Environment & Ecology — UPSC Notes | Exam-Ki-Aisi-Ki-Taisi.com

Topics Covered

1. Ecology Basics 2. Biodiversity 3. Climate Change 4. International Treaties 5. Indian Environmental Laws 6. Protected Areas

Ecology Basics

Ecosystem

Components

Abiotic: Non-living — sunlight, water, temperature, soil, minerals
Biotic: Living — Producers (plants), Consumers (animals), Decomposers (fungi, bacteria)
Trophic Levels: Producers → Primary consumers → Secondary → Tertiary → Apex predators
10% Law (Lindemann): Only 10% of energy transfers to next trophic level

Biogeochemical Cycles

Key Cycles

Carbon Cycle: Photosynthesis, respiration, decomposition, fossil fuel combustion; CO₂ is key greenhouse gas
Nitrogen Cycle: Nitrogen fixation (Rhizobium), nitrification, denitrification; nitrogen = 78% of atmosphere
Water Cycle: Evaporation, transpiration (evapotranspiration), condensation, precipitation, runoff

Ecological Succession

Primary succession: Pioneer community establishes on bare substrate (no soil) — e.g., rock, new lava field. Secondary succession: After disturbance where soil remains — faster than primary. Both end in a stable Climax Community.

Biodiversity

India's Biodiversity

India is one of 17 Megadiverse countries. 7–8% of world's recorded species in 2.4% of world's area. India has 4 Biodiversity Hotspots:

Biodiversity Hotspots in India

1. Himalayas (entire Himalayan range)
2. Western Ghats (includes Sri Lanka in the broader hotspot)
3. Indo-Burma (NE India)
4. Sundaland (Andaman & Nicobar Islands part of this broader hotspot)
A hotspot: >1500 endemic vascular plant species AND lost >70% original vegetation

Types of Biodiversity

Genetic diversity: Variation within species (gene pool)
Species diversity: Variety of species in an ecosystem (species richness)
Ecosystem diversity: Variety of ecosystems in a region

Conservation

Method	Examples
In-situ conservation (in natural habitat)	Wildlife sanctuaries, National Parks, Biosphere Reserves, Tiger Reserves
Ex-situ conservation (outside habitat)	Zoological parks, Botanical gardens, Gene banks, Seed banks, Cryopreservation

India's Protected Area Network

106 National Parks, 567 Wildlife Sanctuaries, 18 Biosphere Reserves (12 in UNESCO network), 55 Tiger Reserves (Project Tiger — 1973), 33 Elephant Reserves (Project Elephant — 1992)

Climate Change

Greenhouse Effect & Global Warming

Greenhouse Gases (GHGs)

CO₂ (most abundant; long-lived), CH₄ (methane — 28x CO₂ warming potential), N₂O (nitrous oxide — 265x), HFCs, PFCs, SF₆ (most potent — 23,500x)
Global warming potential (GWP) measured over 100 years

IPCC

Intergovernmental Panel on Climate Change — set up by UNEP & WMO. Not a research body — assesses existing scientific literature. Reports used by UNFCCC negotiations. AR6 (6th Assessment Report) released 2021-22.

India's Climate Commitments

India's NDC (Nationally Determined Contribution)

Reduce emissions intensity of GDP by 45% by 2030 (vs 2005 levels)
50% cumulative electric power from non-fossil fuels by 2030
Net zero emissions by 2070
Restore 26 million hectares of degraded land by 2030

International Environmental Conventions

Convention	Year	About
UNFCCC	1992 (Rio Earth Summit)	Climate change framework; COP meetings annually
Kyoto Protocol	1997	Binding emission targets for developed countries (Annex I)
Paris Agreement	2015 (COP21)	Limit warming to 1.5°C; NDCs; all countries
CBD (Convention on Biological Diversity)	1992 (Rio)	Conservation of biodiversity; Nagoya Protocol (ABS — Access and Benefit Sharing)
CITES	1975	International trade in endangered species; Appendices I, II, III
Ramsar Convention	1971	Wetlands of international importance; India has 75 Ramsar sites
Vienna Convention + Montreal Protocol	1987	Phase out ozone-depleting substances (CFCs, HCFCs)
Basel Convention	1989	Control transboundary movement of hazardous wastes
Stockholm Convention	2001	Persistent Organic Pollutants (POPs); 12 "Dirty Dozen" chemicals
Minamata Convention	2013	Mercury pollution control

Mnemonic — Important Summits

Stockholm 1972 (first Earth Summit), Rio 1992 (UNFCCC, CBD, UNCCD), Rio+20 2012, Paris 2015 (COP21), Glasgow 2021 (COP26 — Phase down coal), Dubai 2023 (COP28 — First Global Stocktake)

Indian Environmental Laws

Act	Year	Key Provisions
Wildlife Protection Act	1972	Schedules I–VI for species protection; National Parks, Sanctuaries; amended 2022
Forest Conservation Act	1980	Prior Central Govt approval for diversion of forest land
Environment Protection Act	1986	Umbrella act (post Bhopal gas tragedy); Central Govt power to protect environment
Air (Prevention and Control of Pollution) Act	1981	State Pollution Control Boards; standards
Water (Prevention and Control of Pollution) Act	1974	CPCB (Central Pollution Control Board) at national level
Biological Diversity Act	2002	National Biodiversity Authority (NBA), State Biodiversity Boards
National Green Tribunal Act	2010	Specialised court for environmental disputes

Protected Areas & Biosphere Reserves

Biosphere Reserve Zones

Core Zone: Strictly protected; no human activity; natural processes
Buffer Zone: Research, education, tourism permitted
Transition Zone: Sustainable development; human habitation allowed
India's 18 Biosphere Reserves: 12 are in UNESCO's World Network of Biosphere Reserves

IUCN Red List Categories

Extinct (EX) → Extinct in Wild (EW) → Critically Endangered (CR) → Endangered (EN) → Vulnerable (VU) → Near Threatened (NT) → Least Concern (LC)
CR, EN, VU together = "Threatened" categories
Examples: Bengal Tiger (EN), Indian Elephant (EN), Lion-tailed Macaque (EN), Indian One-horned Rhinoceros (VU), Snow Leopard (VU)