Climate Change — The Science

Climate change refers to long-term shifts in temperatures and weather patterns, primarily driven by human activities since the Industrial Revolution (1750s onwards).

ConceptDetail
Greenhouse effectNatural process — GHGs (CO₂, CH₄, N₂O, CFCs) trap heat in the atmosphere, keeping Earth ~33°C warmer than it would be without them
Enhanced greenhouse effectHuman emissions of GHGs intensify the natural effect → global warming
Global temperature rise~1.1°C above pre-industrial levels (as of 2023); on track for 2.5-2.9°C by 2100 under current policies
Carbon budgetRemaining budget for 1.5°C: ~250 Gt CO₂ (at current emissions, exhausted by ~2030)
Major GHGsCO₂ (76%), CH₄ (16%), N₂O (6%), F-gases (2%)

Prelims Fact: Water vapour is the most abundant greenhouse gas in the atmosphere, but it is NOT directly increased by human activities — it acts as a feedback (warming → more evaporation → more water vapour → more warming). UPSC tests this distinction.


International Climate Architecture

UNFCCC (1992)

FeatureDetail
Adopted1992 at Rio Earth Summit; entered into force 1994
Members198 Parties (near-universal)
PrincipleCommon But Differentiated Responsibilities (CBDR) — all countries share the responsibility, but developed countries must lead (historical emissions)
AnnexesAnnex I (developed countries + economies in transition); Annex II (developed countries — must provide finance); Non-Annex I (developing countries including India)
Key obligationDeveloped countries must take the lead in combating climate change; developing countries get financial and technology support

CBDR is India's cornerstone argument: India insists that developed countries, having caused ~80% of cumulative historical emissions, must bear greater responsibility. This principle — enshrined in UNFCCC Article 3 — underpins India's stance in every climate negotiation.

Kyoto Protocol (1997)

FeatureDetail
Adopted1997 at COP3, Kyoto; entered into force 2005
ApproachTop-down — legally binding emission reduction targets for Annex I countries only
First commitment period2008-2012: 5.2% reduction below 1990 levels
Second commitment period2013-2020 (Doha Amendment)
MechanismsClean Development Mechanism (CDM), Joint Implementation (JI), Emissions Trading
WeaknessUSA never ratified; Canada withdrew; no targets for developing countries

CDM and India: India was the second-largest host of CDM projects (after China). Indian companies earned carbon credits by reducing emissions below baseline — these credits were sold to Annex I countries. CDM has been replaced by Article 6 mechanisms under the Paris Agreement.

Paris Agreement (2015)

FeatureDetail
Adopted12 December 2015 at COP21, Paris; entered into force 4 November 2016
ApproachBottom-up — each country sets its own Nationally Determined Contribution (NDC)
Temperature goalLimit warming to well below 2°C, pursue efforts for 1.5°C above pre-industrial levels
NDCsNationally Determined Contributions — each Party's climate action plan, updated every 5 years with increasing ambition (ratchet mechanism)
Global StocktakeEvery 5 years, assess collective progress (first GST completed at COP28, 2023)
Article 6Market mechanisms — carbon trading between countries (Article 6.2: bilateral ITMO trading; Article 6.4: UN-supervised crediting mechanism replacing CDM)
Loss and DamageAcknowledged but no liability framework (separate from adaptation)
FinanceDeveloped countries to mobilise $100 billion/year (achieved in 2022, two years late)

First Global Stocktake (COP28, 2023)

The first GST found that while near-universal climate action has been achieved, the world is not on track to meet Paris goals. Key outcomes:

  • Projected warming reduced from 3.7-4.8°C (2010 estimates) to 2.4-2.6°C under current policies — progress, but still far above 1.5°C
  • First-ever COP text calling for "transitioning away from fossil fuels" in energy systems — historic language after 30 years of negotiations
  • Called for tripling renewable energy capacity and doubling energy efficiency globally by 2030
  • Aligned climate action with the Kunming-Montreal Global Biodiversity Framework for the first time

Loss and Damage Fund

MilestoneDetail
COP27 (2022)Agreement to establish a Loss and Damage Fund; Transitional Committee set up to draft operational details
COP28 (2023)Fund operationalised on Day 1 of COP28; World Bank invited to host it as a Financial Intermediary Fund (FIF) for an interim 4-year period
Initial pledges~$700 million pledged at COP28 by multiple countries — widely criticised as inadequate given estimated $400 billion/year in loss and damage costs
Governance26-member Board with balanced developed/developing country representation; HQ in Philippines

Prelims Trap: The Paris Agreement is NOT legally binding on emission targets — NDCs are voluntary and self-determined. What IS legally binding is the process: countries MUST submit NDCs, participate in Global Stocktake, and update their targets every 5 years. This "pledge and review" model is fundamentally different from Kyoto's top-down targets.


Key COP Outcomes

COPYearLocationKey Outcome
COP212015ParisParis Agreement adopted
COP262021GlasgowGlobal Methane Pledge; India's net zero 2070 pledge; "phase down" coal language; 500 GW RE target
COP272022Sharm el-SheikhLoss and Damage Fund agreed in principle; India submitted LT-LEDS
COP282023DubaiFirst Global Stocktake; "transitioning away from fossil fuels"; Loss and Damage Fund operationalised
COP292024BakuNew Collective Quantified Goal: $300 billion/year by 2035 from developed to developing countries; Baku-Belém roadmap to $1.3 trillion
COP302025Belém (Brazil)$1.3 trillion/year climate finance target confirmed; Loss and Damage Fund's first $250 million call for proposals; fossil fuel transition pledge

For Mains: COP29's $300 billion finance target was criticised by developing countries as grossly inadequate (they demanded $1.3 trillion). COP30 set the $1.3 trillion trajectory but much of it relies on private finance, not public grants. India's position: climate finance must be predominantly public, grant-based, and new — not recycled development aid or private loans. This is a recurring Mains theme.


India's Climate Commitments

NDC Targets

Target2030 NDC (Updated August 2022)2035 NDC (Approved March 2026)
Emissions intensityReduce by 45% from 2005 levelsReduce by 47% from 2005 levels
Non-fossil electricity50% of installed capacity from non-fossil sources60% of installed capacity from non-fossil sources
Carbon sinkAdditional carbon sink of 2.5-3 billion tonnes CO₂ equivalent through additional forest/tree coverContinued
Net zero2070 (announced at COP26, Glasgow)Reaffirmed

Ahead of schedule: India achieved 52.57% non-fossil fuel electricity capacity by February 2026 — meeting the 2030 target of 50% five years early. This is why the 2035 target was raised to 60%.

India's Climate Actions

InitiativeDetail
National Action Plan on Climate Change (NAPCC)2008; 8 National Missions (see detailed table below)
International Solar Alliance (ISA)Co-founded by India and France (2015); HQ: Gurugram; 120+ member countries; promotes solar energy in tropical countries
Coalition for Disaster Resilient Infrastructure (CDRI)Launched by India at UNGA 2019; builds climate-resilient infrastructure
LiFE (Lifestyle for Environment)Launched at COP26; demand-side climate action through individual behaviour change
Green Credit Programme2023; incentivises environmental actions by individuals, communities, private sector
PanchamritPM Modi's 5 climate pledges at COP26 (1 November 2021, Glasgow): 500 GW non-fossil capacity by 2030; 50% RE share; 1 billion tonnes emission reduction by 2030; carbon intensity down 45%; net zero by 2070

NAPCC — The 8 National Missions

MissionLaunchedKey Target / Focus
National Solar Mission (Jawaharlal Nehru NSM)2010Original target: 20 GW by 2022; revised to 100 GW by PM Modi in 2015; target far exceeded
National Mission for Enhanced Energy Efficiency2010PAT (Perform, Achieve, Trade) scheme for energy-intensive industries; market-based energy efficiency trading
National Mission on Sustainable Habitat2010Energy efficiency in buildings, urban transport, solid waste management
National Water Mission201120% improvement in water use efficiency; integrated water resource management
National Mission for Sustaining the Himalayan Ecosystem2010Prevent glacial retreat; conserve Himalayan biodiversity; monitor glacial health
National Mission for a Green India2014Afforestation of 10 million hectares including 6 million hectares of degraded forest land
National Mission for Sustainable Agriculture2014Climate-resilient crops, weather insurance, dryland farming, soil health management
National Mission on Strategic Knowledge for Climate Change2010Climate research, data sharing, capacity building, global collaboration

India's Renewable Energy Progress

SourceInstalled Capacity (February 2026)Growth
Solar~140 GWCrossed 100 GW in January 2025; 35 GW added in 2025 alone
Wind~55 GW5.8 GW added in 2025
Large Hydro~47 GWStable growth
Biomass/Small Hydro~15 GW
Nuclear~8.8 GW11 reactors under construction
Total Non-Fossil~266.7 GW52.57% of total installed capacity
Total Installed~507 GW

India added a record 44.5 GW of renewable energy capacity in 2025 — nearly double the 24.7 GW added in 2024. At this pace, the 500 GW non-fossil target by 2030 is achievable.

Key Renewable Energy Programmes

ProgrammeDetail
PM-KUSUMSolar pumps and grid-connected solar for farmers
Rooftop Solar (PM Surya Ghar)Target: 1 crore households with rooftop solar by 2027
National Green Hydrogen Mission2023; target: 5 MMTPA green hydrogen production by 2030; Rs 19,744 crore outlay
Offshore WindTarget: 37 GW by 2030; first 1 GW tender off Gujarat coast
Battery StorageViability Gap Funding for 4,000 MWh battery energy storage systems

Carbon Markets and Article 6

MechanismDetail
Article 6.2Bilateral carbon credit trading between countries (Internationally Transferred Mitigation Outcomes — ITMOs)
Article 6.4UN-supervised carbon crediting mechanism (replaces CDM); rules finalised at COP29, Baku (2024)
India's Carbon Credit Trading Scheme (CCTS)Launched 2023; domestic carbon market; BEE (Bureau of Energy Efficiency) is the nodal agency; mandatory for designated energy-intensive industries

For Mains: India's domestic carbon market (CCTS) coexists with international Article 6 mechanisms. The key policy question: should India sell carbon credits internationally (earning revenue) or retain them to meet its own NDC targets? Selling credits to developed countries could undermine India's own climate ambition.


Climate Change Impact on India

SectorImpact
AgricultureWheat yields declining in Indo-Gangetic plains; shifting monsoon patterns; increased drought/flood frequency
WaterHimalayan glaciers retreating (ISRO: 85% of studied glaciers retreating); river flow changes; groundwater stress
CoastalSea-level rise threatens 170 million coastal residents; Mumbai, Chennai, Kolkata at risk
HealthHeat-related mortality increasing; vector-borne disease expansion; air pollution synergies
BiodiversityCoral bleaching (Gulf of Mannar, Lakshadweep); species migration; ecosystem disruption
EconomyClimate-vulnerable sectors (agriculture, fisheries) employ ~42% of workforce; GDP loss estimated at 3-10% by 2100

India's vulnerability paradox: India contributes ~7% of global emissions (3rd largest emitter) but has per capita emissions of only 2.0 tonnes CO₂ (global average: 4.7 tonnes; USA: 14.9 tonnes). Yet India is among the most climate-vulnerable countries due to its geography, population density, and dependence on climate-sensitive sectors. This asymmetry is central to India's equity argument in climate negotiations.


Key Concepts for Prelims

TermMeaning
CBDRCommon But Differentiated Responsibilities — foundational UNFCCC principle
NDCNationally Determined Contribution — each country's climate action plan under Paris Agreement
Global StocktakeFive-yearly collective assessment of progress toward Paris goals
Loss and DamageClimate impacts beyond what adaptation can address (irreversible losses)
Carbon sinkNatural or artificial reservoir that absorbs CO₂ (forests, oceans, soil)
Carbon neutralityNet zero CO₂ emissions (emissions = removals)
Net zeroAll GHG emissions (not just CO₂) balanced by removals
Climate financeMoney flowing from developed to developing countries for mitigation and adaptation
AdaptationAdjusting to climate impacts (flood defences, drought-resistant crops)
MitigationReducing GHG emissions (renewable energy, energy efficiency)
ITMOsInternationally Transferred Mitigation Outcomes — carbon credits traded between countries under Article 6.2
PanchamritPM Modi's 5 climate pledges at COP26, Glasgow (1 November 2021) — India's headline climate commitment
Green Climate Fund (GCF)Main UNFCCC financial mechanism for developing countries; GCF-2 replenishment raised ~$12.8 billion (2024-2027)
PAT SchemePerform, Achieve and Trade — market-based energy efficiency mechanism under NAPCC's Enhanced Energy Efficiency Mission

UPSC Relevance

Prelims Focus Areas

  • UNFCCC — when adopted, CBDR principle, Annex I vs Non-Annex I
  • Kyoto Protocol — commitment periods, CDM, who ratified/didn't
  • Paris Agreement — temperature goal, NDCs, Global Stocktake, Article 6
  • India's NDC targets (2030 and 2035) — emissions intensity, non-fossil share
  • International Solar Alliance — founders, HQ, members
  • Renewable energy capacity — solar, wind, total non-fossil
  • COP outcomes (especially COP28-30)
  • Loss and Damage Fund — when agreed, first disbursement

Mains Focus Areas

  • Climate justice and equity — India's per capita emissions (~2.0 tonnes) vs global average (~4.7 tonnes) and historical responsibility argument
  • Paris Agreement effectiveness — voluntary NDCs sufficient? Global Stocktake findings
  • Climate finance gap — $300 billion vs $1.3 trillion debate; Green Climate Fund (GCF-2 raised ~$12.8 billion from 31 countries, but US rescinded $3 billion pledge in 2025)
  • Loss and Damage Fund — operationalisation, adequacy of $700 million vs $400 billion estimated annual need
  • India's energy transition — balancing development with decarbonisation
  • Renewable energy targets — achievements and challenges (grid stability, land acquisition, storage)
  • Carbon markets — domestic CCTS and Article 6 linkage; policy dilemma of selling vs retaining credits
  • Climate change impact on Indian agriculture and food security
  • Green hydrogen as industrial decarbonisation pathway
  • NAPCC and National Missions — implementation gaps after 18 years

Recent Developments (2024–2026)

COP29 Baku 2024 — NCQG and Carbon Markets

COP29 (Baku, Azerbaijan, November 2024) delivered two major outcomes. First, the New Collective Quantified Goal (NCQG): developed nations committed to mobilising at least $300 billion per year for climate finance by 2035, with a broader aspirational figure of $1.3 trillion from all sources. India and G77 nations rejected this as "abysmally poor" — the Global South had demanded $1.3 trillion in grant-equivalent public financing annually. Second, Article 6.4 mechanism for a UN-supervised international carbon market was operationalised, though with controversy over whether carbon credits should include removals (forests/soils) vs. avoidance.

India's position at COP29 emphasised historical responsibility of developed nations (CBDR-RC principle), the inadequacy of $300 billion (which is less than 0.1% of global GDP), and the need for grants rather than loans. The COP30 Presidency was passed to Brazil, which will host the summit in Belém, Amazon, in November 2025 — making Amazon deforestation a central backdrop.

UPSC angle: COP29 NCQG outcomes, India's criticism, Article 6.4 mechanism, and COP30 Brazil are Mains GS-2/GS-3 anchor facts.


India's Updated NDC 2031–2035 — Cabinet Approval March 2026

India's Union Cabinet approved the updated NDC for 2031–2035 on 25 March 2026. The new targets: (a) 47% reduction in emissions intensity of GDP from 2005 levels by 2035 (upgraded from 45% by 2030 in the previous NDC); (b) 60% of installed electricity capacity from non-fossil fuel sources by 2035; (c) carbon sink of 3.5–4 billion tonnes CO₂ equivalent through additional forest and tree cover.

India has already achieved several 2030 targets ahead of schedule: non-fossil fuel capacity crossed 52.57% by February 2026 (target was 50% by 2030); total renewable energy installed capacity reached 220 GW by early 2025 (target 500 GW by 2030 on track). India's CO₂ emissions grew by only 0.7% in 2024 — slowest pace in over two decades — as renewable energy increasingly displaced coal in the power sector.

UPSC angle: Updated NDC targets (47% intensity, 60% non-fossil), India's pre-schedule achievements, and net-zero 2070 timeline are critical Prelims/Mains facts.


Global Stocktake Results — UAE COP28 and COP29 Follow-up

The first Global Stocktake (GST) — a comprehensive assessment of collective progress toward Paris Agreement goals — was completed at COP28 Dubai (December 2023) and its findings drove discussions at COP29 in 2024. The GST found the world is "not on track" to limit warming to 1.5°C, with a significant emissions gap. The UAE Consensus called for "transitioning away from fossil fuels" — landmark language never used in prior COP decisions.

India's contribution to the GST highlighted: (a) its per-capita emissions are well below global averages (1.9 tCO₂ per person vs 4.7 global average); (b) India has met its 2020 NDC targets and most 2030 targets ahead of schedule; (c) climate finance flows from developed to developing nations remain far below promised levels. India maintained its position that loss and damage, adaptation, and mitigation must be equally financed.

UPSC angle: Global Stocktake, UAE Consensus on fossil fuel "transition away" language, India's per-capita emissions, and CBDR-RC are Mains GS-2 (international relations) and GS-3 topics.


COP30 Belém, Brazil — Belém Package and $1.3 Trillion Climate Finance (November 2025)

COP30 was held in Belém, Brazil, from 10–22 November 2025. The conference adopted the Belém Package as its key negotiated outcome, with the landmark agreement calling for mobilisation of USD 1.3 trillion annually by 2035 to support developing nations in climate action — building on the Baku-to-Belém Roadmap and doubling adaptation finance by 2025 and tripling it by 2035. The Loss and Damage Fund established at COP27 issued its first $250 million call for proposals.

A major disappointment was the failure to agree on a roadmap for phasing out fossil fuels — efforts to include binding language fell short, though the COP30 presidency separately agreed to create two parallel roadmaps (on fossil fuels and on forests). India's delegation, leading the BASIC group (Brazil, South Africa, India, China) and Like-Minded Developing Countries (LMDC) bloc, consistently advocated for: climate finance as a legal obligation (not voluntary pledge) under Article 9.1 of the Paris Agreement; equity and CBDR-RC as foundational principles; and rejection of conditionality on climate finance. India welcomed the creation of a Just Transition Mechanism as an important step. PM Modi did not attend the leaders' summit (India participated at delegation level), along with leaders from China and the USA.

UPSC angle: COP30 Belém Package ($1.3 trillion/year by 2035), fossil fuel roadmap failure, India's BASIC/LMDC leadership, Just Transition Mechanism, and CBDR-RC vs developed-world conditionality debate are core Mains GS-2 and GS-3 content for 2026.


Vocabulary

Decarbonisation

  • Pronunciation: /diːˌkɑːbənaɪˈzeɪʃən/
  • Definition: The process of reducing and ultimately eliminating carbon dioxide emissions from a country's economy, energy systems, and industrial processes to mitigate climate change.
  • Origin: From English de- ("removal") + carbon (from Latin carbo, "coal, charcoal") + -isation (suffix denoting a process); earliest known use in the 1830s, originally referring to removal of carbon from metals, with the climate-policy sense emerging in the late 20th century.

Carbon Credit

  • Pronunciation: /ˈkɑːr.bən ˈkred.ɪt/
  • Definition: A tradable permit or certificate representing the right to emit one metric tonne of carbon dioxide or its equivalent, used within market-based mechanisms to incentivise greenhouse gas emission reductions.
  • Origin: From Latin carbo ("coal") + Latin creditum ("a loan, thing entrusted"), from credere ("to believe, trust"); the term was first used in 1990 and gained wide currency after the Kyoto Protocol (1997) introduced market-based emission reduction mechanisms.

Greenhouse

  • Pronunciation: /ˈɡriːn.haʊs/
  • Definition: A structure with glass or translucent walls and roof used to cultivate plants under controlled conditions; in climate science, the term refers to the "greenhouse effect" whereby atmospheric gases trap heat radiated from the Earth's surface, warming the planet.
  • Origin: Compound of English green + house; first attested in 1664 in the writings of John Evelyn to describe a glass building for growing plants; the meteorological analogy "greenhouse effect" was coined in the 19th century to describe atmospheric heat-trapping.

Key Terms

UNFCCC

  • Pronunciation: /juː.en.ef.siː.siː.siː/
  • Definition: The United Nations Framework Convention on Climate Change, an international treaty adopted on 9 May 1992 and opened for signature at the Rio Earth Summit (UNCED) in Rio de Janeiro on 4 June 1992, which established the foundational framework for global climate negotiations. Its ultimate objective (Article 2) is to stabilise greenhouse gas concentrations in the atmosphere "at a level that would prevent dangerous anthropogenic interference with the climate system" within a timeframe that allows ecosystems to adapt, food production to continue, and economic development to proceed sustainably. It entered into force on 21 March 1994 and now has 198 Parties — near-universal membership.
  • Context: On 12 June 1992, 154 nations signed the UNFCCC at the Rio Earth Summit. The Convention categorises parties into Annex I (developed countries and economies in transition — must take the lead in emission reductions), Annex II (developed countries — must provide financial and technological support to developing countries), and Non-Annex I (developing countries including India — no binding emission targets). The cornerstone principle is Common But Differentiated Responsibilities and Respective Capabilities (CBDR-RC, Article 3), which acknowledges that developed countries, having caused approximately 80% of cumulative historical emissions, must bear greater responsibility. The UNFCCC serves as the parent treaty for both the Kyoto Protocol (1997) and the Paris Agreement (2015), and the annual Conference of the Parties (COP) is the supreme decision-making body.
  • UPSC Relevance: GS3 Environment. Prelims tests adoption year (1992), entry into force (1994), 198 Parties, the Annex I/Non-Annex I distinction, the CBDR principle (Article 3), and the objective of preventing "dangerous anthropogenic interference." Mains expects understanding of the UNFCCC as the parent framework under which Kyoto and Paris operate. India's cornerstone negotiating argument — that developed countries caused ~80% of cumulative emissions and must lead on climate finance and emission reductions — is rooted in UNFCCC's CBDR-RC principle. Essential for any climate negotiation answer; always cite CBDR as India's foundational position.

Kyoto Protocol

  • Pronunciation: /kiˈoʊ.toʊ ˈproʊ.tə.kɒl/
  • Definition: An international treaty adopted on 11 December 1997 at COP3 in Kyoto, Japan, which extended the UNFCCC by setting legally binding greenhouse gas emission reduction targets for 36 industrialised (Annex I) countries, averaging 5.2% below 1990 levels during the first commitment period (2008-2012). All 36 participating countries complied with their first-period targets. The second commitment period (2013-2020) was established through the Doha Amendment, though several major emitters (Canada, Japan, Russia) did not participate.
  • Context: Named after Kyoto, Japan; entered into force on 16 February 2005 after ratification by 55 Parties covering at least 55% of Annex I emissions. The Protocol introduced three flexible market mechanisms: the Clean Development Mechanism (CDM — allowed developed countries to earn emission credits by funding emission-reducing projects in developing countries; India was the second-largest CDM host after China), Joint Implementation (JI — similar projects between Annex I countries), and Emissions Trading (cap-and-trade between Annex I countries). The Protocol's key weakness was that the USA never ratified it (despite signing), Canada withdrew in 2011, and developing countries including China and India had no emission reduction obligations — undermining its global effectiveness. CDM has been superseded by Article 6 mechanisms under the Paris Agreement.
  • UPSC Relevance: GS3 Environment. Prelims tests the three market mechanisms (CDM, JI, Emissions Trading), first commitment period (2008-2012), the entry into force year (2005), and the key distinction that Kyoto imposed binding targets only on Annex I (developed) countries while developing countries like India had no emission reduction obligations. Mains expects comparison between Kyoto (top-down, legally binding, limited participation by developed countries only) and Paris (bottom-up, voluntary NDCs, universal participation by all countries). Two frequently tested facts: the US never ratified Kyoto, and India was the second-largest CDM host.