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GS Paper: GS3-18.Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment.

  • [9th January 2025] The Hindu Op-ed: River interlinking, the fount of environmental disaster

    PYQ Relevance:

    Q) The interlinking of rivers can provide viable solutions to the multi-dimensional inter-related problems of droughts, floods, and interrupted navigation. Critically examine. (UPSC CSE 2020)

    Mentor’s Comment: UPSC mains have always focused on Benefits of interlinking of rivers in (2020), and ‘Advantages and challenges of River water linking ’  in (2017).

    On December 25, 2024, Prime Minister Narendra Modi started the Ken-Betwa River Link Project to address water shortage in the Bundelkhand region, covering parts of Uttar Pradesh and Madhya Pradesh. The project includes building a dam inside the Panna Tiger Reserve, causing worries about flooding the area. It plans to connect the Ken River, believed to have extra water, with the Betwa River to help the drought-hit Bundelkhand region, which had 58% forest cover back in 1938.

    Today’s editorial talks about the challenges of the river linking project and what could the alternatives to address the water scarcity in India. This content can be used in GS mains paper III to substantiate the argument related to river water linking projects.

    _

    Let’s learn!

    Why in the News? 

    Political leaders need to understand that linking rivers causes significant environmental damage and harms rivers and deltas in the long run.

    What are the environmental consequences of river interlinking projects?

    • Ecosystem Disruption: The construction of dams and canals can lead to the submergence of critical habitats, particularly in sensitive areas like the Panna Tiger Reserve. This threatens biodiversity and disrupts local ecosystems that depend on natural water flow patterns.
    • Altered Hydrology: Diverting rivers can change the natural hydrological cycle, affecting groundwater recharge and leading to increased salinity in deltaic regions.
      • This can have dire consequences for agriculture and local livelihoods, as seen in the case of the Indus Delta.
    • Loss of Eco-services: Rivers provide essential services such as sediment transport, nutrient cycling, and habitat support for various species. By treating river water as a mere resource for transfer, these projects overlook the ecological roles rivers play in sustaining biodiversity and maintaining soil fertility.

    How do river interlinking initiatives affect local communities and socio-economic dynamics?

    • Displacement and Livelihood Loss: Projects like the Ken-Betwa initiative can displace communities living in affected areas, leading to the loss of homes and agricultural land. The Daudhan Dam alone is expected to submerge around 9,000 hectares of land, impacting numerous villages.
    • Water Access Disparities: While these projects aim to provide irrigation and drinking water to drought-prone areas, they may inadvertently prioritize certain regions over others, exacerbating existing inequalities. 
    • Economic Dependency on Infrastructure: There is a risk that local economies become overly dependent on these large projects, which may not deliver sustainable benefits. The anticipated prosperity from such initiatives may not materialize if ecological degradation occurs or if the projects do not function as intended.
    What alternatives exist to address water scarcity without compromising ecological integrity?

    • Integrated Water Resource Management (IWRM): This approach emphasizes the need for holistic management of water resources by involving local communities in decision-making processes. It focuses on sustainable practices that balance human needs with ecological health.
    • Modern Irrigation Techniques: Implementing efficient irrigation methods such as drip irrigation can significantly reduce water usage while maintaining agricultural productivity. Israel’s success in this area demonstrates the potential for technology to enhance water efficiency without large-scale environmental disruption.
    • Rainwater Harvesting and Watershed Management: Encouraging local practices like rainwater harvesting can help communities manage their own water resources sustainably. This method enhances groundwater recharge and reduces dependence on external water transfers.

    Way forward: 

    • Promote Sustainable Water Management Practices: Implement Integrated Water Resource Management (IWRM) with community participation, modern irrigation techniques like drip irrigation, and local solutions such as rainwater harvesting to reduce dependence on large-scale projects.
    • Prioritize Ecological and Social Impact Studies: Conduct comprehensive studies on the environmental and social consequences of river interlinking projects to ensure sustainable development and protect biodiversity, livelihoods, and deltaic ecosystems.

    ttps://www.thehindu.com/opinion/lead/river-interlinking-the-fount-of-environmental-disaster/article69077414.ece 

  • What is a Polar Vortex?

    What is a Polar Vortex?

    Why in the News?

    The United States is facing severe winter storms as the polar vortex is expanding southward from the Arctic and driving temperatures as low as -50°C (-60°F).

    What is a Polar Vortex?

    • The polar vortex is a band of fast-moving air that traps cold Arctic air within the Polar Regions.
    • It is a natural atmospheric phenomenon, typically spinning in a counter-clockwise direction around the North Pole.
    • Wind speeds in the polar vortex can reach up to 250 km/h (155 mph).
    • Causes of a Polar Vortex:
    1. Stable State: Under normal conditions, the polar vortex remains strong and well-contained within the Arctic Circle, keeping frigid air confined to the Polar Regions.
    2. Weakened State:
    • The vortex weakens when rising warm air from the lower atmosphere disrupts its circular flow, allowing Arctic air to spill southward.
    • Factors contributing to a weakened state include: Significant weather patterns (e.g., powerful winds in mountainous regions); Changes in tropical climate systems or sea surface temperatures. Climate change causing uneven warming, especially at the poles..

    What are its types?

    1. Tropospheric Polar Vortex:
    • It occurs in the lowest atmospheric layer (troposphere) where most weather phenomena take place.
    • Typically results in milder weather across northern latitudes.
    1. Stratospheric Polar Vortex:
    • Forms 16–48 km above the Earth’s surface in the Stratosphere.
    • Stronger and more stable but can weaken due to disruptions, leading to southward extensions of Arctic air.
    • It emerges in autumn and dissipates by spring each year.

  • What is Net-Zero Banking Alliance (NZBA)?

    Why in the News?

    Several major US banks have recently withdrawn from the Net-Zero Banking Alliance (NZBA), raising concerns about the banking sector’s commitment to combating climate change.

    What is Net-Zero Banking Alliance (NZBA)?

    • Established as a bank-led, UN-convened initiative, the NZBA commits members to align their lending, investment, and capital market activities with achieving net-zero greenhouse gas (GHG) emissions by 2050.
    • It is a part of the UNEP Financial Initiative’s Principles for Responsible Banking, serving as a climate accelerator.
    • NZBA retains 142 members from 44 countries, with 80 European banks representing the majority of the alliance’s $64 trillion in assets.
    • No Indian banks are signatory to this NZBA.
    • Structural Mandate:
      • Overseen by a Steering Group representing diverse geographies and business models.
      • Supported by the UNEP FI Secretariat and governed under documents updated in August 2023 and March 2024.
    • Commitments of Member Banks:
      • Transition operational and portfolio emissions to align with net-zero pathways.
      • Set 2030 targets (or sooner) within 18 months of joining and establish intermediate targets every five years.
      • Publish annual reports on absolute emissions and emissions intensity.

    What is the Net-Zero Greenhouse Gas (GHG) Emissions Target by 2050?

    • Net-zero greenhouse gas (GHG) emissions by 2050 refer to achieving a balance between the amount of GHGs emitted into the atmosphere and the amount removed or offset by natural or technological means.
    • This target is critical for limiting global warming to 1.5°C above pre-industrial levels, as outlined in the Paris Agreement.

    About the Glasgow Financial Alliance for Net Zero (GFANZ)

    • The GFANZ is a global coalition of leading financial institutions committed to accelerating the transition to a net-zero economy and achieving net-zero GHG emissions by 2050.
    • It was established in April 2021 in the lead-up to the COP26 climate summit in Glasgow.
    • Membership comprises over 550 financial institutions across 50 countries.
      • Includes banks, insurers, asset managers, and other financial players managing a combined $150 trillion in assets.
    • It is chaired by Mark Carney, former Governor of the Bank of England and current UN Special Envoy for Climate Action and Finance.
    • It is supported by global initiatives like the UN Race to Zero campaign and other financial alliances.

    PYQ:

    [2016] The term ‘Intended Nationally Determined Contributions’ is sometimes seen in the news in the context of:

    (a) Pledges made by the European countries to rehabilitate refugees from the war-affected Middle East.

    (b) Plan of action outlined by the countries of the world to combat climate change.

    (c) Capital contributed by the member countries in the establishment of the Asian Infrastructure Investment Bank.

    (d) Plan of action outlined by the countries of the world regarding Sustainable Development Goals.

  • Migratory Bats ‘surf’ storm front winds to save energy

    Migratory Bats ‘surf’ storm front winds to save energy

    Why in the News?

    The Common Noctule Bats are surf over the storm winds when they migrate thousands of miles across continents, reveals new research.

    About the Common Noctule Bats (Nyctalus noctula)

    • The common noctule bat (Nyctalus noctula) is one of the largest bat species in Europe.
    • It has a body length of 7–9 cm, a wingspan of 32–40 cm, and weighs between 18–40 grams.
    • Its fur is reddish-brown to golden-brown, darker on the back and lighter underneath, while its wings are long and narrow, designed for fast and sustained flight.
    • Features: 
      • Common noctules are known for their swift and high-altitude flight, reaching heights of up to 3,000 meters.
      • They are primarily insectivorous, feeding on moths, beetles, and other flying insects.
      • Their echolocation abilities allow them to detect and hunt prey with precision, even in complete darkness.
      • Although classified as Least Concern by the IUCN, common noctule bats face several threats, including habitat loss due to deforestation and urbanization.
    • Habitat:
      • The common noctule bat is widely distributed across Europe, North Africa, and Asia, extending into Siberia and parts of China.
      • It is migratory, especially in central and eastern Europe, traveling long distances between summer breeding sites and winter hibernation sites.
      • It inhabits forests and woodlands, where it uses hollow trees for roosting, as well as urban areas, where it often roosts in buildings, attics, and bat boxes.
      • These bats also thrive in wetlands and grasslands, hunting over water bodies and open fields where insect populations are abundant.

    PYQ:

    [2012] Consider the following kinds of organisms:

    1. Bat

    2. Bee

    3. Bird

    Which of the above is/are pollinating agent/agents?

    (a) 1 and 2 only

    (b) 2 only

    (c) 1 and 3 only

    (d) 1, 2 and 3

  • How are Zebrafishes able to repair damaged hearts?

    Why in the News?

    A recent research revealed that the Zebrafish (a popular aquarium fish) can regenerate damaged heart muscle within 60 days, a capability absent in humans. The Hmga1 protein plays a key role in this process, offering potential insights for heart repair in mammals.

    Discovery of Hmga1’s Role in Zebrafish Heart Regeneration:

    • In zebrafish, the Hmga1 protein plays a pivotal role in activating dormant genes necessary for regeneration.
    • It removes molecular “roadblocks” on chromatin (DNA-packaging structures), shifting genes from an inactive state to active regeneration mode.
    • The Hmga1 gene, active during embryonic development in mice and humans, becomes inactive after birth.
    • In zebrafish, however, the gene remains active during heart regeneration, enabling the repair process.

    About Zebrafish

    • Zebrafish are small freshwater fish measuring 2-3 cm in length.
    • It is named for the horizontal blue stripes running along their bodies.
    • It is native to South Asia’s Indo-Gangetic plains and is commonly found in paddy fields, stagnant water, and streams.
    • It is classified as Least Concern by the IUCN.

    Features of Zebrafish

    • Zebrafishes are known for their ability to regenerate almost all major organs, including the heart, brain, eyes, and spinal cord.
    • This unique trait makes them an important model in developmental biology and disease research.
    • They share approximately 70% of their genes with humans.
    • Over 80% of human disease-related genes have counterparts in zebrafish, making them valuable for studying genetic disorders.
    • They produce hundreds of embryos in a single clutch, enabling large-scale studies.
    • They are now preferred over rodent (guinea pigs) models for certain vertebrate development studies.
    • Widely used for regenerative biology and drug discovery due to their cost-effectiveness and rapid breeding.

  • Chhattisgarh first state to link Forest Ecosystem with Green GDP

    Why in the News?

    For the first time in India, Chhattisgarh has introduced an innovative framework that integrates the ecosystem services of its forests into the calculation of Green Gross Domestic Product (Green GDP). This initiative highlights the critical role forests play in supporting both environmental sustainability and economic growth.

    Highlights of the Chhattisgarh’s Plan

    • Forest contributions like carbon absorption, climate regulation, and biodiversity preservation will now be formally quantified and included in the state’s economic planning.
    • The initiative ensures forests are valued not just for their resources but for their broader ecological services.
      • With 44% of its land under forest cover, Chhattisgarh’s natural resources are vital for the livelihoods of millions and play a significant role in mitigating climate change.
    • The initiative aligns with ‘Developed India 2047’ vision, focusing on long-term ecological and economic sustainability.

    About Green GDP

    • Green GDP is an alternative metric for assessing economic growth that includes the environmental costs of economic activities.
    • It subtracts the value of natural resource depletion and environmental degradation from traditional GDP to provide a more accurate picture of economic well-being.
    • Introduced in the 1993 United Nations Handbook of National Accounting: Integrated Environmental and Economic Accounting under the System of Environmental-Economic Accounting (SEEA) framework.
    • Key Features:
      • Aims to measure the sustainability of economic growth.
      • Focuses on valuing ecosystem services like carbon sequestration, soil conservation, and water resources.
      • Provides insights into the trade-offs between economic growth and environmental conservation.
    • Calculation:
      • Green GDP = Traditional GDP – Costs of Environmental Degradation – Costs of Resource Depletion.
    • Challenges: Incomplete environmental data, reliance on subjective assumptions, difficulty in valuing ecosystem services, and the absence of a universal calculation framework, often oversimplifying nature’s intrinsic worth.

    Government Initiatives for Green GDP Accounting

    • Green National Account Framework: It integrates environmental considerations into national accounting systems. It captures the value of natural resources, costs of pollution, and benefits of ecosystem services like clean air and water.
    • System of Environmental-Economic Accounting, 2012 (SEEA): It was adopted by India under UN guidelines to create databases for natural capital accounting and informed policymaking.
    • RBI Estimates: Green GDP for 2019 was ₹167 trillion, reflecting a 10% adjustment from traditional GDP. It is supported by organizations like TERI and Indian Statistical Institute to refine valuation methodologies.

  • India’s emissions inventory & efforts at mitigation

    Why in the News?

    India recently shared a report about its efforts to fight climate change. The report includes details about how much greenhouse gases (GHG) the country produces and the steps it has taken to reduce these emissions as part of its global climate promises.

    What is the Biennial Update Report (BUR)?

    • The Biennial Update Report (BUR) is a detailed report that developing countries, including India, submit to the United Nations Framework Convention on Climate Change (UNFCCC). This report outlines their efforts toward climate action, as mandated under the Paris Agreement.
    • BURs include an overview of national circumstances related to climate, socio-economic factors, and forestry, along with a comprehensive inventory of national greenhouse gas (GHG) emissions and their sources. They also detail national action plans for emission mitigation and the support received for climate-related initiatives.

    What are the BUR-4’s highlights and submissions on emissions inventory?

    • Total GHG Emissions: In 2020, India’s total GHG emissions were reported at 2,959 million tonnes of CO2 equivalent. After accounting for land use, land-use change, and forestry (LULUCF), net emissions were 2,437 million tonnes, reflecting a 7.93% decrease from 2019 levels.
    • Reduction in Emissions Intensity: The report indicates that from 2005 to 2020, India’s emissions intensity of GDP decreased by 36%. This metric measures GHG emissions per unit of economic output, highlighting improved energy efficiency and a shift towards renewable energy sources.
    • Sectoral Contributions: The energy sector was the largest contributor to emissions, accounting for 75.66%, with electricity production alone responsible for 39% of total emissions. Agriculture contributed 13.72%, while industrial processes and waste management accounted for 8.06% and 2.56%, respectively.

    What does BUR-4 say about the status of India’s climate commitments?

    • The BUR-4 outlines India’s commitment to its Nationally Determined Contributions (NDCs) under the Paris Agreement, aiming for a 45% reduction in GDP emission intensity by 2030 compared to 2005 levels.
    • The report notes that between 2005 and 2021, India created an additional carbon sink of approximately 2.29 billion tonnes of CO2 equivalent through enhanced forest and tree cover, contributing significantly to its climate goals.

    What has the report said about India’s tech needs for climate-conscious growth? (Way forward)

    • Advanced Technologies for Low-Carbon Growth: The report emphasizes the necessity for adopting cutting-edge technologies across various sectors, including solar energy, wind energy, bioenergy, electric vehicles, and carbon capture and storage.
    • Capacity Building: Strengthening institutional frameworks and workforce capabilities is essential for effective implementation of climate policies and programs. This involves training personnel and developing skills necessary to manage and operate advanced technologies.
    • Financial and Technological Support: The BUR-4 identifies a significant gap in technology transfer from developed countries, which hampers India’s ability to implement necessary climate solutions. India calls for increased international cooperation to facilitate technology transfer, eliminate intellectual property barriers, and provide financial assistance to support its climate initiatives.
    • Integration of Technology in Key Sectors: The report highlights the importance of integrating advanced technologies into critical sectors that contribute to emissions, such as agriculture and energy.

    Mains PYQ:

    Q ‘Clean energy is the order of the day.’ Describe briefly India’s changing policy towards climate change in various international fora in the context of geopolitics. (UPSC IAS/2022)

  • Annual Ground Water Quality Report – 2024

    Why in the News?

    The Annual Groundwater Quality Report 2024 was released by the Union Minister of Jal Shakti.  Conducted by the Central Ground Water Board (CGWB), the report provides a scientific baseline for groundwater quality across India.

    Annual Groundwater Quality Report, 2024: Key Highlights

    Monitoring Scale

    • Data collected from 15,200 locations and 4,982 trend stations both before and after the monsoon.

    Contamination Levels

    • Nitrate
      • 20% of samples exceeded the safe limit of 45 mg/L.
      • Hotspots include Rajasthan, Tamil Nadu, Maharashtra (>40% of samples), Telangana (27.48%), Andhra Pradesh (23.5%), and Madhya Pradesh (22.58%).
      • States such as Arunachal Pradesh, Assam, Mizoram, Nagaland remain within safe limits.
    • Fluoride
      • 9.04% of samples above permissible limits.
      • Affected states: Rajasthan, Haryana, Karnataka, Andhra Pradesh, and Telangana.
    • Arsenic
      • Detected in Ganga-Brahmaputra floodplains (West Bengal, Assam, Bihar, Uttar Pradesh).
      • Linked to cancer and skin lesions.
    • Uranium
      • 42% of Rajasthan and 30% of Punjab samples exceed 100 ppb.
      • Over-exploited zones in Gujarat, Haryana, Tamil Nadu, Andhra Pradesh also show elevated levels, posing kidney damage risks.

    Agricultural Suitability

    • SAR (Sodium Adsorption Ratio) & RSC (Residual Sodium Carbonate): 81% of samples suitable for irrigation; 100% suitability in North-Eastern states.
    • High Sodium: Elevated levels in Andhra Pradesh, Gujarat, Haryana, risking soil degradation.
    • Salinity (as a measure of Electrical Conductivity (EC)): High in Rajasthan, Delhi, Gujarat, Haryana, Punjab, Karnataka.

    Temporal Trends

    • Seasonal Improvements: Post-monsoon recharge improves EC (salinity) and fluoride levels.
    • Stable Nitrate since 2015 in Rajasthan, Madhya Pradesh, Gujarat.
    • Rising Nitrate (2017–2023) in Uttar Pradesh, Tamil Nadu, Andhra Pradesh, Haryana.

    Hotspots of Contamination

    • Nitrate:
      • Rajasthan (Barmer, Jodhpur), Maharashtra (Wardha, Jalgaon), Andhra Pradesh (Palnadu), Tamil Nadu (Villupuram), Punjab (Bathinda).
    • Uranium:
      • Over-exploited aquifers in Rajasthan, Punjab, Gujarat.
    • Arsenic:
      • Ganga-Brahmaputra floodplains in West Bengal, Assam, Bihar.

    What are the key factors contributing to decline in Groundwater quality?

    Groundwater quality declines due to:

    • Industrialization, with untreated waste introducing heavy metals and chemicals into aquifers, and agricultural practices, where excessive use of fertilizers and pesticides leads to nitrate contamination.
    • Urbanization worsens the problem through improper waste disposal, sewage leakage, and landfill contamination.
    • Over-extraction for agriculture and domestic use lowers water tables, exposing aquifers to pollutants like arsenic and uranium.
    • Climate change and poor livestock waste management further exacerbate contamination and reduce aquifer recharge.

    Government Initiatives to conserve Groundwater

    • Jal Jeevan Mission – Groundwater Component (2023): Ensures source sustainability for rural water supply by focusing on groundwater recharge and sustainable extraction with local governance participation.
    • Jal Shakti Abhiyan – Catch the Rain (2021): A nationwide campaign promoting rainwater harvesting and groundwater recharge, emphasizing the creation of water conservation structures.
    • National Aquifer Mapping and Management Program (Updated 2020): Maps groundwater aquifers to guide sustainable management, particularly in over-exploited areas.
    • Atal Bhujal Yojana (2019): Focuses on sustainable groundwater management through community participation in seven water-stressed states, with decentralized planning involving Gram Panchayats.

    PYQ:

    [2021] With reference to the water on the planet Earth, consider the following statements:​

    1. The amount of water in the rivers and lakes is more than the amount of groundwater.​

    2. The amount of water in polar ice caps and glaciers is more than the amount of groundwater.​

    Which of the statements given above is/are correct?​

    (a) 1 only ​

    (b) 2 only​

    (c) Both 1 and 2 ​

    (d) Neither 1 nor 2​

  • In news: Similipal Tiger Reserve

    Why in the News?

    Tigress Zeenat, originally from Maharashtra’s Tadoba, was relocated to Odisha’s Similipal Tiger Reserve after straying through Jharkhand into West Bengal, complicating tracking efforts.

    In news: Similipal Tiger Reserve

    About Similipal Tiger Reserve (STR)

    Details
    Geographical Features
    • Situated in the Mayurbhanj District, Northern Odisha, surrounded by high plateaus and hills.
    • Twin peaks Khairiburu and Meghashini, rising to 1515 meters above mean sea level.
    • Undulating and hilly terrain, interspersed with open grasslands and wooded areas.
    • Inhabited by tribes like Kolha, Santhala, Bhumija, Gondas, Khadia, Mankadia, and Sahara.
    • Declared a Tiger Reserve in 1956; brought under Project Tiger in 1973.
    • Included in the World Network of Biosphere Reserves in 2009.
    Flora and Fauna
    • Flora: Home to 1078 species of plants, including 94 species of orchids, with Sal as the dominant tree species.
    • Fauna: Rich wildlife, including Leopards, Gaurs, Elephants, Langurs, Barking Deer, Spotted Deer, Sloth Bears, Mongoose, Flying Squirrels, Porcupines, Pythons, Sambar, Pangolins, and more.
    • It is critical habitat for birds, including migratory species like Bar-Headed Geese and Brahmini Ducks, and home to freshwater snails (Radix genus) in its water bodies.
    • Melanistic Tigers:
      • Similipal hosts 27 of Odisha’s 30 tigers (AOTE-2023-24), including 13 pseudo-melanistic tigers with unique black-striped patterns due to a mutation in the Taqpep gene.
      • It is the only wild habitat in the world with pseudo-melanistic tigers.

     

    PYQ:

    [2011] Two important rivers – one with its source in Jharkhand (and known by a different name in Odisha), and another, with its source in Odisha – merge at a place only a short distance from the coast of Bay of Bengal before flowing into the sea. This is an important site of wildlife and biodiversity and a protected area.

    Which one of the following could be this?

    (a) Bhitarkanika

    (b) Chandipur-on-sea

    (c) Gopalpur-on-sea

    (d) Simlipal

  • Marine Heatwave killed four million Alaska seabirds

    Why in the News?

    The 2014-2016 Pacific marine heatwave (MHW) killed over four million common murres (Uria aalge) (IUCN: Least Concerned) in Alaska. A study published in Science revealed that this event marked the largest recorded vertebrate die-off linked to warming oceans.

    About Marine Heat Waves (MHWs)

    Details
    What is it?
    • As per the National Oceanic and Atmospheric Administration (NOAA), prolonged periods of sea surface temperatures rising 3 to 4°C above average for at least five consecutive days.
    • IMD defines a marine heat wave (MHW) as a period when the sea’s temperature is above the 90th percentile(seasonally varying threshold) for at least 5 consecutive days.
    • Can last from weeks to years, depending on intensity and extent.
    • Frequency: Increasing in both occurrence and intensity due to climate change.
    • Identified as one of the most significant stressors on global marine ecosystems, causing large-scale disruptions.
    Key Observations on MHWs 2014-2016 Pacific MHW:

    • Caused the death of over 4 million common murres (Uria aalge) in Alaska, the largest vertebrate die-off linked to warming oceans.
    • Highlighted rapid and severe population declines in marine birds and a lack of ecosystem recovery even years later.
    • Increasing frequency and intensity are reshaping ecosystems, creating new survival challenges for marine species.
    • Evidence of shifts in marine environments, disrupting population dynamics.
    Impacts of MHWs On Ecosystems: 

    • Mass Mortality: Loss of habitat-forming species like kelps and corals, degrading ecosystems.
    • Trophic Cascades: Displacement of lower-trophic species and reduced ecosystem productivity.

    On Marine Species: 

    • Reduced breeding success and increased mortality.
    • Example: 2014–2016 Pacific MHW killed half the common murre population in Alaska.

    On Biodiversity: 

    • Loss of key predators disrupts food webs.
    • Threatened species face survival challenges due to limited adaptability.

     

    PYQ:

    [2020] With reference to Ocean Mean Temperature (OMT), which of the following statements is/are correct?

    1. OMT is measured up to a depth of 26ºC isotherm which is 129 meters in the south-western Indian Ocean during January-March.
    2. OMT collected during January-March can be used in assessing whether the amount of rainfall in monsoon will be less or more than a certain long term mean.

    Select the correct answer using the code given below:

    (a) 1 only

    (b) 2 only

    (c) Both 1 and 2

    (d) Neither 1 nor 2