Intergovernmental Panel on Climate Change (IPCC)

Background

The Intergovernmental Panel on Climate Change (IPCC) is the United Nations’ apex scientific body for assessing climate change.

It was established in 1988 by:
- United Nations Environment Programme (UNEP) and
- World Meteorological Organization (WMO)

📌 Important clarity for beginners:
👉 The IPCC does NOT do experiments or original research.
👉 Instead, it assesses, evaluates, and synthesizes existing global scientific research on climate change.

Think of IPCC as:

🧠 The world’s most authoritative “examiner” of climate science, not a laboratory.

Why was IPCC created?

The purpose of IPCC is to provide scientific evidence for:

Understanding human-induced climate change
Assessing risks and impacts
Suggesting adaptation and mitigation options

These scientific assessments directly support global climate negotiations under the United Nations Framework Convention on Climate Change (UNFCCC).

📌 In simple words:
Policy is made by governments, but science is provided by IPCC.

How does IPCC work? (Very important for UPSC)

The work of IPCC is divided into three Working Groups (WGs) and one Task Force:

🔹 Working Group I (WG I)

Studies the physical scientific basis
Deals with:
- Temperature rise
- Greenhouse effect
- Climate models
- Ice melt, sea level rise

👉 This is pure climate science.

🔹 Working Group II (WG II)

Assesses impacts, adaptation, and vulnerability
Focus areas:
- Agriculture
- Water
- Health
- Ecosystems
- Human settlements

👉 This connects climate change with society and economy.

🔹 Working Group III (WG III)

Focuses on mitigation
Studies:
- Reduction of GHG emissions
- Renewable energy
- Carbon pricing
- Policy tools

👉 This is about solutions.

📌 UPSC Tip:

If a question asks about science → WG I
If it asks about impacts → WG II
If it asks about solutions → WG III

IPCC Assessment Reports (ARs): The backbone of climate policy

Since its formation, IPCC publishes Assessment Reports approximately every 6–7 years.

Assessment Report	Year	Key Contribution
AR1	1990	Basis of UNFCCC
AR2	1995	Basis of Kyoto Protocol
AR3	2001	Improved climate projections
AR4	2007	Nobel Peace Prize
AR5	2014	Basis of Paris Agreement
AR6	2021–23	Global Stocktake

Highlights of Individual Assessment Reports

🔸 AR1 (1990)

Global temperature rise: 0.3–0.6°C in last 100 years
Projected rise:
- 2°C by 2025
- 4°C by 2100
Sea level rise: 65 cm by 2100

📌 Historical importance:
👉 Scientific foundation of the United Nations Framework Convention on Climate Change (1992)

🔸 AR2 (1995)

Revised temperature rise to 3°C by 2100
Sea level rise estimate: 50 cm

📌 Outcome:
👉 Led to the Kyoto Protocol

🔸 AR3 (2001)

Temperature increase range: 1.4°C – 5.8°C by 2100
Sea level rise: 80 cm by 2100
Rainfall expected to increase globally

👉 Shows growing scientific confidence.

🔸 AR4 (2007)

Worst-case temperature rise: 4.5°C
Sea level rise: 60 cm
IPCC awarded the Nobel Peace Prize 🏆

📌 Why Nobel?
For enhancing understanding of human-induced climate change and laying foundations for global action.

🔸 AR5 (2014)

Temperature rise could reach 4.8°C by 2100
CO₂, CH₄, N₂O concentrations highest in last 800,000 years
Heat waves: “Virtually certain”
Large fraction of species at risk of extinction

📌 Most important outcome:
👉 Scientific basis of the Paris Agreement

AR6 in Detail

WG I to AR6 (Physical Science Basis – Feb 2021)

This report answers a fundamental question:

“What is happening to Earth’s climate, and why?”

Crossing the 1.5°C Threshold

The global average temperature is likely to cross 1.5°C above pre-industrial levels between 2021 and 2040.
For the first time, the IPCC states clearly:

⚠️ 1.5°C warming is inevitable, even under the best-case emission scenario.

📌 Why is this historic?
Earlier reports spoke in probabilities. AR6 speaks in certainty — the science has matured.

What does 1.5°C warming actually mean?

At 1.5°C global warming, the world will experience:

More frequent and intense heat waves
Longer warm seasons
Shorter and weaker cold seasons

👉 Climate change is no longer about the future — it is about changes in seasons we already observe.

Can warming still be stopped?

Yes — but only conditionally:

GHG emissions must be halved by 2030
Net-zero emissions must be achieved by 2050

📌 This aligns directly with the Paris Agreement temperature goals, but demands unprecedented global action.

India-specific scientific findings

WG I provides strong scientific backing to India’s climate diplomacy:

Historical cumulative emissions, not present emissions alone, are the root cause of today’s crisis.
Air pollution and aerosols have:
- Reduced monsoon rainfall intensity
- Altered rainfall patterns across India and South Asia
Urbanisation + aerosols have increased intense rainfall events in Indian cities.

👉 Climate change in India is not just about temperature — it is about monsoon instability.

WG II to AR6 (Impacts, Adaptation & Vulnerability – Feb 2022)

This report answers:

“Who is affected, how badly, and can we adapt?”

Cities: The epicentre of risk

More than half of the world’s population lives in cities
Cities face the highest climate risks due to:
- Heat stress
- Flooding
- Water scarcity
- Poor adaptive capacity

📌 Urban climate risk is now a development issue, not just an environmental one.

Escalating impacts with every fraction of warming

Climate impacts do not increase linearly — they escalate sharply with each additional degree.
Losses increase disproportionately as warming rises.

Biodiversity under existential threat

At different warming levels:

1.5°C → 14% species at very high risk of extinction
3°C → 29% species
4°C → 39% species

📌 This shows that even small temperature differences matter enormously.

Irreversible and near-irreversible losses

Some climate impacts cannot be undone, such as:

Species extinction
Glacier retreat
Thawing of permafrost (especially in the Arctic)

👉 These processes can self-accelerate, creating positive feedback loops.

Human health impacts

Climate change has already:

Affected physical health (heat stress, malnutrition)
Affected mental health (climate anxiety, disaster trauma)

Future risks include:

Food insecurity
Water scarcity
Flood disasters

WG III to AR6 (Mitigation – Apr 2022)

This report focuses on:
“How do we reduce emissions, and is it happening fast enough?”

Current emission status

Global GHG emissions reached 59 GtCO₂e in 2019
Increase of 54% since 1990
Growth rate has slowed slightly, but absolute emissions remain high

📌 Slowing growth is not enough — emissions must decline sharply.

Positive signals

18 countries have reduced emissions continuously for over 10 years
Achieved through:
- Energy efficiency
- Renewable energy
- Reduced energy demand

Carbon Inequality & Least Developed Countries (LDCs)

This is one of the most powerful moral findings of AR6.

LDCs emitted only 3% of global emissions in 2019
Per capita emissions (1990–2019):
- LDCs: 1.7 tCO₂e
- Global average: 6.9 tCO₂e
Historical contribution (1850–2019): <0.4%

📌 Yet, LDCs suffer the worst climate impacts — a classic case of climate injustice.

Why current pledges are insufficient

Existing commitments make it very likely that 1.5°C will be breached
To stay within 1.5°C:
- Global emissions must fall 43% by 2030
- Follow the C1 pathway with minimal overshoot

👉 Current Nationally Determined Contributions (NDCs) fall far short.

Low-Emission Technologies: Cost Revolution

Since 2010:

Solar energy cost ↓ 85%
Wind energy cost ↓ 55%
Lithium-ion batteries cost ↓ 85%

Deployment growth:

Solar → 10×
EVs → 100×

📌 Climate action is no longer limited by technology — it is limited by policy and will.

Land Use, Food Systems & Climate Change

Emissions from land and food systems

If entire food systems are considered:

Contribution may reach 37–50% of global emissions

Break-up:

Agriculture → 15%
Deforestation for food → 18%
Transport, storage, waste → 17%

IPCC recommendations

Shift diets towards:
- Coarse grains
- Pulses
- Fruits, vegetables, nuts
Reduce meat consumption
Reduce food loss and waste (~25% of food wasted globally)

Land as a carbon sink

Soil, forests, plantations absorb CO₂ via photosynthesis
Therefore:
- Deforestation
- Urbanisation
- Cropping pattern change
  directly affect GHG emissions.

Synthesis Report of IPCC AR6

The Synthesis Report integrates findings of WG I, II, and III.

Key conclusions

Earth has already warmed 1.1°C due to human activities
There is a 50% probability of crossing 1.5°C by 2030
This threatens the core objective of the Paris Agreement

Maladaptation (Very Important Concept)

Maladaptation occurs when:
Adaptation actions unintentionally increase vulnerability instead of reducing it.

Examples:

Flood embankments increasing downstream flooding
Cooling solutions increasing energy demand

📌 Poor adaptation can be worse than no adaptation.

Conclusion

IPCC AR6 establishes with high confidence that human-induced climate change is accelerating, impacts are escalating and becoming irreversible, current pledges are insufficient, and immediate, equitable, and transformative action is the only viable pathway forward.

Till now, we discussed Assessment Reports, which are broad and comprehensive.
In the next section we will understand IPCC Special Reports, which are theme-specific, sharper, and policy-critical.

Think of them as “emergency scientific briefings” released when the world needs focused answers on urgent climate issues.