Ice ages are mysterious times when our planet sinks into cold and ice. I wonder how they begin and when did the current ice age begin? Let’s find out.
What is an ice age?
An ice age is a long period of time when global temperatures are below normal and large areas of the Earth are covered with ice. There have been five such periods in our history, the longest of which lasted more than 300 million years. But the interesting thing is that we are still in one of them.
Now we are in an interglacial period
Although we are used to thinking that the ice ages have long since ended, we are in fact still in one of them. About 3 million years ago, an ice age began and continues to this day. Technically speaking, we are still living in an ice age.
How do ice ages begin?
The reasons for the beginning of ice ages can vary. One is a change in the level of carbon dioxide in the atmosphere. When its content decreases, the global temperature drops and an ice age begins. Another reason is the disruption of ocean circulation. The shifting of continents can change the flow of ocean currents, which also causes the planet to cool.
For example, the Pleistocene Ice Age, which began about 2.6 million years ago, was caused by the formation of the Isthmus of Panama between North and South America. This land bridge prevented the exchange of tropical water between the Atlantic and Pacific Oceans. As a result, warm water began to head north, resulting in increased precipitation in the high latitudes of the Northern Hemisphere. Snow accumulated, and glaciers and ice sheets gradually formed.
Biological Causes of Ice Ages
Some ice ages may have biological causes. For example, the Huron Ice Age, which lasted more than 300 million years, was probably caused by the evolution of photosynthesis in the oceans. Through this process, the amount of greenhouse gases in the atmosphere decreased, causing the planet to cool and ice to form.
The Late Paleozoic Ice Age, which occurred after the Huronian, was caused by the evolution of plants on land. An increase in oxygen and a decrease in greenhouse gases also caused the planet to cool and ice to form.
What other factors influence ice ages?
There are also other factors that influence the onset and retreat of ice ages. One is the change in the Earth’s orbit due to Jupiter’s gravity. The Earth’s orbit changes over 96,000 years, which can cause shifts in temperature and the onset of ice ages.
The history of ice ages is an interesting and mysterious topic. We still don’t fully understand all the mechanisms that lead to the beginning and end of these periods. But thanks to modern research and new discoveries, we are gradually expanding our knowledge of past ice ages and trying to predict future climate changes.