Ice Age

The Ice Age was the area of time when the Earth was much colder than it is now.  This was a time when much of the Earth was covered by ice sheets.  The Ice Age is thought to have started more than 70,000 years ago and it ended around 10,000 years ago, according to some scientists.

Ice age map of northern Germany

How Much of the Earth Was Covered by Ice?

Many scientists believe that 1/3 of the entire Earth was covered by some type of ice.  It is thought that there were sheets of ice that were over a mile thick.  It is said that New York was covered by ice that was thicker than 1,000 feet.

Why Did the Ice Age Happen?

Many people feel that the Ice Age happened because of the temperature changes that happened on the Earth.  When the Earth cools down and warms up again, it causes there to be different things that can happen, and one is thought to be the Ice Age.


Some believe that the way that the Earth was positioned and the sun was hitting the Earth and the way that the tilt of the Earth changed, that this caused the weather to change and it caused to currents of the ocean to change and this created the Ice Age.

How Do People Know About the Ice Age?

When people study the Earth and the land around it, they find out things about the world that other people do not know.  They are able to study things that have happened in the past by looking at fossils and different chemicals that are found in the rocks.


Scientists have studied the land and have found that there is evidence that in Northern Europe and in North America that the Ice Age really existed.  Some of the things that have been discovered could have only happened if there were large pieces of ice or giant glaciers that were moved.

Quaternary Ice Age

Some scientists believe that we are still living in part of the Ice Age called the Quaternary Ice Age.  This is where the Earth is warmer than the earlier period of the Ice Age but colder than other times when the Earth was warmer.  This is also called interglacial period.

Interglacial Period

Scientists believe that there are different parts of the Ice Age and the interglacial period is the time of the Ice Age where the weather is warmer and where glaciers are getting smaller or going away all together.

Glacial Period

The Glacial Period, as described by scientists, is the period when the Earth is colder and when glaciers are getting bigger or forming.

What Are the Different Ice Ages?

According to some scientists, there have been five different ice ages over the past millions of years and even 11 different ice ages in the past 4.6 billion years.  These last few include Huronian, Cryogenian, Andean-Saharan, Karoo and Quaternary.

  • Huronian-This ice age was thought to happen because of volcanic activity and there is less carbon dioxide in the atmosphere.  This ice age lasted more than 2100 million years ago.  This is considered one of the longest ice ages.
  • Cryogenian-This ice age happened more than 635 million years ago and had ice sheets that reached all around the world, even close to the equator.
  • Andean-Sahar-This ice age was more than 430 million years ago.
  • Karoo-This ice age lasted more than 100 million years and is known for many glacial tills.  These glacial tills happened in South Africa and that is why it is named Karoo after Karoo, South Africa.
  • Quaternary-This ice age is where we are living now and is said to have started more than 2 million years ago and is still happening today.

The last ice age that happened is sometimes called the “Great Ice Age” and this was when 1/3 of the Earth was covered in ice.


When the ice age formed, many glaciers were formed as well.  Glaciers are solid sheets of ice that cover both water ways such as rivers and lakes and land areas, as well.  When the ice would begin to melt, it would freeze again, and this is what caused the ice age to last so long.

What Happened When the Ice Age Ended?

When the Ice Age ended, it caused the glaciers and other ice to melt and this melted ice helped to form rivers, lakes and streams.  It also left different rocks and other debris behind as the glaciers moved across the area.

Why Do Ice Ages Happen?

When there are different changes to the Earth, different things can happen.  Scientists believe that the climate is what caused the ice ages to happen.  Some believe that other things can cause ice ages to form such as:

  • Volcanoes-When there is volcanic activity, it causes gases to enter the atmosphere.  Some believe that if there are fewer volcanoes it can cause the ice age to end but the more volcanoes there are, the more chances there are for more ice ages to happen.
  • Orbit– The orbit of the Earth can cause the Earth to be further or closer to the sun.  When the Earth is closer to the sun, it is hotter and when the Earth is further from the sun, it is cooler.
  • Atmosphere-When there are lower levels of gas in the atmosphere, scientists believe it can cause the Earth to cool down and cause the ice age to happen.
  • Sun-When the sun has less energy, it causes the Earth to be cooler and this can cause an ice age.
  • Ocean currents-the currents of the ocean change the climate of the Earth.  When there are major ocean current changes, it can cause ice to form.
  • Continental drift-As different landmasses move, it causes them to move to places in the planet that are colder.
  • Axis-The Earth’s axis can change the way that it tilts and it can cause the Earth to not be facing the sun as it should be.

Animals of the Ice Ages

There are many different animals that lived in the Ice Ages and these include:

  • Wooly Mammoth
  • Cave Bears
  • Wooly Rhino
  • Saber-toothed Tigers
  • Syndoceras
  • Titanotylopus
  • Baluchitherium
  • Brontotherium
  • Teratorn
  • Dire Wolf
  • Giant Beaver
  • Giant Ground Sloth
  • Irish Elk
  • Musk Ox
  • Giant Bison
  • Gylptodon

Animals that lived during the Ice Ages have become extinct.  This means that they all died off and they no longer exist.

How Do We Know These Animals Existed?

Different scientists and paleontologists have found fossils that prove that these animals once existed during the Ice Ages.

People of the Ice Ages

It is believed that people lived in the Ice Ages and that they hunted and made warm clothing in order to live.  When people hunted animals in the Ice Ages, it is believed that they used all parts of the animal for food, clothing, blankets, shelter, and for weapons.


It is thought that during the Ice Ages that the Earth was all the tundra biome.  Tundra is an area that is cold and where there is little or no trees or vegetation.  Plants have a hard time existing in the tundra biome because it is very cold, and the ground is frozen, so it is hard for plants or trees to grow.

There are still some tundra biomes that exist today in places such as:

  • Europe
  • Asia
  • North America

More Facts About Ice Ages:

  • The interglacial period that the Earth is in is called the Holocene Period.
  • When the temperature over all of the Earth drops just a few degrees, this can cause an ice age to happen.
  • When the sun is reflected by the ice and snow, it can cause the Earth’s temperature to go even lower.
  • A man called Otzi, was found frozen in a glacier.
  • Animals that lived during the Ice Age would have learned to adapt to cold areas.
  • One of the first scientists to study the Ice Age was Louis Aggasiz.  He was a zoologist, paleontologist and geologist.  He also was an ichthyologist.
  • An ichthyologist is a person who studies fish.
  • After the last ice age, the area between Siberia and Alaska appeared.  This happened after the ices melted and there was a strip of land.
  • When the temperature got warmer, the strip of land between Siberia and Alaska disappeared.

What Did You Learn?

  • What are the Ice Ages?
    The Ice Ages is a period of time where much of the Earth, even 1/3 of it, was covered in ice.
  • What caused the Ice Ages to happen?
    Scientists believe that different things can cause the Ice Age to happen such as the way the Earth rotates, the way the Earth sits on its axis, temperature change, ocean currents, and more.
  • Did animals live during the Ice Ages?
    There is proof that many different animals lived during the Ice Ages.  People lived during the Ice Ages too!
  • What caused the Ice Age to end?
    The Ice Age ended when the temperature got warmer.  When this happened, the ice began to melt, and oceans and lakes formed all over the world.
  • Are we in an Ice Age now?
    According to scientists, we are still in an ice age, just a warmer ice age than the “Great Ice Age” period.