Climate Change Science & IPCC Reports | Science & Technology for UPSC CSE PDF Download

Introduction

Climate change refers to long-term shifts in weather patterns due to human activities, primarily the emission of GHGs like carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). These changes cause global warming, sea-level rise, extreme weather, and ecosystem disruption. The IPCC, established in 1988 by the UNEP and WMO, assesses climate science, impacts, and solutions, releasing reports every 5–7 years. Its Sixth Assessment Report (AR6, 2021–2023) underscores the urgency of limiting warming to 1.5°C. India, with its 7,516 km coastline, monsoon-dependent agriculture, and 1.4 billion population, faces high risks from climate impacts. Recent developments, including the 2025-26 Union Budget’s ₹1.97 lakh crore for renewables and India’s role in COP30 preparations, reflect IPCC-driven policy action. This topic is vital for understanding global climate governance and India’s climate strategy.

Climate Change Science

• Greenhouse Effect: GHGs trap heat in the atmosphere, raising global temperatures. CO2 (76% of emissions) from fossil fuels is the primary driver.

• Global Warming: Earth’s average temperature has risen ~1.1°C since pre-industrial times (1850–1900), with 2024 as the warmest year on record (1.3°C above baseline).

• Sources: Fossil fuel combustion (energy, industry), deforestation, agriculture (methane from livestock), and waste management.

• Impacts:

  • Extreme Weather: Increased frequency of heatwaves, cyclones (10% of global cyclones hit India), and floods.

  • Sea-Level Rise: Global rise of ~3.7 mm/year; threatens India’s coastal cities like Mumbai and Chennai.

  • Ecosystem Disruption: Coral bleaching, biodiversity loss (30% species at risk by 2050), and agricultural yield declines (e.g., 10–15% drop in Indian rice yields by 2050).

  • Human Impacts: Health risks (heatstroke, vector-borne diseases), displacement (150 million climate migrants globally by 2050), and economic losses (~5% of India’s GDP by 2050 if unchecked).

Scientific Tools

• Climate Models: General Circulation Models (GCMs) predict future scenarios based on emission pathways (RCPs/SSPs).

• Remote Sensing: Satellites (e.g., ISRO’s RESOURCESAT) monitor CO2, deforestation, and glacier retreat (Himalayas losing 0.5 m/year).

• Carbon Budget: Remaining budget to limit warming to 1.5°C is ~300 GtCO2 (2025), equivalent to 7 years at current emissions.

IPCC Reports

• Mandate: IPCC assesses peer-reviewed climate science, impacts, adaptation, and mitigation for policymakers. It does not conduct original research but synthesizes global data.

• Structure: Three Working Groups (WG):

  • WG I: Physical science basis (climate system, warming trends).

  • WG II: Impacts, adaptation, vulnerability.

  • WG III: Mitigation strategies.

  • Synthesis Report: Integrates findings, guides UNFCCC negotiations (e.g., COP).

• Assessment Cycles: Six completed (AR1–AR6, 1990–2023); AR7 underway (2024–2029).

Key Findings of AR6 (2021–2023)

• WG I (2021): Human influence has warmed the planet by 1.1°C; limiting to 1.5°C requires halving emissions by 2030. Extreme events are intensifying (e.g., 10% more intense rainfall per 1°C warming).

• WG II (2022): 3.3–3.6 billion people live in vulnerable areas (India’s coastal, Himalayan regions). Adaptation gaps widen; irreversible losses (e.g., glaciers) imminent without action.

• WG III (2022): Global emissions must peak by 2025; renewables (solar, wind) and carbon capture critical. Net-zero by 2050 feasible but requires $4 trillion annually.

• Synthesis Report (2023): 1.5°C limit still achievable but requires immediate, transformative action. Equity emphasized: developed nations must finance Global South adaptation.

Recent Developments (2024-2025)

• AR7 Progress: Launched 2024, focusing on climate justice, loss and damage, and technology (e.g., AI for climate modeling). India contributes via 20+ scientists.

• COP30 Preparations: India’s inputs for 2025 Rio Summit emphasize IPCC’s call for $100 billion annual climate finance from developed nations.

• IPCC Special Reports: 2024 report on climate and biodiversity synergies influences India’s NAPCC updates.

India’s Role and Climate Policies

• Vulnerability: India ranks 7th on the Global Climate Risk Index (2024). Impacts include:

  • Monsoon shifts: 20% more erratic rainfall, affecting 70% of agriculture.

  • Himalayan glacier retreat: 30% loss by 2050, threatening 2 billion people’s water supply.

  • Coastal flooding: 40 million at risk by 2050 along 7,516 km coastline.

• Emissions: 2.9 GtCO2e (7% of global total, 2024); per capita ~2.1 tCO2e (vs. global 4.7 tCO2e). Coal (50% of energy mix) and agriculture (14% methane) are key sources.

Policy Framework (NAPCC, 2008)

• National Solar Mission: 97.86 GW installed (2025); targets 280 GW by 2030.

• National Mission for Enhanced Energy Efficiency: Reduced energy intensity by 25% (2005–2025).

• National Mission on Sustainable Habitat: Promotes green buildings, urban resilience.

• National Mission for a Green India: Afforestation of 6 million hectares by 2030.

• Other Missions: Water, agriculture, Himalayan ecosystems, strategic knowledge.

Key Initiatives

• Renewable Energy: 150 GW installed (2025); 500 GW target by 2030 (solar, wind, bioenergy).

• International Solar Alliance (ISA): Co-founded by India (2015), 120+ countries; promotes solar in Global South.

• Green Hydrogen Mission (2023): Targets 5 MMT production by 2030; pilot projects in 2025.

• Carbon Capture: Pilot plants at NTPC (2024); scaling via 2025-26 budget.

• Climate Finance: India seeks $1 trillion from developed nations by 2030 (per IPCC AR6).

Recent Developments (2024-2025)

• Budget 2025-26: ₹1.97 lakh crore for renewables, CCU, and adaptation (e.g., coastal defenses).

• COP30 Role: India leads Global South advocacy for loss and damage funding at 2025 Rio Summit.

• ISRO Contributions: Satellites (e.g., INSAT-3D) monitor climate impacts, supporting IPCC data.

• Climate-Resilient Agriculture: 2025 pilot in 10 states uses IPCC adaptation strategies (e.g., drought-resistant crops).

Global Context and Comparisons

Global Climate Trends

• Emissions: Global GHG emissions ~50 GtCO2e (2024); US (13%), China (30%), EU (8%).

• IPCC Impact: AR6 drove Paris Agreement’s 1.5°C target; influences COP28 (2023) fossil fuel phase-out pledge.

• Adaptation: Global spending $50 billion/year (2024); IPCC estimates $300 billion needed annually for developing nations.

• Mitigation: Renewables (30% global energy mix); carbon capture scaling (e.g., US’s 45Q tax credits).

Comparisons

• China: 11 GtCO2e emissions; leads in solar (500 GW) and CCU. Less vulnerable but faces desertification.

• US: 5 GtCO2e; invests $100 billion in renewables but lags in adaptation funding.

• EU: Net-zero by 2050; 200 GW renewables. Strong IPCC alignment via Green Deal.

• India’s Edge: Low per capita emissions, leadership in ISA, and NAPCC’s multi-pronged approach. Vulnerable but proactive in adaptation.

Challenges, Future Prospects, and Significance

Challenges

• Funding Gap: India needs $2.5 trillion by 2050 for net-zero; global climate finance falls short ($100 billion pledged vs. $20 billion delivered).

• Coal Dependence: 50% of energy mix; phasing out by 2040 challenging.

• Climate Impacts: Rising cyclones, floods cost ~₹1 lakh crore annually; adaptation lags in rural areas.

• Technology Access: High costs for CCU, green hydrogen limit scaling.

• Equity: Developed nations’ historical emissions burden Global South; India pushes for CBDR (Common but Differentiated Responsibilities).

Future Prospects

• Net-Zero by 2070: Scaling renewables (500 GW by 2030), green hydrogen (5 MMT), and CCU via budget support.

• IPCC AR7: India’s inputs will shape climate justice, loss and damage frameworks by 2029.

• Global Leadership: ISA and CDRI (Coalition for Disaster Resilient Infrastructure) position India as a climate leader.

• Tech Innovation: AI-based climate modeling (2025 pilots) and ISRO’s satellite data enhance IPCC assessments.

• Adaptation: Coastal defenses, climate-smart agriculture to cover 50% of farmland by 2030.

Significance for India

• Climate Resilience: Protects 1.4 billion from floods, heatwaves; secures agriculture (70% population dependent).

• Economic Growth: Clean energy adds ~$1 trillion to GDP by 2030; supports $5 trillion economy goal.

• Global Standing: India’s IPCC contributions, ISA leadership strengthen G20/UNFCCC role.
  

Climate change science, underpinned by IPCC reports, provides a critical framework for addressing global warming’s impacts. India, balancing high vulnerability and low per capita emissions, integrates IPCC findings into its NAPCC, renewable energy push, and global advocacy via ISA and COP. Recent developments, like the 2025-26 budget and COP30 preparations, signal robust climate action. By addressing challenges like funding and coal dependence, India can achieve its net-zero and resilience goals, cementing its role as a global climate leader.