Major lakes of the world

Story hook

1996. Russian-American scientists drop a 60-cm metal sphere through 1,300 m of ice at the southern Russian research station Vostok, in Antarctica. Beneath the ice lies a body of water unseen by sunlight for 15 million years — Lake Vostok, the size of Lake Ontario, sealed under the ice for so long that microorganisms recovered from it may represent forms of life unique to Earth's geological past.

A continent away, Lake Baikal in Siberia is so old (25-30 million years), so deep (1,642 m), and so voluminous (23,615 km³) that it holds 20% of all the world's liquid freshwater — more water than all five North American Great Lakes combined. Its dragon-fish, omul, and the world's only freshwater seal (Pusa sibirica) have evolved in it independently of the rest of the planet.

Lakes are not just blue stains on the map. They are isolated evolutionary laboratories, climate archives (their sediment cores log 100,000-year rainfall records), freshwater stores (lakes hold 87% of the world's surface freshwater), and flashpoints (the Aral Sea, once world's 4th-largest, has been drained by Soviet cotton irrigation in living memory).

Why this matters for UPSC

Syllabus location: GS-I — World Physical Geography (major lakes). Asked 2-3 times in Prelims over the last decade — lake-country pairings, deepest/largest combos, lake disasters (Aral, Chad). Mains 2017 used Lake Chad as a climate-conflict case. Solid map + factual zone.