Past and Present Ice Cover

Understanding the history of glaciation — and the evidence used to reconstruct it — is fundamental to A-Level Geography. The Earth has experienced repeated glacial episodes over geological time, with the most recent major period (the Pleistocene) shaping much of the landscape we see today in the UK and across the globe. This lesson examines the causes of glaciation, the evidence for past ice cover, and the current state of the world's ice.

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The Pleistocene Epoch

The Pleistocene epoch lasted from approximately 2.6 million years ago to 11,700 years ago. It was characterised by repeated cycles of glacial and interglacial periods:

• Glacial periods (ice ages) — lasting approximately 80,000–100,000 years; global temperatures 5–8°C lower than today; massive ice sheets covered large areas of the Northern Hemisphere
• Interglacial periods — lasting approximately 10,000–30,000 years; temperatures similar to or slightly warmer than today; ice sheets retreated to polar regions
• We are currently in an interglacial period — the Holocene — which began approximately 11,700 years ago

UK Glacial Chronology