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

PYQ Relevance: [UPSC 2022] Discuss global warming and mention its effects on the global climate. Explain the control measures to bring down the level of greenhouse gases which cause global warming, in the light of the Kyoto Protocol, 1997. Linkage: The article highlight that the world needs to “lower its dependence on fossil fuels” because “greenhouse gas emissions are increasing worldwide,” leading to “rising surface temperatures”. The discussion around Stratospheric Aerosol Injection (SAI) in the sources is presented as a controversial technology proposed to “directly cool the planet rather than bank on reducing emissions alone” as a means of “reducing the impacts of climate change

 

Mentor’s Comment:  The world needs to rely less on fossil fuels, but progress has been slow because of problems like war, poverty, and rising prices. As a result, greenhouse gas emissions are still going up. To deal with this, some scientists suggest using new technologies to cool the Earth directly, instead of only focusing on cutting emissions. One such method is Stratospheric Aerosol Injection (SAI), where tiny particles are sprayed into the upper atmosphere to block sunlight and reduce warming.

Today’s editorial discusses the Stratospheric Aerosol Injection technique, a key topic for GS Paper III (Science, Technology & Environment), highlighting its potential, challenges, and relevance to climate change mitigation efforts.

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Let’s learn!

Why in the News?

A recent study in the journal Earth’s Future shared a new idea that could make SAI cheaper and easier to use, even though many people are still against it.

What was the new idea?  Use of Existing Aircraft: Instead of waiting a decade and spending billions to build special high-altitude planes, the study proposes modifying existing aircraft (like the Boeing 777F) to spray aerosols at lower altitudes. Low-Altitude Injection in Polar Regions: The study suggests carrying out aerosol injections at lower altitudes (around 13 km) in polar and extratropical regions, where the stratosphere is more easily reachable. This approach is more cost-effective, technically simpler, and can be implemented sooner. What is Stratospheric Aerosol Injection (SAI)? SAI is a proposed method of cooling the planet by injecting tiny reflective particles (aerosols) into the stratosphere. It is inspired by volcanic eruptions, which naturally cool the Earth by spewing particles that reflect sunlight. These aerosols reduce the amount of sunlight reaching the Earth’s surface, creating a cooling effect.

Why is the spraying of aerosol needed?

• To Reflect Sunlight and Cool the Planet: Aerosols (like sulphur dioxide) reflect some of the sun’s rays back into space, reducing the heat reaching Earth’s surface. Eg: The 1991 Mount Pinatubo eruption released sulphur dioxide, cooling Earth by about 0.5°C for over a year.
• To Temporarily Reduce Global Warming Effects: SAI can lower atmospheric temperatures temporarily, helping to reduce severe climate effects like heatwaves, ice melt, and sea-level rise. Eg: A study showed spraying 12 million tonnes of sulphur dioxide at 13 km altitude could cool the planet by 0.6°C.
• To Buy Time for Emissions Reductions and Climate Adaptation: While long-term solutions like clean energy are built, SAI could provide a temporary buffer against extreme climate impacts. Eg: It could delay serious effects like crop failure or habitat loss, allowing time for sustainable reforms.

Why is low-altitude SAI seen as cost-effective?

• No Need for Specialized Aircraft: Low-altitude SAI can be conducted using existing aircraft, avoiding the high costs of developing planes that fly above 20 km. Eg: Standard jets like the Boeing 777F can reach stratospheric levels in polar regions, making deployment more affordable.
• Technically Less Challenging: Operating at lower altitudes reduces technical complexity, such as extreme temperature and pressure challenges faced at higher elevations. Eg: Modifying existing jets with pressurized tanks is easier than designing new high-altitude aircraft.
• Faster Implementation Timeline: It enables quicker deployment, avoiding the 10-year delay and multi-billion dollar investment needed for high-altitude SAI systems. Eg: Using current infrastructure, SAI programs could begin much earlier to address urgent climate risks.

Where is low-altitude injection feasible and why? Feasible in Polar and Extratropical Regions: In these regions, the stratosphere starts at lower altitudes, making it accessible to standard aircraft. Eg: Over the Arctic or Antarctic, the tropopause (boundary between troposphere and stratosphere) is around 8–13 km, suitable for existing jets. Infeasible Near the Equator: At equatorial regions, the stratosphere begins at 18 km or higher, which is beyond the reach of most commercial or military jets. Eg: Areas like Indonesia or the Amazon basin would require specially built aircraft for SAI. Altitude Determines Aerosol Effectiveness: While higher altitude injections last longer in the atmosphere, lower altitude in polar zones allows SAI to be conducted with less cost and effort. Eg: Studies show that even at 13 km altitude in polar spring and summer, SAI can cool the planet by ~0.6°C with 12 million tonnes of sulphur dioxide.

How does the use of existing aircraft like the Boeing 777F influence the implementation of SAI technology?

• Reduces Deployment Costs: Using existing aircraft avoids the high capital expenditure needed to design and build specialized high-altitude jets. Eg: The Boeing 777F, a widely available cargo aircraft, can be adapted for SAI at lower stratospheric levels, cutting costs significantly.
• Speeds Up Implementation: Existing jets can be modified and deployed faster, enabling earlier testing and potential use of SAI to address urgent climate risks. Eg: Building high-altitude aircraft may take nearly a decade, but using modified commercial planes could allow operations to start much sooner.
• Requires Feasible Technical Modifications: Though not originally built for aerosol spraying, planes like the Boeing 777F can be retrofitted with specialized equipment. Eg: An August 2024 study proposed adding insulated double-walled pressurized tanks to safely carry and release sulphur dioxide.

What are the Risks and Controversies of SAI?

• Environmental and Health Side Effects: SAI could lead to acid rain, delayed ozone recovery, and unknown ecological disruptions due to aerosol particles in the atmosphere. Eg: Sulphur dioxide, commonly proposed for SAI, can form sulphuric acid in the atmosphere, harming ecosystems and human health.
• Uneven Global Effects: SAI’s cooling impact may not be uniform worldwide, potentially benefiting some regions while worsening droughts, rainfall patterns, or crop yields in others. Eg: Cooling could be stronger in polar regions, while tropical areas, which face the worst climate impacts, may not benefit equally.
• Governance and Ethical Concerns: SAI affects the entire planet, raising questions about who decides when, where, and how it’s used. It may lead to geopolitical tensions and misuse. Eg: A single country unilaterally injecting aerosols could trigger international disputes, especially if neighbouring regions suffer unintended consequences.

Way forward: 

• Establish a Global Governance Framework: International collaboration is essential to regulate research, testing, and potential deployment of SAI, ensuring transparency, accountability, and consent from all affected nations.
• Focus on Complementary Climate Strategies: SAI should be treated as a temporary, supplementary tool, not a replacement for emission reduction. Massive investments must continue in renewables, carbon capture, and adaptation strategies. 

PYQ Relevance: [UPSC 2013] Constitutional mechanisms to resolve the inter-state water disputes have failed to address and solve the problems. Is the failure due to structural or process inadequacy or both? Discuss. Linkage: India’s water management problems are explicitly stated to be a result of a “fragmented and sectoral approach”. This contrasts sharply with the need for a holistic “new course.” The existing situation is problematic because “rivers and other waterbodies are often interstate and multiple political jurisdictions are involved in administering the same waterbody”.

 

Mentor’s Comment:  In 2025, global water governance takes a historic turn as the United Nations declares it the International Year of Glaciers’ Preservation and launches the Decade of Action on Cryospheric Science (2025–2034). These initiatives, aligned with World Water Day 2025 and World Day for Glaciers (March 21), focus directly on the vital connections between mountain glaciers, freshwater, and ocean ecosystems. They promote the “Source-to-Sea (S2S)” approach, which integrates water governance from glacial sources all the way to ocean outlets, acknowledging their ecological and hydrological continuity.

Today’s editorial will talk about water governance in India and the world. It will help with GS Paper I (Geography), GS Paper II (Policy Making) and GS Paper III (Environment).

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Let’s learn!

Why in the News?

Scientists and decision-makers need to pay attention to the Source to Sea (S2S) approach.

What is the theme of World Water Day 2025? Theme: Glacier Preservation 2025 is also declared the International Year of Glaciers Preservation by the United Nations. Marks the start of a Decade of Action on Cryospheric Science (2025-2034).

Why is it significant?

• Crucial Source of Freshwater: Glaciers act as natural water reservoirs, supplying freshwater to millions downstream. Their preservation ensures sustained water availability for drinking, agriculture, and ecosystems. Eg: The Himalayan glaciers feed rivers like the Ganga and Brahmaputra, supporting millions of people in India.
• Indicator of Climate Change: Glaciers are sensitive to global warming; their rapid melting signals climate change impacts. Protecting them helps monitor and mitigate broader environmental risks. Eg: Melting Himalayan glaciers contribute to changing river flows, affecting flood and drought patterns in South Asia.
• Supports Sustainable Development: Preserving glaciers helps maintain mountain ecosystems and supports downstream communities dependent on glacier-fed waters for their livelihoods and economic activities. Eg: Alpine glaciers support mountain agriculture and tourism, critical to local economies in regions like Uttarakhand and Himachal Pradesh.

Why is the Source-to-Sea (S2S) approach important for global water governance?

• Integrated Management of Water Systems: S2S treats freshwater and marine systems as a connected continuum, ensuring that actions upstream (rivers, lakes) consider their impact downstream (coastal and marine environments). Eg: Pollution control in river basins like the Ganges directly affects the health of the Bay of Bengal ecosystem.
• Improves Coordination Across Jurisdictions: S2S promotes cooperation among multiple stakeholders and political jurisdictions, bridging fragmented governance to manage shared water resources effectively. Eg: The Manila Declaration encourages countries to work together on ridge-to-reef management to protect water quality from land to ocean.
• Facilitates Sustainable Solutions for Water and Marine Challenges: By addressing the entire water cycle, S2S enables holistic strategies that tackle issues like pollution, water diversion, and habitat loss, benefiting both terrestrial and marine biodiversity. Eg: Initiatives under the SIWI Action Platform connect freshwater and marine experts to develop better water management practices globally.

What is the cryosphere?  The cryosphere includes all frozen water parts of Earth, such as glaciers, snow, sea ice, and permafrost. It helps regulate the climate, reflects sunlight, and stores Earth’s freshwater.

How does the changing mountain cryosphere impact downstream water resources?

• Altered Water Flow Patterns: Melting glaciers and shrinking snowpacks change the timing and volume of water flow downstream, leading to seasonal water shortages or floods. Eg: Reduced glacial melt in the Himalayas affects the flow of rivers like the Ganges, impacting water availability for millions.
• Reduced Water Storage Capacity: Glaciers act as natural reservoirs, storing water during cold months and releasing it slowly. Their retreat means less buffering capacity during dry periods, causing water stress downstream. Eg: Declining glacier size in the Alps affects water supplies for European river basins in summer.
• Increased Risk of Natural Hazards: Glacier melt can lead to the formation and sudden breach of glacial lakes, causing flash floods and damaging downstream ecosystems and communities. Eg: Glacial Lake Outburst Floods (GLOFs) in the Himalayas pose risks to villages and infrastructure along rivers like the Indus.

What are the key challenges India faces in managing its water resources? 

• Groundwater Depletion: Over-extraction of groundwater for irrigation, industrial use, and domestic consumption has led to alarming depletion rates of aquifers. This poses a significant threat to long-term water availability and agricultural productivity. Eg, states like Punjab, Haryana, and Rajasthan report over 100% utilization of groundwater resources, leading to critical water scarcity.
• Water Pollution: Water pollution from industrial effluents, untreated sewage, and agricultural runoff has made large quantities of freshwater unusable. According to the Central Pollution Control Board, more than 70% of India’s surface water is polluted, with rivers like the Ganga and Yamuna being majorly affected.
• Climate Change and Erratic Weather Patterns: Changing rainfall patterns, prolonged droughts, and frequent floods induced by climate change are altering water availability. The Indian Meteorological Department has noted a decline in monsoon rainfall, which is critical for replenishing rivers, lakes, and groundwater reserves.

What are the steps taken by the Indian Government? Formulation and Revision of National Water Policies: The government introduced the first National Water Policy in 1987, and since then, it has been periodically updated to address emerging challenges. The latest draft policies emphasize integrated water resource management and sustainability. Eg, the 2019 draft National Water Policy focuses on water conservation, efficient use, and equitable distribution. Institutional Reforms and Coordination Bodies: Committees have been set up to improve water governance by restructuring key institutions. Eg, in 2015, a committee was formed to merge the Central Water Commission and Central Ground Water Board into a unified National Water Commission to foster better coordination and planning. Promotion of Sustainable and Integrated Approaches: The government supports approaches like Source-to-Sea (S2S) management, which integrates land, freshwater, coastal, and marine resource management. Eg, pilot projects in the Indo-Gangetic basin and Delhi waterbodies are being explored under the S2S framework to address pollution and water quality comprehensively.

Way forward: 

• Adopt Source-to-Sea (S2S) Approach Nationwide: Implement integrated water governance that connects glacial sources to coastal ecosystems, ensuring coordinated action across sectors and regions.
• Strengthen Climate-Resilient Water Infrastructure: Invest in glacier monitoring, early warning systems, and sustainable groundwater management to adapt to climate-induced water variability and safeguard water security.

PYQ Relevance: [UPSC 2024] Explain the role of millets for ensuring health and nutritional security in India. Linkage: In this article, discuss how millets, classified as Neglected and Underutilized Species (NUS) and now as “opportunity crops,” are nutritionally dense and climate-resilient. This question directly aligns with the core components of ‘biohappiness’ that emphasize “nutrition security” and bringing “forgotten foods back to the table”.

 

Mentor’s Comment:  India’s traditional food habits, especially in tribal and rural areas like Arunachal Pradesh, are at risk because many local plants and crops are disappearing. This loss is not just about rare plants but also about losing foods that are nutritious, climate-resilient, and hold cultural importance, along with the traditional knowledge that supports them.

Today’s editorial will talk about the quick loss of biodiversity and traditional food knowledge in India. It will help with GS Paper II (Policy Making) and GS Paper III (Agriculture & Environment).

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Let’s learn!

Why in the News?

The fast loss of biodiversity and food knowledge, caused by cash crops, global diets, and weak policies, urges India to use new science and revive orphan crops (Neglected and Underutilized Species) like millets for better food and environment.

What are Neglected and Underutilized Species (NUS)? NUS are traditional crops like millets, legumes, tubers, and wild fruits that have been largely ignored or underused in modern agriculture and food systems. These species are nutritionally rich, climate-resilient, and well-adapted to local environments, offering potential to improve food security and support sustainable farming.

Why are they now referred to as “opportunity crops”?

• Nutritionally Dense: These crops are rich in essential nutrients, vitamins, and minerals, making them excellent for improving health. Eg: Small millets are high in fiber and micronutrients compared to rice and wheat.
• Climate-Resilient: They can withstand harsh environmental conditions like drought and poor soils, helping farmers adapt to climate change. Eg: Finger millet (ragi) grows well in dry and marginal lands.
• Locally Adapted: These crops are naturally suited to local soils and climates, reducing the need for chemical fertilizers and irrigation. Eg: Buckwheat thrives in the hilly regions of Northeast India without intensive inputs.
• Support Biodiversity: Cultivating these crops preserves agrobiodiversity and traditional farming knowledge, maintaining ecological balance. Eg: Indigenous legumes help fix nitrogen in soil, improving fertility naturally.
• Economic Potential: Reviving these crops can create new market opportunities, increase farmers’ incomes, and diversify food production. Eg: Millet-based products are gaining popularity in urban markets for their health benefits.

Why is agrobiodiversity declining in Northeast India?

• Rapid Disappearance of Traditional Plants: Many native plant species are disappearing quickly due to changing land use and environmental pressures. Eg: Traditional greens and wild fruits once common in Arunachal Pradesh are becoming rare.
• Loss of Traditional Knowledge: Indigenous knowledge about the nutritional and medicinal properties of local plants is being lost as younger generations move away from traditional lifestyles. Eg: Nyishi and Apatani tribes’ understanding of forest plants is fading.
• Shift to Commercial Crops: Farmers are moving from diverse local crops to cash crops for better income, reducing crop variety. Eg: In Kolli Hills, many farmers switched from millets to coffee and pepper.
• Environmental Changes and Species Extinction: Habitat loss and climate change are causing a rise in species extinction, mirroring a global trend. Eg: Forest degradation in Northeast India is threatening native biodiversity.
• Lack of Awareness and Support: There is limited awareness and institutional support for conserving local agrobiodiversity, leading to neglect. Eg: Many minor millets remain neglected in government schemes despite their benefits.

Where has millet revival been successfully implemented? Kolli Hills, Tamil Nadu: The M.S. Swaminathan Research Foundation (MSSRF) has worked with local farmers for over 20 years to prevent millet diversity loss. Efforts include documenting traditional knowledge, improving soil health, diversifying crops, and enhancing income, especially among women farmers. Eg: Farmers shifted back from cash crops to locally adapted millets. Koraput District, Odisha: Collaboration with the Odisha Millet Mission has supported a community-led millet revival, focusing on seed conservation to consumption, expanding the range of millets beyond the commonly promoted ragi, jowar, and bajra. Eg: Minor millets are being reintroduced into local diets and markets.

How does a few crops’ dominance affect global nutrition?

• Over-Reliance on Few Crops: Global food systems mainly depend on rice, wheat, and maize, which provide over 50% of plant-based calories. This limits dietary diversity. Eg: Many populations rely heavily on rice, leading to monotonous diets.
• Loss of Biodiversity: Dominance of a few crops causes a decline in agricultural biodiversity, reducing availability of diverse nutrients. Eg: Traditional millets and legumes are neglected, despite being nutrient-rich.
• Nutritional Imbalances: Diets based on a limited number of staple crops can cause deficiencies in vitamins, minerals, and proteins. Eg: Populations depending mainly on wheat may face iron and zinc deficiencies.
• Vulnerability to Climate Shocks: Dependence on few crops makes food systems more susceptible to climate change impacts, threatening food security. Eg: Droughts affecting maize crops can lead to widespread shortages.
• Rise in Non-Communicable Diseases: Limited crop diversity correlates with an increase in diseases like diabetes and obesity, due to poor diet quality. Eg: High consumption of refined wheat and maize products contributes to obesity trends.

What are the steps taken by the Indian government?  International Year of Millets & Shree Anna Yojana: Launched focused strategies to enhance millet production, productivity, consumption, and export, while raising awareness about health benefits. State Millet Missions: Several states have started their own Millet Missions to support local cultivation, value chain strengthening, and branding of millets. Inclusion in Public Distribution System (PDS): Efforts are underway to include minor millets in the PDS to promote wider access and consumption among the population.

Way forward: 

• Expand Millet Coverage and Integration: Broaden the focus beyond major millets (ragi, jowar, bajra) to include minor millets and other neglected crops in state missions and the Public Distribution System (PDS) for greater reach and impact.
• Strengthen Farmer Empowerment and Research: Support community-led conservation, improve value addition technologies, and invest in interdisciplinary researchto enhance crop resilience, nutritional value, and market opportunities.