The planet Earth has an estimated surface of 510.1 million km², with 70% occupied by bodies of water of different sizes. In its immensity, it is home to a large number of species, both plant and animal, and incredible natural settings; all this working in harmony. However, there are a series of changes in the environment, due to the action of certain factors, which can modify the living conditions of all species. One of these is the glaciation. This phenomenon is studied by glaciology, one of the Earth sciences, which defines it as "a period or epoch in which there are polar caps in both the northern and southern hemispheres."
As such, for several centuries glaciations have been considered as periods in which the global temperature drops, resulting in the expansion of the polar caps. According to glaciology, we are currently going through a period of glaciation, since a large part of the ice caps in Greenland and Antarctica are still preserved. It should be noted that the oldest ice age took place 2.7 billion years ago. The most severe known occurred more than 850 million years ago and ended 650 million years ago; this, in the same way, has been classified as "the most documented", due to the historical impact it had on the inhabitants of that time.
During the glaciation, there are a series of periods in which the temperature becomes warmer, which is known as "interglacial". When these take place, the caps diminish and the climate becomes hotter. This occurs as a process to reestablish the equilibrium in temperature, in which erosion, sea level and summer sun rays intervene.
