Department of Bio-science

A Review of Climate Change Impacts, Adaptation, and Mitigation in South Asia.

Sun, 01 Jan 2023 00:00:00 GMT

A Review of Climate Change Impacts, Adaptation, and Mitigation in South Asia. Vijitharan, S. Climate change is a critical global issue, challenging and threatening various sectors in different ways. South Asia is one of the front-line regions to the impacts of climate change. According to the World Bank estimates, in 2021, around 1.9 billion people were in South Asia, including Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka. Therefore, this review aims to assess the impacts of climate change and the existing mitigation and adaptation measures with effectiveness across the South Asian region. We reviewed published reports, journal articles, policy documents, and other grey literature for this study. The findings of this study revealed that total greenhouse gas emissions in South Asia increased from 2.11 TgCO2 in 2000 to 4.16 TgCO2 equivalent in 2019, with an annual rate of change of 5.11%. In total greenhouse gas emissions in 2019, approximately 70% was captured by carbon emissions from 51% in 2000. Among these eight nations, India was the leading greenhouse gas emitter, followed by Pakistan and Bangladesh. South Asia is highly vulnerable to cyclones, floods, erosion, sea level rise, and other natural disasters. Agricultural production is a crucial source of income. Food insecurity was growing due to decreased agricultural yield due to global warming. Not only the agriculture sector, it severely affects other sectors such as health, coastal and marine, energy, water resources, forests, and other ecosystems. The economic cost associated with climate change on a long-term basis is showing an increase by the end of this century. A higher percentage of financial losses can be expected in India. The impacts of climate change can further aggravate water insecurity, the spread of diseases, and biodiversity loss. India, Bangladesh, and the Maldives’ average annual Gross Domestic Product (GDP) growth (%) was nearly equal. However, the CO2 emissions of Bangladesh, Pakistan, and Maldives were 30, 12, and 1,516 times less than India’s, respectively. Noticeably, we found that climate finance and CO2 emissions were strongly and positively correlated, r(6) = .92, p < .05. Similarly, a positive correlation was observed between the average loss due to climate hazards and climate finance, r(6) = .96, p < .01. Therefore, South Asia is witnessing severe effects of climate change, hurting several economic sectors and creating serious obstacles to the area's sustainable development. To lessen these effects and increase resilience to adapt to the changing climate, prompt action is needed in the form of low-carbon development plans, climate-smart agriculture, climate-resilient strategies, Nature-based solutions, sustainable forest and ecosystem management, and strict policies and governance.

Blue Carbon Potential of Mirissanduwa and Kadolgasnelella Conservation Mangrove Forest, Negombo Estuary, Sri Lanka

Wed, 01 Jan 2025 00:00:00 GMT

Blue Carbon Potential of Mirissanduwa and Kadolgasnelella Conservation Mangrove Forest, Negombo Estuary, Sri Lanka Fernando, W.T.S.; Vijitharan, S.; Chathurani, S.H.U.; Jayasundara, J.M.N.M. Mangroves are unique ecosystems thriving in harsh tropical and warm temperate conditions. These ecosystems are crucial for fighting climate change due to their ability to capture and store "blue carbon". The significant carbon stored in mangroves underscores their immense worth as a natural solution for climate change mitigation. Despite mangroves being a recognized source of climate change mitigation, there are limited studies on their role in the Negombo Estuary. The research intends to provide data supporting the protection, restoration, and sustainable management of these vital habitats to directly reduce atmospheric CO2 and enhance climate resilience. Sri Lanka's coastlines host 21 true mangrove species, with significant patches in the Negombo Estuary. The study investigated blue carbon reserves and environmental conditions. Ten 5 m x 5 m plots were randomly sampled to analyse blue carbon. Aboveground biomass (AGB), Belowground biomass (BGB) and Carbon stocks of mangrove biomass were estimated using Diameter at Breast Height (DBH) measurements and allometric equations. A total number of 10 soil samples were randomly collected from each plot to a depth of 30 cm, each using a soil corer. Soil samples were collected to determine pH, salinity, and Total Organic Carbon (TOC). TOC was measured using Loss on Ignition (LOI) method. The total blue carbon was calculated by adding aboveground carbon, belowground carbon and TOC. The study revealed that Rhizophora mucronata was the dominant species. Calculated total aboveground, belowground, TOC and blue carbon stocks were 776.23, 318.71, 438.40 and 1533.34 Mg C ha-1 respectively. Average soil pH was 7.62 ± 0.19 and salinity was 2.90 ± 0.66%. This research enhances our understanding of blue carbon storage in mangroves, underscoring their role in climate change mitigation. Further studies on blue carbon storage and promoting mangrove-based eco tourism are recommended for sustained conservation and economic developmentment.

Revitalizing Traditional Tank Systems: Case Study Insights From Sri Lanka's Village Tank Cascade Systems for Climate Resilience and Water Governance

Thu, 01 Jan 2026 00:00:00 GMT

Revitalizing Traditional Tank Systems: Case Study Insights From Sri Lanka's Village Tank Cascade Systems for Climate Resilience and Water Governance Nanthakumaran, A.; Maheshwari, B. Village tank cascade systems (VTCS) are a long-established form of water management in Sri Lanka's dry zone. However, their role in groundwater recharge, climate adaptation, and water governance remains insufficiently recognized in policy and planning. In this study, we examine the hydrological and institutional functions of VTCS in Sri Lanka's dry zone, with a focus on Vavuniya District. Using field validation, GIS-based cascade mapping, tank status assessment, and correlation analysis between tank water levels and nearby wells, the study identifies a strong hydrological relationship, most notably at Vavuniyakulam, where a correlation coefficient of 0.88 was observed. These findings highlight the significance of tanks in sustaining groundwater availability, especially during dry periods. However, decades of neglect, socio-political conflict, and fragmented institutional mandates have led to widespread degradation of tank systems and erosion of community-based governance structures. The study shows that VTCS offer critical ecosystem services beyond irrigation, including groundwater recharge, domestic water supply, climate buffering, and livelihood support. Drawing from the Vavuniya case, the paper argues for repositioning village tanks within national water policy and climate resilience frameworks. Revitalization efforts need to combine scientific assessment, participatory governance, local ecological knowledge, and institutional coordination to restore the multifunctional role of VTCS. The Vavuniya case offers wider lessons for dryland and postconflict regions where small-scale water systems remain central to groundwater security, rural livelihoods, and climate-resilient water governance.

Anthropogenic Disturbances to Enhalus acoroides Meadows along the Mannar Causeway, Sri Lanka

Thu, 01 Jan 2026 00:00:00 GMT

Anthropogenic Disturbances to Enhalus acoroides Meadows along the Mannar Causeway, Sri Lanka Keerthanaram, T.; Priyanchanaa, S. Seagrass ecosystems provide essential ecological services, including habitat provision, coastal stabilization, and fisheries support; however, they are increasingly threatened by localized anthropogenic pressures. This study evaluates the condition of Enhalus acoroides meadows along the western coastal margin of the Mannar Causeway, Sri Lanka, with emphasis on mechanical disturbance, pollution stress, and community awareness. A quantitative assessment of seagrass leaf condition (n=500) revealed that freshly cut leaves constituted , significantly exceeding naturally senescent leaves 17.6% Although no comparative control site was available during this preliminary survey, the unusually high occurrence of fresh leaf cuts observed near heavily used anchoring locations suggests a possible association with intense boat activity and propeller disturbance. Field observations further identified severe disturbance levels, with frequent propeller scarring and anchoring-induced sediment disruption. Oil pollution was also evident, with visible films observed on seagrass leaf surfaces during the field survey, suggesting direct disposal of engine waste and contributing to localized water quality degradation. A preliminary socio-ecological survey of 30 fishermen selected, through convenience sampling, indicated that while all respondents (100%) were aware of seagrass presence and its importance for fisheries, only 30% understood the impacts of mechanical damage, and 23.3% recognized pollution-related effects. Notably, 60% of respondents admitted to disposing of oil waste directly into coastal waters. Despite this, 80% expressed willingness to adopt conservation practices if appropriate guidance were provided. The findings demonstrate that E. acoroides meadows in the Mannar region are under significant anthropogenic stress, driven by both physical disturbance and behavioral factors. As a future recommendation to improve the study of seagrass leaf condition, additional ecological indicators such as shoot density, percentage cover, biomass, and leaf area index would further strengthen ecosystem health evaluations. This study highlights the urgent need for integrated management strategies combining regulatory measures, pollution control, and targeted awareness programs to ensure the long-term sustainability of seagrass ecosystems and associated fisheries.