An ice age is a period in the history of the Earth when the ice on the polar caps greatly extended and covered the Earth with continental ice sheets and alpine glaciers due to the overall drop in the temperature of the Earth’s surface and atmosphere. Earth has experienced at least five major ice ages in its history: the earliest Ice Age occurred over 2 billion years ago, and the most recent one began roughly 3 million years ago, and it is still ongoing today (yes, we are living in an Ice Age!). This Ice Age peaked roughly about 20,000 years ago, and at the time, the Earth was probably around 10°F cooler than it is now. But how do scientists know about the Ice Age, which dates back millions and billions of years? Let’s find it out.
How do scientists know about the Ice Age?
Scientists have figured out about past ice ages by analyzing the geology and chemistry of the land, as well as the geographical distribution of fossils.
Geology and Chemistry of the Land
There are many geological features in Northern Europe and North America that can only be explained by the movements of giant glaciers. And this geological evidence for ice ages comes in various forms, including rock scouring and scratching, glacial moraines, drumlins, valley cutting, and the deposition of till or tillites and glacial erratics. This glacial erratic is a type of rock that is not naturally found in the region where it is discovered but was instead deposited by glaciers. They are carried by glaciers, often over distances of hundreds of kilometers.
Geographical Distribution of Fossils
Another source of evidence to look for is the changes in the geographical distribution of fossils. Organisms that preferred warmer climates became extinct during cold periods, whereas organisms that liked colder climates migrated into lower latitudes. Though this evidence is challenging to interpret, the study of ice core and ocean sediment cores has provided a conceivable record of glacials and interglacials over the last few million years.
These types of evidence demonstrate the existence of the Ice age throughout the history of Earth. Please Wait! You may be aware that climate change is causing the ice in the poles to melt. Please do whatever you can do to help the Earth from climate change. And if you’re not sure where to start, click here to learn about the actions you can take to save the world from Climate change.
Thumbnail Image, 1: Image by Joe from Pixabay 2: No machine-readable author provided. Williamborg assumed (based on copyright claims)., Public domain, via Wikimedia Commons 3: Photo by Alejandro Quintanar