International Journal of Environment and Climate Change

Floating Treatment Wetlands for Emerging Contaminants in Wastewater: A Critical Review of Removal Mechanisms, Performance and Sustainability

P. B. Adhithya, A. Jinu, P. S. Sheeja — Mon, 21 Sep 2026 00:00:00 +0000

Floating treatment wetlands (FTWs) are buoyant, vegetated treatment systems in which plant roots and associated biofilms develop directly within the water column. They are increasingly presented as low-energy, modular nature-based technologies for polishing wastewater and contaminated surface waters, yet their capacity to manage emerging contaminants remains less certain than their performance for nutrients, suspended solids and some conventional pollutants. This critical narrative review evaluates evidence for removal of pharmaceuticals and personal care products, antibiotics, pesticides, per- and polyfluoroalkyl substances, endocrine-active compounds and microplastics, while examining the mechanisms and sustainability trade-offs that determine whether apparent removal represents transformation, retention or simple transfer between environmental compartments. Literature from 2010 to 18 July 2026 was synthesised alongside selected earlier methodological and foundational studies. The evidence indicates that contaminant behaviour is strongly compound-specific and governed by hydrophobicity, ionisation, persistence, plant traits, rhizosphere activity, hydraulic residence time, biofilm maturity and water chemistry. Mesocosm studies demonstrate substantial attenuation of some pharmaceuticals, endocrine-active compounds and pesticides, but persistent compounds such as carbamazepine and perfluoroalkyl acids are less consistently removed. PFAS studies show that plant uptake, sedimentation and sorption can attenuate aqueous concentrations without destroying terminal PFAS, creating a requirement for biomass and sediment management. Antibiotic studies show that bioaugmentation can increase parent-compound removal, but commonly use concentrations far above those found in receiving waters and provide little evidence on antibiotic-resistance genes. Microplastic evidence introduces a further sustainability concern because floating polymer components can become contaminant sources. Hybridisation with sorbents, immobilised microorganisms or bioelectrochemical systems can improve treatment, but also increases material, maintenance and end-of-life burdens. The field therefore requires mass-balance designs, transformation-product analysis, environmentally realistic exposures, long-term field validation and lifecycle-aware performance metrics before FTWs can be regarded as broadly reliable treatment barriers for emerging contaminants.

Allelopathy in Sustainable Weed Management: From Chemical Interference to Field-scale Integration

Niru Kumari, Prerna Roy, Amit Kumar Pandey, Pavan Shukla, Ashutosh Singh — Mon, 21 Sep 2026 00:00:00 +0000

Allelopathy has long been proposed as a biological route to reduce reliance on synthetic herbicides, yet the agricultural evidence is more conditional than the frequency of laboratory phytotoxicity reports suggests. This critical narrative review evaluates allelopathy as a component of sustainable weed management by integrating evidence on allelochemical production, release and fate; crop–weed interference; breeding and phenotyping; cover crops and residues; plant extracts and natural-product herbicide discovery; and field-scale implementation. Literature was considered through 6 July 2026, with emphasis on peer-reviewed studies that linked biological effects to plausible chemical mechanisms and agronomic outcomes. The evidence is strongest for well-characterised chemical systems such as momilactones in rice, sorgoleone in sorghum, and benzoxazinoids in rye and wheat. Even in these systems, however, chemically mediated inhibition in the rhizosphere is difficult to separate from resource competition, canopy effects, residue-mediated physical suppression and microbial transformation. Field studies of weed-suppressive cultivars and cover crops demonstrate practically useful suppression, but they often establish an interference phenotype rather than allelopathic causality. Plant extracts and formulated allelochemicals provide credible leads for reduced-herbicide programmes and bioherbicide development, although dose realism, stability, selectivity, formulation, non-target effects and economic performance remain major translational constraints. The most defensible role for allelopathy is therefore not as a universal replacement for herbicides but as one ecological and biochemical hurdle within diversified integrated weed management. Future progress depends on field experiments that combine genetic contrasts, chemical quantification, spatial rhizosphere measurements, competition controls, microbiome-aware fate analysis and multi-environment agronomic validation. Such evidence would allow allelopathy to move from recurrent proof-of-concept towards reproducible, selective and economically credible weed-management functions.

Plant Biostimulants and Crop Yield and Quality under Climate Change: A Critical Review of Mechanisms, Field Evidence and Translational Constraints

Harika Kareti, J. K. Singh — Wed, 23 Sep 2026 00:00:00 +0000

Climate change is reducing the stability of crop production through more frequent drought, heat, salinity and combined stresses, while rising atmospheric carbon dioxide threatens the nutritional quality of staple crops. Plant biostimulants, defined by their capacity to improve nutrient use efficiency, abiotic stress tolerance, quality traits or nutrient availability independently of their nutrient content, are increasingly promoted as adaptation tools. The evidence underpinning these claims is extensive but fragmented across controlled-environment physiology, product-specific field trials, meta-analyses of heterogeneous studies and a small number of multi-site agronomic networks. This critical narrative review evaluates how far the available evidence supports the use of plant biostimulants to protect or enhance crop yield and quality under climate-related stress. Peer-reviewed literature published between January 2014 and July 2026 was identified through searches of agricultural, biomedical and multidisciplinary scholarly indexes, supplemented by citation tracking and institutional sources, and was appraised thematically with attention to study design, scale, heterogeneity and conflicts of evidence. The synthesis indicates that mechanistic plausibility is well established for several categories, particularly seaweed extracts, protein hydrolysates, humic substances and beneficial microorganisms, which modulate hormonal signalling, water relations, osmotic adjustment, antioxidant capacity and root function. Quantitative syntheses consistently report mean yield gains in the mid-teens, with larger responses in arid environments, degraded or nutrient-poor soils and low-yielding systems. These averages conceal very high heterogeneity, and large regional field networks have reported negligible or modest responses for some commercial products. Quality responses are frequently positive for antioxidants, vitamins and micronutrients but can involve trade-offs such as nitrate accumulation. Inconsistent product composition, poor viability of some microbial inoculants, limited reporting of stress intensity, publication bias, geographical concentration and scarce multi-season data substantially constrain confidence. Evidence concerning combined stresses, elevated carbon dioxide, waterlogging and long-term soil effects remains particularly thin. Plant biostimulants are best regarded as context-dependent complements to breeding, water management and nutrient stewardship rather than as generic climate solutions. Standardised stress-explicit field protocols, independent multi-environment testing, product characterisation and integrated yield-quality-economic assessment are required before strong adaptation claims can be justified.

Carbon Sequestration in Agricultural Soils through Agronomic Management: Mechanisms, Evidence, Accounting Boundaries and Research Priorities

Thu, 24 Sep 2026 00:00:00 +0000

Agricultural soils have lost substantial organic carbon through land conversion, intensive cultivation and insufficient organic inputs, creating a technically important but highly context-dependent opportunity for carbon restoration. This critical narrative review evaluates whether agronomic management can produce additional, measurable and sufficiently durable soil organic carbon (SOC) gains while maintaining agricultural production. Literature published from 1 January 1990 to 6 July 2026 was considered, with earlier or later-dated online records excluded from the evidentiary synthesis when outside this interval. The evidence indicates that SOC responses are governed principally by changes in plant-derived carbon inputs, microbial transformation, mineral association, aggregation, erosion and vertical redistribution rather than by any agronomic label alone. Cover crops, diversified rotations that increase biomass inputs, residue retention, perennial phases and agroforestry generally provide credible pathways for endogenous carbon accrual, although effect sizes vary with biomass production, soil mineralogy, climate, starting SOC and duration. Reduced and no-tillage frequently increase near-surface SOC but do not consistently increase whole-profile stocks when equivalent soil mass and deeper sampling are used, making tillage a particularly sensitive case for carbon accounting. Manure, compost and biochar can substantially increase measured soil carbon, but their climate value depends on carbon-source counterfactuals, processing emissions, displacement of organic resources and non-CO₂ greenhouse gases. Nutrient and water management can enhance SOC indirectly by increasing crop carbon inputs, yet gains must be evaluated against fertiliser-related nitrous oxide and energy emissions. Across practices, finite sink capacity, reversibility, spatial heterogeneity and measurement uncertainty constrain claims of permanent sequestration. The most defensible strategy is therefore not a universal practice hierarchy, but context-specific agronomic design that increases photosynthetic carbon inputs, protects soil from loss, verifies stock change across an appropriate soil mass and depth, and evaluates whole-system greenhouse-gas consequences. Future research should prioritise long-term, profile-scale, carbon-source-aware experiments and monitoring frameworks that connect total SOC change with particulate and mineral-associated fractions, crop performance, permanence and full greenhouse-gas accounting.

Climate-driven Harmful Algal Blooms and Marine Aquaculture: A Critical Appraisal of Early Warning, Fish Mortality, Exposure Mechanisms and Farm-level Adaptation

Sakshi Patil, Talib Mohammad, Ashmita Pandey, Shubham Soni, Pranjali H. Chopra — Sat, 26 Sep 2026 00:00:00 +0000

Harmful algal blooms represent one of the few climate-sensitive hazards capable of destroying an entire marine farm's standing biomass within days, yet the scientific literature that underpins farm protection remains fragmented across oceanography, fish pathology, sensor engineering and resource economics. This review critically examines the evidence connecting climate variability and change to bloom hazard in aquaculture regions, the quantification of farmed fish mortality, the cellular and physiological mechanisms through which exposure becomes death, and the effectiveness of early warning systems and farm-level adaptation. Peer-reviewed literature was identified through structured searching of open scholarly databases and indexes, supplemented by backward and forward citation searching, and appraised for design adequacy, measurement validity, ecological realism and consistency with independent evidence. Four conclusions emerge with differing degrees of confidence. Attribution of increased bloom frequency to climate forcing remains contested at the global scale because observational effort has expanded alongside aquaculture itself, although regional attribution is considerably stronger where hydroclimatic anomalies have been reconstructed independently of bloom records. Mortality quantification rests largely on cell-abundance thresholds whose transferability between species, sites and years is weak, and which conflate very different killing mechanisms. Mechanistic work has converged on reactive oxygen species, lipophilic and polyketide toxins, and mechanical gill injury as complementary rather than competing pathways, but laboratory potency rankings predict field outcomes poorly because exposure dose, water-column structure and prior gill condition are rarely measured concurrently. Early warning systems have matured technologically while remaining substantially under-evaluated against operational decision criteria, and most farm-level mitigation measures are supported by mechanistic plausibility and small-scale trials rather than by controlled comparison at commercial scale. Priorities include standardised exposure reporting, prospective forecast verification against farm decisions, and evaluation of mitigation under realistic bloom conditions.

Managing Soil Acidity and Fe–Al Toxicity in Submerged Paddy Soils: Biogeochemical Processes, Environmental Implications and Integrated Amelioration Strategies

Mon, 28 Sep 2026 00:00:00 +0000

Submergence transforms acidic rice soils into a dynamic biogeochemical environment in which redox potential, pH, iron and aluminium speciation, nutrient availability and microbial activity change throughout the cropping period. These transformations can partly alleviate aluminium toxicity through pH-mediated hydrolysis, while simultaneously increasing soluble Fe(II) through microbial reduction of Fe(III) minerals. Consequently, acid-affected submerged rice soils may experience a shifting combination of acidity, aluminium toxicity, iron toxicity and nutrient imbalance rather than a single, static constraint. This review synthesises the mechanisms governing these changes and evaluates the roles of liming materials, phosphogypsum, dolomite, magnesium sulphate, calcium silicate, organic amendments and biological approaches. Particular attention is given to the complementary functions of amendments: acidity neutralisation, calcium and magnesium supply, aluminium detoxification, silicon-mediated stress tolerance and modification of the rhizosphere environment. The review also considers water management and the environmental implications of amendment use, including nutrient imbalance, amendment quality, sulphur cycling and the need to avoid excessive inputs. Evidence indicates that no single amendment can reliably resolve all constraints in strongly acid, Fe-rich submerged soils. A site-specific strategy that integrates soil diagnosis, temporal monitoring, complementary amendment functions and appropriate water management is therefore more defensible than blanket application. Future research should combine time-resolved soil chemistry with plant responses, amendment interactions, environmental risk assessment and field-scale validation to develop resilient and resource-efficient management strategies for acid-affected rice ecosystems.

Benzophenone-3 in Aquatic Environments: Sources, Occurrence, Toxicity and the Prospects for Microalgae-based Bioremediation

Bhavana R. Dhawad, Surabhi D. Chikate, Atul R. Patil — Tue, 29 Sep 2026 00:00:00 +0000

Benzophenone-3 (BP-3), also known as oxybenzone, is a widely used organic ultraviolet filter incorporated into personal care products, cosmetics, paints and sunscreens. Its photostability, lipophilicity and slow biodegradation promote environmental persistence and facilitate its entry into aquatic systems through recreational activities and wastewater treatment plant effluents. BP-3 has been detected in wastewater, surface water, seawater, sediments, soils and remote marine environments, with reported concentrations spanning ng L^-1 to mg L^-1. Both BP-3 and its transformation products are biologically active, and available evidence indicates endocrine-disrupting, genotoxic, behavioural, reproductive and photosynthetic effects across humans, fish, aquatic invertebrates, corals and microalgae. Conventional wastewater treatment shows variable removal, while advanced oxidation processes can achieve high degradation under controlled conditions but may be constrained by cost, incomplete mineralisation and transformation-product formation. Biological treatment is therefore of interest as a potentially lower-cost and environmentally sustainable option. Microalgae are particularly relevant because they can remove contaminants through bioadsorption, bio-uptake and biodegradation while simultaneously supporting nutrient removal, carbon dioxide fixation and biomass production. However, direct evidence for microalgae-mediated BP-3 removal remains limited. Further work should prioritise strain screening, environmentally realistic exposure conditions, real wastewater matrices, transformation-product characterisation, mixture effects and scale-up to clarify the practical feasibility of microalgae-based BP-3 bioremediation.

Quantifying the Urban–forest Trade-off in a Rwandan Secondary City: A 35-Year Multi-temporal Remote Sensing Assessment of Huye District (1990–2025)

Dieudonne Nshimiyimana, Janvier Niyomugabo, Pancras Ndokoye — Mon, 21 Sep 2026 00:00:00 +0000

Rapid urban expansion is transforming land-cover patterns in Rwanda’s secondary cities, with potential consequences for forest resources and sustainable land-use planning. This study assessed long-term changes in built-up and forest cover associated with urban expansion in Huye District, Rwanda, from 1990 to 2025, and examined the spatial relationship between built-up expansion and forest-cover decline. A multi-temporal remote sensing approach was applied using Landsat imagery for four reference years (1990, 1999, 2018, and 2025). The imagery was pre-processed and classified using supervised maximum-likelihood classification into five land-cover classes, with classification accuracy assessed using error-matrix analysis and ground-reference data, achieving overall accuracies exceeding 85% for all years. Post-classification change detection quantified land-cover transitions and changes in built-up and forest areas, while Pearson correlation analysis assessed the association between built-up and forest areas, and a 5-km proximity buffer was used to examine the spatial concentration of forest-cover loss around expanding built-up areas. Built-up land increased from 2.80 km² (0.52% of the district) in 1990 to 49.30 km² (8.94%) in 2025, representing a 1,660.71% increase, while forest cover declined from 74.50 km² (13.79%) to 35.20 km² (6.51%), corresponding to a 52.75% reduction. Consequently, the built-up-to-forest area ratio shifted from approximately 1:26.6 in 1990 to 1.40:1 in 2025, indicating a substantial reversal in the relative extent of these land-cover types. Built-up and forest areas exhibited a strong inverse association across the four observation years (Pearson r = −0.92), although the relationship was not statistically significant at the 5% level (p = 0.078; n = 4). Spatial analysis further indicated that forest-cover loss was disproportionately concentrated within the 5-km zone surrounding expanding built-up areas. Overall, Huye District experienced substantial built-up expansion accompanied by pronounced forest-cover decline over the 35-year period. The strong inverse temporal association and concentration of forest loss near expanding built-up areas suggest that urban growth is an important spatial correlate of forest-cover change, although the limited number of temporal observations constrains statistical inference. The findings highlight the need to integrate forest conservation into secondary-city expansion planning through enforceable urban growth boundaries, protection of forested buffer zones, and targeted reforestation and restoration measures.

Agronomic Evaluation of Suitable Cropping Systems for Bidi Tobacco under Rainfed Conditions in Andhra Pradesh

Mon, 21 Sep 2026 00:00:00 +0000

A field experiment was conducted for Agronomic evaluation of suitable cropping systems for bidi tobacco under rainfed conditions at Regional Agricultural Research Station, Nandyal, ANGRAU under AINP on Tobacco for three years during rabi seasons from 2020-21 to 2022-23 with the objective to evaluate different bidi tobacco based cropping systems for higher productivity, monetary returns and quality of bidi tobacco. The experiment laid out in randomized block design with 3 replications. Treatments comprised of 9 cropping systems viz., Foxtailmillet – Bidi tobacco, Greengram – Bidi tobacco, Blackgram – Bidi tobacco, Sweet corn – Bidi tobacco, Cluster bean – Bidi tobacco, Cowpea – Bidi tobacco, Bajra – Bidi tobacco, Onion – Bidi tobacco and Fallow- bidi tobacco. The pooled results revealed that significantly higher leaf length and width, bidi tobacco equivalent yield (3119 kg/ha) were recorded with Onion followed by bidi tobacco cropping system which is on par with sweetcorn followed by bidi tobacco cropping system. Whereas higher net returns (Rs. 202815/ha) and benefit cost ratio (3.5) was observed in sweet corn followed by bidi tobacco cropping system. Land-use efficiency (LUE) was the highest in onion-bidi tobacco cropping system (90.4 %) and the lowest in Fallow-bidi tobacco cropping system (49.3%). Significantly higher system productivity (9.9 kg/ha) and system profitability (676 Rs./ha) were registered with Sweet corn – Bidi tobacco cropping system. Leaf chemical parameters viz., higher nicotine (6.67 %), reducing sugars (3.90 %) and chlorides (1.21 %) were recorded in onion-bidi tobacco cropping system. Thus, Onion-bidi tobacco and Sweetcorn- bidi tobacco cropping system were more productive and remunerative than the other cropping systems in bidi tobacco growing areas of Kurnool district of Andhra Pradesh.

Agronomic Performance and Soil Chemical Responses of Kharif Rice to Balanced and Reduced P and K Supply in the Red and Lateritic Soils of Paschim Medinipur, West Bengal, India

Mon, 21 Sep 2026 00:00:00 +0000

Balanced fertilisation is essential for sustaining rice productivity and maintaining soil fertility, particularly in acidic red and lateritic soils where nutrient availability and retention can be limiting. Although nitrogen is commonly applied to enhance rice growth, its effectiveness depends on an adequate supply of phosphorus and potassium. However, the short-term agronomic, soil-fertility and economic consequences of reducing or omitting phosphorus and potassium under a fixed nitrogen supply remain insufficiently characterised for Kharif rice in Paschim Medinipur, West Bengal. A field experiment was conducted during the Kharif season of 2025 at the Agricultural Experimental Field of Midnapore City College, Paschim Medinipur, West Bengal, India, to evaluate the effects of different NPK combinations on rice (Oryza sativa L.) growth, yield, post-harvest soil chemical properties and economic performance under red and lateritic soil conditions. The experiment was laid out in a Randomised Block Design with seven treatments and three replications. Nitrogen was maintained at 80 kg ha⁻¹ in all fertilised treatments, while P₂O₅ and K₂O were supplied at recommended, reduced or omitted levels. Treatments were T1 (80:40:40), T2 (80:40:20), T3 (80:40:0), T4 (80:20:40), T5 (80:0:40), T6 (80:20:20) and T7 (0:0:0 kg N:P₂O₅:K₂O ha⁻¹). Growth, yield attributes, yield, post-harvest soil pH, EC, organic carbon and available N, P and K, along with economic returns, were assessed. T1 recorded the highest values for most growth and yield attributes. Grain yield was highest under T1 (5.06 t ha⁻¹), followed by T2 (4.84 t ha⁻¹) and T4 (4.73 t ha⁻¹), while T7 recorded the lowest yield (2.19 t ha⁻¹). T1 increased grain yield by 131.1% over the control; however, its yield was statistically comparable with T2 and T4. Treatments involving P or K omission generally reduced growth and yield. Post-harvest soil analysis showed comparatively higher available N, P and K and organic carbon under nutrient-supplied treatments. T1 also recorded the highest gross return (₹139,363 ha⁻¹), net return (₹86,279 ha⁻¹) and B:C ratio (1.63). The study indicates that balanced NPK supply improved rice productivity, post-harvest soil chemical status and economic returns under the experimental conditions, although multi-season and multi-location evaluation is required for wider recommendation.

Seasonal Incidence of Pod Borer Complex of Pigeonpea in Relation to Weather Parameters at Sehore, Madhya Pradesh, India

Tue, 22 Sep 2026 00:00:00 +0000

The present field investigation was conducted to study the seasonal incidence of pod borer complex of Pigeonpea during Kharif 2025 at the Research Farm of Entomology Department, Rafi Ahmed Kidwai College of Agriculture, Sehore (Madhya Pradesh). Pigeonpea, Cajanus cajan (L.), is the second most important pulse crop after chickpea. India is the world's largest producer of Pigeonpea. The study revealed that pigeonpea was infested by four major pod borers, i.e. gram pod borer, Helicoverpa armigera; leaf webber, Grapholita critica; plume moth, Exelastis atomosa and spotted pod borer, Maruca vitrata. The pests first appeared between the 36th and 41st standard meteorological week and persisted up to the 2nd and 3rd standard meteorological week of the following year attaining peak populations during the 45th - 47th standard meteorological week during the crop period. Correlation studies showed that maximum temperature had non-significant negative correlations (r= -0.328, and -0.030, respectively). Correlation studies revealed that minimum temperature, relative humidity and rainfall had negative and non-significant correlations (r= -0.436, -0.422, -0.413; -0.059, -0.031, -0.263 and -0.192, -0.172, -0.341, respectively) with Gram pod borer, plume moth and spotted pod borer, while maximum temperature showed positive, non-significant associations with leaf webber and plume moth (r= 0.394 and 0.131, respectively). The weak and statistically non-significant correlations with temperature, relative humidity and rainfall indicate that these weather parameters alone did not have a significant influence on pest larval population dynamics during the study period.

Assessing Division-level Variability in Soil Nutrient Retention in a Tropical Forest Reserve: Evidence from the Amrabad Tiger Reserve, India

Tue, 22 Sep 2026 00:00:00 +0000

Aim: The present study aimed to evaluate division-wise variability and interrelationships of key soil physico-chemical properties governing nutrient retention in the Amrabad Tiger Reserve (ATR), a tropical dry deciduous forest ecosystem of the Eastern Ghats, India.

Study Design: A field-based observational study was conducted, and the data were statistically analysed using one-way analysis of variance (ANOVA) followed by Tukey’s HSD test, along with Pearson’s correlation analysis to examine relationships among variables.

Place and Duration of the Study: Soil sampling was carried out across three administrative divisions—Achampet, Amrabad, and Nagarjuna Sagar—within the Amrabad Tiger Reserve, Telangana, India, from 2023 to 2025.

Methodology: A total of 100 composite soil samples were collected from ten forest ranges at a depth of 0–15 cm. Samples were analysed for soil reaction (pH), electrical conductivity (EC), organic carbon (OC), and available nitrogen (N), phosphorus (P), and potassium (K) using standard and widely accepted laboratory procedures. Statistical analyses were employed to assess spatial variability and interrelationships among soil properties.

Results: Significant division-wise variation was observed for soil pH, EC, and available N, P, and K (p < 0.01), whereas organic carbon did not differ significantly among divisions. Nagarjuna Sagar soils exhibited higher pH but comparatively lower nitrogen availability, while Amrabad showed superior nutrient status, particularly for nitrogen, phosphorus, and potassium. Pearson’s correlation analysis identified organic carbon as a key regulator of nutrient availability, showing strong positive associations with available nitrogen (r = 0.355) and potassium (r = 0.381).

Conclusion: The study reveals pronounced spatial heterogeneity in soil nutrient retention within ATR, driven by fine-scale variations in geomorphology, vegetation, and organic matter dynamics. Organic carbon emerged as the central factor controlling nutrient availability, underscoring the need for site-specific soil management and conservation strategies to sustain productivity and ecosystem resilience in tropical dry forest reserves.

Climate Change, Length of Extreme Heat Waves in Tahoua (Niger) during the Year 2024

Tue, 22 Sep 2026 00:00:00 +0000

Extreme heat during the March-April-May hot season is an important climatic concern in Tahoua, Niger. This study assessed the duration of heatwaves in Tahoua city during 2024 using daily maximum temperature observations from the Tahoua station. Two identification approaches were compared: the absolute 40°C threshold used by ACMAD, under which a heatwave occurs when the maximum temperature exceeds 40°C for at least three consecutive days, and percentile-based thresholds at the 85th, 90th, and 95th percentiles. The threshold approach identified eight periods of sustained high temperature during March-April-May, including several episodes lasting at least three consecutive days. The percentile analysis showed that estimated heatwave duration depended strongly on the selected percentile. At the 95th percentile (43.7°C), one heatwave episode lasting 5 days was identified. At the 90th percentile (42.8°C), four heatwave episodes lasting 4–9 days were recorded. At the 85th percentile (41.6°C), six episodes lasting 3–19 days were identified, including longer events from late March to early April and from late April to early May. These results demonstrate that the estimated number and duration of heatwave episodes in Tahoua during 2024 varied with the operational threshold used. The findings provide a station-level description of extreme-heat duration during the 2024 hot season and support careful selection of percentile or absolute thresholds when characterising heatwave conditions in Tahoua.

Impact of Abiotic Factors on Arthropod Communities and Natural Enemies in Paddy (Oryza sativa L.) - Based Agro and Agroforest Ecosystems

Sravani Pasham, I. Aruna Sri, M. Deepa, D. Srinivasa Chary — Sat, 26 Sep 2026 00:00:00 +0000

Weather variables can influence the abundance and distribution of arthropods in rice ecosystems, including both pest taxa and their natural enemies. This study evaluated arthropod abundance and its association with selected abiotic factors in a paddy agroecosystem and paddy agroforest ecosystem at Kanchanpally village, Kowdipally Mandal, central Telangana, during the 2024 Kharif season (July–November). One-acre plots representing the two ecosystem types were sampled using pitfall, sticky and pheromone traps, visual counts and sweep netting. Maximum and minimum temperature, maximum and minimum relative humidity, and rainfall were related to arthropod populations by correlation analysis. A total of 3,618 arthropod individuals were recorded, comprising 1,712 individuals in the agroecosystem and 1,906 in the agroforest ecosystem. Weather relationships varied among arthropod orders and between ecosystems. For Lepidoptera, rainfall was significantly negatively correlated with abundance in the agroecosystem (r = −0.539) but significantly positively correlated in the agroforest ecosystem (r = 0.581). Natural enemies were more numerous in the agroforest ecosystem (765 individuals) than in the agroecosystem (623 individuals). Rice yield was 6,918.8 kg ha⁻¹ in the agroforest ecosystem and 6,424.6 kg ha⁻¹ in the agroecosystem, corresponding to a 7.69% increase. The findings indicate ecosystem-specific relationships between weather variables, arthropod communities and natural-enemy abundance, while supporting further investigation of agroforest-based paddy systems.

Evaluation of an Experimental Climate Information of Health Product for Vector-borne Diseases: An Initiative towards Climate Services for the Health Sector in India

Mon, 28 Sep 2026 00:00:00 +0000

Aims: To evaluate the usefulness of the experimental Climate Information for Health (CIH) product issued by the India Meteorological Department (IMD) for malaria and dengue against observed disease-occurrence data for 2017.

Study Design: A retrospective, observational verification study using categorical (contingency-table) analysis of forecast climatic suitability against reported vector-borne disease (VBD) occurrence.

Place and Duration of Study: Office of Climate Research and Services, India Meteorological Department, Pune, India, covering all Indian states/meteorological subdivisions from May to December 2017.

Methodology: As a requirement of the WMO Global Framework for Climate Services (GFCS), IMD initiated weekly Climate Information for Health (CIH) bulletins for malaria and dengue on an experimental basis. The bulletins used two-week-ahead maximum/minimum temperature forecasts from its Extended Range Prediction System (ERPS) and were issued every Friday from the second week of May 2017. States were classified into four categories according to whether climatic suitability for VBD occurrence was anticipated and whether the disease was subsequently reported, using monthly, state-wise disease data from the National Vector Borne Disease Control Programme, FluTrackers, state health departments and municipal corporations. Skill scores (probability of detection, false alarm ratio, miss rate, bias, critical success index and Heidke skill score) were computed from the resulting contingency tables.

Results: CIH was found to be useful for malaria in most states and months from June to October 2017 (probability of detection [POD] ≈ 0.97; false alarm ratio [FAR] ≈ 0.03). For dengue, its usefulness was limited to the winter months of November and December (POD ≈ 0.38; FAR ≈ 0.11 for the full study period). This was attributable mainly to the absence of a validated maximum-temperature threshold for dengue transmission in the Indian context.

Conclusion: The experimental CIH product provides a useful, low-cost early signal for malaria risk in India and a starting point for dengue, but region-specific temperature (and possibly humidity and rainfall) thresholds for dengue transmission need to be developed in collaboration with the health sector to improve its reliability outside the winter season.

Stakeholders' Strategies and Channels of Climate Communication in the Bamenda Highlands, Cameroon

Yongka Bernard Nyuyse, Zephania Nji Fogwe, Awuh Mbia Ekolok — Thu, 01 Oct 2026 00:00:00 +0000

This paper assesses the current communication strategies and channels used by different stakeholders in disseminating climate information in the Bamenda Highlands of Cameroon. The assessment goes beyond cataloguing what exists to examine whether the identified strategies and channels are capable of communicating climate variability and change information effectively. Climate variability and change information is understood here as scientifically grounded content on shifting rainfall patterns, temperature trends, increasing frequency of extreme weather events, and the consequences of these shifts for agricultural systems and community livelihoods. Drawing on a mixed-methods design that combined a stratified survey of 408 respondents, 30 key-informant interviews, eight focus-group discussions and 45 structured field observations across eight Sub-Divisions (Bamenda I–III, Kumbo Central, Nkambe Central, Santa, Oku and Fundong), the study maps participatory methods, media channels, institutional actors and communication frequency. Focus-group discussions dominate participatory approaches, yet function mainly as general environmental sensitisation rather than structured climate-science communication. Heat maps, a correlation matrix, labelled scatter plots and radar profiles of the eight Sub-Divisions show that regular programming co-varies with private weather services and independent media, that reactive communication is the statistical inverse of that cluster, and that mobile applications substitute for radio–television combinations in the most infrastructure-poor settings. Citizen-science initiatives remain under-utilised despite their direct relevance to local observation and monitoring. Radio, often combined with television or mobile applications, is the principal channel; dedicated climate-variability content is limited even in the best-performing programmes. Local NGOs are the most visible stakeholders but operate largely in isolation from government meteorological services, private weather companies and academic institutions, and three Sub-Divisions have no independent media outlet at all. Communication is predominantly reactive (when the need arises), with regular monthly and daily programming remaining marginal even in the best-resourced administrative centres. The findings reveal systemic fragmentation and call for a Regional Climate Communication Coordination Platform under the Ministry of Environment, Protection of Nature and Sustainable Development to serve as a network administrative organisation capable of aligning strategies, channels, and content standards.

Adaptive Capacity of Resettled Flood-prone Communities to Recurring Floods in Tana River County, Kenya

Zaccheous Nguku Mutunga, Simon Maingi — Mon, 28 Sep 2026 00:00:00 +0000

This study evaluated whether resettlement had strengthened the capacity of flood-prone communities in Tana River County, Kenya, to anticipate, withstand, respond to and recover from recurring flood events. A household-based approach was used to assess socioeconomic characteristics, adaptation strategies, perceived effectiveness, institutional support and factors influencing adaptive capacity among 185 valid respondents. Descriptive statistics, Pearson’s chi-square tests and binary logistic regression were used to analyse the data. Early evacuation was the most widely adopted adaptation strategy (85.4%), followed by relocation to safer ground (78.4%) and livestock relocation (74.1%), while construction of barriers was least common (37.3%). Early warning was perceived as the most effective adaptation measure (M = 4.32, SD = 0.71), followed by evacuation (M = 4.18, SD = 0.76), whereas institutional support received the lowest effectiveness rating (M = 3.41, SD = 1.08). Socioeconomic factors, including education, income and livelihood diversification, were significantly associated with adaptive capacity (p < 0.05). Logistic regression showed that early-warning access had the strongest influence on adaptive capacity (AOR = 2.58, 95% CI: 1.39–4.79, p = 0.003), followed by livelihood diversification, education, community participation, income, institutional support and previous flood experience. The study concludes that resettlement alone was insufficient to ensure high adaptive capacity and that resilience depended on complementary socioeconomic, institutional and community-level support. The study recommends strengthening early-warning systems, livelihood diversification, disaster-preparedness training, institutional coordination, community participation and post-resettlement infrastructure and social services to enhance long-term resilience to recurring floods.

Flood Inundation Assessment in the 9th District of N'Djamena, Chad, Using an Integrated HEC-HMS-HEC-RAS Framework

Tidjani Bahar, Wasna Galdima, Beramadje Robyangue — Tue, 29 Sep 2026 00:00:00 +0000

Flooding is a major natural hazard in rapidly growing African cities, where hydrological variability, urban expansion, and limited drainage capacity can increase exposure. N'Djamena, the capital of Chad, is recurrently affected by flooding associated with the Chari-Logone River system. The Chari-Logone watershed forms the principal active drainage area of the Lake Chad Basin and covers approximately 613,000 km². This study evaluates an integrated HEC-HMS, HEC-RAS, and Geographic Information System workflow for reconstructing historical flood conditions in neighbourhoods of the 9th District of N'Djamena. Hydro-climatic conditions for 2021-2023 were analysed, and the 2023 monthly discharge series at the N'Djamena station was used for HEC-HMS calibration. The calibration produced a Nash-Sutcliffe efficiency (NSE) of 0.50, a root mean square error (RMSE) of 562.93 m³/s, and a Pearson correlation coefficient (r) of 0.86. These statistics indicate moderate calibration performance, with a substantial overestimation of the principal discharge peak. HEC-HMS outputs were subsequently used in HEC-RAS to generate flood-inundation maps for 2021, 2022, and 2023. The mapped patterns were qualitatively consistent with historically affected areas, although no independent spatial accuracy metric was available for flood extent or depth. The modelling framework therefore provides a useful basis for historical inundation assessment and planning support, while its predictive application requires independent hydrological and spatial validation.

Climate-Smart Agriculture (CSA): An Alternative to Relief for Producers in Southeastern Benin

WOKOU Guy Cossi — Thu, 01 Oct 2026 00:00:00 +0000

Climate variability represents a major challenge for rain-fed agricultural production systems in southeastern Benin. This study analyses the relationships between climate variability, agro-climatic constraints, and crop production and examines potential adaptation and environmental sustainability options within the framework of Climate-Smart Agriculture (CSA).

The methodological approach combines long-term rainfall data from Météo-Bénin, agricultural statistics from the Ministry of Agriculture, Livestock and Fisheries (MAEP) for the period 1995–2018, demographic and socio-economic data from the 2013 Population and Housing Census, and field surveys conducted among 205 farming households.

The results show marked interannual rainfall variability, with 50% of the years analysed classified as dry, 38.16% as wet, and 11.84% as normal. However, no consistent relationship was found between annual rainfall totals and interannual variations in maize, cassava, cowpea, and groundnut yields. Crop performance appears to be more closely associated with rainfall distribution during the growing season and with the occurrence of critical events such as dry spells, delayed onset and early cessation of the rainy season, floods, and high-temperature events at sensitive stages of crop development. Farmers’ perceptions support this interpretation: delayed onset of the rainy season was the most frequently reported climatic constraint (25%), followed by early cessation of rainfall (20%). These disturbances can induce water stress and disrupt cropping calendars and crop development, thereby contributing to production losses and reduced farm income, with potential consequences for household food security. Adaptation options include the use of improved varieties (short-cycle and/or drought- and disease-resistant varieties), soil mulching (using crop residues or polyethylene film), and the Improved Production System (IPS)—involving crop sequencing and rotation—as well as sowing management (re-sowing, overseeding, stale seedbed techniques, dry sowing, and adjusting sowing dates). Agroforestry, capacity building for family farmers, and climate micro-insurance and safety nets for Climate-Smart Agriculture constitute the main mitigation measures in southern Benin. Overall, the results highlight the importance of combining climatic observations with farmers’ local knowledge to identify critical agro-climatic events better and support locally appropriate Climate-Smart Agriculture strategies.