Ice ages, mammoths and us
Quaternary
Cenozoic Era · 2.58 million years ago – today
The Quaternary is the current period of Earth's history, beginning 2.58 million years ago and continuing today. It is defined by the ice ages: dozens of cycles in which vast ice sheets grew across the northern continents and then melted back again.
It is also the age of humans. Our genus spread out of Africa, our own species appeared, and by the end of the last ice age people had reached every continent except Antarctica — and begun reshaping the planet itself.
Key facts
- Began
- 2.58 MaMillion years ago
- Ended
- OngoingWe live in it
- Duration
- 2.58 million years
- Era
- Cenozoic“Recent life”
- Global temperature
- ~14°CRoughly 14–15°C · today 14.5°C
- Plants on land
- Flowering plants
- Atmospheric CO₂
- ~180 ppm in glacials, ~280 in interglacials; 420+ today
- Oxygen
- ~21%
- Sea level
- ~120 m lower than today at the Last Glacial Maximum
- Continents
- Modern positions; ice sheets repeatedly cover the north
- Signature life
- Woolly mammoths, sabre-toothed cats, Homo sapiens
- Began with
- Intensifying Northern Hemisphere glaciation
- Ends
- Ongoing — we live in it
Ages follow the International Chronostratigraphic Chart (ICS). Global temperatures are rough reconstructions after Scotese et al. (2021); ancient CO₂, oxygen and sea-level values carry large uncertainties.
Epochs of the Quaternary
- Pleistocene2.58 Ma – 11,700 years ago
- Holocene11,700 years ago – Today
Continents and oceans
The continents have barely moved during the Quaternary; what changed was ice and water. At the height of glacial periods, ice sheets up to about 3 kilometres thick covered Canada and much of the northern United States, Scandinavia and northern Britain, and the Patagonian and Alpine ice caps were greatly enlarged.
Locking up so much water on land lowered sea levels by around 120 metres at the Last Glacial Maximum. Land bridges emerged: Beringia joined Siberia and Alaska, Britain was connected to mainland Europe across Doggerland, and New Guinea, Australia and Tasmania formed a single landmass called Sahul.
Climate and atmosphere
Quaternary climate is paced by small, regular changes in Earth's orbit and tilt, known as Milankovitch cycles, amplified by feedbacks from ice, oceans and carbon dioxide. Early on, glacial cycles repeated about every 41,000 years; after the Mid-Pleistocene Transition, roughly 1.2 to 0.7 million years ago, they became longer and more intense, recurring about every 100,000 years.
The most recent glacial peak, the Last Glacial Maximum, lasted from about 26,000 to 19,000 years ago. Air bubbles trapped in Antarctic ice show that carbon dioxide swung between roughly 180 and 280 parts per million for at least 800,000 years; human activity has now pushed it above 420.
Life in the Quaternary
Animals and plants shifted their ranges back and forth with each glacial cycle. Cold-adapted giants thrived on the vast, grassy 'mammoth steppe' that stretched from western Europe to the Yukon, while other species retreated to warmer refuges and expanded again during interglacials.
Ice age megafauna
Woolly mammoths, woolly rhinoceroses, cave bears and giant deer roamed Eurasia. The Americas had sabre-toothed cats such as Smilodon, giant ground sloths and armoured glyptodonts, while Australia was home to Diprotodon, a wombat relative the size of a rhinoceros.
The human family
Homo erectus appeared around 2 million years ago and was the first hominin known to have spread beyond Africa. Neanderthals lived across Europe and western Asia, and other relatives included the Denisovans and the small Homo floresiensis of Indonesia.
Homo sapiens
Our own species arose in Africa; fossils from Jebel Irhoud in Morocco are about 300,000 years old. Modern humans spread across Eurasia and into Australia by roughly 50,000 years ago or earlier, and into the Americas by the end of the last ice age, interbreeding with Neanderthals and Denisovans along the way.
The megafaunal extinctions
Over the past 50,000 years or so, many large animals disappeared, especially in Australia and the Americas. Scientists continue to debate the balance between climate change and human hunting, but the timing in many regions closely follows the arrival of people.
Timeline of key events
- 2.58 Ma
Quaternary begins
Northern Hemisphere ice sheets intensify, opening an era of repeated glacial cycles.
- 2 Ma
Homo erectus appears
A long-legged human relative emerges in Africa and soon becomes the first hominin to spread into Asia.
- 1 Ma
Mid-Pleistocene Transition
Glacial cycles lengthen from about 41,000 to about 100,000 years and become more severe.
- 0.3 Ma
Homo sapiens emerges
Early members of our species live in Africa, as shown by fossils from Jebel Irhoud in Morocco.
- 40,000 years ago
Neanderthals disappear
The last Neanderthals vanish from Europe, leaving traces of their DNA in many living people.
- 26,000 years ago
Last Glacial Maximum begins
Ice sheets reach their greatest recent extent and sea level falls about 120 metres below today's.
- 11,700 years ago
Holocene begins
The last ice age ends 11,700 years ago and a warmer, more stable climate sets in.
Is the Quaternary over?
No. The Quaternary is ongoing, and we live in its current epoch, the Holocene, which began 11,700 years ago as the last ice age ended. The Holocene's relatively stable climate coincided with the invention of farming, the growth of cities and the whole of written history.
Many scientists argued that human impact — from greenhouse gases and nuclear-test fallout to plastics and mass extinctions — justified a new epoch, the Anthropocene, starting in the mid-20th century. In March 2024 the proposal was rejected as a formal epoch by the relevant ICS subcommission and the decision was upheld by the IUGS, although the term remains widely used informally to describe humanity's planetary footprint.
Where to see Quaternary fossils
The La Brea Tar Pits in Los Angeles have yielded millions of fossils, from Smilodon and dire wolves to mammoths, trapped in natural asphalt over the past 50,000 years. The Mammoth Site in Hot Springs, South Dakota, preserves dozens of mammoths in an ancient sinkhole, and Naracoorte Caves in South Australia record ice age marsupials.
Siberian permafrost has given up astonishingly complete frozen mammoths, such as the baby mammoth Lyuba. Human fossils and tools can be seen at sites such as Zhoukoudian near Beijing, home of 'Peking Man', and the cave sites of Europe, including Kents Cavern in Devon.
Surprising facts about the Quaternary
- Woolly mammoths survived on Wrangel Island in the Arctic Ocean until about 4,000 years ago, after the Great Pyramid of Giza had been built.
- During the last interglacial, about 125,000 years ago, hippos lived in Britain; their bones have been found beneath Trafalgar Square in London.
- At the Last Glacial Maximum, you could have walked from Britain to the Netherlands across Doggerland, now beneath the North Sea.
- Ice cores drilled in Antarctica contain tiny bubbles of ancient air that record the atmosphere for at least the past 800,000 years.
- Most people of non-African descent carry roughly 1–2% Neanderthal DNA, a legacy of interbreeding tens of thousands of years ago.
- Homo floresiensis, a human relative only about a metre tall, lived on the Indonesian island of Flores until roughly 50,000 years ago.
Where it sits in deep time
The globe beside this article shows Earth today, reconstructed from the PALEOMAP paleo-elevation models. Step to another period and watch the continents drift into place.