NEWS 1
GS1 • Geography; GS3 • Environment and Climate Change
Source: The Hindu
A Distant Pacific Pattern May Be Drying North India
Context: A study by the India Meteorological Department (IMD) and the Indian Institute of Tropical Meteorology (IITM), published in MAUSAM, examines shifts in India's climate zones over seven decades and the possible influence of the Pacific's Victoria Mode on rainfall.
Köppen Climate Classification: Major Types
Basis & groups
Classifies climates mainly by temperature and precipitation; has five principal groups (A–E), each with subtypes.
Classifies climates mainly by temperature and precipitation; has five principal groups (A–E), each with subtypes.
A, B and C
A — Tropical: rainforest (Af), monsoon (Am), savannah (Aw); B — Dry: desert (BW) and steppe (BS), e.g., western Rajasthan; C — Temperate: humid subtropical (Cwa/Cfa) and Mediterranean-type (Cs).
A — Tropical: rainforest (Af), monsoon (Am), savannah (Aw); B — Dry: desert (BW) and steppe (BS), e.g., western Rajasthan; C — Temperate: humid subtropical (Cwa/Cfa) and Mediterranean-type (Cs).
D and E
D — Continental: cold winters, large seasonal differences, not a major group in India; E — Polar: tundra (ET) and ice cap (EF), mainly polar regions; high Himalayan areas have distinct alpine conditions.
D — Continental: cold winters, large seasonal differences, not a major group in India; E — Polar: tundra (ET) and ice cap (EF), mainly polar regions; high Himalayan areas have distinct alpine conditions.
Major Findings: Climate-Zone Shifts (1951–80 to 1991–2020)
Northwest India
Hot semi-arid steppe zone expanded from 25.7% to 33.1%, while the temperate zone fell from 25.8% to 18.7%.
Hot semi-arid steppe zone expanded from 25.7% to 33.1%, while the temperate zone fell from 25.8% to 18.7%.
Uttar Pradesh
The eastern boundary of the steppe zone shifted towards eastern Uttar Pradesh, indicating expanding drier conditions.
The eastern boundary of the steppe zone shifted towards eastern Uttar Pradesh, indicating expanding drier conditions.
Northeast India
Tropical savannah fell from 18.4% to 11.8%; the temperate zone rose from 74.8% to 82.5%.
Tropical savannah fell from 18.4% to 11.8%; the temperate zone rose from 74.8% to 82.5%.
Peninsular India & others
Steppe zone contracted from 30.3% to 16.4%; tropical savannah expanded from 61.6% to 75.7%; Marathwada and West Vidarbha shifted towards semi-arid conditions; tropical monsoon zones expanded along parts of the western coast.
Steppe zone contracted from 30.3% to 16.4%; tropical savannah expanded from 61.6% to 75.7%; Marathwada and West Vidarbha shifted towards semi-arid conditions; tropical monsoon zones expanded along parts of the western coast.
Victoria Mode (VM) and Indian Rainfall
Definition
A recurring pattern of warm and cool sea-surface temperatures in the North Pacific Ocean.
A recurring pattern of warm and cool sea-surface temperatures in the North Pacific Ocean.
Link to rainfall
The study associates the negative phase with reduced moisture transport towards northern India; Pacific sea-surface changes may contribute to declining rainfall in parts of Uttar Pradesh, Bihar and Gangetic West Bengal.
The study associates the negative phase with reduced moisture transport towards northern India; Pacific sea-surface changes may contribute to declining rainfall in parts of Uttar Pradesh, Bihar and Gangetic West Bengal.
Major Implications
Impacts
Agriculture: altered crop suitability, sowing schedules and irrigation needs; food security; water stress and groundwater depletion; rural livelihoods; possible migration from stressed regions.
Agriculture: altered crop suitability, sowing schedules and irrigation needs; food security; water stress and groundwater depletion; rural livelihoods; possible migration from stressed regions.
Key Takeaway: The study's headline is two-way — northwest India and parts of Uttar Pradesh are getting drier (steppe zone up from 25.7% to 33.1%) while peninsular India shows the opposite pattern (steppe down from 30.3% to 16.4%), and a distant Pacific cycle is proposed as one possible influence.
Prelims Practice MCQ
+2 correct • −0.66 wrongConsider the following statements:
1. The Köppen classification has five principal climate groups, labelled A to E.
2. According to the study, the hot semi-arid steppe zone in northwest India contracted between 1951–80 and 1991–2020.
3. The Victoria Mode is a recurring pattern of warm and cool sea-surface temperatures in the North Pacific Ocean.
Which of the statements given above is/are correct?
Explanation: Statements 1 and 3 are correct. Statement 2 is incorrect — the steppe zone in northwest India expanded from 25.7% to 33.1%.
UPSC Mains Question
10 Marks • 150 WordsDiscuss the shifts in India's climate zones identified by the IMD–IITM study and examine their implications for agriculture and water security.
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Use after attempting the Mains answer
- Name the five Köppen groups (A Tropical, B Dry, C Temperate, D Continental, E Polar) with Indian examples; D is not a major group in India.
- Memorise the zone shifts — NW steppe 25.7%→33.1%, NW temperate 25.8%→18.7%, NE savannah 18.4%→11.8%, NE temperate 74.8%→82.5%, peninsular steppe 30.3%→16.4%, savannah 61.6%→75.7%.
- Define the Victoria Mode and its negative-phase link to reduced moisture transport to northern India.
- State the study details — IMD and IITM, published in MAUSAM, 1951–80 vs 1991–2020.
- Link to the 1 October topic on the 2026 monsoon deficit for the rainfall context.
