Increase In Atmospheric Temperature Research Articles

Correlations between the increase in atmospheric CO2 and temperature, and the subsequent increase in silica, and groundwater organisms

Rising atmospheric temperature and CO2 impact all freshwater systems. In groundwater, one such impact is CO2- and temperature-induced weathering, which leads to more intense weathering of silicate rocks. Here, we tested whether the increased CO2 levels, the weathering, or rather the increasing temperature, impacted on fauna and prokaryotes in the groundwater ecosystem. We also conducted the analyses separately for two groups of wells, one of which contained wells that were secluded from the surface (and often rather deep), and wells tapping the quaternary aquifers (often rather shallow) which exchange with the surface more intensely. Organism abundances and relative composition did not correlate with temperature or CO2 levels. While many organisms rely on silica, in contrast, we found negative correlations between silica concentrations and fauna. The increases in silica concentrations over time, i.e. temporal trends, also partly correlated negatively with organisms. We hypothesize that the unexpected negative correlations are not direct effects, but indirectly indicate that groundwater communities do not adapt rapidly enough to changes in silica concentrations, but also more generally to changes for which silica might only be a proxy. Groundwater fauna take part in the ecosystem service of water self-cleaning and are thus considered beneficial for sustainable raw water for drinking water production. The propensity of groundwater fauna to decrease with increases in silica, jeopardizes future drinking water production.

Enhancing outdoor comfort in urban hot climates: investigating the cooling impact of two tropical trees through shade provision and transpiration

ABSTRACT One key ecosystem service widely known and attributed to trees in the urban environment is their ability to provide shade through their canopies and undertake evapotranspiration cooling. These in turn contribute to reduced atmospheric temperatures. A lesser-known aspect with little quantitative data is the heterogeneous temperature environment beneath the canopies at pedestrian or street level where the cooling will benefit thermal comfort. This study was conducted throughout 2022. It collected data where air temperature was measured under the canopies of two urban tropical tree species, Samanea saman and Peltophotum pterocarpum, at three different heights, which were 1, 3 and 5 m, respectively, from the ground. This was to investigate whether crown architectures and the associated shade and cooling effects via transpiration can have a significant change in the surrounding temperature. The study observed surface and air temperatures coupled with meteorological data across cool, warm, and hot periods of the year. It was observed that soil temperature increased alongside increases in atmospheric temperatures with a more significant rise observed for P. pterocarpum despite the observation of greater wind speeds for both night and day at the site where this species was situated. The soil moisture potential data indicated the reverse where S. saman showed more negative values with the greatest increase under warm conditions. Interestingly, sap flow rates also indicated that P. pterocarpum had more efficient rates whether conditions were cool, warm, or hot, suggestive of more active transpirational cooling. This was despite a lower leaf area index, smaller crown volume and sap wood area for this species. Relationship analyses between sap flow and air temperatures at different heights under the canopies showed a positive correlation. This demonstrates that apart from shade provided by the canopies, transpiration is also an important parameter for cooling. The mean daytime air temperature indicated that the greatest cooling effect was experienced at the lowest level from the ground (at 1 m), and this was consistent for both species across cool, warm, and hot conditions with a significant cooling effect of between 2.3 and 4°C. Temperature data under the canopy (1 to 5 m from the ground) compared to the air temperature of the grass that was shaded indicated temperature differences of between 2.3 and 7.9°C at 5 m and between 1.9 and 5.6°C at 1 m (for both species) with a bigger reduction attributed to S. saman.

Direct and Remote Sensing Monitoring of Plant Salinity Stress in a Coastal Back-Barrier Environment: Mediterranean Pine Forest Stress and Mortality as a Case Study

The increase in atmospheric and soil temperatures in recent decades has led to unfavorable conditions for plants in many Mediterranean coastal environments. A typical example can be found along the coast of the Campania region in Italy, within the “Volturno Licola Falciano Natural Reserve”, where a pine forest suffered a dramatic loss of trees in 2021. New pines were planted in 2023 to replace the dead ones, with a larger tree layout and interspersed with Mediterranean bushes to replace the dead pine forest. A direct (in situ) monitoring program was planned to analyze the determinants of the pine salinity stress, coupled with Sentinel-2 L2A data; in particular, multispectral indices NDVI and NDMI were provided by the EU Copernicus service for plant status and water stress level information. Both the vadose zone and shallow groundwater were monitored with continuous logging probes. Vadose zone monitoring indicated that salinity peaked at a 30 cm soil depth, with values up to 1.9 g/L. These harsh conditions, combined with air temperatures reaching peaks of more than 40 °C, created severe difficulties for pine growth. The results of the shallow groundwater monitoring showed that the groundwater salinity was low (0.35–0.4 g/L) near the shoreline since the dune environment allowed rapid rainwater infiltration, preventing seawater intrusion. Meanwhile, salinity increased inland, reaching a peak at the end of the summer, with values up to 2.8 g/L. In November 2023, salts from storm-borne aerosols (“sea spray”) deposited on the soil caused the sea-facing portion of the newly planted pines to dry out. Differently, the pioneer vegetation of the Mediterranean dunes, directly facing the sea, was not affected by the massive deposition of sea spray. The NDMI and NDVI data were useful in distinguishing the old pine trees suffering from increasing stress and final death but were not accurate in detecting the stress conditions of newly planted, still rather short pine trees because their spectral reflectance largely interfered with the adjacent shrub growth. The proposed coupling of direct and remote sensing monitoring was successful and could be applied to detect the main drivers of plant stress in many other Mediterranean coastal environments.

The patterns of potential evapotranspiration and seasonal aridity under the change in climate in the upper Blue Nile basin, Ethiopia

Evapotranspiration is one of the determinant components of the hydrological process, highly influenced by climate change due to the increase in atmospheric temperature at global and regional scales. This study was designed to evaluate the extent to which climate change affects the Potential Evapotranspiration (PET) and the consequent Aridity Index (AI) in the high-emission scenario of Representative Concentration Pathways (RCPs) in the Gilgel Abay, Ribb, Gumara, and Megech watersheds using six Global Climate Models in the 2011–2040, 2041–2070, and 2071–2100 relative to the 1971–2000 (baseline period). The average PET is simulated using the Soil Water Assessment Tool (SWAT) model. Penman-Monteith and Hargreaves methods were used in the computation of PET using the water balance technique, and the Hargreaves method was found more efficient in calibration and validation processes. The Aridity Index (AI) of watersheds is calculated using the ratio of precipitation and potential evapotranspiration. The study revealed that the change in annual average PET is showing an increasing pattern in the three time periods, and the highest rate of changes in Megech, Gilgel Abay, Ribb, and Gumara, watersheds are 16.66%, 15.53%, 14.68%, and 13.46%, respectively in the 2071–2100 time period. Seasonally, the highest rate of change in PET is 20.37% (September), 19.29% (April), 17.46% (March), and 17.02% (March) in the Megech, Gilgel Abay, Ribb, and Gumara, respectively. Similarly, the seasonal highest change in Aridity Index (AI) is also likely to be observed in the 2071–2100 in which in the dry season, it accounts –0.303 (March), –0.299 (March), –0.285 (April), and –0.276 (April) in the Ribb, Gumara, Gilgel Abay, and Megech, respectively, whereas in the rainy season, the change is 0.263, 0.258, 0.238, and 0.211 in the Gilgel Abay, Gumara, Ribb, and Megech, respectively. In general, due to the rising atmospheric temperature, the amount of moisture during dry seasons in the headwater catchments of the upper Blue Nile basin is expected to deplete in the 21st century. Therefore, it is highly recommended to use different climate change adaptation mechanisms including adopting suitable physical and biological water conservation techniques to enhance the amount of water stored in the subsurface and joining the groundwater during the rainy season.

Global assessment of production benefits and risk reduction in agroforestry during extreme weather events under climate change scenarios

Climate change and extreme weather events are threatening agricultural production worldwide. The anticipated increase in atmospheric temperature may reduce the potential yield of cultivated crops. Agroforestry is regarded as a climate-resilient system that is profitable, sustainable, and adaptable, and has strong potential to sequester atmospheric carbon. Agroforestry practices enhance agroecosystems’ resilience against adverse weather conditions via moderating extreme temperature fluctuations, provisioning buffers during heavy rainfall events, mitigating drought periods, and safeguarding land resources from cyclones and tsunamis-type events. Therefore, it was essential to comprehensively analyze and discuss the role of agroforestry in providing resilience during extreme weather situations. We hypothesized that integrating trees in to the agro-ecosystems could increase the resilience of crops against extreme weather events. The available literature showed that the over-story tree shade moderates the severe temperature (2–4°C) effects on understory crops, particularly in the wheat and coffee-based agroforestry as well as in the forage and livestock-based silvipasture systems. Studies have shown that intense rainstorms can harm agricultural production (40–70%) and cause waterlogging. The farmlands with agroforestry have been reported to be more resilient to heavy rainfall because of the decrease in runoff (20–50%) and increase in soil water infiltration. Studies have also suggested that drought-induced low rainfall damages many crops, but integrating trees can improve microclimate and maintain crop yield by providing shade, windshield, and prolonged soil moisture retention. The meta-analysis revealed that tree shelterbelts could mitigate the effects of high water and wind speeds associated with cyclones and tsunamis by creating a vegetation bio-shield along the coastlines. In general, existing literature indicates that implementing and designing agroforestry practices increases resilience of agronomic crops to extreme weather conditions increasing crop yield by 5–15%. Moreover, despite its widely recognized advantages in terms of resilience to extreme weather, the systematic documentation of agroforestry advantages is currently insufficient on a global scale. Consequently, we provide a synthesis of the existing data and its analysis to draw reasonable conclusions that can aid in the development of suitable strategies to achieve the worldwide goal of adapting to and mitigating the adverse impacts of climate change.

Predicting Climatic Parameters Using the ARIMA Time Series and LSTM Deep Learning Models for Vidarbha Region

A daily increase in atmospheric temperatures causes changes in rainfall patterns. It has a substantial impact on environmental problems worldwide. Understanding these variations is essential, especially concerning how changes in rainfall affect natural calamities like droughts, floods, and global warming. The Vidarbha region of Maharashtra, India, is selected as a subject of this work. Climate change impacts groundwater levels because the temperature rise reduces it. After considering all the factors, it is a must to apply any forecasting model so that future disasters can be predicted. The study evaluates dataset accuracy and visualises data using RStudio. The work tries forecasting rainfall, humidity, and groundwater data using the ARIMA Time Series model and LSTM machine-learning algorithm. Also, a comparative analysis of both approaches is given here. This thorough investigation has consequences for the area's hydrological planning, disaster preparedness, and economic development.

Evaluating the effect of ambient air temperature on the sustainability aspect of naphtha‐based gas turbine power plant

AbstractThe exergy‐based sustainability indices have been a cause of concern for gas turbine power plant as its performance is very sensitive to air temperature. Hence, the present study evaluates the impact of atmospheric air temperature on exergy sustainability and ecological function of a naphtha‐based gas turbine power plant using EES. The outcome of the study shows that combustion chamber (CC_1) needs more attention compared with other components present, and it has least improvement potential as compared with other components. Further while carrying out parametric analysis with respect to ambient air, it was observed that for a 1.1°C increase in atmospheric air temperature a reduction in sustainability index about 0.66% was observed respectively, for GT_1. Thus, this study established that the power plant's exergy sustainability performance has a negative impact at high ambient air temperatures on exergy sustainability indices.

Changes in litter and nitrogen deposition differentially alter forest soil organic matter biogeochemistry

Global climate change has altered forest productivity across the globe. Although extreme drought and temperature have lowered forest productivity in some regions, increased productivity has been observed in many forests over the last few decades due to increases in atmospheric carbon dioxide, temperature, and nitrogen (N) deposition. These factors can lead to changes in both the quantity and quality of litterfall and root inputs to soil. Additionally, few studies have investigated multifactorial treatments (e.g., detrital changes and N deposition), on soil carbon (C) sequestration. To investigate the long-term compositional changes to soil organic matter (SOM) in response to litter and N inputs, soil samples were collected from the University of Michigan Biological Station (UMBS) Detrital Input and Removal Treatment (DIRT) site after 15 years of experimental treatments. The samples were characterized using elemental analysis, targeted SOM compound analyses, nuclear magnetic resonance spectroscopy and microbial biomass and community composition measurements. The exclusions of C inputs (litter and/or roots) resulted in molecular-level biogeochemical changes, however, the soils at UMBS are seemingly more resistant to losses in soil C compared to other DIRT studies. Although the addition treatments (Double Litter, Double Wood, Double Litter + N, and N) led to increased soil C concentrations at UMBS, we found evidence for enhanced SOM decomposition occurring with litter additions. Notably, the observations made from the concurrent treatment of Double Litter + N demonstrated that the responses of individual treatments are not representative of simultaneous applications. Collectively, these results demonstrate that soil C biogeochemistry is sensitive to fluctuations in C and N deposition and overall, these processes are dictated by site-specific ecological properties.

Experimental Characterisation of BGBC OTFT for Indoor CO<sub>2</sub> Gas Sensing

Global warming is a concern nowadays due to excessive release of harmful gasses to the environment, leading to greenhouse effect phenomena worldwide. Based on the data provided by global pollution agencies, the release of greenhouse gasses to the atmosphere is the main cause of pollution and the increase in atmospheric temperature due to warming. Greenhouse gasses (GHGs) contents released to the environment is worrying, with carbon dioxide (CO2) is reported at the highest concentration compared to other gasses. There are many studies conducted to develop and evaluate the performance of harmful gas sensors incorporating inorganic and organic semiconductive materials. Organic semiconductors (OSCs) are environmentally friendly materials, relatively cheaper technology, and comprised of a wide range of materials with good carrier mobility. Therefore, in this work, Organic Thin Film Transistor (OTFT) is developed for gas sensor application. As global warming is becoming more serious, this solution is instead a sustainable solution to the environment, as organic molecules which are held together via Van der Waals bond are easily processed via low-temperature deposition and solution processing as compared to more complicated processes involved in conventional inorganic counterpart. In addition, the developed sensor is generally robust due to the ability to withstand high humidity conditions and can be fabricated on flexible substrates. In this work, suitable materials are identified in basic OTFT construction, which are the electrodes, dielectric and substrate. The scope is mainly focusing on the development of bottom gate OTFT construction, incorporating p-type active material which are Trisisopropylsilylethynyl Pentacene (TIPS Pentacene), Aluminium (Al) as drain and source electrodes, PEDOT: PSS as gate electrode and Polyvinyl alcohol (PVA) as gate dielectric. The materials in bottom gate bottom contact (BGBC) configuration, fabricated via screen printing technique is experimentally tested towards CO2 detection. CO2 is initially detected at 1618 ppm with contact resistance of 15 kΩ, and at 10 ml/minute flow rate, the developed configuration is demonstrated able to achieve sensitivity of 2.069 Ω/ppm. In conclusion, the studied BGBC OTFT has demonstrated suitability and applicability in CO2 gas sensing for sustainable environmental condition monitoring, that could lead to safer environment for the living things on earth. With the proposed dimensions, in the future it is possible to proceed with this work to be fabricated by using more advanced techniques such as photolithography and many others.

Zero carbon emission CCGT power plant with integrated solid fuel gasification

The development of a high-capacity power plant with zero CO2 emissions is an urgent task that will curb the increase in atmospheric temperature. It should have an efficiency comparable with existing TPPs, a low metal consumption rate, a high fuel versatility, and high flexibility. To meet these conditions, oxygen combustion is conducted in an environment of inert CO2, and most of the condensation heat from the combustion products is usefully utilized. This work presents a combined cycle gas turbine (CCGT) power plant with solid fuel gasification, oxy-fuel combustion, and a pressurized heat recovery steam generator (PHRSG). The two plant options are compared with the natural gas plant previously proposed. In the PHRSG, the low metal intensity is achieved by high average temperature differences, the pinch point value at 8–12 °C, and the intensification of heat transfer caused by the high pressure of combustion products and the condensation of water vapor in the tail surfaces. The developed plants are highly efficient when using coal, 51%, and 57.3% when using peat, and have acceptable CO2 avoidance costs of 72.7 €/t and 60.4 €/t. By combining these factors, and using well-developed materials, it will take less time to develop and implement this plant widely.

Enhancing Cowpea Tolerance to Elevated Temperature: Achievements, Challenges and Future Directions

Despite its ability to thrive in high-temperature environments, cowpea productivity can be hampered by heat stress, particularly when night air temperatures exceed 17 °C. The crop’s germplasm pool potentially possesses significant genetic variability that can be harnessed to breed for heat-tolerant varieties. Progress in improving the crop for heat tolerance has been limited, especially under the hot, short-day environments typical of sub-Saharan Africa. Only a few heat-tolerant varieties have been released, partly due to the limited understanding of heat stress tolerance mechanisms and environmental interaction effects on genotypes, as well as imprecise phenotyping. This review contributes to the literature on cowpea heat stress by highlighting key achievements, challenges, and future directions in breeding heat-tolerant cowpea genotypes and by providing additional information from the recent literature. We opine that the genetic variability for heat tolerance-related traits in cowpea has not been sufficiently exploited in developing varieties adapted to the target production environments. Therefore, attention should be given to assessing the crop’s genetic repository by targeting adaptive, morphological, and physiological traits that enhance heat stress tolerance. We propose that breeding programs integrate phenotyping of whole-plant physiological traits and molecular breeding to identify breeder-friendly markers for routine selection. This should be followed by introgression of the heat-tolerant favourable alleles to adapted susceptible varieties using rapid and precise approaches that take advantage of modern genetic and genomic resources such as innovative genetic resources, genomic selection, speed breeding, and genome editing technologies. These tools hold great promise in fast-tracking the development of improved heat-tolerant varieties and incorporating the must-have traits preferred by cowpea farmers and consumers. In view of the likely increase in atmospheric temperature to be occasioned by climate change, there is an urgent need to develop heat-tolerant cowpea varieties to ensure the sustainability of current and future cropping and agri-food systems.

Diverse projected climate change scenarios affect the physiology of broccoli plants to different extents.

Climate change caused by global warming involves crucial plant growth factors such as atmospheric CO2 concentration, ambient temperature or water availability. These stressors usually co-occur, causing intricate alterations in plant physiology and development. This work focuses on how elevated atmospheric CO2 levels, together with the concomitant high temperature, would affect the physiology of a relevant crop, such as broccoli. Particular attention has been paid to those defence mechanisms that contribute to plant fitness under abiotic stress. Results show that both photosynthesis and leaf transpiration were reduced in plants grown under climate change environments compared to those grown under current climate conditions. Furthermore, an induction of carbohydrate catabolism pointed to a redistribution from primary to secondary metabolism. This result could be related to a reinforcement of cell walls, as well as to an increase in the pool of antioxidants in the leaves. Broccoli plants, a C3 crop, grown under an intermediate condition showed activation of those adaptive mechanisms, which would contribute to coping with abiotic stress, as confirmed by reduced levels of lipid peroxidation relative to current climate conditions. On the contrary, the most severe climate change scenario exceeded the adaptive capacity of broccoli plants, as shown by the inhibition of growth and reduced vigour of plants. In conclusion, only a moderate increase in atmospheric CO2 concentration and temperature would not have a negative impact on broccoli crop yields.

Changing climate yet healthy forest stand of Tsuga dumosa in temperate zone of central Nepal

Nepal Himalaya is experiencing a faster rate of temperature rise than the global average, and the temperature has altered the growth patterns and distribution of mountain trees. A dendrochronological study was conducted for Tsuga dumosa (D.Don) Eichler to analyze growth-climate relationship from the temperate forest of central Nepal. We developed 116 year-long tree ring width chronology spanning from 1905 to 2020 CE. The study area showed a significant increase in atmospheric temperature and a decrease in rainfall during the past 42 years. It is found that the spring season (March–May) climate is sensitive to the radial growth of T. dumosa. Ring width indices showed a substantial positive correlation with the minimum temperature of January, March, and June of the growth year. Conversely, a negative correlation was observed with the maximum temperature of the previous year's months (July, September, and November), March, and September of the current year, and rainfall during June and November. Basal Area Increment (BAI) trend is positive, indicating the forest is healthy despite the decline in the years 1942, 1978, and 1998. We conclude that the warming of the spring season (March–May), previous year's late growing season and moisture supply (precipitation) during June are critical to the radial growth of Tsuga dumosa in the region. However, responses from multiple species and their exposure to different climate regimes would ideally be required to make predictions on the growth climate relationships of forest trees.

The climate impacts and potential benefits of services export growth in developing countries

Promoting the services trade is considered an effective means of revitalizing the economy at a marginal environmental cost in the post-pandemic era. However, the impact of services trade growth and how to promote services development remain to be addressed. This study investigates the performance of the services trade for both developed and developing countries as well as the impact of their services trade growth on the Paris Agreement climate target and the possible synergy for achieving the Sustainable Development Goals (SDGs). Moreover, policy recommendations are provided for developing countries to facilitate services trade growth. Input–output analysis, comparative advantage theory, and the Model for the Assessment of Greenhouse Gas Induced Climate Change (MAGICC) are used in this study. The results show that services trade accounted for 44.4 % of global trade-induced value added but only 14.7 % of CO2 emissions. Services trade growth would lead to 199.8 Mt and 311.2 Mt CO2 emissions under the ServGrow scenario and DoubDeve scenario, respectively, suggesting that vigorously promoting services exports growth of developing countries has limited carbon implications. Further simulation indicates that the global atmospheric temperature increase caused by services trade growth in both scenarios is within 0.05 °C. Notably, accelerating services exports growth in developing countries helps to mitigate the inequality between developed and developing countries. The findings of this study can inform policymakers regarding the formulation and implementation of policies for economic recovery, reducing inequality, addressing climate change, and contributing to the achievement of the SDGs.

Potential reduction in carbon fixation capacity under climate change in a Pinus koraiensis forest

There has been an increasing recognition of the crucial role of forests, responsible for sequestering atmospheric CO2, as a moral imperative for mitigating the pace of climate change. The complexity of evaluating climate change impacts on forest carbon and water dynamics lies in the diverse acclimations of forests to changing environments. In this study, we assessed two of the most common acclimation traits, namely leaf area index and the maximum rate of carboxylation (Vcmax), to explore the potential acclimation pathways of Pinus koraiensis under climate change. We used a mechanistic and process-based ecohydrological model applied to a P. koraiensis forest in Mt. Taehwa, South Korea. We conducted numerical investigations into the impacts of (i) Shared Socioeconomic Pathways 2–4.5 (SSP2-4.5) and 5–8.5 (SSP5-8.5), (ii) elevated atmospheric CO2 and temperature, and (iii) acclimations of leaf area index and Vcmax on the carbon and water dynamics of P. koraiensis. We found that there was a reduction in net primary productivity (NPP) under the SSP2-4.5 scenario, but not under SSP5-8.5, compared to the baseline, due to an imbalance between increases in atmospheric CO2 and temperature. A decrease in leaf area index and an increase in Vcmax of P. koraiensis were expected if acclimations were made to reduce its leaf temperature. Under such acclimation pathways, it would be expected that the well-known CO2 fertilizer effects on NPP would be attenuated.

Carbon Sequestration Potential of Trees in Urban Vegetation Islands: A Case Study

Aim: Increasing levels of atmospheric carbon dioxide (CO2) and other “greenhouse” gases contribute to an increase in atmospheric temperature. Trees act as a sink for CO2 by fixing carbon during photosynthesis and storing excess carbon as biomass. The current study focuses on the contribution of vegetation within Janki Devi Bajaj Government Girls College, Kota towards carbon sequestration potential and climate regulation.
 Study Design: Non-destructive method of biomass estimation was used to measure the GBH of individual trees on the campus.
 Place and Duration: The study was conducted in Janki Devi Bajaj Government Girls College, Kota in Rajasthan, India from July 2022 to June 2023.
 Methodology: Above-ground biomass (AGB) and below-ground biomass (BGB) were calculated with the help of field measures of diameter at breast height (DBH) of the trees using allometric equations and Carbon equivalent was calculated with scientifically verified formula.
 Results: The present study enumerated a total of 849 trees belonging to 43 tree species on the campus. The most dominant species was Syzygium cumini (L.) Skeels with a total of 163 trees followed by Phoenix sylvestris (L.) Roxb (121 trees) and Eucalyptus obliqua L'Her (97 trees). The above-ground biomass (AGB) and below-ground biomass (BGB) of all the trees on the campus are equivalent to 373937 kg and 56090.54 kg, respectively. The total biomass accumulated is 430027.5 kg and the total carbon content of the campus trees is equal to 215013.75 kg. The total carbon sequestered by all the trees in a year is 788.38 tons. In other words, on average carbon sequestered by an individual tree on the campus is 928.60 kg/year or 0.93 tons/year.
 Conclusion: Urban green islands are likely to have a wider impact on biomass accumulation in turn carbon storage and sequestration in comparison to other structural parameters like species richness or density. Thus, in urban areas, the amount of potential carbon storage is positively influenced by increasing biomass.

Assessing the Robustness of Arctic Sea Ice Bi‐Stability in the Presence of Atmospheric Feedbacks

AbstractArctic sea‐ice loss is influenced by multiple positive feedbacks, sparking concerns of accelerated loss in the coming years or even a tipping point, where a sea‐ice equilibrium disappears at a given CO2 value and sea ice rapidly evolves to a new steady state. Such a tipping point would imply a bi‐stability of the Arctic climate—where multiple steady‐state Arctic climates are possible at the same CO2 value. Previous works have sought to establish the existence of bi‐stability using a range of models, from zero‐dimensional sea ice thermodynamic models to fully coupled global climate models, with conflicting results. Here, we present a new model of the Arctic that includes both sea‐ice thermodynamics and key atmospheric feedbacks in a simple framework. We exploit the model's simplicity to identify physical mechanisms that control the timing and extent of sea‐ice bi‐stability, and the abruptness of ice loss. We show that longwave radiation feedbacks can have a strong influence on Arctic surface climate from atmospheric temperature increases alone, even without major contributions from clear‐sky moisture or convective clouds suggested previously. While winter sea‐ice bi‐stability is robust to changes in uncertain model parameters in this study, summer sea ice is more sensitive. Finally, our model indicates that positive feedbacks may modulate the CO2 threshold of sea‐ice loss and the width of bi‐stability much more strongly than the abruptness of loss. These results lead to a comprehensive understanding of the conditions that favor Arctic sea‐ice bi‐stability, particularly the role of atmospheric feedbacks, in both future and past climates.

Modelisation of desorption isotherms and estimation of the thermophysic and thermodynamic properties of tropical woods in Cameroon: The case of Ayous and Ebony woods

A review at various models illustrates the necessary of choosing a model that can best describe each wood in relation to its isotherms of desorption. The theoretical models enable us to deduce several thermo physical parameters. The models of Dent and G.A.B are quite appropriate in the evaluation of the isotherms of desorption of Ayous and Ebony woods taking the humidity of the atmosphere air into consideration. The parameters of Dent’s model vary favourably with regard to the theoretical precisions. The level of humidity at fiber saturation points are at 0.2944 for Ayous wood and 0.19141 for Ebony wood. The specific surface area occupied by the woods under study decreases when there is a consequent increase in temperature. The specific surface area of Ayous wood ranges between 295 and 162 m2/g whereas that of Ebony ranges between 183 and 96 m2/g, while the wood temperatures vary between 20 and 60°C. It is realised that, there is a powerful relationship existing between the primary hydrophiles of Ebony and the first layer of mater molecules. The desorption heat of multi layers of our woods are superior to latent heat condensation of pure water. The heat condensation of water vapour constitutes a specific given which is superior to the heat isosteric adsorption of the woods in question. The soret effect is more important in the drying of Ayous wood than that of Ebony. However, temperature does not influence the soret effect for Ebony wood, relative air humidity is less than 0.85. This limits Ayous wood at 0.9. Above these limits soret effect increases when there is an increase in atmospheric air temperature.

Remote sensing of glacier change (1965–2021) and identification of surge-type glaciers on Severnaya Zemlya, Russian High Arctic

Abstract Glaciers in the Russian High Arctic have undergone accelerated mass loss due to atmospheric and oceanic warming in the Barents–Kara Sea region. Most studies have concentrated on the western Barents–Kara sector, despite evidence of accelerating mass loss as far east as Severnaya Zemlya. However, long-term trends in glacier change on Severnaya Zemlya are largely unknown and this record may be complicated by surge-type glaciers. Here, we present a long-term assessment of glacier change (1965–2021) on Severnaya Zemlya and a new inventory of surge-type glaciers using declassified spy-satellite photography (KH-7/9 Hexagon) and optical satellite imagery (ASTER, Sentinel-2A, Landsat-4/5 TM and 8 OLI). Glacier area reduced from 17 053 km2 in 1965 to 16 275 in 2021 (−5%; mean: −18%, max: −100%), with areal shrinkage most pronounced at land-terminating glaciers on southern Severnaya Zemlya, where there is a recent (post-2010s) increase in summer atmospheric temperatures. We find that surging may be more widespread than previously thought, with three glaciers classified confirmed as surge-type, eight as likely to have surged and nine as possible, comprising 11% of Severnaya Zemlya's 190 glaciers (37% by area). Under continued warming, we anticipate accelerated retreat and increased likelihood of surging as basal thermal regimes shift.

Three decades of ocean warming impacts on marine ecosystems: A review and perspective

Ocean warming, primarily resulting from the escalating levels of greenhouse gases in the atmosphere, leads to a rise in the temperature of the Earth's oceans. These gases act as heat-trapping agents, contributing to the overall phenomenon of global warming. In order to gain a comprehensive understanding of how ocean warming impacts marine ecosystems, a thorough literature review was conducted over a span of three decades, involving 2484 initial publications. The systematic literature review screening was facilitated by utilizing Abstrackr's web-based application to efficiently select relevant abstracts, resulting in a final list of 797 publications aligned with the study's objectives. Since the advent of the industrial revolution, greenhouse gas emissions have witnessed an exponential surge, leading to a cumulative increase in atmospheric temperatures at an average rate of 0.08 °C (0.14 °F) per decade since 1880. Over the past 50 years, the ocean has emerged as a primary heat reservoir, absorbing and distributing the majority of the Earth's warming, with more than 90% of the heat gain occurring within its waters. Between 1950 and 2020, the global sea surface temperature (SST) increased by 0.11 °C (0.19 °F). The consequences of ocean warming extend significantly to the environment and climate. It induces the expansion of the ocean, alters its stratification and currents, diminishes oxygen availability, elevates sea levels, and intensifies hurricanes and storms. It also affects marine species' physiology, abundance, distribution, trophic interactions, survival, and mortality and can also cause stress and consequences for human societies that depend on impacted marine resources. Ocean warming is projected to increase from 2 to 4 and 4–8 times under climate scenarios Shared Socioeconomic Pathways 1–2.6 and Shared Socioeconomic Pathways 5–8.5, respectively, with an additional 0.6–2.0 °C added by the end of the century. We summarize its impacts and detailed negative or positive responses on marine taxonomic groups. We also provide critical information to help stakeholders, scientists, managers, and decision-makers to mitigate and adapt while improving biodiversity conservation and sustainability of marine ecosystems.