Ice Age Facts For Kids
An ice age is a time when Earth becomes much colder and giant ice sheets cover land, changing coastlines and reminding us Earth changes slowly.
About this topic
Earth’s long story has warm stretches and cold stretches. The cold stretches with lots of ice are called ice ages, while the warmer stretches have much less ice. These changes happen slowly over thousands or millions of years.
Quick Facts
Key Points
Photos of Ice Age
Haukalivatnet lake (50 meters — 164 feet — above sea level) where Jens Esmark in 1823 discovered similarities to moraines near existing glaciers in the high mountains
Ice age map of northern Germany and its northern neighbours. Red: maximum limit of Weichselian glacial; yellow: Saale glacial at maximum (Drenthe stage); blue: Elster glacial maximum glaciation.
Sediment records showing the fluctuating sequences of glacials and interglacials during the last several million years
Pattern of temperature and ice volume changes associated with recent glacials and interglacials
Northern hemisphere glaciation during the last ice ages. The setup of 3 to 4 kilometer thick ice sheets caused a sea level lowering of about 120 m.
Timeline of glaciations, shown in blue
Stages of proglacial lake development in the region of the current North American Great Lakes
![Diagram of key climate-carbon cycle feedbacks linking Quaternary climates and temperatures, Generalized Milankovitch Theory (GMT), to atmospheric CO2 and ice sheets.[53] Positive feedbacks amplify and negative feedbacks dampen environmental change, with slow-acting responses shown as dashed arrows.](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e8/Fig3_Q-climate-CO2-feedbacks_V2.png/960px-Fig3_Q-climate-CO2-feedbacks_V2.png)
Diagram of key climate-carbon cycle feedbacks linking Quaternary climates and temperatures, Generalized Milankovitch Theory (GMT), to atmospheric CO2 and ice sheets.[53] Positive feedbacks amplify and negative feedbacks dampen environmental change, with slow-acting responses shown as dashed arrows.
📘 Evidence
Other evidence comes from chemistry and preserved layers. Scientists study shells and mud for tiny chemical clues, and they drill into ice to get long tubes called ice cores. These cores hold layers and tiny air bubbles that tell us about old air and temperatures. Fossils show where animals and plants lived, so when warm-loving species suddenly disappear from a place, it can mean that area became much colder.
🔎 Major Ice Ages
Later long cold times include the Andean-Saharan and the late Paleozoic ice ages. The most recent long cold time is the Quaternary Ice Age, which started a few million years ago and includes the small ice advances and retreats humans remember from long-ago times.
🧭 Glacials And Interglacials
These back-and-forth cycles happened in other ice ages too and changed where rivers flowed and where forests and animals could live. When ice grew, sea level fell and land patterns changed; when ice melted, seas rose again and new habitats opened up.
💡 Causes — Orbit And Sunlight
When summers stay cooler because of less sunlight, winter snow can survive and pile up. Over many years that snow turns to ice and builds ice sheets. As ice grows, sea level falls (because water is stored in ice), and big ice sheets can also change ocean currents and weather far away.
🌟 Causes — Changes In Earth's Atmosphere
Most scientists think changes in sunlight from Earth’s orbit begin the move toward an ice age, and greenhouse gases then make the change larger. Other slow helpers, like rocks wearing down and volcanoes adding gas, can also change how much carbon dioxide is in the air and so change the climate over long times.
🧩 Effects Of Glaciation.
Huge ice sheets reshaped the land. They carved deep U-shaped valleys, left piles of rocks called moraines, and made many lakes. Because so much water was frozen, sea levels dropped and sometimes opened land bridges that let animals and people move to new places.
🧠 Take the Quiz about Ice Age
Frequently asked questions
What is an ice age?
An ice age is a time when Earth becomes much colder than usual and large sheets of ice grow over continents and mountains. These sheets can cover whole countries, and glaciers move slowly like frozen rivers. Because so much water is locked up as ice, oceans can be lower and coastlines look different.
What is a glacier?
A glacier is a smaller river of ice that moves slowly across the land.
How do scientists learn about past ice ages?
Scientists find signs in rocks, tiny chemical clues, and fossils. Moving ice scratches rocks and leaves piles of mixed stones when it melts, and ice cores hold layers and tiny air bubbles that tell us about old air and temperatures.
What are glacials and interglacials?
Inside an ice age, there are colder times called glacials and warmer times called interglacials. During glacials, ice sheets grow; during interglacials, the ice pulls back and climates warm. For example, a warm interglacial not long before our modern time is called the Eemian.
What are Milankovitch cycles?
Milankovitch cycles are slow, natural changes in how Earth moves around the Sun and how much the planet tilts. These changes affect how much warm sunlight the Northern Hemisphere gets in July.
What was the Last Glacial Maximum?
The Last Glacial Maximum was about 26,000 to 13,300 years ago when ice covered much more land than today. Ice sheets could be up to 3–4 kilometers thick in some places, sea levels dropped, and land bridges opened.