UPSC Prelims · Bite-size lessons
Environmental Ecology, Biodiversity and Climate Change
About 7 min · General Studies Paper I · English
Time worked out from the lesson's 494 words at 150 words a minute, plus a minute for each question.
This section tests your understanding of ecological concepts, India's biodiversity wealth, conservation mechanisms, pollution issues, and global climate agreements. Questions can be application-based, linking current environmental news with foundational concepts.
Key ideas
- Ecosystem Services: Four categories — provisioning (food, water), regulating (climate, flood control), cultural (recreation, spiritual), and supporting (nutrient cycling, soil formation).
- Ecological Succession: Primary succession occurs on bare substrate (lava, rock); secondary succession on disturbed but soil-present areas. Climax community represents the stable, final stage.
- Biodiversity Hotspots: 36 globally; India has 4 — Western Ghats, Himalayas, Indo-Burma, Sundaland. Criteria: at least 1,500 endemic vascular plants AND at least 70% habitat loss.
- In-situ vs Ex-situ Conservation: In-situ (on-site) includes national parks, sanctuaries, biosphere reserves. Ex-situ (off-site) includes zoos, seed banks, botanical gardens, cryopreservation.
- Carbon Cycle and Sinks: Oceans are the largest carbon sink, followed by forests and soil. Deforestation and ocean acidification reduce sink capacity.
Watch out for
- Confusing weather with climate → Weather is short-term atmospheric conditions; climate is long-term average (typically 30 years). IPCC deals with climate, not weather prediction.
- Assuming all protected areas prohibit human presence → National Parks are strictest; Wildlife Sanctuaries can permit limited grazing and human rights; Biosphere Reserves have people living in buffer and transition zones.
- Mixing up Montreal and Kyoto Protocols → Montreal Protocol addresses ozone layer (CFCs/HCFCs); Kyoto Protocol addresses greenhouse gases (climate change). The Kigali Amendment to Montreal added HFCs, creating overlap.
Quick reference
- 4 Indian biodiversity hotspots: Western Ghats, Himalayas, Indo-Burma, Sundaland
- IUCN threat order: CR > EN > VU > NT > LC
- Biosphere Reserve zones: Core (strict) → Buffer (research) → Transition (human settlements)
- Paris Agreement: NDCs + 1.5/2°C target + Global Stocktake every 5 years
- India's net-zero target: 2070 (announced at COP26)
Check yourself: 3 questions
1. Biosphere reserves in India are designated under which of the following programmes?
2. Consider the following statements regarding India's Nationally Determined Contributions (NDCs) under the Paris Agreement: 1. India has committed to reduce emissions intensity of its GDP by 45% by 2030 from 2005 levels. 2. India aims to achieve 50% cumulative electric power installed capacity from non-fossil fuel-based energy resources by 2030. 3. India pledged to create an additional carbon sink of 2.5 to 3 billion tonnes of CO2 equivalent through forest and tree cover by 2030. Which of the statements given above is/are correct?
3. The Western Ghats are recognized as one of the world's biodiversity hotspots. Which of the following factors contribute to the high biodiversity of the Western Ghats? 1. High rainfall and tropical climate 2. Varied altitude ranging from sea level to over 2500 meters 3. Geographical isolation from other mountain ranges 4. Ancient geological history with limited disturbance Select the correct answer using the code given below:
This lesson is cut from the topic's note, not rewritten. Fact-checked on 21 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.
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