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Environment & Ecology Climate Change GS Paper III

Climate Change: Science, the UNFCCC and the Paris Agreement

Climate change for UPSC: greenhouse effect, gases and GWP, IPCC findings, UNFCCC, Kyoto Protocol, Paris Agreement articles, COP milestones, India's NDCs and NAPCC.

SyllabusGS III · General issues on climate change (Prelims); conservation, environmental pollution and degradation (GS III)

By UPSC Notes Editorial Team 12 min read Updated Oct 2026 #environment#climate-change#unfccc

Prerequisites: Climate Change — overview · Climatology

The Hook: The First Global Stocktake

Connect: In the News → Concept

In December 2023, the 28th Conference of the Parties (COP28) to the UNFCCC in Dubai concluded the first Global Stocktake under the Paris Agreement — a collective check of whether the world is on track. Its decision called on countries to contribute to “transitioning away from fossil fuels in energy systems, in a just, orderly and equitable manner”, and to triple global renewable energy capacity and double the rate of energy-efficiency improvement by 2030. On the conference’s first day, parties also operationalised the fund for responding to loss and damage agreed a year earlier at Sharm el-Sheikh.

The questions it raises: what is the science behind these targets, which treaty obliges whom to do what, and where does India stand?

The Core Concept

The science in five steps

  1. The natural greenhouse effect. The Earth absorbs incoming solar radiation and re-emits it as infrared (long-wave) radiation. Greenhouse gases absorb part of this outgoing radiation and re-radiate it, warming the lower atmosphere. Without this natural effect, the Earth’s average surface temperature would be about −18 °C instead of about 15 °C.
  2. The enhanced greenhouse effect. Burning fossil fuels, deforestation, agriculture and industry have raised GHG concentrations. Carbon dioxide has risen from about 280 ppm before the industrial era to above 420 ppm in recent annual averages recorded at Mauna Loa (NOAA, 2023–24).
  3. Warming. The IPCC’s Sixth Assessment Report (AR6, Synthesis Report, March 2023) states that human activities have unequivocally caused global warming, with global surface temperature in 2011–2020 about 1.1 °C above 1850–1900.
  4. Feedbacks amplify or dampen warming: melting ice lowers albedo (more absorption), thawing permafrost can release methane and carbon dioxide, and warmer air holds more water vapour.
  5. Impacts: sea-level rise, more intense heatwaves and extreme rainfall, glacier retreat, ocean warming and ocean acidification (absorbed carbon dioxide forms carbonic acid, harming corals and shell-forming organisms).

Greenhouse gases

GasMain sources100-year GWP (IPCC AR5)
Carbon dioxide (CO₂)Fossil fuels, cement, deforestation1 (reference)
Methane (CH₄)Rice paddies, livestock (enteric fermentation), landfills, fossil fuel leaksAbout 28
Nitrous oxide (N₂O)Nitrogen fertilisers, industrial processesAbout 265
Hydrofluorocarbons (HFCs)Refrigeration and air-conditioningHundreds to thousands, varying by gas
Perfluorocarbons (PFCs)Aluminium smelting, electronicsThousands
Sulphur hexafluoride (SF₆)Electrical switchgear insulationAbout 23,500 — the highest of the Kyoto gases

The Kyoto Protocol covered six gases: CO₂, CH₄, N₂O, HFCs, PFCs and SF₆; the Doha Amendment added nitrogen trifluoride (NF₃). Water vapour is the most abundant natural greenhouse gas but is not directly controlled by human emissions. Black carbon, methane, tropospheric ozone and HFCs are grouped as short-lived climate pollutants: cutting them slows near-term warming quickly.

The Intergovernmental Panel on Climate Change (IPCC)

  • Set up in 1988 by the World Meteorological Organization (WMO) and the UN Environment Programme (UNEP).
  • Does not conduct its own research; it assesses published literature through three working groups (physical science; impacts, adaptation and vulnerability; mitigation) and a task force on GHG inventories.
  • Shared the 2007 Nobel Peace Prize with Al Gore.
  • Six assessment reports so far (AR1 in 1990 to AR6, completed in 2023).

The global climate regime

graph LR
    A[IPCC set up - 1988] --> B[UNFCCC adopted - 1992]
    B --> C[Kyoto Protocol - 1997]
    C --> D[Kyoto in force - 2005]
    D --> E[Paris Agreement - 2015]
    E --> F[Paris in force - 2016]
    F --> G[First Global Stocktake - 2023]

UNFCCC (1992). Opened for signature at the Rio Earth Summit in June 1992 and in force from 21 March 1994; secretariat in Bonn. Its ultimate objective (Article 2) is to stabilise GHG concentrations “at a level that would prevent dangerous anthropogenic interference with the climate system”. It enshrines common but differentiated responsibilities and respective capabilities (CBDR-RC) and divides parties into:

GroupWhoObligation
Annex IIndustrialised countries and economies in transitionLead in reducing emissions
Annex IIOECD members of Annex IAlso provide finance and technology to developing countries
Non-Annex IMostly developing countries, including IndiaGeneral commitments; no binding reduction targets under Kyoto

The Conference of the Parties (COP) is the supreme decision-making body and meets annually.

Kyoto Protocol (COP3, 1997). In force from 16 February 2005. It set legally binding targets for developed countries listed in its Annex B — together, at least 5% below 1990 levels in the first commitment period (2008–2012). The Doha Amendment (2012) set a second commitment period (2013–2020). Its three flexible mechanisms:

MechanismHow it works
Clean Development Mechanism (CDM)Developed countries earn credits from emission-reduction projects in developing countries
Joint Implementation (JI)Credits from projects in another developed (Annex B) country
International Emissions TradingAnnex B countries trade surplus allowances

Paris Agreement (COP21, 2015). In force from 4 November 2016. India ratified it on 2 October 2016. It replaced Kyoto’s top-down targets with bottom-up pledges from all parties.

ArticleContent
2Hold warming well below 2 °C above pre-industrial levels and pursue efforts to limit it to 1.5 °C; align finance flows
4Every party prepares and communicates successive Nationally Determined Contributions (NDCs), every five years, each a progression on the last
6Voluntary cooperation, including carbon markets (6.2 bilateral transfers; 6.4 a UN-supervised mechanism)
7Global goal on adaptation
8Loss and damage (averting, minimising and addressing)
9Developed countries provide finance to developing countries
13Enhanced Transparency Framework
14Global Stocktake every five years; the first concluded in 2023

NDCs are self-determined. The obligation to prepare and communicate them is binding; achieving the targets is not enforced by penalties.

COP milestones worth knowing

COPYear and placeOutcome
COP11995, BerlinBerlin Mandate — talks that led to Kyoto
COP31997, KyotoKyoto Protocol
COP152009, CopenhagenCopenhagen Accord; goal of mobilising USD 100 billion a year by 2020
COP162010, CancunGreen Climate Fund established
COP192013, WarsawWarsaw International Mechanism for Loss and Damage; Warsaw Framework for REDD+
COP212015, ParisParis Agreement
COP262021, GlasgowGlasgow Climate Pact; “phase-down” of unabated coal power; Article 6 rules finalised
COP272022, Sharm el-SheikhAgreement to establish a loss and damage fund
COP282023, DubaiFirst Global Stocktake; “transitioning away from fossil fuels”; loss and damage fund operationalised
COP292024, BakuNew Collective Quantified Goal on finance: at least USD 300 billion a year by 2035 for developing countries

India’s commitments and policy

NDCs. India’s first NDC (2015) and its updated NDC (August 2022) include:

ElementFirst NDC (2015)Updated NDC (2022)
Emissions intensity of GDPReduce by 33–35% by 2030 from 2005 levelsReduce by 45% by 2030 from 2005 levels
Non-fossil share of installed electric power capacityAbout 40% by 2030About 50% by 2030
Additional carbon sink2.5–3 billion tonnes CO₂-equivalent through forest and tree cover by 2030Retained
Lifestyle—Promote LiFE (Lifestyle for Environment) as a mass movement

At COP26 (November 2021), India announced the “Panchamrit” — including 500 GW of non-fossil capacity by 2030 and net-zero emissions by 2070.

National Action Plan on Climate Change (NAPCC), 2008 — eight national missions:

  1. National Solar Mission
  2. National Mission for Enhanced Energy Efficiency
  3. National Mission on Sustainable Habitat
  4. National Water Mission
  5. National Mission for Sustaining the Himalayan Ecosystem
  6. National Mission for a Green India
  7. National Mission for Sustainable Agriculture
  8. National Mission on Strategic Knowledge for Climate Change

States prepare State Action Plans on Climate Change (SAPCCs). The Energy Conservation (Amendment) Act, 2022 enabled a domestic carbon market, and the Carbon Credit Trading Scheme was notified in 2023.

Memory Anchors

NAPCC’s eight missions — “Solar Energy Has Water; Himalayan Green Agriculture Knows”: Solar · Energy efficiency · Habitat · Water · Himalayan ecosystem · Green India · Agriculture · Knowledge

Kyoto’s six gases — “Can My New Hat Prevent Sunburn”: CO₂ · Methane · N₂O · HFCs · PFCs · SF₆

Kyoto vs Paris

FeatureKyoto ProtocolParis Agreement
ApproachTop-down, assigned targetsBottom-up NDCs
Who has targetsOnly developed (Annex B) countriesAll parties
Legal force of targetsBinding emission limitsBinding to submit; achievement not penalised
ReviewCommitment periodsFive-year NDC cycle and Global Stocktake

One-line Mains hook: India is home to about a sixth of humanity, yet its historical contribution to cumulative emissions is small — the core of its argument for climate justice and CBDR-RC.

For Prelims

Facts worth a mark
  • IPCC: 1988, set up by WMO and UNEP; assesses literature; AR6 completed in 2023.
  • UNFCCC in force 1994; secretariat Bonn; Article 2 states the ultimate objective.
  • Kyoto: adopted 1997, in force 2005; mechanisms — CDM, JI, emissions trading.
  • Paris: adopted 2015, in force 4 November 2016; global stocktake every five years from 2023.
  • Highest GWP among Kyoto gases: SF₆. Methane GWP about 28 and N₂O about 265 (AR5, 100-year).
  • Green Climate Fund: Cancun, 2010. Loss and damage mechanism: Warsaw, 2013; fund agreed 2022, operationalised 2023.
  • India’s updated NDC (2022): 45% emissions-intensity cut and about 50% non-fossil installed capacity by 2030; net zero by 2070.
  • NAPCC: 2008, eight missions.

For Mains

  • Dimensions: scientific (warming, feedbacks), economic (energy transition, stranded assets, green jobs), equity (CBDR-RC, historical responsibility, carbon space), financial (adequacy of climate finance, loss and damage), adaptation (agriculture, water, coasts, heat), geopolitical (critical minerals, carbon border measures).
  • Keywords: climate justice, carbon budget, just transition, adaptation gap, loss and damage, net zero, nature-based solutions, carbon markets, green finance, LiFE.
  • Value-addition: IPCC AR6 (1.1 °C warming by 2011–2020); COP28’s first Global Stocktake; COP29’s finance goal; India’s NDC targets and NAPCC; Supreme Court’s March 2024 recognition (in M.K. Ranjitsinh v. Union of India) of a right against the adverse effects of climate change under Articles 14 and 21.

Common Traps

Trap #1: 'The IPCC conducts climate research'
The IPCC assesses existing scientific literature; it does not run its own experiments or monitoring. It was set up by WMO and UNEP, not by the UNFCCC.
Trap #2: 'Paris NDCs are legally binding targets with penalties'
Parties are bound to prepare, communicate and maintain NDCs and report transparently. The targets themselves are nationally determined and there is no penalty for missing them.
Trap #3: A single hot year breaches the Paris goal
The 1.5 °C goal refers to long-term average warming (typically assessed over about 20 years), not one calendar year. A year above 1.5 °C is a warning sign, not a formal breach.

In the News

  • November 2021 — COP26, Glasgow: India announces net zero by 2070.
  • August 2022 — India’s updated NDC approved and communicated to the UNFCCC.
  • December 2023 — COP28, Dubai: first Global Stocktake concluded.
  • November 2024 — COP29, Baku: new finance goal of at least USD 300 billion a year by 2035.
  • See current affairs for the latest COP outcomes.

Practice

Prelims

UPSC Practice · Prelims GS I Qcc-1

Which of the following are flexible mechanisms under the Kyoto Protocol?

  1. Clean Development Mechanism
  2. Joint Implementation
  3. International Emissions Trading
  4. REDD+

Select the correct answer using the code given below.

  1. A 1 and 2 only
  2. B 1, 2 and 3 only
  3. C 3 and 4 only
  4. D 1, 2, 3 and 4
Solution

The Kyoto Protocol’s three flexible mechanisms are the Clean Development Mechanism, Joint Implementation and International Emissions Trading. REDD+ (reducing emissions from deforestation and forest degradation) was developed later under the UNFCCC — the Warsaw Framework for REDD+ came in 2013 — and is recognised in the Paris Agreement; it is not a Kyoto mechanism.

Answer: B

UPSC-pattern practice question
UPSC Practice · Prelims GS I Qcc-2

With reference to the Paris Agreement, consider the following statements:

  1. It aims to hold the increase in global average temperature to well below 2 °C above pre-industrial levels and to pursue efforts to limit it to 1.5 °C.
  2. It provides for a global stocktake every five years, the first of which was concluded in 2023.
  3. Only developed countries are required to submit Nationally Determined Contributions.

Which of the statements given above is/are correct?

  1. A 1 only
  2. B 2 and 3 only
  3. C 1 and 2 only
  4. D 1, 2 and 3
Solution

Statements 1 and 2 are correct (Articles 2 and 14). Statement 3 is incorrect — under Article 4, every party, developed or developing, prepares and communicates NDCs. Assigning targets only to developed countries was the Kyoto model.

Answer: C

UPSC-pattern practice question
UPSC Practice · Prelims GS I Qcc-3

Among the following greenhouse gases, which one has the highest global warming potential over a 100-year horizon?

  1. A Carbon dioxide
  2. B Methane
  3. C Nitrous oxide
  4. D Sulphur hexafluoride
Solution

Sulphur hexafluoride (SF₆), used in electrical switchgear, has a 100-year GWP of about 23,500 (IPCC AR5) — far above nitrous oxide (about 265), methane (about 28) and carbon dioxide (1, the reference). Carbon dioxide matters most overall because of its sheer volume, not its per-molecule potency.

Answer: D

UPSC-pattern practice question

Mains

UPSC Practice · Mains GS III 15 marks · 250 words Qcc-m1

“India’s climate commitments seek to balance development needs with global responsibility.” Discuss with reference to its Nationally Determined Contributions and the principle of common but differentiated responsibilities.

Solution

Introduction: The UNFCCC recognises common but differentiated responsibilities and respective capabilities (CBDR-RC). India, with low historical and per-capita emissions but large development needs, has framed its commitments around this principle while taking on ambitious targets.

Body:

  • India’s commitments:
    • Updated NDC (2022): 45% reduction in emissions intensity of GDP by 2030 (2005 base); about 50% non-fossil installed power capacity by 2030; 2.5–3 billion tonnes CO₂e additional sink; LiFE.
    • Net zero by 2070 (COP26, 2021); NAPCC’s eight missions; carbon credit trading scheme.
  • How they balance development and responsibility:
    • Intensity targets allow growth while decoupling emissions from GDP.
    • Focus on clean energy also serves energy security and air quality.
    • Insistence on finance and technology transfer from developed countries (Article 9).
  • Challenges:
    • Coal dependence for base-load power; storage and grid integration of renewables.
    • Inadequate and uncertain international finance; carbon border measures by trading partners.
    • Adaptation needs in agriculture, water and coastal regions.
  • Way forward: green hydrogen and storage, just transition for coal regions, adaptation finance, domestic carbon markets, and leadership through platforms such as the International Solar Alliance.

Conclusion: India’s approach — ambitious intensity and capacity targets anchored in CBDR-RC — shows that climate action and development can be complementary, provided global finance and technology flows match the scale of the challenge.

UPSC-pattern practice question

Quick Revision

PointOne-liner
IPCC1988; WMO + UNEP; AR6 2021–23
UNFCCC1992 Rio; in force 1994; Bonn secretariat
Kyoto1997; in force 2005; Annex B targets; CDM, JI, ET
Paris2015; in force 2016; NDCs from all; GST every five years
GCFCancun, 2010
Loss and damageWarsaw mechanism 2013; fund agreed 2022, operationalised 2023
India NDC 202245% intensity cut; about 50% non-fossil capacity by 2030
India net zero2070
NAPCC2008; eight missions

Key Takeaways

Key Takeaways
  1. Kyoto bound only developed countries to targets; Paris asks every party for NDCs but does not penalise missed targets.
  2. Prelims picks one feature per COP — memorise the milestone table.
  3. India’s position rests on CBDR-RC and climate justice, backed by intensity, capacity and net-zero targets.
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