Ecosystems, biodiversity, climate change and environmental conventions on one page. For explanations, go back to the [chapter](/geography/environment-ecology/).

{{< callout type="tip" title="How to use this sheet" >}}
Scan it top to bottom in the week before Prelims. **Bold** entries are the facts examiners return to most often. Figures marked with a year can change; check the latest before Mains.
{{< /callout >}}

## Ecosystems

| Fact | Detail |
|------|--------|
| "Ecology" / "Ecosystem" coined | Haeckel (1866) / **Tansley (1935)** |
| Energy transfer | **10% law** (Lindeman, 1942); energy flow is **one-way** |
| Pyramid never inverted | **Energy** |
| Biomass pyramid inverted | Open sea (phytoplankton) |
| Number pyramid inverted | Single tree with insects |
| Gaseous vs sedimentary cycles | C, N, O vs **P**, S |
| Nitrogen fixation | Rhizobium (legume nodules), Azotobacter, cyanobacteria |
| Nitrification | **Nitrosomonas** (NH₃ → nitrite), **Nitrobacter** (nitrite → nitrate) |
| Denitrification | Pseudomonas, Thiobacillus |
| Pioneer species | Lichens (rock, xerarch); phytoplankton (water, hydrarch) |
| Ecotone | Transition zone; **edge effect** = more species |
| Biomagnification | DDT, mercury rising up the food chain |
| SO₂ indicator | Lichens |
| Coral reef areas of India | Gulf of Mannar, Gulf of Kachchh, Lakshadweep, Andaman–Nicobar |
| Ecosystem services (MEA 2005) | Provisioning, regulating, cultural, supporting |

## Biodiversity

| Fact | Detail |
|------|--------|
| Definition | CBD Article 2: within species, between species, of ecosystems |
| Levels | Genetic, species, ecosystem |
| India | ~2.4% of land, ~7–8% of recorded species; one of **17 megadiverse** countries |
| Biogeographic zones | **10**; largest = **Deccan Peninsula** (most of Chhattisgarh) |
| Hotspot criteria | **≥1,500 endemic vascular plants + ≥70% habitat lost** (Myers, 1988) |
| Hotspots | **36** worldwide; **4** in India: Himalaya, Indo-Burma, Western Ghats–Sri Lanka, Sundaland (Nicobar) |
| Threats | **HIPPO** + climate change |
| IUCN | 1948, Gland (Switzerland); threatened = **CR, EN, VU** |
| Biological Diversity Act | 2002; **NBA Chennai**, SBBs, BMCs (People's Biodiversity Registers); amended 2023 |
| CG state animal / bird / tree | Wild water buffalo / hill myna / sal |

## Climate Change

| Fact | Detail |
|------|--------|
| Natural greenhouse effect | Earth ~+15°C instead of ~−18°C |
| CO₂ (2024) | **423.9 ppm**, ~52% above pre-industrial; rise of 3.5 ppm in a year (WMO, 2025) |
| Warmest year | **2024** (~1.55°C above pre-industrial); 2015–2025 the eleven warmest |
| GWP (100 yr) | CO₂ 1; CH₄ ~28; N₂O ~265–273 |
| Paddy fields emit | **Methane** |
| IPCC | **1988**, WMO + UNEP, Geneva; AR6 synthesis March 2023 |
| NAPCC | **30 June 2008**; 8 original missions |
| Chhattisgarh SAPCC | Approved 2014; revision under way |
| NDC (2015) | 33–35% intensity cut, 40% non-fossil capacity, 2.5–3 Gt sink by 2030 |
| **NDC update (2022)** | **45%** intensity cut, **50%** non-fossil by 2030 |
| **NDC 2035** | **47%**, **60%**, 3.5–4.0 Gt sink; Cabinet approval **26 March 2026** |
| **Net zero** | **2070** (COP26, Glasgow, 2021) |
| 50% non-fossil capacity | Reached; announced July 2025 |
| Emissions intensity fall | ~36% between 2005 and 2020 |

## Conventions

| Treaty | Year | Subject |
|--------|------|---------|
| **Ramsar** | 1971 (India 1982) | Wetlands; World Wetlands Day 2 Feb |
| Stockholm Conference | 1972 | UNEP (Nairobi); World Environment Day 5 June |
| **CITES** | 1973 (India 1976) | Wildlife trade; Appendices I–III |
| CMS (Bonn) | 1979 | Migratory species |
| Vienna | 1985 | Ozone framework |
| **Montreal** | 1987 | Ozone-depleting substances; World Ozone Day 16 Sept |
| Basel | 1989 | Hazardous waste movement |
| **UNFCCC, CBD** | 1992 (Rio) | Climate; biodiversity |
| UNCCD | 1994 | Desertification |
| **Kyoto** | 1997 (in force 2005) | Binding targets for Annex I; CDM, JI, trading |
| **Cartagena** | 2000 | Biosafety (LMOs) |
| Stockholm Convention | 2001 | POPs |
| **Nagoya** | 2010 | Access and benefit sharing |
| Minamata | 2013 | Mercury |
| **Paris** | 2015 (in force 2016; India 2 Oct 2016) | Well below 2°C, pursue 1.5°C; NDCs every 5 years |
| **Kigali** | 2016 | HFC phase-down; India freeze 2028, 85% cut by 2047 |
| **Kunming-Montreal GBF** | 2022 | 23 targets; **30 by 30** |
| BBNJ (High Seas) | Adopted 2023; in force 17 Jan 2026 | Biodiversity beyond national jurisdiction |

## Recent COPs

| COP | Outcome |
|-----|---------|
| COP26 Glasgow (2021) | Coal "**phase down**"; India's net zero 2070 |
| COP27 Sharm el-Sheikh (2022) | Loss and Damage fund agreed |
| COP28 Dubai (2023) | Fund operationalised; **first Global Stocktake**; "transitioning away from fossil fuels" |
| COP29 Baku (2024) | **NCQG: US$300 bn a year by 2035** |
| COP30 Belém (2025) | **Global Mutirão** decision; triple adaptation finance by 2035 |
| COP31 Antalya (Nov 2026) | Türkiye hosts; Australia presides over negotiations |
| CBD COP17 | Yerevan, Armenia, 19–30 Oct 2026 |

## Indian Laws and Cases

| Law / case | Year | Point |
|------------|------|-------|
| Arts 48A, 51A(g) | 1976 (42nd Amendment) | DPSP and Fundamental Duty on environment |
| Wildlife (Protection) Act | 1972 | Amended 2022 |
| Forest (Conservation) Act | 1980 | Renamed Van (Sanrakshan Evam Samvardhan) Adhiniyam in 2023 |
| Environment (Protection) Act | 1986 | After Bhopal (1984) |
| Forest Rights Act | 2006 | Individual and community forest rights |
| NGT Act | 2010 | Chhattisgarh under Central Zone bench, Bhopal |
| Vellore Citizens' Welfare Forum | 1996 | Precautionary principle, polluter pays |
| M.C. Mehta v. Kamal Nath | 1997 | Public trust doctrine |

## Don't Confuse

| This | vs | That |
|------|----|------|
| Stockholm **Conference** (1972, UNEP) | vs | Stockholm **Convention** (2001, POPs) |
| **Montreal** Protocol (ozone) | vs | **Kunming-Montreal** GBF (biodiversity) |
| Montreal phases **out** CFCs | vs | Kigali phases **down** HFCs |
| **Cartagena** (biosafety) | vs | **Nagoya** (benefit sharing) |
| **Kyoto** (top-down, Annex I) | vs | **Paris** (bottom-up, all parties) |
| **Hotspot** (rich + threatened) | vs | **Megadiverse** (rich only) |
| **Intensity** target | vs | **Absolute** emissions cut |
| UNFCCC — Bonn · IPCC — Geneva | vs | CBD — Montreal · UNEP — Nairobi |
| Biosphere reserve (UNESCO MAB) | vs | Ramsar site (treaty) |

{{< callout type="warning" title="Favourite MCQ traps" >}}
- India's NDC targets are cuts in **emissions intensity**, and the non-fossil target is about **installed capacity**.
- **HFCs** do not deplete ozone; Kigali covers them as greenhouse gases.
- India has **four** hotspots (Sundaland via the Nicobar Islands); **Chhattisgarh is in none**.
- **Data Deficient** and **Near Threatened** are not "threatened" categories.
- The energy pyramid is **never** inverted; the biomass pyramid can be.
{{< /callout >}}

---
Source: https://cgpscnotes.in/geography/environment-ecology/quick-revision/

Geography Environment and Ecology

Environment and Ecology — Quick Revision

One-page CGPSC quick revision for Environment and Ecology: ecosystems, biodiversity, climate change, India's NDCs and every major convention in tables.

5 min read Updated Oct 2026 #quick revision#cgpsc#environment

Ecosystems, biodiversity, climate change and environmental conventions on one page. For explanations, go back to the chapter.

How to use this sheet

Scan it top to bottom in the week before Prelims. Bold entries are the facts examiners return to most often. Figures marked with a year can change; check the latest before Mains.

Ecosystems

Fact	Detail
“Ecology” / “Ecosystem” coined	Haeckel (1866) / Tansley (1935)
Energy transfer	10% law (Lindeman, 1942); energy flow is one-way
Pyramid never inverted	Energy
Biomass pyramid inverted	Open sea (phytoplankton)
Number pyramid inverted	Single tree with insects
Gaseous vs sedimentary cycles	C, N, O vs P, S
Nitrogen fixation	Rhizobium (legume nodules), Azotobacter, cyanobacteria
Nitrification	Nitrosomonas (NH₃ → nitrite), Nitrobacter (nitrite → nitrate)
Denitrification	Pseudomonas, Thiobacillus
Pioneer species	Lichens (rock, xerarch); phytoplankton (water, hydrarch)
Ecotone	Transition zone; edge effect = more species
Biomagnification	DDT, mercury rising up the food chain
SO₂ indicator	Lichens
Coral reef areas of India	Gulf of Mannar, Gulf of Kachchh, Lakshadweep, Andaman–Nicobar
Ecosystem services (MEA 2005)	Provisioning, regulating, cultural, supporting

Biodiversity

Fact	Detail
Definition	CBD Article 2: within species, between species, of ecosystems
Levels	Genetic, species, ecosystem
India	~2.4% of land, ~7–8% of recorded species; one of 17 megadiverse countries
Biogeographic zones	10; largest = Deccan Peninsula (most of Chhattisgarh)
Hotspot criteria	≥1,500 endemic vascular plants + ≥70% habitat lost (Myers, 1988)
Hotspots	36 worldwide; 4 in India: Himalaya, Indo-Burma, Western Ghats–Sri Lanka, Sundaland (Nicobar)
Threats	HIPPO + climate change
IUCN	1948, Gland (Switzerland); threatened = CR, EN, VU
Biological Diversity Act	2002; NBA Chennai, SBBs, BMCs (People’s Biodiversity Registers); amended 2023
CG state animal / bird / tree	Wild water buffalo / hill myna / sal

Climate Change

Fact	Detail
Natural greenhouse effect	Earth ~+15°C instead of ~−18°C
CO₂ (2024)	423.9 ppm, ~52% above pre-industrial; rise of 3.5 ppm in a year (WMO, 2025)
Warmest year	2024 (~1.55°C above pre-industrial); 2015–2025 the eleven warmest
GWP (100 yr)	CO₂ 1; CH₄ ~28; N₂O ~265–273
Paddy fields emit	Methane
IPCC	1988, WMO + UNEP, Geneva; AR6 synthesis March 2023
NAPCC	30 June 2008; 8 original missions
Chhattisgarh SAPCC	Approved 2014; revision under way
NDC (2015)	33–35% intensity cut, 40% non-fossil capacity, 2.5–3 Gt sink by 2030
NDC update (2022)	45% intensity cut, 50% non-fossil by 2030
NDC 2035	47%, 60%, 3.5–4.0 Gt sink; Cabinet approval 26 March 2026
Net zero	2070 (COP26, Glasgow, 2021)
50% non-fossil capacity	Reached; announced July 2025
Emissions intensity fall	~36% between 2005 and 2020

Conventions

Treaty	Year	Subject
Ramsar	1971 (India 1982)	Wetlands; World Wetlands Day 2 Feb
Stockholm Conference	1972	UNEP (Nairobi); World Environment Day 5 June
CITES	1973 (India 1976)	Wildlife trade; Appendices I–III
CMS (Bonn)	1979	Migratory species
Vienna	1985	Ozone framework
Montreal	1987	Ozone-depleting substances; World Ozone Day 16 Sept
Basel	1989	Hazardous waste movement
UNFCCC, CBD	1992 (Rio)	Climate; biodiversity
UNCCD	1994	Desertification
Kyoto	1997 (in force 2005)	Binding targets for Annex I; CDM, JI, trading
Cartagena	2000	Biosafety (LMOs)
Stockholm Convention	2001	POPs
Nagoya	2010	Access and benefit sharing
Minamata	2013	Mercury
Paris	2015 (in force 2016; India 2 Oct 2016)	Well below 2°C, pursue 1.5°C; NDCs every 5 years
Kigali	2016	HFC phase-down; India freeze 2028, 85% cut by 2047
Kunming-Montreal GBF	2022	23 targets; 30 by 30
BBNJ (High Seas)	Adopted 2023; in force 17 Jan 2026	Biodiversity beyond national jurisdiction

Recent COPs

COP	Outcome
COP26 Glasgow (2021)	Coal “phase down”; India’s net zero 2070
COP27 Sharm el-Sheikh (2022)	Loss and Damage fund agreed
COP28 Dubai (2023)	Fund operationalised; first Global Stocktake; “transitioning away from fossil fuels”
COP29 Baku (2024)	NCQG: US$300 bn a year by 2035
COP30 Belém (2025)	Global Mutirão decision; triple adaptation finance by 2035
COP31 Antalya (Nov 2026)	Türkiye hosts; Australia presides over negotiations
CBD COP17	Yerevan, Armenia, 19–30 Oct 2026

Indian Laws and Cases

Law / case	Year	Point
Arts 48A, 51A(g)	1976 (42nd Amendment)	DPSP and Fundamental Duty on environment
Wildlife (Protection) Act	1972	Amended 2022
Forest (Conservation) Act	1980	Renamed Van (Sanrakshan Evam Samvardhan) Adhiniyam in 2023
Environment (Protection) Act	1986	After Bhopal (1984)
Forest Rights Act	2006	Individual and community forest rights
NGT Act	2010	Chhattisgarh under Central Zone bench, Bhopal
Vellore Citizens’ Welfare Forum	1996	Precautionary principle, polluter pays
M.C. Mehta v. Kamal Nath	1997	Public trust doctrine

Don’t Confuse

This	vs	That
Stockholm Conference (1972, UNEP)	vs	Stockholm Convention (2001, POPs)
Montreal Protocol (ozone)	vs	Kunming-Montreal GBF (biodiversity)
Montreal phases out CFCs	vs	Kigali phases down HFCs
Cartagena (biosafety)	vs	Nagoya (benefit sharing)
Kyoto (top-down, Annex I)	vs	Paris (bottom-up, all parties)
Hotspot (rich + threatened)	vs	Megadiverse (rich only)
Intensity target	vs	Absolute emissions cut
UNFCCC — Bonn · IPCC — Geneva	vs	CBD — Montreal · UNEP — Nairobi
Biosphere reserve (UNESCO MAB)	vs	Ramsar site (treaty)

Favourite MCQ traps

India’s NDC targets are cuts in emissions intensity, and the non-fossil target is about installed capacity.
HFCs do not deplete ozone; Kigali covers them as greenhouse gases.
India has four hotspots (Sundaland via the Nicobar Islands); Chhattisgarh is in none.
Data Deficient and Near Threatened are not “threatened” categories.
The energy pyramid is never inverted; the biomass pyramid can be.

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