Climate Change & Global Environmental Issues

Greenhouse Effect वह natural process है जिसमें greenhouse gases Earth's atmosphere में heat को trap करते हैं — Earth को warm and habitable बनाते हैं।

How it Works:

• Incoming solar radiation: Sun's energy reaches Earth
• Earth absorbs and re-emits: Earth's surface warms and emits infrared radiation (heat)
• GHG trap heat: Greenhouse gases absorb and re-emit infrared radiation, trapping heat in the atmosphere
• Natural vs Enhanced: Natural greenhouse effect is essential for life; enhanced effect (due to human activities) causes global warming

Greenhouse Gases वे gases हैं जो infrared radiation को absorb और re-emit करती हैं — causing the greenhouse effect.

Major GHGs:

• CO₂ (Carbon Dioxide) — कार्बन डाइऑक्साइड: Most abundant GHG; from fossil fuel burning, deforestation
• CH₄ (Methane) — मीथेन: 25x more potent than CO₂; from agriculture, livestock, landfills
• N₂O (Nitrous Oxide) — नाइट्रस ऑक्साइड: 298x more potent than CO₂; from agriculture (fertilisers), industrial processes
• CFCs (Chlorofluorocarbons) — CFC: Ozone-depleting and potent GHGs; from refrigerants, aerosols
• Water Vapour (H₂O) — जल वाष्प: Most abundant GHG; natural
• Ozone (O₃) — ओजोन: Tropospheric ozone is a GHG

GWP (Global Warming Potential):

• CO₂ = 1 (baseline)
• CH₄ = 25
• N₂O = 298
• CFCs = Thousands

Global Warming Earth's average temperature में long-term increase है — primarily due to enhanced greenhouse effect caused by human activities.

Causes:

• Burning of fossil fuels (CO₂ emissions)
• Deforestation (reduces CO₂ absorption)
• Agriculture and livestock (CH₄, N₂O)
• Industrial processes (GHG emissions)
• Waste decomposition (CH₄)

Effects:

• Rising global temperatures
• Melting ice caps and glaciers
• Sea level rise
• Extreme weather events
• Ocean acidification

Climate Change weather patterns में long-term shift है — temperature, precipitation, wind patterns में changes — primarily due to global warming.

Difference: Global Warming vs Climate Change

• Global Warming: Increase in average global temperature
• Climate Change: Broader concept — includes temperature changes + precipitation, wind, storms, etc.

Key Observations:

• Rising global average temperature
• Changing precipitation patterns
• Increasing frequency of extreme weather
• Melting ice and rising sea levels

• Environmental Impacts:
  • Melting glaciers and ice sheets
  • Rising sea levels
  • Ocean acidification
  • Loss of biodiversity
  • Changes in ecosystems and habitats
• Social/Economic Impacts:
  • Agriculture and food security
  • Water scarcity
  • Health impacts (heat stress, disease spread)
  • Climate refugees
  • Economic losses (damage to infrastructure, reduced productivity)
• Extreme Weather Events:
  • More frequent and intense heatwaves
  • Heavy rainfall and floods
  • Droughts and wildfires
  • Stronger cyclones and storms

• Mitigation — शमन: Greenhouse gas emissions को reduce या prevent करना — addressing the cause of climate change.
  • Renewable energy (solar, wind)
  • Energy efficiency
  • Reforestation and afforestation
  • Carbon capture and storage
  • Reducing deforestation
  • Transition to low-carbon economy
• Adaptation — अनुकूलन: Climate change के effects को manage करना — adjusting to the consequences.
  • Building flood defences
  • Drought-resistant crops
  • Early warning systems
  • Climate-resilient infrastructure
  • Water conservation

Climate Justice का अर्थ है कि climate change के impacts और responsibilities को fairly distributed किया जाए — especially for vulnerable and marginalised communities.

Key Points:

• Climate change affects poor and vulnerable communities the most
• Developed countries have contributed most emissions
• Developing countries have limited resources to adapt
• Climate justice demands equity in mitigation and adaptation
• Includes intergenerational and intragenerational equity

Common But Differentiated Responsibilities and Respective Capabilities (CBDR-RC) — climate action में all countries have common responsibility, but differentiated based on their historical emissions and capabilities.

Key Points:

• All countries must act on climate change
• Developed countries have greater responsibility (historically emitted more)
• Developing countries have less capacity and need support
• Developed countries should provide climate finance and technology transfer
• Included in UNFCCC and Paris Agreement

Ozone Depletion stratospheric ozone layer का thinning है — primarily caused by CFCs (Chlorofluorocarbons) and other ozone-depleting substances (ODS).

Key Points:

• Ozone layer: Protects Earth from harmful UV-B radiation
• CFCs: Used in refrigerants, aerosols, solvents
• Other ODS: Halons, methyl bromide, carbon tetrachloride
• Ozone hole: Thinning over Antarctica (discovered 1985)

Effects:

• Increased UV radiation reaches Earth
• Skin cancer and cataracts in humans
• Damage to plants and marine ecosystems

Montreal Protocol (1987):

• International treaty to phase out ODS
• Most successful environmental treaty
• Ozone layer is recovering

Ocean Acidification ocean water का pH decrease है — due to absorption of atmospheric CO₂.

How it Works:

• Atmospheric CO₂ dissolves in ocean water
• Forms carbonic acid (H₂CO₃)
• Releases H⁺ ions → pH decreases (more acidic)
• Impacts marine organisms

Effects:

• Shell-forming organisms (corals, shellfish, plankton) — their calcium carbonate shells dissolve
• Coral bleaching and reef degradation
• Disruption of marine food webs
• Reduced fish populations

Biodiversity Earth पर life की variety है — genes, species, ecosystems. Biodiversity Loss इस variety का decline है.

Causes:

• Habitat destruction — आवास विनाश: Deforestation, urbanisation, agriculture
• Climate Change — जलवायु परिवर्तन: Alters habitats and ranges
• Pollution — प्रदूषण: Air, water, soil pollution
• Overexploitation — अत्यधिक दोहन: Overfishing, hunting, poaching
• Invasive Species — आक्रामक प्रजातियाँ: Non-native species disrupting ecosystems

Impacts:

• Loss of ecosystem services
• Food and water insecurity
• Medicinal resource loss
• Ecosystem instability

• UNFCCC (1992) — संयुक्त राष्ट्र जलवायु परिवर्तन फ्रेमवर्क कन्वेंशन: Framework for climate change action; Rio Summit 1992; CBDR principle
• Kyoto Protocol (1997) — क्योटो प्रोटोकॉल: Legally binding emission reduction targets for developed countries (Annex I countries)
• Paris Agreement (2015) — पेरिस समझौता: Global climate agreement — all countries; goal to limit warming to 1.5°C-2°C; NDCs (Nationally Determined Contributions)
• Montreal Protocol (1987) — मॉन्ट्रियल प्रोटोकॉल: Phase out ozone-depleting substances (CFCs)
• CBD (1992) — Convention on Biological Diversity: Conservation of biodiversity, sustainable use, equitable sharing of benefits

• Trap 1: Global warming = climate change → ❌ Global warming is one aspect of climate change.
• Trap 2: Ozone depletion = global warming → ❌ Ozone depletion is caused by CFCs; global warming is caused by GHGs.
• Trap 3: CO₂ is the most potent GHG → ❌ CO₂ is most abundant but less potent than CH₄, N₂O, CFCs.
• Trap 4: Ocean acidification = ocean pollution → ❌ Ocean acidification is caused by CO₂ absorption, not pollution.
• Trap 5: CBDR = all countries equal responsibility → ❌ CBDR means differentiated responsibility based on historical emissions.
• Trap 6: Montreal Protocol = climate change → ❌ Montreal Protocol is for ozone depletion (CFCs).
• Trap 7: Paris Agreement = legally binding targets → ❌ Paris Agreement uses NDCs (voluntary, not legally binding targets).

Which of the following is NOT a greenhouse gas?

• A. CO₂
• B. CH₄
• C. O₂
• D. N₂O

Explanation: O₂ (oxygen) is not a greenhouse gas. CO₂, CH₄, and N₂O are GHGs.

The Montreal Protocol is associated with:

• A. Climate change
• B. Ozone depletion
• C. Biodiversity
• D. Desertification

Explanation: The Montreal Protocol (1987) was designed to phase out ozone-depleting substances (CFCs).

CBDR-RC is a principle associated with:

• A. Ozone depletion
• B. Climate change
• C. Biodiversity
• D. Desertification

Explanation: CBDR-RC (Common But Differentiated Responsibilities and Respective Capabilities) is a key principle of climate change governance (UNFCCC, Paris Agreement).

Which gas has the highest Global Warming Potential (GWP)?

• A. CO₂
• B. CH₄
• C. N₂O
• D. CFCs

Explanation: CFCs have the highest GWP (thousands of times more potent than CO₂). N₂O is 298x, CH₄ is 25x, CO₂ is 1x.

Ocean acidification is caused by:

• A. Excess nutrients
• B. CO₂ absorption
• C. Oil spills
• D. Plastic waste

Explanation: Ocean acidification is caused by the absorption of atmospheric CO₂, which forms carbonic acid and lowers pH.

The Paris Agreement was adopted in:

• A. 1992
• B. 1997
• C. 2005
• D. 2015

Explanation: The Paris Agreement was adopted in 2015 (entered into force in 2016).

GHGs (GWP):

• CO₂ = 1, CH₄ = 25, N₂O = 298, CFCs = thousands

Mitigation vs Adaptation:

• Mitigation = Reduce emissions (cause)
• Adaptation = Manage impacts (effect)

Ozone Depletion:

• Cause: CFCs | Treaty: Montreal Protocol (1987)

Climate Agreements:

• UNFCCC (1992): Framework
• Kyoto Protocol (1997): Binding targets for developed
• Paris Agreement (2015): All countries, NDCs, 1.5°C-2°C

CBDR-RC:

• Common But Differentiated Responsibilities and Respective Capabilities

Biodiversity Loss:

• Causes: Habitat loss, climate change, pollution, overexploitation, invasive species

Exam Formula:

UGC NET में Climate Change & Global Environmental Issues के questions GHGs, agreements, ozone depletion, ocean acidification, और CBDR-RC पर based होते हैं।