What Is an Ice Age?

The north and south poles are still covered in ice!

Did you know that we are in an ice age right now? It’s true! An ice age is a long period of time when Earth’s temperatures are colder and ice covers much of the land. But it does not stay cold the whole time. There are cold periods and warm periods. We are in a warm period right now. 

During an ice age, glaciers [large masses of ice that move slowly] reshape the land. The sea level drops because much of Earth’s water is frozen. Land bridges appear that connect continents [large areas of land].

There have been at least five major ice ages. The most recent ice age began about 2.6 million years ago.

The last ice age is known for the many large land mammals that lived during that time. Giant mammoths, mastodons, and saber-toothed cats roamed the land. Many of these animals went extinct about 11,000 years ago.

Scientists drill into ice sheets to collect samples.

How do we know about ice ages? Scientists study clues left by glaciers, ice and sediment cores, and fossils. Ice and sediment cores tell us about past temperatures.

What Do You Think?   How do scientists know we are in an ice age?

Photo Credit: (t)Denis Crawford/Alamy Stock Photo, (b)ARCTIC IMAGES/Alamy Stock Photo