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Reconstructing the spatio-temporal dynamics of glaciations and permafrost largely relies on surface deposits and is therefore a challenge for every glacial period older than the last due to erosion. Consequently, glaciations and permafrost remain poorly constrained worldwide before ca. 30 ka. Since speleothems (carbonate cave deposits) form from drip water and generally indicate the absence of an ice sheet and permafrost, we evaluate how speleothem growth phases defined by U series dates align with past glacial–interglacial cycles. Further, we make the first systematic comparison of the spatial distribution of speleothem dates with independent reconstructions of the history of the British–Irish Ice Sheet (BIIS) to test how well geomorphologic ice reconstructions are replicated in the cave record. The frequency distribution of 1020 U series dates based on three different dating methods between 300 and 5 ka shows statistically significant periods of speleothem growth during the last interglacial and several interstadials during the last glacial. A pronounced decline in speleothem growth coincides with the Last Glacial Maximum before broad reactivation during deglaciation and into the Holocene. Spatio-temporal patterns in speleothem growth between 31 and 15 ka agree well with the surface-deposit-based reconstruction of the last BIIS. In data-rich regions, such as northern England, ice dynamics are well replicated in the cave record, which provide additional evidence about the spatio-temporal distribution of permafrost dynamics. Beyond the Last Glacial Maximum, the distribution of speleothem dates across the British Isles offers the opportunity to improve chronological constraints on past ice sheet variability, with evidence for a highly dynamic Scottish ice sheet during the last glacial. The results provide independent evidence of ice distribution complementary to studies of surface geomorphology and geology, and the potential to extend reconstructions into permafrost and earlier glacial cycles. Whilst undersampling is currently the main limitation for speleothem-based ice and permafrost reconstruction even in relatively well-sampled parts of the British Isles, we show that speleothem dates obtained using modern mass spectrometry techniques reveal a higher spatio-temporal resolution of glacial–interglacial cycles and glacial extent than previously possible. Further study of leads and lags in speleothem growth compared to surface deposition may provide new insights into landscape-scale dynamics during ice sheet growth and retreat.

Sea surface temperature (SST) variability in the south-eastern tropical Indian Ocean is crucial for rainfall variability in Indian Ocean rim countries. A large body of literature has focused on zonal variability associated with the Indian Ocean Dipole (IOD) which peaks in austral spring. In today's climate, northward shifts of the Tropical Convergence Zone (TCZ) co-vary with the IOD, and it is unclear whether these shifts may also occur independently. We have developed a new monthly resolved Sr/Ca record from a sub-fossil coral cored at Enggano Island (Sumatra, Indonesia). Core sections containing diagenetic phases are omitted from the SST reconstruction. U/Th dating shows that the Sr/Ca-based SST record extends from 1869–1918 and from 1824–1862 with a relative age uncertainty of ±3 years (2σ). At Enggano Island, coastal upwelling and cooling in austral spring impact SST seasonality and are coupled to the latitudinal position of the TCZ. The sub-fossil coral indicates an increase in SST seasonality between 1856 and 1918 relative to the 1930–2008 period. We attribute this to enhanced cooling due to stronger south-easterly (SE) winds driven by a northward shift in the TCZ in austral spring. A nearby sediment core indicates colder SSTs and a shallower thermocline prior to ∼1930. These results are consistent with an increase in the north–south SST gradient in the eastern Indian Ocean, calculated from historical temperature data, that is not seen in the zonal SST gradient. We conclude that the relationship between meridional and zonal variability in the eastern Indian Ocean is non-stationary and modulated by the long-term evolution of temperature gradients.

The Devonian is a warmer-than-present geological period spanning from 419 to 359 million years ago (Ma) characterized by multiple identified ocean anoxic/hypoxic events. Despite decades of extensive investigation, no consensus has been reached regarding the drivers of these anoxic events. While growing geological evidence has demonstrated a temporal correlation between astronomical forcing and anoxia during this period, underlying physical mechanisms remain unknown, hence questioning causality. Here, we perform multiple sensitivity experiments, using an Earth system model of intermediate complexity (cGENIE), to isolate the influences of specific Devonian climate and palaeogeography components on ocean oxygen levels, contributing to the better understanding of the intricate interplay of factors preconditioning the ocean to anoxia. We quantify the impact of continental configuration, ocean–atmosphere biogeochemistry (global mean oceanic PO4 concentration and atmospheric pO2), climatic forcing (pCO2), and astronomical forcing on background oceanic circulation and oxygenation during the Devonian. Our results indicate that continental configuration is crucial for Devonian ocean anoxia, significantly influencing ocean circulation and oxygen levels while consistently modulating the effects of other Devonian climate components such as oceanic PO4 concentration, atmospheric pO2 and pCO2, and orbital forcing. The evolution of continental configuration provides a plausible explanation for the increased frequency of ocean anoxic events identified during the Middle and Late Devonian periods, as it contributed to the expansion of oxygen-depleted zones. Our simulations also show that both the decreased atmospheric pO2 and increased oceanic PO4 concentration exacerbate ocean anoxia, consistent with established knowledge. The variation of pCO2 reveals a wide range of ocean dynamics patterns, including stable oscillations, multiple convection cells, multistability, and hysteresis, all leading to significant variations of the ocean oxygen levels and therefore strongly impacting the preconditioning of the ocean to anoxia. Furthermore, multistability and important hysteresis (particularly slow ocean time response) offer different mechanisms to account for the prolonged duration of some ocean anoxic events. Finally, we found that astronomical forcing substantially impacts ocean anoxia by altering ocean circulation and oxygen solubility, with obliquity consistently emerging as the primary orbital parameter driving ocean oxygen variations.

Climate variability in the last millennium (past 1000 years) is dominated by the effects of large-magnitude volcanic eruptions; however, a long-standing mismatch exists between model-simulated and tree-ring-derived surface cooling. Accounting for the self-limiting effects of large sulfur dioxide (SO2) injections and the limitations in tree-ring records, such as lagged responses due to biological memory, reconciles some of the discrepancy, but uncertainties remain, particularly for the largest tropical eruptions. The representation of volcanic forcing in the latest generation of climate models has improved significantly, but most models prescribe the aerosol optical properties rather than using SO2 emissions directly and including interactions between the aerosol, chemistry, and dynamics. Here, we use the UK Earth System Model (UKESM) to simulate the climate of the last millennium (1250–1850 CE) using volcanic SO2 emissions. Averaged across all large-magnitude eruptions, we find similar Northern Hemisphere (NH) summer cooling compared with other last-millennium climate simulations from the Paleoclimate Modelling Intercomparison Project Phase 4 (PMIP4), run with both SO2 emissions and prescribed forcing, and a continued overestimation of surface cooling compared with tree-ring reconstructions. However, for the largest-magnitude tropical eruptions in 1257 (Mt. Samalas) and 1815 (Mt. Tambora), some models, including UKESM1, suggest a smaller NH summer cooling that is in better agreement with tree-ring records. In UKESM1, we find that the simulated volcanic forcing differs considerably from the PMIP4 dataset used in models without interactive aerosol schemes, with marked differences in the hemispheric spread of the aerosol, resulting in lower forcing in the NH when SO2 emissions are used. Our results suggest that, for the largest tropical eruptions, the spatial distribution of aerosol can account for some of the discrepancies between model-simulated and tree-ring-derived cooling. Further work should therefore focus on better resolving the spatial distribution of aerosol forcing for past eruptions.

Climate variability and change, as well as extreme weather events, have notable impacts on human health and mortality. In historical times, the effect of climate on health and mortality was stronger than today, owing to factors such as poor housing and healthcare, along with the nutrition status that was meditated through climatic impacts on food production. Despite this, climatic impacts on mortality in the past remain poorly understood. This study aims to improve the understanding of climate effects on mortality using annual mortality records and meteorological data from Sweden between 1749 and 1859. The analysis includes the entire population, as well as subgroups based on sex and age. A statistically significant negative correlation was found between late winter and spring temperatures and mortality (i.e. lower temperatures equal higher mortality, and vice versa). We demonstrate that colder late winter and spring seasons were linked to higher mortality levels, not only for the same year but also for the following year. Conversely, no statistically significant associations were observed between summer or autumn temperatures and mortality, and only weak associations existed with hydroclimate. The impact of late winter and spring season temperature on mortality was most pronounced for the same year in southern Sweden and during the 19th century but stronger for the following year in central Sweden and during the 18th century. These findings call for further research, especially with respect to investigating specific diseases and additional factors contributing to the observed increase in mortality following cold late winter and spring seasons in Sweden during the late pre-industrial period.

Oxygen isotope ratios (δ18O) of tree-ring cellulose and historical documentary records are widely used to explore the hydroclimatic conditions of the past. In this study, we attempted to reconstruct chronologies of local climate disasters spanning 4 centuries in central Japan using these proxy data. For tree-ring δ18O measurements, we prepared cellulose samples from a long-living cedar tree with continuously broad ring widths. To enhance the temporal resolution, we divided each annual ring into several (mainly six) segments. Analysis of the correlations with observed relative humidity and precipitation data revealed that the intra-ring δ18O variations in the sample tree reflected the hydroclimatic conditions from April to July in each year. Subsequently, we chronologically listed the occurrence of eight types of disasters in the 17th to 19th centuries in the area adjacent to the sample tree according to 20 titles of “Town/City history”, which is a compilation of historical documentary records from the local municipality. By comparison with the intra-ring δ18O data, we found that most of the major droughts and long rains recorded in the historical documents occurred in the Baiu rainy season (typically June–July) or pre-Baiu season, corresponding to the growing season of the sample tree. Based on an analysis of the intra-ring δ18O variation for documentary-based drought and long-rain years, we set thresholds of intra-ring δ18O values to identify and extract drought and long-rain years. Drought and long-rain chronologies obtained by applying these thresholds were temporally continuous, complementing those based on documentary records. They depicted the relationships between the frequency of these climate disasters and the occurrence of major famines and the long-term tendency of length and magnitude of the Baiu rainy season in historical times.

The response of the East Antarctic Ice Sheet to warmer-than-present climate conditions has direct implications for projections of future sea level, ocean circulation, and global radiative forcing. Nonetheless, it remains uncertain whether the ice sheet is likely to undergo net loss due to amplified melting coupled with dynamic instabilities or whether such losses will be balanced, or even offset, by enhanced accumulation under a higher-precipitation regime. The glacial depositional record from the central Transantarctic Mountains (TAM) provides a robust geologic means to reconstruct the past behaviour of the East Antarctic Ice Sheet, including during periods thought to have been warmer than today, such as the mid-Pliocene Warm Period (∼3.3–3.0 Ma). This study describes a new surface-exposure-dated moraine record from Otway Massif in the central TAM spanning the last ∼9 Myr and synthesises these data in the context of previously published moraine chronologies constrained with cosmogenic nuclides. The resulting record, although fragmentary, represents the majority of direct and unambiguous terrestrial evidence for the existence and size of the East Antarctic Ice Sheet during the last 14 Myr, and it thus provides new insight into the long-term relationship between the ice sheet and global climate. At face value, the existing TAM moraine record does not exhibit a clear signature of the mid-Pliocene Warm Period, thus precluding a definitive verdict on the East Antarctic Ice Sheet's response to this event. In contrast, an apparent hiatus in moraine deposition both at Otway Massif and the neighbouring Roberts Massif suggests that the ice sheet surface in the central TAM was potentially lower than present during the late Miocene and earliest Pliocene.

This study introduces a novel dynamical systems model designed to capture the highly non-periodic nature of Dansgaard–Oeschger (DO) events. Such events are difficult to model adequately due to their variable durations (some lasting around 1 century, while others span multiple millennia) and the occurrence of short precursor events that precede longer DO events despite similar boundary climate conditions. Utilising a simplified two-equation framework derived from the Stommel model, our approach integrates an internal control parameter which acts as a feedback parameter on the Antarctic Bottom Water (AABW) formation. Through both analytical and numerical methods, we establish a suitable parameter domain within which the newly adjusted models can accurately replicate the palaeoclimatic records of DO events as described by summary statistics derived from ice-core data. The analysis also shows that, without the novel control parameter, the model does not have a suitable parameter domain in which it can reproduce the wide range of event characteristics seen in the ice-core record. The study provides new insights into the underlying mechanisms driving these highly significant climate phenomena and the necessary timescale in which they are forced by allowing the new model's parameters to vary through time. This allows our model to achieve unprecedented precision in capturing a realistic sequence of DO events with timing characteristics matching those of the observational record. This refined model not only enhances our understanding of the DO cycles but also demonstrates the potential of simple dynamical systems to simulate complex climate interactions.

The Eocene–Oligocene transition (EOT) is marked by a sudden δ18O excursion occurring in two distinct phases approximately 500 kyr apart. These phases signal a shift from the warm middle to late Eocene greenhouse climate to cooler conditions, with global surface air temperatures decreasing by 3–5 °C and the emergence of the first continent-wide Antarctic ice sheet (AIS). While ice sheet modelling suggests that ice sheet growth can be triggered by declining pCO2, it remains unclear how this transition was initiated, particularly the first growth phase that appears to be related to oceanic and atmospheric cooling rather than ice sheet growth. Recent climate model simulations of the late Eocene show improved accuracy but depict climatic conditions that are not conducive to the survival of incipient ice sheets throughout the summer season. This study therefore examines whether it is plausible to develop ice sheets of sufficient scale to trigger the feedback mechanisms required to disrupt the atmospheric regime above the Antarctic continent during warm and moist late Eocene summers and establish more favourable conditions for ice expansion. We aim to assess the sustainability of an incipient AIS under varying radiative, orbital and cryospheric forcing. To do so, we evaluate Community Earth System Model 1.0.5 simulations, using a 38 Ma geographical and topographical reconstruction, considering different radiative and orbital forcings. The climatic conditions prevailing during (and leading up to) the EOT can be characterised as extremely seasonal and monsoon-like, featuring a short yet intense summer period and contrasting cold winters. A narrow convergence zone with moist convection around the region with high sub-cloud equivalent potential temperature exhibits a ring-like structure, advecting moist surface air from the Southern Ocean in both summer and winter. This advection leads to high values of moist static energy and subsequent precipitation in coastal regions. Paradoxically, this atmospheric regime – particularly its coastal precipitation in winter – appears to be necessary for the sustenance of the moderately sized regional ice sheets we imposed on the continent, contrary to our assumption that these ice sheets would disrupt the atmospheric regime. This underscores a hysteresis effect for regional ice sheets on the Antarctic continent, suggesting the potential for a significant volume of ice on the continent without imminent full glaciation prior to the EOT.

During the Pliocene, atmospheric CO2 concentrations (pCO2) were probably sometimes similar to today's, and global average temperature was ∼3 °C higher than preindustrial. However, the relationships and phasing between variability in climate and pCO2 on orbital timescales are not well understood. Specifically, questions remain about the nature of a lag of pCO2 relative to benthic foraminiferal δ18O in late Pliocene Marine Isotope Stage (MIS) M2 (3300 ka), which was longer than during the Pleistocene. Here, we present a multiproxy paleoceanographic reconstruction of the late Pliocene subtropical–subantarctic zone. New dinoflagellate cyst assemblage data are combined with previously published sea surface temperature reconstructions to reveal past surface conditions, including latitudinal migrations of the subtropical front (STF) over the late Pliocene at Ocean Drilling Program (ODP) Site 1168, offshore of western Tasmania. We observe strong oceanographic variability at the STF over glacial–interglacial timescales, especially the interval (3320–3260 ka) across MIS M2. By providing tight and independent age constraints from benthic foraminiferal δ18O, we find that, much more than benthic δ18O or local SST, latitudinal migrations of the STF are tightly coupled to global pCO2 variations across the M2. Specifically, a northerly position of the STF during the MIS M2 deglaciation coincides with generally low pCO2. We postulate that the Southern Ocean CO2 outgassing varied strongly with migrations of the STF and that this in part accounted for the variability in pCO2 across MIS M2.

We present novel explainable deep learning techniques for reconstructing South Asian palaeomonsoon rainfall over the last 500 years, leveraging long instrumental precipitation records and palaeoenvironmental datasets from South and East Asia to build two types of models: dense neural networks (“regional models”) and convolutional neural networks (CNNs). The regional models are trained individually on seven regional rainfall datasets, and while they capture decadal-scale variability and significant droughts, they underestimate inter-annual variability. The CNNs, designed to account for spatial relationships in both the predictor and target, demonstrate higher skill in reconstructing rainfall patterns and produce robust spatiotemporal reconstructions. The 19th and 20th centuries were characterised by marked inter-annual variability in the monsoon, but earlier periods were characterised by more decadal- to centennial-scale oscillations. Multidecadal droughts occurred in the mid-17th and 19th centuries, while much of the 18th century (particularly the early part of the century) was characterised by above-average monsoon precipitation. Extreme droughts tend to be concentrated in southern and western India and often coincide with recorded famines. The years following large volcanic eruptions are typically marked by significantly weaker monsoons, but the sign and strength of the relationship with the El Niño–Southern Oscillation (ENSO) vary on centennial timescales. By applying explainability techniques, we show that the models make use of both local hydroclimate and synoptic-scale dynamical relationships. Our findings offer insights into the historical variability of the Indian summer monsoon and highlight the potential of deep learning techniques in palaeoclimate reconstruction.

During the Quaternary, ice sheets experienced several retreat–advance cycles, strongly influencing climate patterns. In order to properly simulate these phenomena, it is preferable to use physics-based models instead of parameterizations to estimate the surface mass balance (SMB), which strongly influences the evolution of the ice sheet. To further investigate the potential of these SMB models, this work evaluates the BErgen Snow SImulator (BESSI), a multi-layer snow model with high computational efficiency, as an alternative to providing the SMB for the Earth system model iLOVECLIM for multi-millennial simulations as in paleo-studies. We compare the behaviors of BESSI and insolation temperature melt (ITM), an existing SMB scheme of iLOVECLIM during the Last Interglacial (LIG). Firstly, we validate the two SMB models using the regional climate model Modèle Atmosphérique Régional (MAR) as forcing and reference for the present-day climate over the Greenland and Antarctic ice sheets. The evolution of the SMB over the LIG (130–116 ka) is computed by forcing BESSI and ITM with transient climate forcing obtained from iLOVECLIM for both ice sheets. For present-day climate conditions, both BESSI and ITM exhibit good performance compared to MAR despite a much simpler model setup. While BESSI performs well for both Antarctica and Greenland for the same set of parameters, the ITM parameters need to be adapted specifically for each ice sheet. This suggests that the physics embedded in BESSI allows better capture of SMB changes across varying climate conditions, while ITM displays a much stronger sensitivity to its tunable parameters. The findings suggest that BESSI can provide more reliable SMB estimations for the iLOVECLIM framework to improve the model simulations of the ice sheet evolution and interactions with climate for multi-millennial simulations.

Predictions of future sea-level change and ice-sheet stability rely on accurate reconstructions of sea levels for past warm intervals, such as the mid-Pliocene Warm Period (MPWP; 3.264–3.025 Ma). The magnitude of MPWP glacial cycles and the relative contribution of meltwater sources remain uncertain. We explore this issue by modeling processes of glacial isostatic adjustment for a wide range of possible MPWP ice-sheet melt zones, including North America, Greenland, Eurasia, and West Antarctica, as well as the Wilkes Basin, the Aurora Basin, and the embayment of Prydz Bay in East Antarctica. As a case study, we use a series of ice histories together with a suite of viscoelastic Earth models to predict global changes in sea level from the Marine Isotope Stage (MIS) M2 glacial to the MIS KM3 interglacial. At the Whanganui Basin (New Zealand), a location with stratigraphic constraints on Pliocene glacial–interglacial sea-level amplitude, the calculated local-sea-level (LSL) rise is on average ∼ 15 % lower than the associated change in the global mean sea level (GMSL) in the ice-sheet scenarios explored here. In contrast, the calculated LSL rise over the deglaciation from MIS M2 to MIS KM3 at Enewetak Atoll is systematically larger than the GMSL change by 10 %. While no single LSL observation (field site) can provide a unique constraint on the sources of ice melt observed during this period, combinations of observations have the potential to yield a stronger constraint on GMSL change and to narrow the list of possible sources.

The Arctic stratospheric polar vortex (SPV) is a key driver of winter weather and has been found to modify winter climate variability and its predictability in Eurasia and North America on inter-annual and decadal timescales. However, to what extent this relationship plays a role in driving climate variability on glacial–interglacial timescales is still unknown. Here, by systematically analysing SPV changes in four sets of PMIP4 (Paleoclimate Modelling Intercomparison Project – Phase 4) simulations for the Last Glacial Maximum (LGM) and the pre-industrial (PI) period, we explore how the SPV changed during the glacial climate and how it influenced climate variability. Our results show that under LGM conditions, the SPV stretched towards the Laurentide ice sheet; this was accompanied by anomalous upward wave propagation and enhanced SPV variability, which increased the likelihood of cold-air outbreaks into the mid-latitudes. During the LGM, this stretched SPV pushed cold Arctic air further equatorwards, increasing winter climate variability over the more southern mid-latitudes. In particular, in winter, this strengthened cooling over the mid-latitudes extended beyond the coverage of the Laurentide ice sheet (unlike in summer). SPV-induced temperature variability also explains the inter-model spread as removing SPV variation from the model results reduces the inter-model spread by up to 5°C over mid-latitude Eurasia. These results highlight the critical role of the SPV in connecting the polar region and mid-latitudes on glacial–interglacial timescales. These connections are reminiscent of intra-seasonal stratosphere–troposphere coupling.

This paper examines the influence of COVID-19-related factors on PM2.5 concentrations (PM2.5) in Singapore, Indonesia, and Thailand from January 2018 to December 2021. Using data from four sources, cluster analysis based on six socioeconomic indices was employed to select these countries for focused analysis. Generalized Additive Mixed Models (GAMM) were applied to assess associations between PM2.5 and COVID-19 factors, including new cases, deaths, vaccinations, stringency index, time series (STOL), and COVID-19 status (dummy variable). Results show that PM2.5 levels in Singapore and Indonesia were significantly impacted by COVID-19 measures, with F-statistics for new cases (22.875, p < 0.001), deaths (12.563, p = 0.012), as well as significant associations for vaccinations (t = 5.976, p < 0.001), stringency index (t = 5.124, p < 0.001), and the dummy variable (t = 6.624, p < 0.001). In contrast, PM2.5 levels in Thailand were unaffected by these factors, likely due to seasonal pollution sources. The model explains 90.3% of the variation in PM2.5 (adjusted R² = 0.872). This paper offers important insights for policymakers on incorporating air quality into health policies and highlights how pandemic responses varied across countries. By examining the impact of COVID-19 factors on PM2.5 in different nations, the study enhances understanding through detailed data and averaging periods. It reveals differences in how countries’ air quality responded to the pandemic, contributing to discussions on environmental management and public health. These findings inform policy decisions and facilitate discussions on better managing environmental and health challenges during global crises.

The article addresses the issue of assessing the impact of road rebuilding on traffic noise pollution. To assess noise hazards, parameters expressed on the decibel scale were used, and a new measure was proposed - a scalar reference that compares the sound level value to the recommended threshold. This measure is based on Weber Fechner's law, which relates to human perception of changes in sound levels. It was derived through the decibel algebra applied to measurement results and is called the “coefficient of exceedance of the recommended sound level”. Its usefulness was verified by analyzing the results of measurements of traffic and noise parameters before and two years after the reconstruction of a section of the national road in Kielce. An assessment was made of traffic volume, vehicle speed, and road vehicle noise. The analysis evaluated the absolute values, variability and uncertainty of results obtained for the entire year, Fridays and Sundays. Significant differences in traffic parameter values were observed between the lanes entering and leaving the city on weekdays and weekends. The analysis showed a 28% increase in traffic volume following the road reconstruction. The current measure, which compares the difference in noise levels before and after the road reconstruction, indicates that while noise levels have decreased, they still exceed the normative values. For the same parameters, the median coefficient of exceedance decreased by approximately 17%, and the maximum coefficient of exceedance decreased by approximately 15%. The diagnostic usefulness of the coefficient of exceedance was further assessed using noise simulations based on the Cnossos-EU model. These simulations showed the high sensitivity of the proposed scalar noise measure to changes in vehicle speed and traffic volume. The simulations also indicated that to meet the Polish noise normative values, traffic volume would need to reduced by 50%, and the vehicle speed would need to be capped at 50 km/h. Additionally, the simulations suggested that even more stringent traffic restrictions would be necessary to meet the World Health Organization's noise recommendations.

Air quality is a critical aspect of environmental health, and its assessment and prediction serve as pivotal components in mitigating the adverse effects of air pollution. This study focuses on advancing air quality prediction in India through the application of cutting-edge deep learning techniques, specifically the Stacked Bidirectional Long Short-Term Memory (Bi-LSTM) and Convolutional Neural Network (CNN) architecture. Through meticulous preprocessing - encompassing missing value handling, normalization, and temporal sequencing - the dataset is prepared for the Stacked Bi-LSTM and CNN hybrid model. The model architecture leverages the temporal sequence-capturing capabilities of Stacked Bi-LSTM layers, enhancing it with the spatial feature extraction prowess of CNN layers. This integrated approach aims to address the intricate and nonlinear dependencies present in air quality time series data. During the training phase, the Adam optimizer is used to fine-tune the model’s hyperparameters, with Mean Squared Error (MSE) serving as the loss function. Important assessment metrics, including as Mean Absolute Percentage Error (MAPE), Root Mean Squared Error (RMSE), and MSE, are used to evaluate the performance of the model. Furthermore, this study conducts a detailed temporal analysis, unraveling diurnal, seasonal, and long-term trends in air quality fluctuations. The study aims to offer valuable insights into the temporal and spatial patterns of air quality in India, thereby aiding environmental policymakers, urban planners, and researchers in formulating effective strategies for air quality management. The application of Stacked Bi-LSTM and CNN architectures in this research holds promise for enhancing real-time forecasting accuracy and facilitating informed decision-making towards sustainable environmental practices.

The present paper experimentally analyses the subjective assessment of indoor environment comfort based on a questionnaire survey conducted in a climate chamber located at Kielce University of Technology (Poland), if two types of face masks are worn by the respondents: thin (medical) and thick (cotton-made) masks. Air temperature and relative humidity in the chamber ranged from around 19 to 28oC and 20 – 70%, respectively. Precise measurement of the microclimate parameters was obtained with a microclimate meter, which recorded air temperature and relative humidity at the moment of completing the questionnaires. The respondents were of similar age (22 – 31 years old) and wore two types of clothing during the experiments: summer and winter, which differed by thermal resistance. This value amounted to 0.5 clo for the summer outfit and 0.8 clo for the winter one.In total 960 questionnaires were analysed in the study. The results indicate that the increase in air temperature led to poorer overall comfort, while the largest comfort sensation was recorded for the most favourable thermal sensation range. In general, thicker masks provided lower overall comfort than thinner masks for all relative humidity values.

The subject of studies was one-year-old needles of Scots pine (Pinus sylvestris L.), collected from various characteristic landscape zones of Poland, reflecting different conditions of air pollutant emission and deposition (Integrated Monitoring of the Natural Environment base stations, industrial centers, and large cities). Analyses were carried out using a Quanta 250 FEI scanning electron microscope equipped with an EDAX Genesis X-ray spectroscopy microanalyzer. The needle surfaces were examined to identify natural structures (e.g., stomata, pollen, fungi) and anthropogenic structures (e.g. particulates with heavy metals) under conditions of diversified anthropopressure. In samples from areas with no significant local pollution sources (Wigry, Borecka Forest, Parsęta, Tuchola Forest), particles of mineral origin (resulting from rock weathering) containing Si, Al, Ca were identified. Needles collected in Roztocze, Łysogóry, Kampinos and Karkonosze, contained round technogenic particles (spherules) containing Fe, Al and Si, which had traveled significant distances. In Katowice, Poznań and Kraków, particles deposited on the bioindicators’ surfaces were composed of Ca, Si, Al, Fe, Cu, and other heavy metals. Micrographs obtained from the analysis were used to develop a model for identifying air pollutants using artificial intelligence.

With the gradual increase of microplastics in water bodies, it is essential to understand the current treatment processes for their removal. This study aims to investigate the removal of microplastics in synthetic solution by electrocoagulation (EC). The effects of electrode type, contact time (min), agitation speed (rpm) and current density (A/m²) were evaluated using a fractional factorial design. The results showed that the aluminum anode achieved a higher removal of microplastics than the iron anode, reaching 98.04% removal with the aluminum operational configuration within 15 min at 70 rpm and a current density of 20 A/m². A high correlation between the predicted and observed removal was evidenced, with values of R²= 0.99 and adjusted R²= 0.98, indicating a good agreement between the model and the experimental data, confirming the validity and feasibility of the adopted linear model. This study demonstrates that the electrocoagulation process has a great potential for the removal of microplastics.

The advanced type of cyclone was applied to separate wood particulate matter from the air. The cyclone was designed in the laboratory of Vilnius TECH. A series of experimental studies was conducted both in the lab and under industrial conditions. These studies aimed to specify the air velocity and aerodynamic resistance in the experimental and pilot six-channel cyclone with spiral casings and curvilinear semi-rings. Air treatment efficiency was also determined. The highest air treatment efficiency achieved using experimental cyclone was 91.4%, while the pilot cyclone achieved an efficiency of 94. 5%. The industrial and experimental cyclones were found to have similar air treatment efficiency

Thermal effects accompanying gas sorption on micro- and mesoporous materials provide unique insights into the type, course, and efficiency of sorption. In this study, metal-organic frameworks (MOFs) with different topologies and chemical structures were synthesized and investigated: HKUST-1, Ni-MOF-74, UiO-66, and MIL-140A. These MOFs were characterized structurally and sorptively with respect to selected greenhouse gases (GHGs). Sorption capacities for CO2 and CH4 were determined at several temperatures and measurement pressures, and the maximum sorption capacity was determined using the Langmuir-Freundlich model. Thermal effects accompanying adsorption were quantified through the isosteric heat of adsorption parameter. For each MOF, the values of isosteric heat of adsorption were higher for CO2 than for CH4. The values of this parameter was determined in the following order: HKUST-1 > Ni-MOF-74 > UiO-66 > MIL-140A. Energy homogeneity of the adsorbent surface was observed in nearly all cases, except for UiO-66 during CO2 adsorption. Changes in the determined isosteric heat of adsorption of CO2 with increasing sorption capacity were in the range of 5-15 kJ/mol, while for CH4 they ranged from 1.4 to 17 kJ/mol, respectively. The level of thermal selectivity of CO2 over CH4 was determined in the following order: UiO-66 (1.9) > Ni-MOF-64 (1.7) > MIL-140A (1.5) > HKUST-1 (1.1).

To achieve high levels of municipal waste recovery through a system employing mechanical-biological waste processing technologies, effective management of the over-sieve fraction of mixed municipal waste (preRDF) is crucial. This preRDF cannot be landfilled due to its combustion heat exceeding 6 MJ/kg. Therefore, thermal treatment of waste and subsequent energy recovery become pivotal in the national waste management system, particularly amidst energy crises and fluctuating energy prices. Waste-derived energy can serve as a valuable renewable energy source. To ascertain the true efficiency of the plant in terms of energy, environmental impact, and economics, it is vital to organize the concepts of energy efficiency for thermal waste treatment plants. The energy efficiency of a waste gasification plant should be comprehensively assessed from three standpoints: energy efficiency of thermal waste treatment (i.e., energy efficiency index), energy efficiency of recovering chemical energy contained in waste (actual energy efficiency of the plant), and the efficiency of renewable energy production. A thermal waste processing plant qualifies as a renewable energy source, when it generates electricity and heat from the biodegradable fraction of waste. This article endeavours to determine the potential contribution of chemical energy from the biodegradable waste fraction, relying on preRDF fraction test results..

Acid mine drainage has always been of global concern, primarily due to its low pH, high concentration of heavy metals and toxic substances, and serious impact on the surrounding environment and ecology of mines. However, the research progress and hotspots in this field of acid mine drainage processing are still unclear. To better understand the research hotspots and trends of acid mine drainage processing from 2004 to 2023, we used CiteSpace bibliometric software to visually analyze 1142 English-language research articles and reviews from the Web of Science core database. Results indicated that this field has received increas-ing attention from researchers worldwide, especially since 2017. The USA and China stand out as major contributors, yet their international collaboration doesn't match South Africa robust partnerships. Strengthening cooperation with other nations should be a priority for both the USA and China. The University of Quebec and University of South Africa were the most production institution. Vhahangwele Masindi from South Africa was the most active author. The top two core journals in this field were Science of the Total Environment and Water Re-search. Additionally, through keyword co-occurrence, clustering, and burst analysis, it is evi-dent that research on heavy metal mechanisms and resource recovery will be the future re-search hotspots in this field of acid mine drainage. This study provides researchers with an opportunity to understand the hotspots and trends in acid mine drainage research from a bibliometric perspective, and serves as a reference for future studies.

The aim of the study was to determine the effect of the type of road surface (asphalt and concrete) and the presence of noise barriers (acoustic screens) on the magnetic susceptibility and chemical composition of road dust collected from national roads and motorways in central and southern Poland. Four roads with asphalt surfaces and four with concrete surfaces were selected for the study. Samples were taken at three control points: in the space between noise barriers, in the space without barriers and at road exits. Magnetic susceptibility measurements and elemental composition analysis (using an energy dispersive X-ray fluorescence spectrometer) were carried out. The results showed high variability with no clear differences between samples taken from asphalt and concrete roads. Magnetic susceptibility values were higher for road dust taken from asphalt pavements near noise barriers and motorway exits, while for open space samples the susceptibility values were about 1.3 times higher for dust from concrete pavements. A similar relationship was observed for the elemental composition. The results showed no clear differences between samples taken from asphalt and concrete roads. The location of the sampling point had a greater influence on the results: the surface of noise barriers, open spaces or motorway exits. Calculated enrichment factors indicated an extremely high enrichment of dust in elements such as Cr, Cu and Zn, a very high enrichment in Pb only for dust collected at motorway exits, and a significant and moderate enrichment in other elements.

An additive based on iron oxides was applied to reduce the amount of produced sludge and to increase the production and quality of biogas. The C/N ratio was 11.0–11.3 and the pH of the sludge mixture was 7.3 before the anaerobic digestion. The determined optimal dose of the additive was 0.35 g/g of sludge dry matter over 20 days. This allowed a reduction in the sludge retention time up to 6–11 days. Consequently, maximum biogas production was reached on average 1.6 times faster, volatile solids degradation increased by 56.7%, biogas production increased by 75%, specific biogas production increased by 11.5%, and methane concentration in the biogas increased by 8.4%–18.2%. When the additive was applied, the quantity of phosphate phosphorus in the supernatant was reduced by up to 19%, and hydrogen sulfide reduction efficiency in the biogas ranged between 55% and 62%. In sludge treatment facilities, using an iron oxide-based additive could reduce the dewatering and drying costs for digested sludge by up to 35% .

Light pollution in the form of artificial sky glow affects not only the immediate surroundings of the towns that generate it but also more distant areas, including protected regions. This study examines the extent of the impact of the artificial sky glow, originating from Zakopane and the surrounding towns, on the western part of the Tatra National Park (TPN) in Poland. Due to the specific challenges of conducting night measurements in mountainous terrain, the valleys of the Western Tatras– Lejowa, Kościeliska and Chochołowska - were selected for the study. Sky brightness measurements were taken using Sky Quality Meter photometers (type SQM-L) under both cloudless and completely overcast conditions. The results show that in the case of a cloudless sky, the range of sky glow from nearby towns extends approximately 2-2.5 km from the valleys outlets. However, under cloudy conditions, this range increases to approximately 6 km. It was also observed that the ground illumination caused by the brightened sky is significantly lower than that produced by the brightest natural object in the sky, the Moon. Nevertheless, the night sky’s brightness exceeds natural levels, which undoubtedly affects local mountain ecosystems

Wastewater treatment and the efficient use of sewage sludge biochar are critical in addressing the needs of ever-increasing population in the world. Recently, phosphorus (P) removal from wastewater has become highly relevant and important, primarily to reduce eutrophication in surface waters. Using sewage sludge biochar as an adsorbent for phosphate removal from wastewater offers an opportunity to reuse sewage sludge (SS) and return phosphorus to the biogeochemical cycle. In this study, the efficiency of two phosphate removal methods - batch adsorption and fixed-bed column process – was investigated using pyrolyzed sewage sludge biochar (PSSB) produced at different temperatures (300 °C, 400 °C, 500 °C, 600 °C). In the batch adsorption experiment, direct mixing of 600 °C pyrolyzed sewage sludge biochar with wastewater resulted in a relatively low phosphate removal efficiency (only about 18 %) at an initial phosphate concentration of 100 mg/l. In contrast, the fixed-bed column process, using PSSB as a filter for phosphate adsorption, showed significantly better results. The highest phosphate removal efficiency (up to 90%) was achieved after 30 min of filtration, using an initial phosphate concentration of 30 mg/l initial and biochar pyrolyzed at 600 °C.

La viande, une denrée périssable, est perçue, depuis des décennies, comme le moyen de transmission de plusieurs pathogènes responsables de nombreuses maladies d'origine alimentaire chez les humains. De l’animal vivant à la conversion en carcasses puis en viande, elle présente souvent des risques de contamination accrus à des microorganismes pendant le processus d’abattage, de transport et de conservation. L’objectif général de cette étude était d’évaluer la qualité bactériologique de la viande bovine issue de l’Abatoir Public de Masina dans la Commune de Masina en vue de contribuer à l’amélioration de la qualité de cette infrastructure pour protéger les consommateurs en République Démocratique du Congo (RDC). Il s’agissait d’une étude descriptive transversale qui a été réalisée sur un échantillon de 20 bovins provenant de diverses stations zootechniques environnant la Ville Province de Kinshasa en RDC. Nos prélèvements ont concerné les morceaux des muscles, des poumons et des intestins dont une analyse bactériologique a été effectuée au Laboratoire Vétérinaire Central de Kinshasa avec la technique de dénombrement des colonies. L’étude a révélé que les échantillons prélevés sur les bovins provenant de N’Djili et de Sogenac/Mushie étaient impropres à la consommation, car dépassant les normes de 30 colonies bactériennes pour les denrées alimentaires, qui sont recommandées par l’Association Française des Normes (FNOR) et la FAO. Les résultats de cette étude contribueront à la formulation des politiques et actions nécessaires pour l’amélioration des infrastructures sanitaires pour la protection contre les maladies émergentes et réémergentes.

La zone côtière guinéenne, longue d’environ 300 km, est dynamique, surtout dans la zone de Kaback. La dynamique côtière constitue des enjeux environnementaux résultant des facteurs naturels et anthropiques et Kaback est connu comme l’un des greniers de la Guinée. Cette recherche a donc pour but d’évaluer les effets des actions anthropiques et de la dynamique du trait de côte à Kaback. La présente étude a consisté à déterminer la dynamique du trait de côte entre 1975 et 2016 et évaluer l’occupation du sol à Kaback entre 1990 et 2022. Pour ce faire, les méthodes de télédétection, de SIG et d’enquête ont été utilisées. Pour le traitement d’images satellitaires, les données d’enquête. Les résultats de l’occupation du sol montrent une augmentation de superficies en Bâti, cultures et jachères et une diminution de la végétation, de la mangrove et de l’eau. Pour la présente étude, une longueur de 25 km de trait de côte a été considérée. À Kaback, l’évolution globale du trait de côte est caractérisée par un recul moyen d’environ 2,26 m/an avec une moyenne de taux d'érosion de 9,02 m/an. Les zones de changements dues à la dynamique côtière se retrouvent en plusieurs endroits. Sur la base des écarts entre les traits de côte et des calculs statistiques, le logiciel DSAS 5.0 nous a permis de connaitre la vitesse d’évolution du trait de côte et de faire la simulation de son évolution automatiquement pour une période de 20 années. Ainsi, la projection de recul du trait de côte pour 2036 est estimée à 8,35 m/an. En définitive, l’érosion côtière et l’impact des actions humaines sont une réalité à Kaback. Le manque d’utilisation des données de plusieurs sources constitue une des limites de l’étude.

Le bassin versant du Banco est caractérisé par un relief de plateau accidenté et fortement incisé par une série de vallées ramifiées. Au fil des années dans le bassin versant du Banco, l’érosion des sols cause d’énormes dégâts suite aux conditions naturelles et à l’impact humain. L’objectif de cette étude est de cartographier la sensibilité du bassin versant du Banco à l’érosion hydrique. La méthodologie utilisée s’appuie sur une modélisation basée sur l’intégration des principaux facteurs de l’érosion hydrique dans un système d’information géographique. Les résultats obtenus mettent en relief une forte sensibilité du bassin versant du Banco à l’érosion hydrique avec une perte de sol moyenne annuelle de 25,44 t/ha/an. La cartographie de la sensibilité à l’érosion hydrique effectuée établit une hiérarchie des zones sensibles à l’érosion hydrique. Elle se présente aussi comme un outil d’aide à la décision pour les autorités au niveau local et pour les projets d’aménagement afin d’orienter les différentes actions de conservation des eaux et des sols.

Les variations des paramètres climatiques, associées à la dégradation du couvert végétal due aux activités humaines, entrainent un appauvrissement des sols durant les périodes de fortes pluies. Cette perte des éléments fertiles du sol pousse les agriculteurs à déplacer leurs activités vers des zones humides telles que les bas-fonds, les cuvettes et les vallées. Ces espaces, cependant, restent vulnérables aux phénomènes climatiques extrêmes comme les inondations et les pluies intenses. Cette étude vise à mettre en évidence la contribution des services climatiques dans l’amélioration des agrosystèmes, en intégrant des informations climatiques spécifiques à l’agriculture pour renforcer la résilience des producteurs. Les méthodologies employées incluent le calcul de l’indice standardisé des pluies (ISP), l’analyse du régime pluviométrique pour détecter les tendances climatiques, l’utilisation d’indices d’extrêmes climatiques (RX5day, CDD, CWD, R99p) pour évaluer leurs impacts sur les agrosystèmes, ainsi que des techniques de télédétection. Les résultats montrent une augmentation des cumuls pluviométriques et une probable intensification des évènements climatiques extrêmes. A moyen et long terme, ces phénomènes pourraient accentuer les inondations, les glissements de terrain et l’érosion des sols. Néanmoins, l’utilisation des services climatiques, notamment les prévisions des saisons culturales, les prédictions des dates de début et de fin des périodes pluvieuses et sèches, ainsi que les alertes sur les épisodes de fortes pluies, peut aider les agriculteurs à protéger leurs cultures contre les effets négatifs de ces événements climatiques extrêmes.

La pression humaine sur un espace entraine d’importants impacts sur l’environnement, qui doivent être mesurés spatialement. L’objectif de ce travail est de déterminer la dynamique d’occupation du sol et la transformation du couvert végétal à Galim, zone fortement anthropisée avec pour principale activité l’agriculture. Des images landsat de trois périodes (2002, 2013 et 2024) ont été utilisées. La méthode de classification supervisée par maximum de vraisemblance a été utilisée pour déterminer l’état et les changements des unités d’occupation. Les résultats montrent une forte dynamique des unités d’occupation du sol caractérisée par une conversion de l’espace de végétation boisée en bâtis et savanes. Entre 2002 et 2024, une augmentation du bâti est observée, passant respectivement de 314,92 ha à 2581,70 ha. Cette augmentation des superficies du bâti est de 2266,78 ha en vingt-deux ans soit 103,03 ha de couverture végétale transformée annuellement. Cependant, on observe une diminution du couvert boisé qui passe de 3814,68 ha en 2002 à 1796,54 ha en 2024 soit une perte de 2018,14 ha entre 2002 et 2024 ; d’où une régression d’environ 91,73 ha annuellement au cours de cette période. Le taux de déboisement observé est de -52,90 % et indique donc une importante baisse de la couverture végétale dans la zone d’étude.

La lagune Ono connait une eutrophisation importante marquée par la présence des plantes aquatiques envahissantes. Cette eutrophisation résulte de pratiques agro-industrielles dans son bassin versant. Ce cours d’eau est en constante pollution par les agro-industrielles. La présente étude vise à évaluer la contribution des fertilisants agricoles dans la prolifération des plantes aquatiques envahissantes dans la lagune Ono. Pour ce faire, des données sur les pratiques agricoles ont été collectées par choix raisonné. Une classification des images satellitaires pour l’analyse de la dynamique des VAE et la caractérisation physico-chimique du milieu aquatique ont été également faites. Les résultats montrent une forte utilisation d’engrais azotés et phosphorés par les deux principaux blocs agro-industriels. De plus, les faibles teneurs des paramètres physico-chimiques mesurés dans l’eau justifient la prolifération des plantes aquatiques envahissantes par une forte consommation des nutriments notamment le phosphore. Leur superficie est passée de 66 hectares à 394 hectares entre 2000 et 2020.

En zone sud-soudanienne, la biomasse fait l’objet de plusieurs usages. Les ressources fourragères constituent la principale source d’alimentation des animaux dans les zones à forte vocation pastorale au Burkina Faso, notamment dans la zone sud-soudanienne. Ces ressources sont constituées majoritairement de la paille des herbacées et de celle des résidus de culture (mil, sorgho). Ces ressources, en plus de leur utilisation pour l’alimentation des animaux, font l’objet de diverses autres utilisations. La durabilité de la ressource durant la période sèche constitue donc la problématique principale. Cette étude est basée essentiellement sur les enquêtes et entretiens auprès d’un échantillon de 450 personnes réparties dans 06 communes de la région du sud-ouest du Burkina. De ces enquêtes et entretiens, il ressort que les principaux utilisateurs de ces ressources sont repartis en fonction de leurs activités socio-économiques. Le profil socio-économique des acteurs illustre les principales utilisations de ces ressources. Mais ces ressources, en plus de leurs utilisations, sont soumises à des facteurs de dégradation qui entrainent la diminution voire la perte de ces ressources. Ces facteurs sont d’ordre naturel et d’ordre anthropiques avec principalement des prélèvements pour les différentes utilisations par les populations. La connaissance de tous ces paramètres permet d’avoir une appréhension sur les usages de la paille des herbacées et celle des résidus de culture.

Les pays de l’Afrique subsaharienne sont fortement affectés par les aléas des changements climatiques qui affectent la production agricole, moteur de leur développement socioéconomique. Le présent article vise à analyser les stratégies endogènes d’adaptation face à la vulnérabilité des cultures maraîchères dans la Commune de Za-Kpota au Sud-Bénin. Les données et informations relatives aux différents paramètres climatiques perçus par les producteurs, leurs incidences directes sur la production maraîchère sont utilisées. De plus, les informations relatives aux stratégies endogènes d’adaptation ont été collectées. A cet effet, 150 producteurs maraîchers ont été choisis dans 06 localités réparties sur l’étendue de la Commune de Za-Kpota. Les entretiens individuels ont été utilisés à l’aide de questionnaire et des entretiens de groupes (focus groups) au moyen d’un guide d’entretien. L’utilisation de la statistique descriptive (moyenne, fréquence, tableaux et graphes) a permis le traitement et l’analyse des données. Les résultats indiquent que 98 % des producteurs maraichers se plaignent d’une insuffisance de pluie, de forte chaleur, etc. Les conséquences des aléas climatiques sur le maraîchage se traduisent par la baisse des rendements, la perte des récoltes, les attaques parasitaires et la baisse des revenus agricoles. Face à ces contraintes, les producteurs mettent en œuvre plusieurs mesures adaptatives sur la base des savoirs endogènes et des conseils des techniciens agricoles : arrosage accru, traitements phytosanitaires, récoltes précoces, diversification culturale.

Cet article se propose d’analyser les stratégies d’adaptation mises en place par les agriculteurs de la commune de Loul Séssène pour faire face à la salinisation progressive des terres agricoles. L’accent est mis sur la diversification des activités, en particulier l’essor de la saliculture, comme mécanisme de réponse aux effets délétères de la salinisation sur la production agricole. La méthodologie combine une analyse de la littérature et une enquête socioéconomique, offrant ainsi une vue d’ensemble des réponses locales à ce phénomène. Les résultats montrent une variabilité spatiale dans l’impact de la salinisation, avec des perceptions divergentes d’un village à l’autre. Cependant, une corrélation nette émerge entre la proximité des villages avec les zones d’incursion marine et l’intensité de la salinisation. Cette dynamique saline se traduit par une dégradation progressive de la fertilité des sols et une diminution des rendements agricoles, forçant une réorientation vers des pratiques alternatives. Parmi celles-ci, la saliculture s’impose comme une activité à haute rentabilité, surpassant même l’agriculture traditionnelle. Cette transition est soutenue par une main-d’œuvre diversifiée qui contribue à revitaliser le tissu socio-économique local. Ainsi, l’exploitation artisanale du sel s’affirme comme un moteur essentiel de la reconversion socio-économique de la Commune de Loul Séssène, offrant de nouvelles perspectives dans un contexte de mutation des systèmes agraires traditionnels.

Depuis la tenue du forum des nouveaux acteurs le 08 avril 1999 à Bogandé, au Burkina Faso, de nouveaux types de producteurs se sont introduits dans le monde rural. Certains producteurs ont opté pour la production semencière. Mais tout au long du processus, cette activité a révélé qu’elle n’était pas une simple routine paysanne. Au regard de la loi semencière qui la régit, des moyens économiques et financiers mobilisés, cette activité s’avère être celle de la transcription des rapports d’inégalités et de pouvoir. L’objectif de cet article est d’analyser les faciès de ces rapports. Pour l’atteinte de cet objectif, cet article a mobilisé les données de thèse en cours depuis 2021. Ces données ont été collectées à partir d’un guide d’entretien, d’abord durant le mois de juin 2022, puis d’août à octobre 2022 et en janvier 2023. Pendant cette enquête, cinquante-six entretiens ont été réalisés. Il ressort de l’analyse des données collectées que la production semencière est révélatrice de rapports de pouvoir. Cette activité a en effet produit ou révélé une élite rurale appelée semencier. Les territoires qu’ils ont conquis sont aussi révélateurs de leur pouvoir. Leur image de semencier a aussi été forgée par la loi semencière faisant d’eux soit des semenciers du forum des nouveaux acteurs, soit de la loi semencière, tous investis d’un insigne de pouvoir.

Le sable est une ressource non renouvelable dont la demande pour assouvir les besoins de l’urbanisation à travers le Monde va croissant. L’extraction du sable sur les lits d’écoulement constitue un défi majeur environnemental, détruisant les niches écologiques des ressources halieutiques et perturbant également la structure et le fonctionnement de l’écosystème aquatique. La présente étude a comme objectif de déterminer les enjeux environnementaux et socio-économiques de l’extraction du sable dans les cours d’eau de la vallée de la Kwilu. Transversale, l’étude s’est appuyée sur l’observation directe et la télédétection. Les résultats ont démontré que les aléas géomorphologiques et climatiques sont à la base du risque d’ensablement des fonds de vallée de la Kwilu. Aussi, les cours d’eau dans le milieu d’étude constituent les lieux d’extraction du sable de façon artisanale. L’activité de l’extraction du sable dans les cours d’eau de la vallée de la Kwilu est bénéfique à la population, car elle lui permet de développer la région dans le domaine d’infrastructures, mais elle participe en même temps à la dégradation de la qualité de l’écosystème aquatique.

En Guinée Forestière, le transport des populations et des marchandises a lieu sur l’axe Kissidougou-Lola de la RN2 Mamou-Lola, et ses bifurcations. A travers ces routes, il y a des transactions entre la région et les territoires limitrophes, facteurs de développement socioéconomique de cette région de la Guinée. Cet article se propose de cerner et de valoriser l’importance de ces transactions de populations et de marchandises, en tant que facteurs de développement socioéconomique de la Guinée Forestière. Pour atteindre cet objectif, les enquêtes de terrain ont été menées auprès de 282 individus choisis volontairement. Les données recueillies par entretien de terrain ont été traduites en figure (carte) grâce au logiciel QGis, en iconographies (tableaux) et en verbatim grâce aux logiciels SPSS (Statistical Package for the Social Sciences) et Word. Celles de l’observation de terrain ont été exprimées en photographies. Selon les résultats de l’étude menée, le développement socioéconomique de la Guinée Forestière s’appréhende à travers les populations et les marchandises déplacées via la RN2 Kissidougou-Lola et ses traverses.

Saint-Louis, ville tricentenaire et située dans le nord-ouest du Sénégal, est dans un processus d’urbanisation irréversible. Ses quartiers historiques, souvent mal planifiés et situés sur un site fragile, souffrent de nombreux dysfonctionnements. La médiocrité du site conjuguée à la cherté du marché locatif et au changement de statut socioprofessionnel a fait naître de nouveaux quartiers à la périphérie de la ville à l’instar de Boudiouck qui offre de nouvelles opportunités. Cette dernière est devenue la nouvelle destination privilégiée des acquéreurs de logement. D’autres foyers viennent gonfler cette périphérie en provenance des autres villes du Sénégal. Cette étude analyse ces nouvelles mobilités résidentielles afin de comprendre le profil des individus impliqués dans ces déplacements, les raisons de ces changements de logement et leurs trajectoires. Le couple recherche bibliographique et enquêtes de terrain a permis d’obtenir des résultats qui contribuent à la compréhension de ce phénomène. Les conclusions de cette recherche indiquent qu’une nouvelle bourgeoisie est davantage encline à changer de résidence grâce à ses moyens financiers. Les aspirations socioprofessionnelles, la précarité immobilière et environnementale ainsi que les charges locatives dans les quartiers centraux ont encouragé la mobilité résidentielle vers Boudiouck, avec des itinéraires résidentiels variés.

Cette étude modélise le concept de territoire, matière première du travail du géographe, en formalisant les mécanismes structurels souvent méconnus qui sous-tendent sa production par les groupes humains. À travers la mise en place de structures d’encadrement (institutions, normes communautaires, valeurs culturelles, etc.) et la satisfaction des besoins essentiels (habiter, approprier, exploiter, échanger, gérer), les territoires se construisent et s’organisent en structures spatiales imbriquées : habitat, maillage, lieux de travail et treillage des connexions. Ce système territorial, à la fois ouvert et dynamique, favorise la création de richesse et l’émergence de modernités, tout en générant des déséquilibres spatiaux, sociaux ou économiques (entropies) qui nécessitent des politiques correctives pour en assurer la durabilité et la résilience. Fondé sur des théories établies et des expériences pratiques issues de l’accompagnement des collectivités territoriales, ce modèle offre un cadre analytique et applicable à toutes les échelles pour des recherches et analyses efficaces en développement territorial.

Bingerville enregistre une remarquable croissance démographique, alimentée par des populations en provenance essentiellement de la ville d'Abidjan. Un tel flux de populations, par hypothèse, peut s’expliquer aussi bien par la situation sécuritaire de cette localité semi-rurale en tant que destination que par celle de la ville d’Abidjan en tant que lieu de départ. Des études montrent que l’insécurité quotidienne à Abidjan contribue au caractère répulsif de la capitale. Mais la réalité sécuritaire de la banlieue abidjanaise, dont Bingerville fait partie, a été faiblement examinée de manière scientifique. A Bingerville, il s’est agi donc de comprendre si la situation sécuritaire de la sous-préfecture participe à son caractère attractif pour les populations, nombreuses, à la choisir comme lieu de résidence ou si l’insécurité représente un défi. Au plan méthodologique, l’enquête de victimation a permis d’interroger l’expérience de sécurité des citoyens de Bingerville. D’après les résultats des investigations, trois niveaux de défis se dégagent : ils ont trait aux manifestations des délits, à l’extension spatiale du fléau et aux caractéristiques des victimes. En conclusion, Bingerville présente un profil sécuritaire méritant une attention dans le cadre des politiques de développement local.

The sedimentary sequence in Scladina Cave (Belgium) is well-known for its rich Middle Paleolithic assemblages and its numerous faunal remains. Of particular interest is the presence of a nearly complete mandible of a Neanderthal child. To place all of these finds into the correct chronostratigraphic context, various dating techniques have been applied over the past decades. This resulted in a reasonably well-constrained age model, roughly spanning the last glacial cycle. Age constraints of the lower part of the Scladina sequence as well as from the underlying Sous-Saint-Paul Cave were, however, absent until now. Previous attempts to date several speleothem layers in Scladina Cave using U–Th dating were only partly successful, presumably because diagenetic alteration of speleothem material compromised the ages. In the present study we reassessed U–Th dating of various speleothem levels in Scladina Cave, applying state-of-the-art U–Th dating and carefully selecting material that experienced little to no diagenetic alteration. The new results constitute a robust age framework for the Scladina sequence, which provides precisely dated stratigraphic anchor points that improve the previous age model. Furthermore, new U–Th analyses for speleothems from the lower part of the Scladina sequence and from the Sous-Saint-Paul sequence document Middle Pleistocene ages, making this one of the longer fossil-rich cave sedimentary sequences in NW Europe. The new data confirm that speleothem growth predominantly took place in periods of warmer climate, while siliciclastic sediments characterize the colder intervals. New speleothem ages further suggest that the Neanderthal mandible found in the sequence and previously placed in Marine Isotope Stage 5a or 5b could potentially be as old as Marine Isotope Stage 5d.

The removal of heavy metal from the soil is necessary in order to protect the environment. Phytoremediation is a process that uses plants to remove the pollutant and helps in the rehabilitation of damaged sites. In different circumstances, along with phytoremediation, chelating chemicals such as ethylenediaminetetraacetic acid (EDTA) are used to enhance the extraction of heavy metals from soil. Experiments were conducted to evaluate the potential role of Portulaca oleracea in the removal of heavy metals from contaminated soil, and to evaluate the effectiveness of EDTA on the removal of heavy metals by Portulaca oleracea. The results revealed that Portulaca oleracea accumulated 126.11 mg/kg of cadmium and 146.22 mg/kg of copper. Translocation factor (TF) for lead, cadmium, chromium, and copper was < 1, and bioconcentration factor (BCF) for cadmium, lead, chromium, and cooper was 4.254, 6.223, 4.385 and 10.97, respectively. After treatment with 0.1 mg/kg of EDTA, the accumulation of cadmium was 187.8 mg/kg, and the accumulation of copper was 196.2 mg/kg. TF for lead, cadmium, chromium, and cooper was > 1 and BCF for lead was 16.19, cadmium 10.75, chromium 8.141 and cooper 12.37. The accumulation of cadmium and lead after treatment with 0.3 mg/kg of EDTA was 222.49 mg/kg and 181.3 mg/kg, respectively. TF for lead, cadmium, chromium, and cooper was > 1 and BCF for lead was 16.34, cadmium 11.53, chromium 8.647 and cooper 7.005. Therefore, the results showed that 0.1 mg/kg of ETDA was the optimal dose for enhanced accumulation of heavy metals.

The Stara Drava water body, located near the village of Bilje, northeast Croatia, with diverse aquatic, wetland and land habitats, maintains numerous wild fauna and flora species. The vascular flora of the Stara Drava was studied in the period from May to September 2020. A total of 142 plant species belonging to 116 genera and 53 families were recorded. The most species-rich plant families were Asteraceae, Poaceae and Lamiaceae, while the most common life forms were hemicryptophytes, hydrophytes and therophytes. Freshwater macrophytes comprise 24 species and have the significant role in the aquatic ecosystem. Alien flora is represented by 19 species, of which 14 are invasive alien plant species. According to their conservation status, five species are designated in one of the threats, and four species are proclaimed as strictly protected species in Croatia.

A study was carried out to analyse and compare the quality of groundwater in Kokrajhar during the pre- and post-monsoon seasons. Kokrajhar is experiencing a significant population growth and urbanisation. Groundwater is vital for the daily activities and consumption of the local population. In order to meet the needs of the local population, it is crucial to evaluate the quality of groundwater. The study involved the collection of groundwater samples from 20 different locations during the pre- and post-monsoon periods. Tests were conducted on groundwater samples to analyse 10 different test parameters. Sample points were located using geographical information system (GIS) and contour maps were generated to represent different test parameters. The assessment of groundwater quality was determined using two different methodologies: the Weighted Arithmetic Index (WAI) method and the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) method. The results obtained by both methods were compared. Minor to significant variations in various test parameters were observed during analysis of pre- and post-monsoon groundwater samples.

The study was carried out to assess the co-occurrence of arsenic and fluoride in groundwater in Chandrapur district, Central India, and their possible future health risk to men, women, and children. A total of 36 groundwater sampling locations (n = 34 from hand pump and n = 2 from dug well) were identified using a systematic random sampling method. The sampling was carried out using the grab sampling method in the post-monsoon season. Various physicochemical parameters were analysed as described in APHA. The results showed that the average concentration of arsenic in the groundwater was 0.0316 mg/L (0.0158 - 0.0414 mg/L), while the average concentration of fluoride was 1.18 mg/L (0.5 - 2.32 mg/L). All groundwater samples had arsenic concentrations above the limit permissible by the Indian standard (0.01 mg/L), while they were within the desirable limit (0.05 mg/L). As for the fluoride in groundwater, 12 samples (33.33 %) were below the desirable limit by the Indian standard (< 1.0 mg/L) and five (13.88 %) were above the desirable limit (> 1.5 mg/L). The co-occurrence of arsenic and fluoride in groundwater from the study area was recorded at 47.22 % (n = 17) of the sampling locations. At 14 sampling locations (38.88 %), the concentrations of both arsenic and fluoride in groundwater were higher, while at 35 sampling locations (97.22 %) there was an elevated concentration of either arsenic or fluoride or both of these contaminants. The plausible reason for the presence of arsenic and fluoride in groundwater can be attributed to geogenic origin. The prolonged ingestion of the groundwater from the study area may pose a threat to the health of the inhabitants. The inhabitants should be aware of these contaminants, and local authorities should use these findings to identify hotspots where these contaminants have occurred. It is necessary to develop and apply low-cost, environment-friendly, and easy-to-adopt methods for the removal of arsenic in combination with fluoride.

Dansgaard–Oeschger (DO) events are a pervasive feature of glacial climates. It is widely accepted that the associated changes in climate, which are most pronounced in the North Atlantic region, are caused by abrupt changes in the strength and/or northward extent of the Atlantic meridional overturning circulation (AMOC), possibly originating from spontaneous transitions in the ocean–sea-ice–atmosphere system. Here we use an Earth system model that produces DO-like events to show that the climate conditions under which millennial-scale AMOC variations occur are controlled by the surface ocean buoyancy flux. In particular, we find that the present-day-like convection pattern with deep-water formation in the Labrador and Nordic seas becomes unstable when the buoyancy flux integrated over the northern North Atlantic turns from negative to positive. It is in the proximity of this point that the model produces transitions between different convection patterns associated with strong and weak AMOC states. The buoyancy flux depends on the surface freshwater and heat fluxes and on sea surface temperature through the temperature dependence of the thermal expansion coefficient of seawater. We find that larger ice sheets tend to stabilize convection by decreasing the net freshwater flux, while CO2-induced cooling decreases buoyancy loss and destabilizes convection. These results help to explain the conditions under which DO events appear and are a step towards an improved understanding of the mechanisms of abrupt climate changes.

Zeolite adsorbents were synthesized through an alkali fusion-hydrothermal process, using coal fly ash as a raw material. Firstly, the coal fly ash was mixed with sodium hydroxide at a mass ratio of 1∶1.2 and then roasted at 850 ℃ for 2 h to obtain the alkali-fused ash. The effects of the Si/Al molar ratio of the precursor, reaction time, temperature, and liquid/solid ratio on the structure of the zeolite adsorbents derived from coal fly ash were investigated through single-factor experiments conducted during the hydrothermal reaction. The synthesized zeolite adsorbents derived from coal fly ash were systematically characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM) and specific surface area and pore size analyzer (BET). Under the optimized conditions of a Si/Al molar ratio of the precursor set at 1.5, a reaction time of 16 h, a reaction temperature of 70 ℃, and a liquid/solid ratio of 8 mL/g in hydrothermal reaction, the relative mass fraction of type X zeolite in the synthesized product was 96.3%, the specific surface area was 489.9 m2/g, and the pore volume was 0.28 cm3/g. Subsequently, the gas adsorption performance of benzene, a typical volatile organic compound, by zeolite adsorbent derived from coal fly ash was investigated and compared with commercial activated carbon. The results showed that at an initial pollutant concentration of 800 μg/L, an adsorption temperature of 100 ℃, a gas flow rate of 200 mL/min, and an adsorbent loading of 0.1 g, the zeolite adsorbents derived from coal fly ash exhibited a saturated adsorption capacity of benzene at 41.5 mg/g, which was higher compared to commercial activated carbon (31.3 mg/g). This study provides a reference for the resource utilization of coal fly ash.