Quaternary glaciation

Long, long ago, and even more recently, huge sheets of ice, like giant frozen blankets, covered parts of our planet. These icy times are called glacial periods. They happened during something called the Quaternary glaciation. Think of it like a giant game of freeze and thaw that has been happening for millions of years. Sometimes the ice grew super big, and sometimes it melted back a lot.

The Quaternary glaciation started about 2.58 million years ago. That's way, way before even the dinosaurs! During the coldest parts, called glacial periods, ice sheets grew bigger than countries. They were so thick, they could be taller than the tallest buildings! When the ice melted back, it was called an interglacial period. We are actually living in one of these warmer times right now!

These giant ice sheets did amazing things to our Earth! They carved out valleys, like giant scoops in the ground, and created millions of lakes, like big puddles left behind. They even changed where rivers flowed! When the ice melted, the land underneath slowly popped back up, like a sponge that's been squished. It's like the Earth was getting a big stretch!

Even though the biggest ice sheets melted away, we still have ice at the North and South Poles. This means scientists say the Quaternary glaciation is still happening! The ice we have today, like in Greenland, is super important. It helps keep our planet cool by reflecting sunlight back into space, like a giant mirror. So, these icy times shaped our world and still help keep it just right.