Chapter Overview

Environment and Ecology (पर्यावरण एवं पारिस्थितिकी) links geography, biology and international relations. Prelims Paper I asks precise facts: food chains and pyramids, nutrient cycles, hotspots and IUCN categories, greenhouse gases, India’s climate targets, and treaty–year matching. Mains Paper IV (GS-II) asks you to explain ecosystem services, threats to biodiversity, climate impacts and India’s position in global negotiations. Chhattisgarh supplies the examples: sal forests, the wild buffalo, rainfed paddy, the coal belt and the Kopra Ramsar site.

What You’ll Learn

By the end of this chapter, you will be able to:

Explain ecosystem structure, the 10% law, ecological pyramids, the carbon and nitrogen cycles and succession
Define biodiversity at three levels, and recall India’s megadiverse status, 10 biogeographic zones and 4 hotspots
Use IUCN Red List categories correctly and describe the Biological Diversity Act, 2002
Explain the greenhouse effect, the main GHGs and their sources, and the IPCC’s key findings (with dates)
State India’s climate commitments: the NDCs of 2015, 2022 and 2035, and net zero by 2070
Match every major convention with its year, place and subject, and summarise COP26 to COP31
Write Mains answers on climate change and biodiversity with a Chhattisgarh angle

Prerequisites

Climate of India — monsoon mechanism and variability
Soils and Natural Vegetation — forest types and soil processes
Forests and Wildlife of Chhattisgarh — the state’s own protected areas

Learning Path

Follow the topics in this order:

graph TD
    A["1. Ecosystems
Structure, energy flow,
cycles, succession"] --> B["2. Biodiversity
Levels, hotspots,
threats, IUCN"]
    B --> C["3. Climate Change
GHGs, IPCC, impacts,
NAPCC, India's NDCs"]
    C --> D["4. Environmental Conventions
Ramsar to Paris,
COPs, CBD, Indian laws"]
    D --> E["5. Quick Revision
One-page sheet"]
    E --> F["Related chapters:
Biodiversity and Conservation,
Pollution and Waste"]

Topics in This Chapter

#	Topic	What it covers
1	Ecosystems	Ecology terms, producers to decomposers, productivity, 10% law, pyramids, nutrient cycles, succession, key species concepts, biomes, wetlands, mangroves, reefs, ecosystem services
2	Biodiversity	Three levels, alpha/beta/gamma, megadiversity, 10 biogeographic zones, 36 hotspots, values, HIPPO threats, IUCN Red List, Biological Diversity Act 2002
3	Climate Change	Greenhouse effect, GHGs and GWP, dated evidence, IPCC, impacts on India and Chhattisgarh, mitigation and adaptation, NAPCC, NDCs, net zero 2070
4	Environmental Conventions	Ramsar, CITES, CMS, Montreal–Kigali, chemicals treaties, Rio, UNFCCC, Kyoto, Paris, COP26–COP31, CBD and its protocols, BBNJ, Indian laws and cases
—	Quick Revision	Every date, number and treaty on one page

Where It Is Asked

Paper	What to expect
Prelims P-I (Part 1, India GS)	Concept MCQs (pyramids, cycles, succession, biomagnification), lists (hotspots, IUCN categories, NAPCC missions), and treaty–year–subject matching. Statement-based questions on recent COPs and India’s NDCs are common. Chhattisgarh facts (Kopra Ramsar site, Achanakmar–Amarkantak biosphere reserve) also appear in Part 2
Mains P-IV (GS-II)	Short answers (mitigation vs adaptation, hotspot definition, Kyoto vs Paris) and longer analytical answers (ecosystem services, threats to biodiversity, climate impacts on agriculture, India’s climate diplomacy)
Mains P-II (Essay)	Climate change, development vs environment and sustainable development are recurring essay themes

Exam focus

High-yield: the pyramid that is never inverted; nitrification bacteria; hotspot criteria and India’s four; threatened IUCN categories; NDC numbers (45/50 by 2030, 47/60 by 2035, net zero 2070); Montreal vs Kigali; Cartagena vs Nagoya; COP26–COP30 outcomes.
Common mistakes: treating India’s targets as absolute cuts (they are intensity targets); calling HFCs ozone-depleting; saying Glasgow agreed to “phase out” coal; counting three hotspots in India instead of four.
Chhattisgarh angle for Mains: rainfed paddy and methane, the Korba coal belt and a just transition, Hasdeo Arand forests, the wild buffalo, the Kopra Ramsar site, the State Action Plan on Climate Change (2014).

Quick Reference: Chapter at a Glance

Item	Key fact
“Ecosystem” coined	A.G. Tansley, 1935
10% law	Lindeman, 1942; energy flows one way
Never-inverted pyramid	Energy
Biodiversity hotspots	36 worldwide; 4 in India; criteria 1,500 endemic plants + 70% habitat loss
Biogeographic zones	10; Chhattisgarh in the Deccan Peninsula
IUCN threatened	CR, EN, VU
CO₂ (2024)	423.9 ppm (WMO)
NAPCC	2008, 8 original missions
India’s NDCs	2030: 45% intensity, 50% non-fossil · 2035: 47%, 60% (approved March 2026) · Net zero 2070
Paris Agreement	2015, in force 2016; NDCs every 5 years
Chhattisgarh’s first Ramsar site	Kopra reservoir, Bilaspur (2025)

Start Learning

Begin with the first topic:

→ Ecosystems: Structure, Energy Flow, Cycles and Succession