Permafrost

noun (uncountable)

/ˈpɜːməfrɒst/

Permanently frozen ground — soil, sediment, or rock — in which temperatures have remained at or below 0°C continuously for two or more years, underlying approximately 25% of the Northern Hemisphere's land surface. The active layer above permafrost thaws seasonally; as permafrost degrades under climate warming, it releases stored carbon (estimated 1,460–1,600 Gt of organic carbon globally) as CO₂ and methane, creating a critical positive feedback loop in climate models. In India, permafrost exists in Ladakh and the high Himalayas, and thawing is linked to glacial lake outburst flood (GLOF) risks monitored by the National Disaster Management Authority.

✍️ Usage in a UPSC answer

Accelerating permafrost degradation in the Ladakh region, as documented by the Geological Survey of India since 2015, threatens the structural integrity of ice stupas and artificial glaciers relied upon by high-altitude communities for summer irrigation.

Synonyms

permanently frozen groundpergelisol (technical synonym)cryotic groundfrozen subsoil

Antonyms

active layerseasonally frozen groundtemperate soiltropical soil

🌱 Word Family

permafrost (noun), permafrosted (adjective, rare), active layer (related compound noun), thermokarst (related noun, permafrost degradation landform)

🔡 Root

Permanent + frost; English compound; permanent from Latin permanere = to remain throughout

📜 Etymology

The English compound 'permafrost' was coined by American geologist Siemon Muller in 1943, contracting 'permanently frozen ground' in a report for the United States Army Corps of Engineers. The concept had been studied in Russian scientific literature since the 18th century under the term vechaya merzlota (eternal frost), following Siberian exploration. Muller's concise English term was rapidly adopted internationally.

🧠 Memory Hook

PERMA-FROST = PERMANENT FROST. The ground never truly thaws — it's frozen 'permanently'. Think of it as the Earth's deep-freeze: a natural refrigerator where ancient organic matter has been stored for thousands of years.

🌍 Geography 📖 Seen in: Plate Tectonics & Volcanism — Continen...

Tip: press Alt+S to hear pronunciation