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GS Paper: GS1-15.Geographical features and their location- Changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.

  • UN Sea Level Declaration

    Why in the News

    A country’s legal existence no longer depends on its coastline: under the Declaration on Sea Level Rise, low lying states threatened by rising seas keep their statehood and maritime zones even if their coasts retreat inland. The United Nations General Assembly (UNGA) adopted the Declaration by consensus.

    What does the Declaration protect?

    1. What it is: The Declaration is a political statement by all UN members on responding to rising seas, like a guarantee that a country’s legal existence outlasts its shoreline.
    2. Statehood preserved: Low lying countries such as Fiji, Tuvalu and Vanuatu keep their statehood, sovereign rights and UN membership.
    3. Maritime zones fixed: Sea zones under the UN Convention on the Law of the Sea (UNCLOS) are measured from the coast. The Declaration keeps them defined even as coasts retreat, so a shrinking shoreline does not shrink a country’s sea.
    4. Citizens’ rights: If the sea swallows a country’s territory, its citizens still keep their nationality and economic rights.
    5. The takeaway: A state can now lose its land without losing its legal existence, its seas or its people’s citizenship.

    How does the Declaration organise action?

    1. Origin: A 2024 high-level meeting gave members a mandate to negotiate an action oriented agreement. This Declaration is the result.
    2. Four areas of action: The four page text groups action under four heads:
      • science and data;
      • adaptation and financing;
      • livelihoods, socio-economic development, data sharing and early warnings;
      • the legal consequences of sea-level rise.
    3. People centred response: It asks countries to respond in ways that protect livelihoods and cultural heritage, involving affected communities.
    4. Continued engagement: Members commit to keep engaging on the issue, including a high-level meeting before the 84th session of the General Assembly ends.

    Why do island states need these assurances?

    1. Existential threat: Rising seas threaten to swallow most or all of the habitable territory of low lying island states in the coming decades.
    2. Collective voice: These states negotiate together as the Alliance of Small Island States (AOSIS) in forums including the Conference of the Parties (COP), the annual UN climate summit.
    3. Pace of rise: Global mean sea level is currently rising by about 4 to 5 mm a year.

    Challenges

    1. Not binding: A General Assembly declaration is a political commitment, not a treaty, so it creates no enforceable obligation.
    2. Legal survival is not physical survival: Retained statehood does not stop the flooding and salt intrusion that make atolls uninhabitable.
    3. Adaptation finance gap: Small islands cannot fund sea walls, raised land or relocation from their own budgets.
    4. Narrow migration routes: Pathways for displaced islanders remain small and bilateral. Eg. The Australia-Tuvalu Falepili Union treaty (2023).

    Way Forward

    1. Codify in law: The International Law Commission should carry its work on sea-level rise into a binding instrument on statehood and maritime zones.
    2. Deposit baselines now: Island states should deposit their baseline coordinates with the UN Secretary-General, so their zones stay fixed as coasts move.
    3. Grant based adaptation finance: Channel grants to small island states through the Fund for Responding to Loss and Damage.
    4. Early warning coverage: Extend the UN Early Warnings for All initiative to every low lying coast.
    5. India’s island partnerships: India should use the Infrastructure for Resilient Island States initiative to back these measures.

    Conclusion

    The Declaration settles what happens in law to a drowning state, but leaves the physical and financial question unanswered. The next test is whether the follow up meeting converts political assurance into binding law and money for adaptation.

    Back2Basics: UN Convention on the Law of the Sea (UNCLOS)

    1. What it is: The treaty adopted in 1982, in force since 1994, that sets the rules for using the world’s oceans and their resources.
    2. Maritime zones: A coastal state’s territorial sea runs up to 12 nautical miles and its Exclusive Economic Zone (EEZ) up to 200 nautical miles.
    3. Institutions: It created the International Tribunal for the Law of the Sea and the International Seabed Authority.
    4. India: India ratified UNCLOS in 1995.

    Matching Previous Year Question

    “[2020] Which one of the following statements best describes the term ‘Social Cost of Carbon’? It is a measure, in monetary value, of the (a) long-term damage done by a tonne of CO2, emissions in a given year. (b) requirement of fossil fuels for a country to provide goods and services to its citizens, (c) efforts put in by a climate refugee to adapt to live in a new place. (d) contribution of an individual person to the carbon footprint on the planet Earth. Answer: (a)”

  • How melting glaciers could ‘put 20% of GDP at risk’

    Why in the News

    A new assessment of the Himalayas has put a monetary value on India’s dependence on the mountain range, estimating that Rs 64.8 lakh crore, or 21.5% of India’s FY24 GDP, rests on Himalayan water and Himalayan economies. The report, ‘A resilient Himalaya: protecting a region at risk and securing future prosperity’, follows the Nepal floods that placed the warming Himalayas under public attention. It converts glacier retreat from an environmental concern into a measurable macroeconomic exposure. The tension it exposes is one of timing. Meltwater flows are rising now and are expected to peak around the middle of this century before declining, while the one driver India can act on quickly, black carbon, is being tackled unevenly across States.

    What is the ‘A resilient Himalaya’ report?

    1. Compiling body: The report was compiled by the consultancy Systemiq, in partnership with the Integrated Mountain Initiative.
    2. Supporting institutions: It was supported by the International Centre for Integrated Mountain Development (ICIMOD), Nepal, and the GB Pant National Institute of Himalayan Environment, Uttarakhand.
    3. Core estimate: It places Rs 64.8 lakh crore, equal to 21.5% of India’s FY24 GDP, as dependent on the Himalayas.

    How was the 20% of GDP figure arrived at?

    1. Direct layer: The Gross State Domestic Product of the Himalayan States is counted in full as Himalaya dependent output.
    2. Indirect layer: Downstream agriculture, manufacturing, hydropower and services reliant on Himalayan fed rivers and on groundwater recharge are added. Rain fed production is expressly excluded from this layer.
    3. Induced layer: Supply chain and wage spending effects are counted, such as tractors sold from southern States into the Indo Gangetic Plains, and wages spent on food and services.

    Why does glacier retreat translate into economic risk?

    1. Three river systems: The Himalayas feed the Indus, Ganga and Brahmaputra systems, which support agriculture, cities and industry downstream.
    2. Named dependent economies: The report ties these flows to wheat and rice across the Indo Gangetic plain, tea in Assam and Bengal, hydropower in the Northeast, and pilgrimage economies in downstream towns.
    3. Disaster concentration: The Himalayas account for 18% of India’s land but roughly 35% of its disasters, making them a standing disaster hotspot rather than an occasional one.
    4. The reconstruction trap: Disasters create food and water insecurity, disrupt supply chains, displace people and raise macroeconomic and sovereign debt pressure. Reconstruction spending then leaves less money available for building future resilience.

    Why do meltwater flows rise before they fall?

    1. Glaciers as storage: Glaciers hold water as ice and release meltwater into rivers, particularly during the dry season when rainfall contributes least.
    2. Peak Water: Himalayan river basins are expected to reach ‘Peak Water’ around the middle of this century, the point at which glacier meltwater reaches its maximum.
    3. The decline after the peak: Flows begin to fall after that point as the ice reserve shrinks, so today’s higher flows are not a durable supply.

    Why is black carbon the driver India can act on fastest?

    1. What black carbon is: Black carbon is soot produced by incomplete combustion, and unlike global warming as a whole it is a pollutant India can act on quickly on its own.
    2. The snow darkening effect: When black carbon lands on snow it darkens the surface, so the snow absorbs more sunlight instead of reflecting it. Modelling shows this adds about 40 watts per square metre of surface heating in the spring season across the Himalaya.
    3. Zigzag kiln technology: Converting brick kilns to zigzag firing, a method that burns fuel more efficiently, cuts black carbon and particulate emissions by roughly 70% and fuel use by 20% to 30%.
    4. Uneven adoption: Punjab and Haryana have completed the switch to zigzag kilns. Uttar Pradesh, India’s largest brick producer, is at only 56%, and the rest of India runs on traditional technology.
    5. Kilns are not the whole story: Real progress requires kilns, cookstoves, transport and crop residue burning to be tackled together rather than one source at a time.

    Challenges to securing the Himalayan economy

    1. Transboundary river dependence: The three river systems the estimate rests on originate outside India in whole or in part, so flow security is not a purely domestic policy variable. Eg. The Indus system is governed by a treaty arrangement with Pakistan, and the Brahmaputra rises in Tibet where upstream storage decisions are not disclosed to India.
      The Fix: Build hydrological data sharing into existing basin level dialogues so flow changes are detected upstream rather than inferred from downstream damage.
    2. Gaps in glacier monitoring: India monitors only a small fraction of its glaciers on the ground, so mass balance estimates rest heavily on modelling. Eg. Glacier and lake monitoring shortfalls were flagged after the February 2021 Chamoli disaster in Uttarakhand.
      The Fix: Expand automated weather station and mass balance networks across benchmark glaciers in each Himalayan basin.
    3. Glacial lake outburst risk: Warming creates and expands moraine dammed lakes whose failure sends a flood wave downstream with little warning time. Eg. The October 2023 South Lhonak lake outburst in Sikkim destroyed the Teesta III hydropower project at Chungthang.
      The Fix: Attach early warning instrumentation and drawdown works to every high risk lake identified in the national expansion inventory.
    4. Construction in a fragile zone: Hydropower, highway and tunnel projects add load and cut slopes in terrain that is already seismically active and steep. Eg. Land subsidence in Joshimath, Uttarakhand, in January 2023 forced the evacuation of hundreds of households.
      The Fix: Make cumulative basin level impact assessment, rather than project by project clearance, the condition for approving new infrastructure in the Himalayan States.
    5. Fiscal asymmetry between hill and plain States: Himalayan States carry the cost of protecting catchments while the economic benefit accrues largely downstream. Eg. Forest cover in the Himalayan States supports irrigation and power generation in the plains without a matching transfer for that service.
      The Fix: Widen ecological and forest cover weightage in Finance Commission devolution so catchment protection is financed rather than assumed.

    Conclusion

    The estimate changes the category of the problem rather than the facts of it. A mountain range treated as an environmental subject now carries a fifth of national output as a stated exposure, which places it inside fiscal and investment planning rather than only inside climate policy. Two things cannot both hold: flows rising toward a mid century peak are being planned against as though they were permanent, while the ice reserve that produces them is shrinking. The near term marker is whether brick kiln conversion moves beyond the two States that have completed it.

    Back2Basics: International Centre for Integrated Mountain Development (ICIMOD)

    1. Nature: An intergovernmental knowledge and learning centre for the Hindu Kush Himalaya region.
    2. Establishment and headquarters: Founded in 1983, with its headquarters at Kathmandu, Nepal.
    3. Membership: Its eight regional member countries are Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan.
    4. Mandate: It supports mountain research, cryosphere monitoring and transboundary cooperation across the Hindu Kush Himalaya.

    Matching Previous Year Question

    “[2020, GS1, 10] How will the melting of Himalayan glaciers have a far-reaching impact on the water resources of India? (हिमालय के हिमनदों के पिघलने का भारत के जल-संसाधनों पर किस प्रकार दूरगामी प्रभाव होगा ?)”

  • Glacial collapse unlikely to halt China’s mega dam plan

    Why in the News

    China is going ahead with construction of a mega dam on the lower reaches of the Yarlung Zangbo, the Brahmaputra, in a seismically active part of Tibet near the border with India. Fresh concerns raised by the glacial collapse along the Nepal-China border have not changed that plan. A month before those flash floods and mudslides, China released its 15th Five-Year Plan for renewable energy, which called for advancing construction of major projects including the Yarlung Zangbo Lower Reaches Hydropower Project. India’s concern is how much water the project will store and how its diversion tunnel will alter downstream flows. Almost nothing about either has been made public, and the one channel through which India receives hydrological data from China has worked irregularly.

    What is the Yarlung Zangbo Lower Reaches Hydropower Project?

    1. What it is: It is a hydropower complex of five power stations on the lower reaches of the Yarlung Zangbo in Tibet, referred to in China as the mega dam project.
    2. How the water is used: Water is taken out of the river at the top of the Great Bend, where the river’s course falls steeply and turns towards India, and carried through a tunnel of about 40 km before rejoining the river below.
    3. The scale committed: A total investment of 1.2 trillion Yuan, around ₹14 lakh crore, was announced for the construction of the five power stations at the groundbreaking in July 2025.
    4. Who builds and runs it: A new State-run entity, the China Yajiang Group, was set up to run the entire project.

    Why has the glacial collapse not changed Beijing’s calculation?

    1. The project sits in a standing plan: The renewable energy Five-Year Plan named the project for advancement before the collapse occurred, so the collapse arrived against a target already fixed.
    2. Political weight is attached to it: China’s Vice Premier visited Nyingchi in Tibet in April and described it as a landmark mega project of the new era. The Premier had called it the project of the century at the groundbreaking.
    3. The safety response is procedural, not a pause: The stated answer to risk is strict enforcement of construction standards and of ecological and environmental protection requirements, with construction progress kept subordinate to quality and safety.
    4. Information has been withheld since the start: There has been little public information about the project since the groundbreaking, and the Vice Premier’s visit is what disclosed the new operating company.

    What exactly is India concerned about?

    1. Storage volume is unknown: How much water will be held in the reservoir is not published, and storage determines how far the timing of downstream flows can be controlled.
    2. The tunnel’s effect on flow is unknown: Diverting the river at the top of the bend and returning it below means the natural channel around the bend carries only what the tunnel does not.
    3. Wider ecological impact is unassessed: No assessment of downstream ecological effects has been released.
    4. The absence of information is itself the obstacle: The lack of published detail prevents India from assessing the impact at all, rather than merely disagreeing with China’s assessment of it.

    Why is the run-of-the-river description contested?

    1. The label implies no storage: A run-of-the-river scheme passes flow through without holding it back, so it carries limited power to change the timing of water reaching a downstream State.
    2. A reservoir is part of the design: The project involves the construction of a reservoir, which a Shanghai-based energy analyst places at the town of Mainling, upstream of Nyingchi, on the basis of reported relocations.
    3. The generating configuration is built around drop: The descending force of the diverted water powers five 12-GW powerhouses, which concentrates head rather than passing the river through unchanged.

    What does China’s earlier dam on the same river show?

    1. The precedent: China has already opened one major dam on the middle reaches of the Yarlung Zangbo at Zangmu, on which construction began in 2010, and a final acceptance meeting was held in June.
    2. The output claimed: Zangmu has generated 22.2 billion kilowatt-hours, described as equivalent to saving approximately 7.4 million tonnes of standard coal and cutting carbon dioxide emissions by around 22.2 million tonnes.
    3. The regional case made for it: State media said the dam had provided a solution to nearly 26 per cent of electricity demand in the Xizang Autonomous Region, and detailed an elaborate fishway designed to move fish between upstream and downstream sections. The project’s design engineer said the fishway would likely be used for future projects.
    4. The new project is of a different order: Chinese analysts project 60 GW of installed capacity and 300 billion kilowatt-hours a year, over three times the Three Gorges, against which Zangmu is small.

    How well does the India-China channel on rivers work?

    1. The forum exists and is about to meet: India and China will hold a meeting of the Expert-Level Mechanism on Trans-border Rivers later this month.
    2. Transmission has been intermittent: The sharing of hydrological data has not been regular and has on occasion been suspended during difficult periods in relations.
    3. China’s stated position denies downstream harm: China’s Foreign Ministry has said it maintains a highly responsible attitude toward transboundary river development, that construction is beneficial for disaster prevention and mitigation throughout the entire river basin, and that it will not have adverse effects on downstream areas.
    4. Cooperation is described in reporting terms: The Ministry cites hydrological reporting, flood control and disaster reduction cooperation with downstream countries, rather than any joint assessment or consent mechanism.

    Challenges to the Yarlung Zangbo Lower Reaches Hydropower Project

    1. Seismic exposure at the Eastern Himalayan syntaxis: The Great Bend sits where the Indian and Eurasian plates converge most sharply, which is among the most earthquake-prone locations in Asia. Eg. The 1950 Assam-Tibet earthquake, of magnitude 8.6, struck this same zone and triggered landslides that blocked and then burst Himalayan river channels.
      The Fix: Publish the seismic design basis and the dam-break inundation modelling for the reach below the project, so downstream authorities can plan against a stated failure scenario.
    2. Sediment trapping changes the floodplain downstream: The Brahmaputra carries one of the world’s heaviest sediment loads, and any storage structure holds back part of it. Eg. Majuli, the river island in Assam, has lost a large part of its area to bank erosion as the balance between deposition and scouring has shifted.
      The Fix: Fix a sediment flushing schedule and share the release calendar with the downstream riparian in advance of each flushing operation.
    3. There is no treaty, only renewable memoranda: India and China share no water-sharing treaty, and data supply rests on memoranda of understanding that expire and must be renewed. Eg. Flood-season hydrological data for the Brahmaputra was not supplied in 2017, the year of the Doklam standoff.
      The Fix: Convert the memoranda into a standing basin instrument with automatic data transmission that does not lapse with the state of political relations.
    4. India’s own detection capacity is thin at the entry point: An anomalous release is useful information only if it is detected before it reaches populated reaches. Eg. Sudden rises and sudden discolouration in the Siang in Arunachal Pradesh have been attributed to upstream activity without independent measurement to confirm the cause.
      The Fix: Build a telemetered gauging network on the Siang and the Lohit reporting in near real time to the Central Water Commission.
    5. The gorge is an ecological zone of its own: The Great Bend gorge holds an unusual altitudinal range of habitat compressed into a short distance, and diversion removes water from that reach. Eg. The Yarlung Tsangpo canyon is among the deepest in the world and carries forest types from subtropical to alpine within a few kilometres.
      The Fix: Require publication of an environmental flow regime for the bypassed reach, stating the minimum discharge to be maintained through the year.

    Conclusion

    The dispute is not yet about water, it is about disclosure. India cannot contest a projection it has not been given. A downstream State that learns a reservoir’s capacity only after commissioning has lost the one point at which design can still be influenced. The meeting of the Expert-Level Mechanism this month is the marker to watch, and the test of it is narrow: whether operating rules are put on the table, or whether the meeting produces another reaffirmation of responsible conduct.

    Back2Basics: Expert-Level Mechanism on Trans-border Rivers

    1. It is the standing India-China official channel on shared rivers, established in 2006 following an agreement between the two governments.
    2. Its declared business is the provision of hydrological information by China during the flood season, and cooperation on emergency management of trans-border rivers.
    3. It covers the Brahmaputra and the Sutlej, the two rivers on which separate memoranda of understanding govern data supply.
    4. It is a consultative forum with no adjudicatory power, and it does not allocate water between the two countries.

    Matching Previous Year Question

    “Identify the river of the Indian sub-continent on the basis of the following information: 1. Antecedent drainage system. 2. Flows through three countries. 3. Originates in the Tibetan Plateau; important for irrigation. 4. Does not form distributaries. Select the answer from the following: (a) Brahmaputra (b) Indus (c) Sutlej (d) Teesta”

  • Sailing on uncertainty

    Why in the News

    Panama has declared a state of emergency over falling water levels in the Panama Canal. The trigger is an El Nino driven drought across the region, which has cut the fresh water the waterway needs to move ships. Canal authorities are rationing passage in response, cutting the number of vessels allowed through each day. A waterway is therefore limiting traffic for reasons of rainfall rather than of shipping demand.

    Why does a rainfall deficit stop ships in the Panama Canal?

    1. Every transit spends fresh water: The canal moves ships between two ocean levels through a series of locks, and each lockage releases stored fresh water that is not recovered.
    2. Rainfall over the watershed is the only refill: The reservoir system that feeds the locks is replenished by rain falling on the canal catchment, so a rainfall shortfall translates directly into fewer lockages the system can support.

    What does rationing transits mean for global shipping?

    1. The canal carries a fixed share of world trade: The shipping route handles 5% of global maritime trade, so a capacity cut is felt across ocean freight rather than in one region alone.
    2. Slots are being withdrawn in two steps: Daily transits fall from 36 to 34 from September 3, and to 32 later in the month.
    3. Vessels wait for the reduced slots: Container ships are queuing outside the canal for passage, adding waiting time to voyages that were scheduled against the old transit count.

    Conclusion

    Drought has turned the Panama Canal from a fixed piece of trade infrastructure into a variable one. Panama’s state of emergency is in force and the second stage of the transit cut takes effect later in September. The next marker is the canal authority’s own restoration notice, which will show whether the catchment has refilled.

    Back2Basics: Panama Canal

    1. What it is: An artificial waterway across the Isthmus of Panama linking the Atlantic Ocean, through the Caribbean Sea, to the Pacific Ocean.
    2. Opened and transferred: It opened in 1914 under United States control, and full control passed to Panama at the end of 1999.
    3. Capacity classes: An expanded set of larger locks opened in 2016, creating the Neopanamax class of vessel alongside the older Panamax limit.

    Matching Previous Year Question

    “[2011] Between India and East Asia, the navigation time and distance can be greatly reduced by which of the following? 1. Deepeing the Malacca straits between Malaysia and Indonesia. 2. Opening a new canal across the Kraisthmus between the Gulf of Siam and Andaman Sea. (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2 ANSWER: (b)”

  • Ladakh’s glaciers are slowing as the mountains warm

    Why in the News?

    A new study in the journal The Cryosphere reports that glaciers in the Zanskar region of Ladakh are moving more slowly than they did 30 years ago, as sustained warming thins them and reduces their driving force. The slowdown carries long term implications for the Indus basin, where glacier melt sustains river flows during dry summer months.

    Why are the Zanskar glaciers slowing down?

    1. Thinning mechanism: When a glacier loses more ice than it gains over many years it becomes thinner, and thinner ice exerts less driving force, causing it to flow more slowly.
    2. Warming link: The study connects mass loss, thinning and reduced flow, showing that thinning is not only a consequence of warming but also weakens the glacier’s ability to move.
    3. Downstream effect: Slower flow means the lower parts of a glacier receive less replenishment from higher elevations, making continued shrinkage more likely.
    4. Local variation: Glacier geometry, debris cover and conditions at the snout influence how quickly each glacier responds.

    What is peak water?

    1. Definition: Peak water is the point at which increased melting from a shrinking glacier temporarily raises river runoff before the water supply begins to decline.
    2. Why it matters: More melting may boost flows in the near term, but once glaciers lose a substantial fraction of their stored ice, their meltwater contribution to rivers is expected to drop.

    What did the study find?

    1. Study design: The researchers examined how glacier flow changed from 1992 to 2023 across 12 glaciers in the Zanskar Himalaya using satellite derived surface velocities.
    2. Velocity decline: Glaciers slowed by 2.4 metres per year per decade on average.
    3. Faster thinning: The pace of surface thinning increased from around 0.22 metres per year between 2000 and 2005 to around 0.57 metres per year between 2015 and 2020.
    4. Sample caveat: The 12 glaciers studied are representative, but the Zanskar basin hosts around 1,755 glaciers, so caution is needed before extending the findings to all of Ladakh.

    What are the implications for the Indus basin?

    1. Summer flows: Glacier melt contributes significantly to Indus river flows during the dry summer months, so long term storage decline threatens that supply.
    2. Multiple dependencies: River flows also depend on snowfall, rainfall, groundwater and water management, so slowing glaciers alone will not immediately cause shortages.
    3. Sectors at risk: Continued thinning and slowdown signal declining long term water storage, with implications for water security, agriculture, hydropower and downstream ecosystems in coming decades.

    Why do the study’s own limitations qualify its conclusions?

    1. Sub surface blind spot: Satellite surface velocity observations cannot directly reveal processes beneath the glacier, such as subglacial hydrology or basal sliding, which strongly influence motion.
    2. Data gaps: Long term field measurements of ice thickness, mass balance and bed conditions remain limited in the region, making full attribution of observed changes difficult.
    3. Exceptions to the trend: Some glaciers can temporarily accelerate due to increased meltwater at the bed, glacier surges, or interactions with proglacial lakes.

    What does the global comparison show?

    1. European Alps and Alaska: Similar glacier slowdowns have been reported, driven by the same thinning and reduced driving stress mechanism.
    2. Canadian Arctic and Andes: These regions show comparable slowdowns linked to warming.
    3. Tibetan plateau: Parts of the plateau display the same dominant mechanism of thinning leading to slower flow.
    4. Shared lesson: Glacier slowdown is becoming widespread globally, though local glacier characteristics still shape individual behaviour.

    Conclusion

    The study establishes that Zanskar glaciers are not only losing mass but slowing down, with thinning reducing their capacity to move and replenish lower reaches. This points to a long term decline in stored water that will eventually reduce Indus basin flows after a phase of peak water. The findings underscore the need for sustained ground based monitoring to validate satellite data and to prepare downstream communities for shifting water availability.

    Back2Basics:

    Foundational Context: The Cryosphere and Himalayan Glaciers

    1. About: The cryosphere comprises the frozen parts of the Earth, including glaciers, snow cover, permafrost and ice, that store and release freshwater.
    2. Third Pole: The Hindu Kush Himalaya holds the largest ice mass outside the polar regions and is often called the Third Pole.
    3. Function: Himalayan glaciers act as natural reservoirs, releasing meltwater in warmer months to sustain rivers, agriculture and ecosystems in otherwise arid areas.
    4. Climate indicator: High altitude glaciers respond distinctly to warming, making them valuable natural indicators of environmental change.

    The Zanskar Region and Indus Basin

    1. Location: The Zanskar region lies in Ladakh and hosts some of the largest and most extensive glaciers in the Himalaya.
    2. Climatic setting: Its glaciers receive most of their snowfall from mid latitude westerly disturbances during winter and sit at high altitude.
    3. Indus basin: The Indus rises in the Tibetan plateau and flows through Ladakh, with glacier melt feeding its dry season flows.
    4. Significance: The basin supports water security, agriculture and hydropower across northern India and beyond.

    Key Facts about Himalayan Glacier Monitoring

    1. Study journal: The findings appear in the journal The Cryosphere.
    2. Zanskar glacier count: The basin hosts around 1,755 glaciers, of which 12 were studied.
    3. Observation record: The study covers more than 30 years, from 1992 to 2023.
    4. Peak water: A key concept describing the temporary runoff increase before long term decline.

    Challenges in Glacier Conservation and Monitoring

    1. Data scarcity: Long term field measurements of ice thickness and mass balance are limited in high altitude terrain.
    2. Warming pace: Rising temperatures accelerate thinning and mass loss.
    3. Black carbon: Soot deposition on ice lowers reflectivity and speeds melting.
    4. Glacial lake hazards: Meltwater expansion raises the risk of glacial lake outburst floods.
    5. Downstream dependence: Millions rely on glacier fed rivers, amplifying the impact of any decline.

    Way Forward

    1. Expand ground monitoring: Add measurements of ice thickness, mass balance and meltwater discharge to validate satellite data.
    2. High altitude weather stations: Install continuous observation stations to capture varied mountain climate conditions.
    3. Basin water planning: Prepare Indus basin water management for the eventual decline after peak water.
    4. Reduce black carbon: Cut regional emissions that hasten glacier melt.
    5. Regional cooperation: Share transboundary glacier and river data across the basin.

    PYQ Relevance

    [UPSC 2020] How will the melting of Himalayan glaciers have a far-reaching impact on the water resources of India?

    Linkage: The PYQ directly relates to the impact of Himalayan glacier melt on India’s water resources. Zanskar glacier slowdown and thinning highlight the emerging risks to Indus basin flows, water security and long-term freshwater availability.

  • Gujarat deluge erases monsoon deficit, but overall rain still low

    Why in News?

    Heavy rainfall in Gujarat erased India’s July rainfall deficit, but the overall southwest monsoon (June-September) remains below normal.

    Key Highlights

    • Cumulative rainfall since 1 June is 16.1% below normal.
    • East & Northeast India: 31.9% rainfall deficit.
    • South Peninsula: 26.8% deficit.
    • Heavy rainfall in Gujarat resulted from a low-pressure system interacting with a Western Disturbance.
    • Over 40,500 people were evacuated and 6,367 rescued due to flooding.
    • Ahmedabad recorded 294.6 mm rainfall in 24 hours, its highest since 2000.
    • Weak El Niño conditions have contributed to uneven monsoon distribution, affecting agriculture.

    El Niño

    • Warm phase of the El Niño-Southern Oscillation (ENSO).
    • Characterised by warming of the central and eastern equatorial Pacific Ocean.
    • Generally leads to weaker southwest monsoon and below-normal rainfall in India.

    IMD Classification of Rainfall

    • Normal: 96% to 104% of Long Period Average (LPA).
    • Below Normal: 90% to 96% of LPA.
    • Deficient: Less than 90% of LPA.

    Southwest Monsoon

    • Contributes nearly 75% of India’s annual rainfall.
    • Normally spans June to September.
    • Two branches:
      • Arabian Sea Branch
      • Bay of Bengal Branch

    PYQ (2014, GS1, 10 Marks) Most of the unusual climatic happenings are explained as an outcome of the El Niño effect. Do you agree?
    [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

  • In dry monsoon, a test of resilience

    Why in the News?

    India’s 2025 monsoon season is forecast to be the weakest in a decade, with 77% of the country’s land area already recording more than 20% rainfall deficit as of June 24. The season has exposed a structural tension: India’s agricultural and energy systems remain deeply dependent on monsoon rainfall. At the same time, the government’s own investments in renewables, rainwater harvesting, and rural employment infrastructure suggest the country may now be better placed to absorb the stress than in any previous deficit year.

    What Has Made the 2025 Deficit Structurally Different from Past Deficits?

    1. Scale of the deficit: As of June 24, 537 of 740 districts recorded over 20% rainfall deficit. Only eight of 36 States/UTs showed no deficiency. IMD forecast low to moderate rainfall across nearly half of India’s landmass.
    2. El Niño is not the primary cause: El Niño emerged in early June, too late to explain the June deficit because its impact on the Indian monsoon occurs with a lag. The dominant driver is the Madden Julian Oscillation (MJO).
    3. MJO as the proximate driver: A moving system of winds and clouds that alternately enhances or suppresses rainfall. In June, its rain-suppressing phase remained over India, with a shift expected in early July.
    4. June is ordinarily a high-rainfall month: IMD had forecast at least 92% of the Long Period Average (LPA) rainfall for June. The actual deficit of over 40% marks a significant departure from expectations.
    5. The La Niña lag: La Niña’s favourable impact on the Indian monsoon also occurs with a lag and was unlikely to influence June rainfall. This raises the possibility of a drier-than-expected monsoon season.

    What Is the Nature of India’s Dependence on the Monsoon and What Has Reduced It?

    1. The baseline dependence: The southwest monsoon provides nearly 75% of India’s annual rainfall. It supports irrigation, groundwater recharge, reservoirs, hydropower, agriculture, food security, rural incomes and economic growth.
    2. Infrastructure investments over a decade: India has expanded irrigation, rainwater harvesting, water storage and conservation. Official reports also show improving groundwater levels.
    3. Renewable energy as the decisive structural shift: Solar and wind power have reduced dependence on hydropower, which relies on reservoir storage. This helps preserve water for irrigation and drinking purposes.
    4. The residual dependence: Better resilience reduces stress but does not eliminate the need for planning and policy intervention.
    5. Rural employment as a demand buffer: MGNREGS has created water conservation and storage assets while providing income support to rural households during rainfall deficits, helping stabilise rural demand.

    What Existing Strengths Make Absorption of the 2025 Deficit Possible?

    1. Major reservoirs at good storage levels: Good rainfall over the last two years has kept reservoir storage comfortable, reducing immediate pressure on irrigation, drinking water and hydropower.
    2. Improvement in groundwater situation: Better groundwater levels provide an additional irrigation source where reservoir supplies become constrained.
    3. Renewable energy reducing reservoir pressure: Expansion of solar and wind power lowers dependence on hydropower, allowing reservoirs to conserve water despite weak monsoon inflows.
    4. Pre-monsoon rainfall altering farmer behaviour: Early forecasts encouraged many farmers to sow kharif crops using pre-monsoon showers, reducing exposure to the subsequent rainfall deficit.
    5. The limits of absorption: Resilience has improved but remains incomplete, requiring continued policy intervention.

    Where Does Resilience End and Vulnerability Begin? 

    1. The central tension: India has strengthened resilience, but climate change is making monsoon deficits more frequent, prolonged and unpredictable, testing existing adaptation measures.
    2. Quantitative unpredictability now exceeds planning assumptions: Climate change is making even good monsoon years less predictable, weakening the idea of a stable “normal monsoon.” The 2025 deficit could represent a recurring pattern rather than an exception.
    3. Hydropower remains a structural vulnerability: Solar and wind reduce dependence on hydropower but cannot replace it entirely. Reservoir shortages during weak monsoons can still affect electricity generation and grid stability.
    4. Agricultural productivity remains rainfall-sensitive: Investments in water conservation reduce drought impacts but cannot fully break agriculture’s dependence on monsoon performance, leaving food security vulnerable during prolonged deficits.
    5. Rural demand suppression risk persists: Poor monsoons lower farm incomes and rural demand. MGNREGS mitigates this impact but cannot fully offset a season-long rainfall deficit.

    What Must India Do That It Has Not Yet Done?

    1. The policy direction is defined: Developing greater climate resilience remains the only long-term solution, as monsoon behaviour cannot be controlled
    2. Quantitative rainfall forecasting must improve: More accurate district-level and sub-seasonal forecasts are essential for planning crop calendars, reservoir operations and water storage.
    3. The transition from input-side to output-side resilience: Investments in storage, groundwater recharge and renewables must translate into stable farm output, rural incomes and food prices during rainfall shocks.
    4. Climate adaptation must be recalibrated to current trajectories, not historical averages: Adaptation must continuously evolve because climate conditions are changing faster than the historical benchmarks used for planning.

    Conclusion

    India’s improved groundwater levels, major reservoir storage, and renewable energy capacity mean that a decade-worst monsoon need not produce a decade-worst crisis. However, the reduction in monsoon dependence is partial. Hydropower reliance persists, agricultural productivity remains rainfall-sensitive, and climate change is making deficits more frequent, longer, and harder to predict. Resilience built for last decade’s weather is already being outpaced by this decade’s climate.

    PYQ Relevance

    [UPSC 2023] Why is the South-West monsoon called ‘Purvaiya’ (easterly) in Bhojpur Region? How has this directional seasonal wind system influenced the cultural ethos of the region?

    Linkage: The PYQ tests understanding of the South-West Monsoon and its significance. The article moves beyond monsoon mechanics to examine how changing monsoon behaviour is reshaping India’s climate resilience.

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