this to the Community Earth System Model version 2 (CESM2) and perform a series of 150‐year simulations with 1% CO2 increase per year (1pctCO2). In real time, the key variables under 1pctCO2 are replaced with those from the current climate, such as downwelling shortwave radiation, wind speed in latent and sensible heat and wind stress. These experiments provide monthly output of global distributions including surface temperatures, winds and precipitation, with a spatial resolution of 1.9° × 2.5° in latitude and longitude and 32 levels for the atmosphere and of ~1° and 60 layers designated as gx1v7 for the ocean. This open access dataset for partial air–sea coupling under climate change can help understand the tropical and polar warming patterns and quantify the relative contributions of forcing and triggering mechanisms.

Investigation of Combine Cycle Power Plants with Low-Grade Heat Utilization Working Methane-Hydrogen Mixtures

The Russian energy sector remains heavily reliant on thermal power plants, with gas generation accounting for approximately 66% of the installed capacity. However, the industry faces challenges such as depletion of reserves, rising prices for hydrocarbons, and increasing concentrations of carbon dioxide in the atmosphere. This study focuses on developing new scientific and technical solutions to increase the efficiency and environmental safety of combined cycle power units. The research involves structural and parametric optimization of trinary cycle power plants operating on a methane-hydrogen mixture, as well as the development and optimization of turbine and heat exchange equipment for low-temperature power plants. The results show that the transition to trinary CCGT (Combine Cycle Gas Turbine) units with deep utilization and the use of hydrogen fuel can significantly reduce specific CO2 emissions and increase energy efficiency up to 0.21% with also increases in capacity of turbine of approximately 17 MW. The aim of this research is to calculate the efficiency, cost effectiveness and environmental-friendly solution for power generation using mixture of hydrogen- methane as fuel in combine cycle power plant that includes ORC. Additionally, the efficiency of the organic Rankine Cycle (ORC) benefits from the increased moisture, with capacity improvements of 1-2 MW observed when the hydrogen proportion rises from 25% to 50%. Moreover, the potential for zero emissions, coupled with significant increases in power output and efficiency, underscores hydrogen's role as a pivotal component in the future of energy production.

Towards Perovskite Oxide-Based Electrocatalysts with Zero-Critical Elements for Sustainable Energy Production

The well-being of the Earth and its inhabitants is compromised by the energy and climate crisis that has arisen from the prolonged and uncontrolled utilization of fossil fuels, which has caused a tremendous increase in anthropogenic CO2 and a consistent depletion of natural energy resources [...]

MODELLING AND EXERGETIC TECHNO-ECONOMIC ANALYSIS OF A SYSTEM FOR HYDROGEN PRODUCTION FROM EMPTY BANANA FRUIT BUNCH

One of the most effective and reliable methods for generating hydrogen fuel using biomass is the gasification method. However, utilization of different biomass feedstock has the ability to withstand production of syngas which can be utilized for several applications. The study investigated the feasibility of hydrogen from Empty Banana Fruit Bunch (EBFB) biomass and the energetic techno-economic analyses of biomass gasification plant with a developed system simulation model aspen plus simulator V11. Five chemical reactions were used in production process and were simulated in ASPEN Plus simulator through biomass gasification method which aimed in removing C, CO, CO2, CH4, and H2O to convert them into hydrogen gas. However, the total exergy out divided by the total exergy in gives exergy efficiency. Hence, total exergy out subtracted from total exergy in depicts exergy destruction. The exego-economic method utilized in the exergo-economic analyses is the Specific Cost method (SPECO). The results affirmed that 80.465 kg/hr of H2 can be produced from 2000 kg/hr of empty banana fruit bunch at every 39.92 k.mol/hr mole flow of EBFB. However, at a temperature below 900 0C CO decreases, CO2 increases. Above 1000 0C, CO increases hence decreases CO2 emission. The system total exergy in, total exergy out, percentage exergy efficiency, and exergy destruction are 4534.77 kJ/kg, 3857.295 kJ/kg, 0.8506 %, and 677.475 kJ/kg. Hence, system exergy stream cost rate, component-related cost rate, component-related cost difference, and component exergoeconomic factor are 407527.644$/h 1555.57$/h, 0.5679%, and 0.9089% respectively. Further studies may concentrate on how to reduce CO through regulated temperature and pressure differences so as to increase the quantity of hydrogen production.

Physiological and Biochemical Responses of Pseudocereals with C3 and C4 Photosynthetic Metabolism in an Environment with Elevated CO2.

The present work aimed to investigate the effect of increasing CO2 concentration on the growth, productivity, grain quality, and biochemical changes in quinoa and amaranth plants. An experiment was conducted in open chambers (OTCs) to evaluate the responses of these species to different levels of CO2 {a[CO2] = 400 ± 50 μmol mol-1 CO2 for ambient CO2 concentration, e[CO2] = 700 ± 50 μmol mol-1 CO2 for the elevated CO2 concentration}. Growth parameters and photosynthetic pigments reflected changes in gas exchange, saccharolytic enzymes, and carbohydrate metabolism when plants were grown under e[CO2]. Furthermore, both species maintained most of the parameters related to gas exchange, demonstrating that the antioxidant system was efficient in supporting the primary metabolism of plants under e[CO2] conditions. Both species were taller and had longer roots and a greater dry weight of roots and shoots when under e[CO2]. On the other hand, the panicle was shorter under the same situation, indicating that the plants invested energy, nutrients, and all mechanisms in their growth to mitigate stress in expense of yield. This led to a reduction on panicle size and, ultimately, reducing quinoa grain yield. Although e[CO2] altered the plant's metabolic parameters for amaranth, the plants managed to maintain their development without affecting grain yield. Protein levels in grains were reduced in both species under e[CO2] in the average of two harvests. Therefore, for amaranth, the increase in CO2 mainly contributes to lowering the protein content of the grains. As for quinoa, its yield performance is also affected, in addition to its protein content. These findings provide new insights into how plants C3 (amaranth) and C4 (quinoa) respond to e[CO2], significantly increasing photosynthesis and its growth but ultimately reducing yield for quinoa and protein content in both species. This result ultimately underscore the critical need to breed plants that can adapt to e[CO2] as means to mitigate its negative effects and to ensure sustainable and nutritious crop production in future environmental conditions.

Anthromes and forest carbon responses to global change

Societal Impact StatementForest ecosystems absorb and store about 25% of global carbon dioxide emissions annually and are increasingly shaped by human land use and management. Climate change interacts with land use and forest dynamics to influence observed carbon stocks and the strength of the land carbon sink. We show that climate change effects on modeled forest land carbon stocks are strongest in tropical wildlands that have limited human influence. Global forest carbon stocks and carbon sink strength may decline as climate change and anthropogenic influences intensify, with wildland tropical forests, especially in Amazonia, likely being especially vulnerable.Summary Human effects on ecosystems date back thousands of years, and anthropogenic biomes—anthromes—broadly incorporate the effects of human population density and land use on ecosystems. Forests are integral to the global carbon cycle, containing large biomass carbon stocks, yet their responses to land use and climate change are uncertain but critical to informing climate change mitigation strategies, ecosystem management, and Earth system modeling. Using an anthromes perspective and the site locations from the Global Forest Carbon (ForC) Database, we compare intensively used, cultured, and wildland forest lands in tropical and extratropical regions. We summarize recent past (1900‐present) patterns of land use intensification, and we use a feedback analysis of Earth system models from the Coupled Model Intercomparison Project Phase 6 to estimate the sensitivity of forest carbon stocks to CO2 and temperature change for different anthromes among regions. Modeled global forest carbon stock responses are positive for CO2 increase but neutral to negative for temperature increase. Across anthromes (intensively used, cultured, and wildland forest areas), modeled forest carbon stock responses of temperate and boreal forests are less variable than those of tropical forests. Tropical wildland forest areas appear especially sensitive to CO2 and temperature change, with the negative temperature response highlighting the potential vulnerability of the globally significant carbon stock in tropical forests. The net effect of anthropogenic activities—including land‐use intensification and environmental change and their interactions with natural forest dynamics—will shape future forest carbon stock changes. These interactive effects will likely be strongest in tropical wildlands.

Highly effective CO2 electroreduction to formate boosted by Ce-doping on Indium oxide electrocatalysts

Electrocatalytic reduction of carbon dioxide (CO2) with high selectivity to generate value-added chemical products and fuels, utilizing renewable electricity sources, offers an effective approach to address the continued increase in atmospheric CO2. Here, we report cerium (Ce)-doped indium oxide (In2O3) electrocatalyst generated in situ on carbon paper (Ce-In2O3/CP), and its application in the electrochemical reduction of CO2 (CO2RR) to formate formation with high Faradaic efficiency (FE) (reaching 97.6% at −1.7 V vs. Ag/AgCl) and excellent stability. Experimental analysis and density functional theory (DFT) calculations indicate that doping Ce onto the (222) plane of In2O3 induces lattice distortion, which promotes electron transfer from Ce to In while adjusting the local electronic structure of the In atoms around Ce, making them more favorable for the adsorption of *OOCH intermediates and effectively lowering the energy barrier of the rate-determining step. Furthermore, Ce doping lowers the overpotential required for formate production and suppresses the hydrogen evolution reaction (HER), effectively enhancing the selectivity of formate.

Enhancing the Photosynthetic and Yield Performance of Rice in Saline Soil by Foliar-Applying Cost-Effective Compounds as Sources of Carbon Dioxide and Potassium

Although rice is highly sensitive to salinity, it is considered one of the best crops to grow in salt-affected mudflat soils to alleviate the salinity problem. Applying chemical compounds for an increase in leaf CO2 and nutrient levels can help mitigate the negative impact of salinity on plants in a cost-effective manner. To identify the benefits of using lithovit (Liv), ethanol (Eth), and potassium carbonate (KC) as a source of CO2 and K to enhance rice production in salt-affected soils, a field study was conducted to assess the effects of these compounds on the agro-physiological parameters of two rice genotypes (Giza178 and Giza179) in saline soils. The compounds were applied as a foliar spray at a concentration of 30 mM each before and after the heading growth stage. The results indicated that the genotype, application time, compounds, and their potential two-way interactions significantly influenced all agro-physiological parameters, with only a few exceptions. The genotype Giza 179 exhibited higher pigment contents, photosynthetic capacity, relative water content (RWC), grain yield, and most yield components compared to Giza 178, with increases ranging from 2.1% to 37.9%. Foliar application of different compounds resulted in a 9.7–37.9% increase in various parameters and a 34.6–43.2% decrease in the number of unfilled grains (NUFG) per panicle compared to untreated treatment. Foliar application of different compounds before heading resulted in an increase in various parameters by 4.8–16.1% and a decrease in the NUFG per panicle by 22.9% compared to those applied after heading. Heatmap clustering analysis revealed that foliar application of Liv before heading was the most effective treatment in enhancing various parameters for both genotypes and mitigating the negative effects of salinity stress on the NUFG. This was followed by Eth and KC before heading for Giza 179. Applying Eth and KC to the leaves after heading had a moderate positive impact on most parameters for Giza 179, outperforming the application after heading for Giza 178. Overall, our findings indicate that spraying readily available compounds that elevate CO2 and K levels in rice leaves can help alleviate the negative impacts of salt stress and improve rice production in salt-affected soils in a cost-effective manner.

Quantifying Global Hydrological Sensitivity to CO2 Physiological and Radiative Forcings Under Large CO2 Increases

AbstractPrediction of surface freshwater flux (precipitation or evaporation) in a CO2‐enriched climate is highly uncertain, primarily depending on the hydrological responses to physiological and radiative forcings of CO2 increase. Using the 1pctCO2 (a 1% per year CO2 increase scenario) experiments of 12 CMIP6 models, we first decouple and quantify the magnitude of global hydrological sensitivity to CO2 physiological and radiative forcings. Results show that the direct global hydrological sensitivity (for land plus ocean precipitation) to CO2 increase only is −0.09 ± 0.07% (100 ppm) −1 and to CO2‐induced warming alone is 1.54 ± 0.24% K−1. The latter is about 10% larger than the global apparent hydrological sensitivity (i.e., including all effects, not only direct responses to warming, = 1.39 ± 0.22% K−1). These hydrological sensitivities are relatively stable over transient 2× to 4 × CO2 scenario. The intensification of the global water cycle are dominated by the CO2 radiative effect (79 ± 12%) with a smaller positive contribution from the interaction between the two effects (6 ± 12%), but are reduced by the CO2 physiological effect (−10 ± 8%). This finding underlines the importance of CO2 vegetation physiology in global water cycle projections under a CO2‐enriched and warming climate.

Synthesis and Photoelectrochemical Properties of Copper Titanate for Pollutant Removal

Copper species are considered one of the materials capable of converting pollutants in add-products values. However, its stability is a challenge when applied in photoelectrocatalytic (PEC) processes. A promissory alternative is to couple copper species with other materials improving their chemical stability, such as TiO2, an p-type semiconductor with excellent charge transfer. The insertion of Cu atoms into the titanium crystal lattice can promote the formation of stable binary copper oxides and/or the production of ternary/quaternary oxides by sharing oxygen between the species1,2. In addition, the presence of TiO2 on CO2 conversion may lead to the reactions for methanol and ethanol formation due to its property to favor the generation of hydroxyl radicals (OH•) and H+ from the oxidation of water. Then, in the present work carried out the preparation of n-type ternary oxide semiconductor based in copper and titanium oxides. Cu–O–Ti was synthesized by a time-efficient, arc-melting method from TiO2 and Cu2O. The particulate product showed in its composition mixture between TiCu2O3 / TiCu3O5 and high crystalline phase. These ternary oxides presented a broad-band absorption in the UV−visible spectral region with absorbance coefficient located at 675 nm. Also, the material showed thermal stability up to ∼475 °C, and cathodic photoelectrochemical activity. Controlled thermal oxidation of copper from the Cu (I) to Cu (II) oxidation state showed that the crystal lattice could accommodate Cu2+ cations up to ∼475 °C, beyond which the compound was converted to CuO and TiCuO3. This process was monitored by powder X-ray diffraction and X-ray photoelectron spectroscopy. The mott-Schottky plots for this ternary oxide exhibited a decrease of capacitance indicating an increase of CO2 absorbing active sites. The efficiency of photocatalyst was evaluated by PEC experiments to CO2 conversion into alcohols. The experiments were carried out bubbling CO2 in 1.0 Mol L-1 NaHCaO3. The ternary oxide favored the ethanol and propane formation, as the final product, exhibiting high selectivity and concentration. Keywords: ternary copper oxide, copper titanate, arc synthesis, p-type semiconductor, photoelectrochemistry, CO2 conversion, C2 products formation.

Effect of CO2 and HClO4 Concentrations on CO2 Reduction Reaction Intermediates at Pt Polycrystalline Electrode

Introduction To achieve carbon neutrality, it is necessary to apply practical CO2 reduction and effective utilization technologies. Recently, there has been an expectation for the electrochemical reduction of CO2 (CO2 Reduction Reaction: CO2RR) using electricity derived from renewable energy. CO2RR with low overvoltage using a polymer electrolyte membrane is an actively researched next-generation technology. It is important to improve Faraday efficiency and analyze CO2RR mechanisms. Cu electrode catalysts are commonly used for CO2RR due to their high Faraday efficiency. However, a challenge remains in reducing the overvoltage of CO2RR to the level of hydrogen generation in normal PEM water electrolysis. Although Pt electrode catalysts have a significantly lower Faraday efficiency for CO2RR than Cu electrode catalysts, they have been reported to have low overvoltage1. Recent research has shown that the presence of water in the supplied CO2 and the alloy composition enhances Faraday efficiency2,3. To reduce CO2RR overvoltage, this study utilized a Pt electrode. Successful CO2RR requires the electrode catalyst surface to have coexisting surface-adsorbed hydrogen (Had) and CO2RR intermediate (COad). This study investigates the effect of electrolyte pH (perchloric acid concentration) and CO2 concentration on the COad and Had, utilizing a Pt polycrystalline electrode. Experimental Electrochemical measurements were carried out using a three-electrode cell. The counter electrode was a Pt mesh, and the reference electrode was a reversible hydrogen electrode (RHE). The working electrode was a φ3 mm Pt polycrystalline disk electrode that was mirror-polished with a 0.05 μm alumina suspension. Cyclic voltammetry (CV) measurements were performed with a sweep range of 0.05-1.0 V vs. RHE and a sweep rate of 50 mV/s or 10 mV/s. The results of the CV measurements are presented after IR correction. To evaluate CO2RR, the concentration of HClO4 was adjusted to 0.01-0.5 M as the electrolyte. The CO2 concentration was varied from 0-100 vol% and bubbled for 30 minutes before the CV measurements. For the electrochemical evaluation of CO2RR, the initial potential was kept at 0.05-0.4 V for 5 minutes before the CV measurements, and then the CV measurement was performed. Results and Discussion 1. CO2RR potential in HClO4 electrolyte saturated with 100% CO2 Figure 2 shows the results of CV measurements performed after holding the initial potentials at 0.05-0.4 V for 5 minutes before starting the CV measurements. The bubbling CO2 concentration during the measurements was 100%, and the HClO4 concentration was 0.1 M. In comparison to the CV peaks observed in the N2 atmosphere, peaks where the CO2RR reduction intermediate (COad) are reoxidized are observed at 0.6-0.7 V in the 100% CO2 atmosphere. The charge of these COad peaks remain constant at low initial holding potentials. However, it decreases significantly as the initial holding potential approaches 0.4 V. Under the measurement conditions of 100% CO2 atmosphere and 0.1 M HClO4 concentration, it can be seen that CO2 is reduced on the Pt electrode at a potential positive of 0 V vs. RHE because the COad peaks are seen between 0.05-0.3 V of the initial holding potentials. 2. Dependence of COad peak on bubbling CO2 concentration CV measurements were performed by changing the CO2 concentration bubbled in 0.1 M HClO4. Figure 3 shows the results of CV measurements at an initial potential hold of 0.05 V, where the CO2 concentration was changed from 0% to 100%. In the Hupd region, the amount of charge decreases in the CO2 atmosphere because CO2 is already surface-adsorbed as COad at 0.05 V, and the decrease is larger as the CO2 concentration increases. It is evident that the peaks of COad increase as the concentration of CO2 increases. Additionally, when the CO2 concentration is low, the peaks of COad are divided into at least two peaks, indicating the generation of COad with different adsorption structures during CO2RR. As the CO2 concentration increases, the peaks of COad appearing on the low potential side also increase. Additionally, the ratio of COad with different adsorption structures might change depending on the CO2 concentration bubbled. Acknowledgements This work was supported by JSPS KAKENHI Grant Number JP23K13835 and TEPCO Memorial Foundation.

Review of Foam with Novel CO2-Soluble Surfactants for Improved Mobility Control in Tight Oil Reservoirs.

CO2-soluble surfactant foam systems have gained significant attention for their potential to enhance oil recovery, particularly in tight oil reservoirs where conventional water-soluble surfactants face challenges such as poor injectability and high reservoir sensitivity. This review provides a comprehensive explanation of the basic theory of CO2-soluble surfactant foam, its mechanism in enhanced oil recovery (EOR), and the classification and application of various CO2-soluble surfactants. The application of these surfactants in tight oil reservoirs, where low permeability and high water sensitivity limit traditional methods, is highlighted as a promising solution to improve CO2 mobility control and increase oil recovery. The mechanism of enhanced oil recovery by CO2-soluble surfactant foam involves the effective reduction of CO2 fluidity, the decrease in oil-gas flow ratio, and the stabilization of the displacement front. Foam plays a vital role in mitigating the issues of channeling and gravity separation often caused by simple CO2 injection. The reduction in gas fluidity can be attributed to the increase in apparent viscosity and trapped gas fraction. Future research should prioritize the development of more efficient and environmentally friendly CO2-soluble surfactants. It is essential to further explore the advantages and challenges associated with their practical applications in order to maximize their potential impact.

A new method to predict return of spontaneous circulation by peripheral intravenous analysis during cardiopulmonary resuscitation: a rat model pilot study

BackgroundEnhancing venous return during cardiopulmonary resuscitation (CPR) can lead to better hemodynamics and improved outcome after cardiac arrest (CA). Peripheral Intravenous Analysis (PIVA) provides feedback on venous flow changes and may indicate an increase in venous return and cardiac output during CPR. We hypothesize PIVA can serve as an early indicator of increased venous return, preceding end-tidal CO2 (etCO2) increase, before the return of spontaneous circulation (ROSC) in a rat model of CA and CPR.ResultsEight male Wistar rats were intubated and ventilated, and etCO2 was measured. Vessels were cannulated in the tail vein, femoral vein, femoral artery, and central venous and connected to pressure transducers. Ventilation was discontinued to achieve asphyxial CA. After 8 min, CPR began with ventilation, epinephrine, and automated chest compressions 200 times per minute until mean arterial pressure increased to 120 mmHg. Waveforms were recorded and analyzed. PIVA was calculated using a Fourier transformation of venous waveforms. Data are mean ± SE. Maximum PIVA values occurred in the tail vein 34.7 ± 2.9 s before ROSC, with subsequent PIVA peaks in femoral vein and centrally at 30.9 ± 5.4 and 25.1 ± 5.0 s, respectively. All PIVA peaks preceded etCO2 increase (21.5 ± 3.2 s before ROSC).ConclusionPIVA consistently detected venous pressure changes prior to changes in etCO2. This suggests that PIVA has the potential to serve as an important indicator of venous return and cardiac output during CPR, and also as a predictor of ROSC.

Estimated human-induced warming from a linear temperature and atmospheric CO2 relationship

Assessing compliance with the human-induced warming goal in the Paris Agreement requires transparent, robust and timely metrics. Linearity between increases in atmospheric CO2 and temperature offers a framework that appears to satisfy these criteria, producing human-induced warming estimates that are at least 30% more certain than alternative methods. Here, for 2023, we estimate humans have caused a global increase of 1.49 ± 0.11 °C relative to a pre-1700 baseline.

Simulating Ips typographus L. outbreak dynamics and their influence on carbon balance estimates with ORCHIDEE r8627

Abstract. New (a)biotic conditions resulting from climate change are expected to change disturbance dynamics, such as windthrow, forest fires, droughts, and insect outbreaks, and their interactions. These unprecedented natural disturbance dynamics might alter the capability of forest ecosystems to buffer atmospheric CO2 increases, potentially leading forests to transform from sinks into sources of CO2. This study aims to enhance the ORCHIDEE land surface model to study the impacts of climate change on the dynamics of the bark beetle, Ips typographus, and subsequent effects on forest functioning. The Ips typographus outbreak model is inspired by previous work from Temperli et al. (2013) for the LandClim landscape model. The new implementation of this model in ORCHIDEE r8627 accounts for key differences between ORCHIDEE and LandClim: (1) the coarser spatial resolution of ORCHIDEE; (2) the higher temporal resolution of ORCHIDEE; and (3) the pre-existing process representation of windthrow, drought, and forest structure in ORCHIDEE. Simulation experiments demonstrated the capability of ORCHIDEE to simulate a variety of post-disturbance forest dynamics observed in empirical studies. Through an array of simulation experiments across various climatic conditions and windthrow intensities, the model was tested for its sensitivity to climate, initial disturbance, and selected parameter values. The results of these tests indicated that with a single set of parameters, ORCHIDEE outputs spanned the range of observed dynamics. Additional tests highlighted the substantial impact of incorporating Ips typographus outbreaks on carbon dynamics. Notably, the study revealed that modeling abrupt mortality events as opposed to a continuous mortality framework provides new insights into the short-term carbon sequestration potential of forests under disturbance regimes by showing that the continuous mortality framework tends to overestimate the carbon sink capacity of forests in the 20- to 50-year range in ecosystems under high disturbance pressure compared to scenarios with abrupt mortality events. This model enhancement underscores the critical need to include disturbance dynamics in land surface models to refine predictions of forest carbon dynamics in a changing climate.

Distinct responses of climate-growth and iWUE in Fagus sylvatica L. at two low elevation sites in southern Italy

In this study, using a dendrological and isotopic approaches, we investigated the responses to climate of two pure Fagus sylvatica L. stands (Campobraca and Falode) in the southernmost part of the distribution range in southern Italy. The δ13C data were used for calculating the intrinsic water use efficiency (iWUE) as a proxy of the balance between the water and carbon cycles. The results showed that the iWUE of both stands was sensitive to the amount of precipitation during the summer months (negative, significant effect) and to atmospheric CO2 concentration. Growth was sensitive to climate only in the Campo Braca site; the most influential variables were the VPD (vapour pressure deficit) and precipitation of the summer months that had a negative and a positive effect, respectively. The iWUE showed a negative correlation with growth in Campo Braca and a non-significant one in Falode. Water availability was the most influential variable on F. sylvatica growth and physiology. The iWUE increase was mainly driven by atmospheric CO2 concentration, and by decreased precipitation, as a response of the trees to drought. Our results highlight the importance of understanding the hydrological changes due to climate change for forecasting/modelling forest responses. CO2 increase does not compensate for the effect of adverse climate on F. sylvatica in the forests of southern Italy, while local conditions play an important role in determining tree growth.