Ice Ages
Scientists collect information from tree rings, ice cores and seafloor sediments to find out what the climate was like long before mankind began keeping records of the weather. This information has revealed that the Earth's climate in the past has switched many times between much colder periods and much warmer ones.
Many tens of millions of years ago, during the age of the dinosaurs, the Earth was much warmer than it is today. Over time, the Earth gradually cooled down because the drifting of continents affected the way heat was stored in the atmosphere and in the oceans, which influenced the climate. In the last few million years, there has always been ice at the North and South Poles, but the amount has repeatedly grown and shrunk, corresponding to colder and warmer climates. The cold periods are known as the Ice Ages, and the last one affected the Earth only 18,000 years ago.
It is believed that the change in Earth's climate between Ice Ages and warm periods is linked to the Earth's changing orbit around the Sun.
| Last Ice Age |
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