Presented By: Dave Heeney, Jeff Lawik, and Wojtek Maroszek

1. Ice Ages Presented By: Dave Heeney, Jeff Lawik, and Wojtek Maroszek

2. In The Next 10 Minutes You Will Learn • What an Ice Age is • What causes them • Where they begin • Potential destruction • Frequency of occurrence • Past events

3. What Is An Ice Age? • A period in history when glaciers have covered a significant portion of the earth’s surface. • Also describes a time with low amounts of insulation of heat resulting in significant cooling of the atmosphere.

4. What Causes Ice Ages? • The Milankovitch Astronomical Theory explains regular climatic changes. • During a certain point in time, at 60 degrees to 70 degrees north, the Arctic Circle does not receive adequate amounts of radiation. • This happens every 100,000 years and lasts a very long time causing polar temperatures to dramatically decrease allowing glaciers to rapidly expand.

5. Other Contributing Factors • Sea levels have been proven to be a contributing factor. • When glaciers form over the ocean, the water level drops. • Water levels drop, more land is exposed, causing temperatures to decrease. • Temperature decrease due to the lack of “heat sinks” on the earth.

6. Where Do Glaciations Begin? • Typically, Ice Ages would begin to be evident in places with high amounts of glaciations, particularly the north and south poles. • The actual physical glaciations would be evident at the poles, but also a global decrease in temperature would be noticed.

7. Potential Destruction • Ice Ages would slowly cover land and "devour" resources as well as anything in its path. • Ice Ages, or glaciations, can not necessarily be referred to as destruction. • Glaciers scrape the land and tear holes into the Earth’s surface, resulting in very important geological features like the Great Lakes.

8. Frequency Of Event • The frequency of ice ages is not for certain. • It can be estimated based upon the previous activity of the Earth's history. • Each Ice Age, or glaciation, begins slowly and can take up to 80,000 years to reach its maximum extent. • A rapid melting of the glaciations begin, followed by the next accumulation of glaciations, only 10,000 to 20,000 years after the climax of the previous glaciation or Ice Age.

9. Past Events • Proterozoic era about 800 and 600 mill years ago • Pennsylvanian and Permian Eras about 350 and 250 million years ago • Neogene era to Quaternary era, only 4 million years ago

10. Important Facts • If the term “Ice Age” is to refer to long, generally cool intervals when glaciers advance and retreat, then we are still in one today. • Geological evidence indicates the global climate has been naturally cooling for the last several thousand years.

11. Important Facts In the distant future, Earth may once again look like this:

12. This Concludes Our PresentationOn Ice Ages