Timeline of glaciation facts for kids

Climate history over the past 500 million years, showing the last three big ice ages: Andean-Saharan (450 million years ago), Karoo (300 million years ago), and Late Cenozoic. A smaller cold time is also shown during the Jurassic-Cretaceous period (150 million years ago).

Our Earth has gone through at least five or six major ice ages over the last 3 billion years. An ice age is a long period when the Earth's climate gets much colder, leading to large areas of land being covered by ice sheets and glaciers.

The Late Cenozoic Ice Age started about 34 million years ago. The most recent part of this ice age is called the Quaternary glaciation, which began 2.58 million years ago and is still happening today.

Inside these big ice ages, there are colder times called glacial periods, when glaciers grow bigger. There are also warmer times called interglacial periods, when the ice melts back. Right now, Earth is in an interglacial period of the Quaternary glaciation. The last very cold period, known as the Last Glacial Period, ended around 11,700 years ago. Our current warm period is called the Holocene epoch. Scientists who study past climates, called paleoclimatologists, use clues from the past to understand these different climate changes.

What are the Main Ice Ages?

Major known ice ages shown in blue on a timeline of Earth's existence.

Scientists have found evidence for several major ice ages throughout Earth's long history. Here's a quick look at the most important ones:

Famous Ice Age Events

One of the most extreme ice ages happened about 720 to 635 million years ago. This was during the Neoproterozoic Era. Some scientists believe Earth became a "Snowball Earth" during this time. This means our planet might have been completely covered in ice, from the poles to the equator!

It's also thought that the end of this super cold period helped cause the Cambrian explosion. This was a time when many new types of multi-celled life forms suddenly appeared and grew diverse during the Cambrian Period. This idea is still being studied, but more and more evidence supports it.

Later, smaller periods of ice growth happened between 460 and 430 million years ago. Then, much larger ice sheets covered parts of the Earth from 350 to 289 million years ago.

The Late Cenozoic Ice Age has seen huge ice sheets covering Antarctica for the last 34 million years. In the last 3 million years, ice sheets also started to grow in the northern half of the world. This recent phase is what we call the Quaternary glaciation. It has had many times of more or less ice. At first, these ice cycles happened about every 41,000 years. But after a big change called the Mid-Pleistocene Transition, the cycles became much bigger and happened about every 100,000 years.

Naming Ice Age Cycles

The Quaternary glaciation is special because its ice sheets covered parts of Europe and North America where many people live today. Early geologists gave names to the different cold and warm periods based on local land features. These names were different depending on the region.

Today, scientists often use a global numbering system called Marine Isotopic Stages (MIS). This system uses clues from ocean sediments to track all past ice ages. Land-based evidence is less complete because new ice ages can erase signs of older ones. However, Ice cores (long tubes of ice drilled from glaciers) also give a full record, but they don't go back as far as ocean data.

Even though the "names" system is mostly replaced by MIS numbers, it's still useful for talking about landforms and connecting them to the global MIS stages.

Ice Age Names in the Alps

Here are some of the historical names for ice ages and warm periods used in the Alps region:

• Biber (2.6–1.8 million years ago)
• Danube (1.8–1.0 million years ago)
• Günz (1.0–0.4 million years ago)
• Mindel (around MIS 12 or 10)
• Mindel-Riss interglacial (a warm period, MIS 9)
• Riss (MIS 8-6)
• Riss-Würm interglacial (a warm period, MIS 5e)
• Würm (MIS 5d-2)

Ice Age Names in Great Britain and Ireland

• Bramertonian Stage
• Baventian Stage/Pre-Pastonian
• Pastonian Stage
• Beestonian stage
• Cromerian Stage (MIS 21-13 ?)
• Anglian Stage (MIS 12, perhaps also MIS 10 ?)
• Hoxnian Stage (MIS 11, perhaps also MIS 9 ?)
• Wolstonian Stage (MIS 8–6, perhaps also MIS 10–9 ?)
• Ipswichian interglacial (a warm period, MIS 5e)
• Devensian glaciation (MIS 5d-2)
• Flandrian interglacial (our current warm period, MIS 1)

Ice Age Names in Northern Europe

• Pre-Tiglian
• Tiglian interglacial
• Eburonian
• Waalian interglacial
• Menapian glacial stage
• Bavelian
• Cromerian complex (MIS 21-13 ?)
• Elster glaciation (MIS 10, perhaps also MIS 12 ?)
• Holstein interglacial (a warm period, MIS 9 ?)
• Saale glaciation (ended with MIS 6)
• Eem interglacial (a warm period, MIS 5e)
• Weichsel glaciation (MIS 5d-2)

Ice Age Names in North America

• Nebraskan glaciation (now often called Pre-Illinoian)
• Aftonian interglacial (now often called Pre-Illinoian)
• Kansan glaciation (now often called Pre-Illinoian)
• Yarmouthian (stage) (now often called Pre-Illinoian)
• Illinoian stage (MIS 6)
• Sangamonian (a warm period, MIS 5e, sometimes also 5d-5a)
• Wisconsin glaciation (MIS 4-2, sometimes also 5d-5a)

Ice Age Names in South America

• Caracoles (Río Frío) glaciation
• Río Llico (Colegual) glaciation
• Santa María (Casma) glaciation
• Valdivia interglacial (a warm period, MIS 5e)
• Llanquihue glaciation (at least MIS 4-2)

Connecting the Names to Global Stages

It can be tricky to match these local names with the global MIS numbers. The MIS system often shows several distinct cold periods that might fall within one traditional regional name. The table below shows how scientists try to connect these different naming systems. It's easier to match them up for the last 200-300 thousand years.

Learn More About Ice Ages

• Brunhes–Matuyama reversal (a change in Earth's magnetic field about 780,000 years ago)
• Geologic time scale (the timeline of Earth's history)
• Glacial history of Minnesota (how glaciers shaped a specific area)
• Glacial period (a time when glaciers grow)
• Ice age (a long period of cold climate)
• Last Glacial Period (the most recent very cold time)
• Thermal history of Earth (how Earth's temperature has changed)
• Geologic temperature record (clues about past temperatures)
• List of periods and events in climate history