UPSC Prelims 2018 Q13: Geography – World Physical Geography
- (a) 1 only
- (b) 2 and 3
- (c) 2 only
- (d) 1 and 3
Answer: (a) 1 only
Explanation
Water Body Shrinkage - Environmental Case Studies
| Water Body | Recent Trend | Cause |
|---|---|---|
| 1. Aral Sea (Central Asia) | Severely shrunk - lost over 90% of its area since 1960 | Soviet-era diversion of Amu Darya and Syr Darya rivers to irrigate cotton fields in Uzbekistan, Kazakhstan; now split into North Aral (partly recovered) and dried-up South Aral. Textbook man-made ecological catastrophe. |
| 2. Black Sea | Not shrunk | Large marginal sea connected to the Mediterranean via Bosphorus. Faces pollution and hypoxia but not desiccation. |
| 3. Lake Baikal | Not shrunk | World's deepest and oldest freshwater lake (Siberia). Faces pollution and invasive algae but stable water levels. |
Answer: (a) 1 only.
Why each option is right or wrong
- (a) CORRECT. Only the Aral Sea has dramatically shrunk due to human-driven river diversion for cotton irrigation.
- (b) Incorrect. Neither the Black Sea nor Lake Baikal has dried up significantly - both retain their water levels.
- (c) Incorrect. The Black Sea faces pollution and eutrophication but is not shrinking.
- (d) Incorrect. Lake Baikal, despite ecological pressures, has not dried up in the recent past.
Key point
Aral Sea = classic case of anthropogenic lake desiccation. Central Asian tragedy from Soviet cotton irrigation diverting Amu Darya and Syr Darya rivers. Kazakhstan has partially revived the North Aral via Kok-Aral dam.
Remember
The Aral Sea in Central Asia has lost more than 90% of its original area since the 1960s because the Soviet Union diverted the Amu Darya and Syr Darya rivers to irrigate cotton plantations. The Black Sea and Lake Baikal, despite facing pollution pressures, have not shrunk significantly in the recent past.
Common mistakes
- Confusing Aral Sea (Central Asia, shrunk) with Dead Sea (Middle East, also shrinking) - both are drying, but only Aral is in this question.
- Thinking Black Sea is landlocked and shrinking - it is a marginal sea connected to the Mediterranean, not shrinking.
- Assuming Lake Baikal is drying up because it is in Siberia - Baikal is the deepest, oldest, and one of the largest freshwater lakes in the world and remains full.
Exam tip
Shrinking water bodies to know: Aral Sea (Central Asia - cotton), Dead Sea (Israel/Jordan - Jordan river diversion), Lake Chad (Africa - overuse + climate), Salton Sea (California). Baikal and Black Sea are NOT in this list.
Sources
- NCERT Class 11 Geography - Fundamentals of Physical Geography (Water in the Atmosphere)
- UNEP Global Environment Outlook - Aral Sea Basin Case Study