Serbian astronomer Milutin Milankovitch discovered that Earth’s orbit changes in predictable cycles.

The world had forgotten the taste of rain.

The reality of an is far more complex, terrifying, and fascinating than a single era of freezing temperatures. In geological terms, an Ice Age isn't just a time when it was "cold"; it is a long-term period of reduction in the Earth's surface and atmospheric temperature, resulting in the presence of continental ice sheets in the northern and southern hemispheres. Surprisingly, we are living in an Ice Age right now.

Surprising to many is the fact that we are currently living in an Ice Age. We are merely in a warm interglacial interval known as the . If you look at a timeline of Earth's history, the "normal" state for the last 2.5 million years has been ice, not warmth. The lush, green world we inhabit is the exception, not the rule.

Given the Milankovitch cycles, astronomers predict that the next is due to begin... roughly 50,000 years from now. Normally, we would be slowly trending toward colder summers, allowing snow to accumulate on Canada and Scandinavia.