Greenhouse Effect and Global Warming – Detailed Analysis

Greenhouse Effect and Global Warming (UPSC Prelims + Mains)

Every day, the Sun sends energy to Earth. This energy keeps our planet warm enough for life. But Earth should not become too hot. So nature has made a balance system. One important part of this balance is the greenhouse effect.

In simple words, the greenhouse effect is like a warm blanket around Earth. This blanket keeps some heat inside so that nights do not become freezing cold. Without this natural blanket, Earth would be too cold for humans, plants, and animals to survive.

The problem starts when this blanket becomes too thick. Human activities are adding extra greenhouse gases into the atmosphere. This makes the greenhouse effect stronger than normal. That is why Earth is warming up slowly over time. This long-term warming is called global warming.

1) Greenhouse Effect: Natural vs Enhanced (Human-Driven)

A) Natural Greenhouse Effect (Good and Necessary)

Earth receives sunlight. Some sunlight is reflected back into space. The rest is absorbed by land, oceans, and clouds. After absorbing energy, Earth releases heat back into the atmosphere. This heat is mainly in the form of infrared radiation (heat radiation).

Some gases in the atmosphere absorb part of this infrared radiation and then re-emit it in all directions. A part of that heat comes back towards Earth. This keeps Earth warmer than it would be without these gases.

This natural greenhouse effect is essential. If Earth had no greenhouse effect, the average temperature would be far below freezing. Life as we know it would be very difficult.

B) Enhanced Greenhouse Effect (Too Much Heat Trapped)

Since the Industrial Revolution, humans have started burning large amounts of coal, oil, and gas. We also cut forests, expand industries, use chemical fertilizers, and create waste. These activities increase greenhouse gases like CO2, CH4, and N2O.

More greenhouse gases means more heat is trapped. This extra heat changes Earth's climate system. That is why we see higher average temperatures, more heatwaves, melting glaciers, sea level rise, and more extreme weather.

2) How the Greenhouse Effect Works (Step-by-Step, Easy Explanation)

Step 1: Incoming Solar Radiation (Shortwave Energy)

The Sun emits energy. This energy reaches Earth mainly as shortwave radiation (visible light and some ultraviolet). This is the main energy input for Earth.

Step 2: Reflection and Absorption

When sunlight reaches Earth:

• Some part is reflected back to space by clouds, snow, ice, and bright surfaces.
• The remaining part is absorbed by land and oceans, warming them.

Step 3: Earth Releases Heat (Infrared / Longwave Radiation)

After warming up, Earth does not keep all energy forever. It releases heat back into the atmosphere as longwave infrared radiation.

Step 4: Greenhouse Gases Trap Heat

Greenhouse gases absorb some of this infrared radiation. After absorbing, they re-emit it in different directions. This means:

• Some heat goes back to space (good).
• Some heat returns to Earth's surface (warming effect).

Step 5: Energy Balance Decides Temperature

Earth's temperature depends on the balance between:

• Energy coming in from the Sun
• Energy going out back to space as heat

When greenhouse gases increase, less heat escapes. So Earth's average temperature rises until a new balance is reached. This is the basic reason behind global warming.

3) Major Greenhouse Gases: Sources, Indian Context, and GWP

Not all gases trap heat equally. Some trap much more heat than CO2. Scientists compare them using a measure called Global Warming Potential (GWP).

Important note: GWP values change slightly in different scientific reports and also depend on the time period used (20-year vs 100-year). For UPSC, focus on the concept and typical ranges.

A) Carbon Dioxide (CO2)

Why it matters: CO2 is not the strongest greenhouse gas per unit, but it is the most important human-driven greenhouse gas because:

• We emit very large amounts of it.
• It stays in the climate system for a long time (parts of it remain for centuries).
• It accumulates, like water filling a bucket.

Main sources:

• Burning coal, oil, and gas (electricity, transport, industries)
• Cement production (chemical process releases CO2)
• Deforestation and land-use change

Indian context: India's growing energy needs are still met largely through coal. Transport, construction, and industries also add CO2. At the same time, India is expanding renewables and energy efficiency to reduce emissions intensity.

B) Methane (CH4)

Why it matters: Methane is much stronger than CO2 over a short period. Even though methane stays in the atmosphere for a shorter time (about a decade), it traps a lot of heat while it lasts.

Main sources:

• Enteric fermentation in livestock (digestive process in cattle)
• Rice paddies (waterlogged fields produce methane)
• Landfills and waste dumps (rotting organic waste without oxygen)
• Leaks from oil and natural gas systems

Indian context and examples:

• India has a large livestock population, so methane from cattle and buffalo is significant.
• Rice is a major crop. Traditional flooded paddy fields produce methane.
• Large urban landfills around big cities (like Delhi, Mumbai, and Bengaluru) emit methane from decomposing waste.

C) Nitrous Oxide (N2O)

Why it matters: N2O is a powerful greenhouse gas and stays in the atmosphere for a long time (more than a century). It also harms the ozone layer.

Main sources:

• Excessive nitrogen fertilizers in agriculture
• Manure and animal waste management
• Some industrial processes

Indian context: To increase crop production, farmers sometimes use more urea and other nitrogen fertilizers than required. This can increase N2O emissions and also causes water pollution (eutrophication).

D) CFCs (Chlorofluorocarbons) and Related Gases

Why it matters: CFCs are extremely powerful greenhouse gases and also destroy the ozone layer. Because of the Montreal Protocol, CFCs have been largely phased out. This is one of the biggest environmental success stories.

But the climate issue continues: Many CFC replacements (like some HFCs) do not harm ozone much, but they can still be strong greenhouse gases. That is why countries agreed to reduce HFCs under the Kigali Amendment.

Indian context: Refrigeration and air-conditioning are growing in India. Proper servicing, recovery, and safe disposal of old refrigerants are important to prevent leaks of high-GWP gases.

E) Water Vapour (Most Abundant, Mostly a Feedback)

Water vapour is the largest contributor to the natural greenhouse effect. But humans usually do not directly control long-term water vapour levels in the atmosphere. Water vapour increases mainly because:

• As temperature rises, evaporation increases.
• Warm air can hold more moisture.

So water vapour acts mainly as a feedback that amplifies warming rather than a primary human-driven cause.

4) Global Warming: Meaning, Evidence, and Trends

What is Global Warming?

Global warming is the long-term increase in Earth's average surface temperature. It is mainly caused by the enhanced greenhouse effect due to human activities.

Evidence of Global Warming (What we observe)

• Rising average temperatures: The last few decades have been warmer than earlier decades.
• More frequent and intense heatwaves: Many regions, including India, experience longer and stronger heat spells.
• Melting glaciers and shrinking snow cover: Mountain glaciers are retreating in many parts of the world, including the Himalayas.
• Rising sea levels: Oceans expand when warmed and also receive water from melting ice, causing sea level rise.
• Warming oceans: Oceans store most of the extra heat, affecting marine life and cyclone patterns.
• Changing rainfall patterns: Some places see heavier downpours, while some face longer dry periods.
• Changes in ecosystems: Timing of flowering, migration, and breeding is changing for many species.

Simple trend idea for UPSC: Global warming does not mean every day becomes hotter. It means the average temperature rises and the climate becomes more unstable. That instability leads to extremes: heatwaves, heavy rain, droughts, and stronger storms.

5) Causes of Global Warming (Main Human Drivers)

A) Burning Fossil Fuels (Coal, Oil, Gas)

This is the biggest cause. Fossil fuels release CO2 when burned for:

• Electricity generation (thermal power plants)
• Transport (cars, trucks, ships, planes)
• Industries (steel, cement, chemicals)
• Household energy (in some regions)

Indian example: India's electricity demand is rising due to growth in industries, services, and urban living. Coal power has been a major supply source. This increases CO2 emissions unless cleaner options expand quickly.

B) Deforestation and Land-Use Change

Forests absorb CO2 through photosynthesis. When forests are cut or burned:

• The stored carbon is released as CO2.
• The future CO2 absorption capacity is reduced.

Indian example: Deforestation linked to urban expansion, infrastructure, mining, and forest fires reduces carbon sink capacity. Protecting forests and improving forest quality matters as much as planting new trees.

C) Agriculture

Agriculture contributes mainly through:

• Methane from livestock and rice paddies
• Nitrous oxide from nitrogen fertilizers

Indian example: Rice-wheat farming systems and high fertilizer use in some states can increase greenhouse gas emissions. Better practices can reduce emissions without reducing yields.

D) Industry and Refrigerants

Industries emit greenhouse gases through:

• Energy use (CO2)
• Cement process emissions (CO2)
• Refrigerants and industrial gases (high GWP)

E) Waste and Landfills

When organic waste rots without oxygen (anaerobic conditions) in landfills, it produces methane.

Indian example: Large landfills near major cities release methane. Better waste segregation, composting, biomethanation, and landfill gas capture can reduce methane emissions.

6) Effects of Global Warming (World + India)

A) Rising Temperatures and Heatwaves

Higher average temperatures make heatwaves more frequent and more dangerous. Heat stress affects:

• Human health (heatstroke, dehydration)
• Worker productivity (construction, farming)
• Electricity demand (more cooling needed)

Indian case study: Ahmedabad Heat Action Plan

Ahmedabad faced deadly heat conditions in the past. The city developed a Heat Action Plan with early warnings, public awareness, and hospital readiness. This shows how planning and awareness can save lives even when heat risk increases.

B) Sea Level Rise and Coastal Risk

Sea level rises mainly due to:

• Thermal expansion (warm water expands)
• Melting glaciers and ice sheets adding water to oceans

Impacts:

• Coastal flooding and storm surge damage
• Saltwater intrusion into groundwater and farms
• Loss of coastal land and erosion

Indian context: India has a long coastline and many people living in coastal districts. Big coastal cities and towns face risk during cyclones and high tides. The Sundarbans region is especially vulnerable because it is low-lying and exposed to cyclones and erosion.

C) Extreme Weather: Heavy Rain, Floods, Droughts

Global warming increases the ability of air to hold moisture. This can lead to heavier rainfall events. At the same time, changing circulation can increase dry spells in some regions.

Indian case study: Kerala floods (2018)

Kerala saw very heavy rainfall and severe floods. Many factors contributed, but such events show India's vulnerability to intense rain and flooding. Better dam management, land-use planning, and early warning systems are crucial.

Indian case study: Chennai water crisis (2019)

Chennai faced a serious water shortage after weak rainfall and poor groundwater conditions. This highlights that climate variability plus poor water management can create a major urban crisis.

D) Stronger Cyclones and Coastal Storm Surges

Warmer oceans provide more energy to cyclones. Not every cyclone becomes stronger because of warming, but warmer seas can increase the chances of intense storms and heavier rainfall.

Indian case study: Cyclone Amphan (2020)

Amphan caused major damage in the Bay of Bengal region, including West Bengal and parts of the Sundarbans. Coastal ecosystems and embankments faced severe stress. Such events show why coastal adaptation and strong disaster management are needed.

E) Himalayan Glaciers, Snow, and Water Security

The Himalayas are sometimes called the "water tower of Asia." Many Indian rivers depend on snow and glacier melt, especially in the dry season. Warming affects:

• Glacier retreat
• Formation of glacial lakes
• Risk of sudden floods from glacial lake outburst floods (GLOFs)

Indian example: The Chamoli disaster (2021) involved a sudden flood event linked to mountain slope instability and ice/rock movement. Such events remind us that fragile Himalayan regions need careful planning, safe infrastructure, and monitoring.

F) Agriculture and Food Security in India

Indian agriculture depends heavily on monsoon timing and temperature. Warming can lead to:

• Heat stress for wheat, especially during grain filling stage
• Changing pest and disease patterns
• Water stress in rainfed regions
• Crop losses due to floods and cyclones

Indian case study: Wheat and heat stress (2022)

India saw unusually high temperatures in some regions during the wheat season. Heat stress can reduce yields. This example shows how temperature extremes can affect food prices, farmer income, and national policy decisions.

G) Biodiversity Loss and Ecosystem Damage

When climate changes fast, many species cannot adapt quickly. Effects include:

• Loss of habitat (especially for mountain and coastal species)
• Coral bleaching due to warm oceans
• Forest fires becoming more frequent in some regions
• Shift in species distribution and migration timing

Indian context: The Himalayas, Western Ghats, and coastal ecosystems like mangroves are biodiversity-rich regions. Climate stress plus human pressure can push ecosystems beyond their limits.

H) Health Impacts

Global warming affects health through:

• Heat-related deaths and illness
• Spread of vector-borne diseases (like dengue) in new areas due to warmer conditions
• Water-borne diseases after floods
• Malnutrition risk if crops fail

7) India-Specific Impacts (Focus Areas for UPSC)

A) Monsoon Changes

The Indian monsoon is influenced by land-ocean temperature difference, winds, and large-scale climate systems. Warming can affect:

• Timing and distribution of rainfall
• More short-duration heavy rainfall events
• Longer dry spells between rainy days

Why it matters: Even if total seasonal rainfall stays similar, uneven distribution can increase floods and droughts in the same season.

B) Himalayan Region and Disaster Risk

The Himalayas are prone to landslides, avalanches, and flash floods. Warming can increase risk by:

• Melting snow and ice
• Weakening slopes (freeze-thaw cycles)
• Expanding glacial lakes

C) Coastal Cities and Infrastructure

Coastal cities like Mumbai, Chennai, Kolkata, Kochi, Visakhapatnam, and Surat face risks from:

• Sea level rise
• Storm surges during cyclones
• Coastal erosion
• Saltwater intrusion

D) Agriculture, Farmers, and Rural Livelihood

Large parts of Indian farming are rainfed. Climate shocks reduce income and can increase rural distress. Climate-resilient agriculture, irrigation efficiency, and crop diversification are key solutions.

E) Urban Heat Island (Extra Warming in Cities)

Cities become hotter than rural areas due to:

• Concrete and asphalt absorbing heat
• Less tree cover
• Waste heat from vehicles and ACs

During heatwaves, this becomes dangerous for poor communities living in crowded housing with limited cooling options.

8) Feedback Mechanisms (Why Warming Can Speed Up or Slow Down)

A) Positive Feedbacks (Make Warming Stronger)

• Water vapour feedback: Warming increases evaporation. More water vapour traps more heat, causing more warming.
• Ice-albedo feedback: When snow and ice melt, darker land or water is exposed. Dark surfaces absorb more sunlight, increasing warming and melting more ice.
• Permafrost methane feedback: In very cold regions, frozen soils store carbon. When they thaw, methane and CO2 can be released, adding more greenhouse gases.
• Forest dieback and fires: Heat and drought can increase forest fires. Burning forests release CO2 and reduce future carbon absorption.

B) Negative Feedbacks (Reduce Warming)

• Planck response: As Earth warms, it naturally emits more infrared radiation to space, which tries to restore balance.
• Some cloud effects: Some clouds can reflect sunlight and cool the surface. But cloud feedback is complex and can vary by type and height.
• CO2 fertilization (limited): Higher CO2 can increase plant growth in some conditions, absorbing more CO2. But this is limited by water, nutrients, and heat stress.

UPSC note: Positive feedbacks are one major reason why climate change is a serious risk. They can make warming faster than expected if tipping points are crossed.

9) Difference Between Greenhouse Effect and Global Warming (Very Important)

• Greenhouse effect is a process that traps heat and keeps Earth warm. It exists naturally and is necessary for life.
• Enhanced greenhouse effect happens when humans increase greenhouse gases, trapping extra heat.
• Global warming is the result of the enhanced greenhouse effect: long-term rise in Earth's average temperature.

Simple one-line difference: Greenhouse effect is the "heat-trapping mechanism"; global warming is the "temperature increase caused by that mechanism becoming stronger."

10) Albedo Effect and Its Role in Climate

Why albedo matters: Albedo decides how much solar energy is reflected back to space. When high-albedo surfaces (snow/ice) reduce due to melting, Earth absorbs more heat. This creates a positive feedback loop.

Indian context examples:

• Himalayan snow cover: Less snow means less reflection and more warming in mountain regions.
• Thar Desert: Sandy surfaces reflect more than dark forests, but land-use changes can still affect local climate.
• Urban surfaces: Dark roads and roofs absorb heat and increase city temperatures. Cool roofs and urban greenery can help.

11) Carbon Cycle and Carbon Sinks (Core Concept for Mitigation)

A) Carbon Cycle (Basic Idea)

Carbon moves naturally between:

• Atmosphere (CO2)
• Plants and animals (biomass carbon)
• Soil (organic carbon)
• Oceans (dissolved carbon)
• Rocks and fossil fuels (stored carbon for millions of years)

Problem today: Humans are taking carbon stored in fossil fuels (coal, oil, gas) and releasing it quickly into the atmosphere. Nature cannot absorb it at the same speed. So CO2 accumulates.

B) Carbon Sinks (Where Carbon is Absorbed and Stored)

Major carbon sinks:

• Forests: Trees absorb CO2 and store carbon in wood and soil.
• Soils: Healthy soils store organic carbon.
• Oceans: Oceans absorb CO2, but this can cause ocean acidification.

Indian examples of sinks:

• Mangroves: Sundarbans, Bhitarkanika, and other mangroves store large carbon (blue carbon) and protect coasts.
• Wetlands: Wetlands store carbon and support biodiversity (but degraded wetlands can emit methane).
• Forests in central and northeastern India: Protecting and improving forest quality increases sink strength.

12) Solutions: Mitigation and Adaptation (UPSC-Focused)

A) Mitigation (Reducing the Cause)

Mitigation means reducing greenhouse gas emissions or increasing carbon sinks.

Key mitigation approaches:

• Clean energy transition: Solar, wind, hydro, and other low-carbon sources reduce dependence on coal and oil.
• Energy efficiency: Efficient appliances, industries, and buildings reduce energy demand. Example: LED programs and efficient motors.
• Cleaner transport: Public transport, EVs, fuel efficiency, rail freight, and better city planning reduce emissions.
• Industrial decarbonization: Cleaner processes in steel and cement, use of green hydrogen, waste heat recovery.
• Methane reduction: Better livestock feed, improved manure management, alternate wetting and drying in rice fields, landfill gas capture.
• Fertilizer efficiency: Soil testing, balanced fertilization, precision agriculture reduce N2O emissions.
• Waste management: Segregation, composting, biomethanation, recycling reduce landfill methane.
• Protect and expand sinks: Afforestation, reforestation, mangrove restoration, and soil carbon improvement.

B) Adaptation (Living with the Impact)

Adaptation means adjusting our systems to reduce harm from climate impacts that are already happening or unavoidable.

Major adaptation strategies in India:

• Heat action plans: Early warning, public advisories, cooling shelters, hospital readiness.
• Climate-resilient agriculture: Drought-resistant seeds, crop diversification, better irrigation, micro-irrigation.
• Water management: Rainwater harvesting, watershed management, groundwater recharge, efficient use.
• Disaster management: Better cyclone shelters, early warning systems, flood forecasting.
• Coastal protection: Mangrove restoration, coastal zoning, resilient housing, raised infrastructure where needed.
• Urban planning: Green spaces, cool roofs, better drainage, and climate-smart infrastructure.

C) Indian Policy Frameworks (Write in Mains Answers)

• National Action Plan on Climate Change (NAPCC): Includes missions like Solar Mission, Energy Efficiency, Sustainable Agriculture, Green India, Sustainable Habitat, Water Mission, Himalayan Ecosystem, and Strategic Knowledge.
• India's climate targets: India has committed to reduce emissions intensity and expand non-fossil electricity capacity, while also creating additional carbon sinks through forests.
• International cooperation: India supports climate justice and the principle of Common But Differentiated Responsibilities (CBDR), while also promoting solutions like the International Solar Alliance.

UPSC Mains tip: Always connect solutions with India's development needs: energy access, poverty reduction, jobs, and climate resilience.

13) PYQs (Previous Year Questions) with Answers

14) 10 MCQs for Prelims Practice (With Explanations)

1. Which statement best describes the greenhouse effect?

   • (A) It is the reflection of sunlight by clouds back to space.
   • (B) It is the trapping of Earth's outgoing infrared radiation by certain gases, keeping Earth warm.
   • (C) It is the cooling of Earth due to evaporation from oceans.
   • (D) It is the removal of CO2 by industries.

   Answer: (B)

   Explanation: Greenhouse gases absorb and re-emit outgoing infrared heat radiation, reducing heat loss to space and warming the surface and lower atmosphere.

2. Which of the following is a correct difference between natural and enhanced greenhouse effect?

   • (A) Natural greenhouse effect cools Earth; enhanced greenhouse effect warms Earth.
   • (B) Natural greenhouse effect is necessary for life; enhanced greenhouse effect traps extra heat due to human-added gases.
   • (C) Natural greenhouse effect is caused only by CO2; enhanced is caused only by methane.
   • (D) Natural greenhouse effect happens only in cities; enhanced happens only in villages.

   Answer: (B)

   Explanation: Natural greenhouse effect keeps Earth habitable. Enhanced greenhouse effect is the human-driven increase in greenhouse gases that leads to extra warming.

3. Global Warming Potential (GWP) is mainly used to:

   • (A) Measure how much oxygen a gas contains
   • (B) Compare the heat-trapping ability of a greenhouse gas relative to CO2
   • (C) Measure how much rainfall a gas can produce
   • (D) Measure sea level rise directly

   Answer: (B)

   Explanation: GWP compares the warming impact of 1 unit of a gas to CO2 over a fixed time period, commonly 100 years.

4. Which greenhouse gas is most strongly linked to rice paddies and flooded fields?

   • (A) CO2
   • (B) CH4
   • (C) N2O
   • (D) O2

   Answer: (B)

   Explanation: Flooded rice fields create low-oxygen conditions where microbes produce methane (CH4).

5. Nitrous oxide (N2O) emissions increase mainly due to:

   • (A) Use of nitrogen fertilizers and manure
   • (B) Use of solar panels
   • (C) Rainwater harvesting
   • (D) Planting mangroves

   Answer: (A)

   Explanation: Excess nitrogen in soils can convert into nitrous oxide through microbial processes, especially when fertilizers are overused.

6. Which of the following is an example of a positive feedback in climate change?

   • (A) More warming leads to more ice, reflecting more sunlight
   • (B) More warming leads to more water vapour, trapping more heat
   • (C) More warming leads to less infrared radiation leaving Earth
   • (D) More warming leads to lower solar radiation from the Sun

   Answer: (B)

   Explanation: Water vapour increases with warming and is itself a greenhouse gas, which amplifies the initial warming.

7. Albedo is best related to:

   • (A) Absorption of infrared radiation by methane
   • (B) Reflection of sunlight by Earth's surfaces like snow and ice
   • (C) Emission of CO2 from factories
   • (D) Evaporation of water from oceans

   Answer: (B)

   Explanation: Albedo measures reflectivity. High-albedo surfaces reflect more sunlight and reduce heating.

8. Which pair is correctly matched?

   • (A) Carbon sink — releases more CO2 than it absorbs
   • (B) Carbon sink — absorbs more CO2 than it releases
   • (C) Carbon sink — only fossil fuels underground
   • (D) Carbon sink — only air pollutants like SO2

   Answer: (B)

   Explanation: Carbon sinks remove CO2 from the atmosphere and store it. Forests, soils, and oceans are major sinks.

9. Which of the following is the most direct link between global warming and sea level rise?

   • (A) Warming increases ocean salinity, raising sea level
   • (B) Warming reduces sunlight reflection, raising sea level
   • (C) Warming causes thermal expansion of seawater and melts land ice, adding water
   • (D) Warming increases winds, which permanently raise sea level everywhere equally

   Answer: (C)

   Explanation: Sea level rises mainly because warm water expands and melting glaciers/ice sheets add water to oceans.

10. Which statement is most accurate?

    • (A) Greenhouse effect and global warming are exactly the same thing.
    • (B) Greenhouse effect is a natural heat-trapping process; global warming is long-term temperature rise mainly due to enhanced greenhouse effect.
    • (C) Global warming happens only due to ozone hole.
    • (D) Greenhouse gases trap sunlight directly and not heat radiation.

    Answer: (B)

    Explanation: Greenhouse effect is the mechanism. Global warming is the result of that mechanism becoming stronger due to human-added greenhouse gases.

15) Quick Revision Points (Prelims-Friendly)

• Natural greenhouse effect is essential; enhanced greenhouse effect is harmful due to extra greenhouse gases.
• Greenhouse effect: trapping of outgoing infrared radiation; global warming: long-term rise in average temperature.
• CO2 is the main long-term driver because of huge emissions and long persistence.
• Methane is stronger than CO2 per unit, especially in short term; major sources: livestock, rice, landfills.
• N2O is very powerful and long-lived; major source: nitrogen fertilizers.
• CFCs are very high-GWP and ozone-depleting; phased out under Montreal Protocol.
• Water vapour is mainly a feedback, not the main direct human forcing.
• Albedo: reflectivity; melting ice reduces albedo and increases warming (positive feedback).
• Carbon sinks: forests, soils, oceans; mangroves and forests are important Indian sinks.
• India impacts: monsoon variability, Himalayan glacier risk, coastal flooding, heatwaves, agriculture stress.

Conclusion

The greenhouse effect is a natural process that makes Earth livable. But human activities have strengthened this process by adding extra greenhouse gases. This enhanced greenhouse effect is driving global warming and disturbing climate patterns.

For India, the challenge is serious because our economy, agriculture, water security, coasts, and health are deeply linked to climate. The solution needs both mitigation and adaptation. Mitigation reduces the cause by cutting emissions and improving sinks. Adaptation reduces damage through planning, resilient infrastructure, early warning systems, and climate-smart farming.

For UPSC, remember the core logic: radiation balance → greenhouse gas trapping → warming → feedbacks → impacts → solutions. If you write answers with clear structure, Indian examples, and practical measures, you can score very well in both Prelims and Mains.