When you read that, an image probably came to mind: giant glaciers, people huddling for warmth, maybe a giant woolly mammoth or two. The problem with that definition of “Ice Age” is it defines what life is like now on Earth as “normal” and giant glaciers over the north and south pole as “abnormal.” But is that true? Are we, in fact, living in a period of relative coolness? Is right now an “abnormal” Earth?
A better description of an ice age would be that it’s a long stretch of time in which both the atmosphere and the planet’s surface have a low temperature, resulting in the presence of polar ice sheets and mountainous glaciers. An Ice Age can last for several million years. Within the Ice Age period, the Earth isn’t uniformly covered in snow. There are periods of glaciation, characterized by ice sheet and glacier expansion over the face of the planet, and interglacial periods, where we would have an interval of several thousand years of warmer temperatures and receding ice.
Turns out just the presence of ice caps on the north and south pole is abnormal! What we currently live in is an “interglacial period” in the middle of an Ice Age!
Nenhum comentário:
Postar um comentário