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End of the last Ice Age
warming from c. 14,700 years ago; Holocene begins c. 9700 BC· Event· Universe & Earth
Well documentedSolid records, physical evidence or scientific consensus.
Between about 14,700 and 11,700 years ago, Earth warmed out of the last glacial period into the stable Holocene climate.
See it on the History map →What happened
At the ice's peak, about 20,000 years ago, sheets up to about 3 km (2 miles) thick covered Canada and northern Europe, and seas stood about 120 m (400 feet) lower. Shifts in Earth's orbit, amplified by rising carbon dioxide, triggered melting. Warming came in jumps, broken by a sharp cold snap, the Younger Dryas, about 12,900–11,700 years ago. Rising seas drowned Beringia and the plains between Britain and Europe. The Curious Science map explains the climate mechanics.
Why it matters
The warmer, wetter, steadier Holocene made farming practical. Every civilization in history has lived inside this unusually stable 11,700-year window.
How we know
Ice cores from Greenland and Antarctica, ocean sediments, pollen in lake beds and ancient shorelines record temperature, carbon dioxide and sea level in fine detail.
Still debated
What caused the Younger Dryas cold snap is debated: most scientists blame meltwater disrupting Atlantic currents; a minority argue for a comet impact.
Connections (3)
▸End of the last Ice Age made possible Agricultural (Neolithic) RevolutionMostly agreed
The connection
Ice Age climate was colder, drier, lower in carbon dioxide and wildly variable, making crops unreliable. After about 11,700 years ago the Holocene brought warmth, more rain, more carbon dioxide for plants and steadier seasons. Within a few thousand years, farming began independently in several regions, first in the Fertile Crescent.
When and how
Worldwide, from about 11,700 years ago; earliest farming in the Fertile Crescent about 9500 BC, among descendants of the Natufian foragers.
How sure are we?
Ice cores and lake sediments record the climate shift; dated crop remains show farming starting only after it, on several continents within a geologically short time.
Debates and open questions
Climate made farming possible, not inevitable. Why people chose it, and whether the Younger Dryas cold snap pushed Natufians toward cultivation, are debated.
▸End of the last Ice Age opened routes for Settlement of the AmericasDebated
The connection
As ice sheets melted, the Pacific coast of Alaska and Canada became free of ice by about 16,000 years ago, and an inland ice-free corridor opened about 14,000 years ago. These openings let people in Beringia move south. Rising seas later drowned the land bridge behind them.
When and how
Coastal Alaska and British Columbia by about 16,000 years ago; an inland corridor between the two great North American ice sheets by about 14,000 years ago.
How sure are we?
Geological dating of the ice retreat. The link is debated because the White Sands footprints suggest people were south of the ice before these routes opened.
Debates and open questions
If people were in New Mexico 23,000 years ago, how did they get past the ice, and did their descendants survive?
▸End of the last Ice Age was natural warming far slower than Human-caused climate changeWell documented
The connection
Ending the Ice Age warmed the planet about 4–7°C (7–13°F) over several thousand years, driven by orbital shifts amplified by carbon dioxide. Today's human-caused warming, about 1.3°C since the late 1800s and driven by burning fossil fuels, is happening at least ten times faster.
When and how
Deglaciation from about 19,000 to 11,700 years ago, worldwide; modern warming since the Industrial Revolution, accelerating after 1950.
How we know
Ice cores, ocean sediments and other natural archives measure past rates; thermometers and satellites measure today's.
Debates and open questions
Past rates vary by region and method, and how ice sheets will respond to today's much faster warming is a major open question.