Ice Age – an interesting concept and truth that we are living in. Unfortunately, most of us are not really aware of what really happens during Ice Age or how it really starts. Some actually tend to believe that it is a phase when the affected areas become uninhabitable. Most of don’t even know how many Ice Ages there have been since the Earth was formed. We are going to clarify some misconceptions and of course produce some facts that will allow a better understanding of what we call Ice Age.
However, before we start with out list of 40 interesting Ice Age facts, we will like to make it clear that our attempts will be keep things as simple as possible. Thus, we will mostly try to convert complex concepts in everyday language. This can lead to certain unintentional discrepancies. In case you spot any such mistake, drop a comment and help us fix the same.
So, let us begin…
Interesting Ice Age Facts: 1-5
1. Ice Age is not a quick event. It is actually a very long term phenomenon which lasts for several million years.
2. During the Ice Age, there is a gradual temperature drop. Both atmospheric as well as surface temperatures drop gradually.
3. During Ice Age, the gradual temperature drop leads to gradual expansion of the alpine glaciers. At the same time, ice sheets that cover the polar regions as well as several areas of different continents also gradually expand.
4. A single Ice Age can last for hundreds of millions of years. However, within a single Ice Age are two different phases that can happen alternately multiple times. These two phases are known as ‘glacials’ and ‘interglacials’.
5. Glacials are often referred to as by the names glaciations or glacial periods. These are actually times when climate becomes very cold.
Interesting Ice Age Facts: 6-10
6. Interestingly, we prefer calling glacials or glaciations or glacial periods as Ice Age but that’s not true. Glacials are not Ice Ages. They are rather phases of Ice Ages.
7. Interglacials on the other hand are intermediate periods in an Ice Age in when climate remains warm.
8. If at all, Ice Age is to be defined, glaciology says that as long as the southern hemisphere and the northern hemisphere remains blanketed by extensive ice sheets, it is an Ice Age.
9. In the times we are living in, the glaciological definitions holds true and hence, we are actually experiencing an Ice Age. Though we are in an Ice Age, we are not experiencing cold climate because we are in an interglacial phase.
10. The interglacial period that we are living in has a name. Well, we humans gave this name just for the sake of record keeping. This interglacial phase in which we are living is known as Holocene.
Interesting Ice Age Facts: 11-15
11. The Holocene is a part of the Ice Age that started some 2.6 million years ago (mya). That’s the time of late Pleistocene Epoch.
12. According to the definition of Ice Age, there should be ice sheets and yes there are! Today ice sheets cover the Antarctic, Arctic and Greenland.
13. Interestingly, Ice Age as a theory started developing back in 1742. However, it was not until 1837 that the first formal Ice Age theory was presented by Louis Agassiz. Agassiz actually worked on glacial activities and Ice Ages as a hobby. By profession, he was a renowned ichthyologist.
14. Though Agassiz’s work was pioneering, no one was actually ready to accept his new theory because it was in direct contradiction with what is climatic history. Back in those days, it was popularly believed that earth has always been cooling since birth.
15. Though the Ice Age theory was actually presented at Schweizerische Naturforschende Gesellschaft meeting held at Neuchâtel in 1837, the world accepted the theory only during the second half of 1870s.
Interesting Ice Age Facts: 16-20
16. According to modern experts, earth has experienced at least 5 major Ice Ages including the most recent one that we are currently experiencing.
17. The five Ice Ages are:
- Huronian Ice Age: started 2.4 billion years ago and ended 2.1 billion years ago.
- Cryogenian Ice Age: started 850 million years ago and ended 630 million years ago.
- Andean-Saharan Ice Age: started 460 million years ago and ended 420 million years ago.
- Karoo Ice Age: started 360 million years ago and ended 260 million years ago.
- Quaternary Glaciation: started about 2.6 million years ago and is still continuing.
18. According to scientists, excluding the Ice Ages, the earth has been completely free of ice. In fact, there has been no ice even at very high altitudes.
19. In Quatemary Glaciation, i.e. our current Ice Age, the glacials and interglacials have come and left in phases lasting 40,000 years to about 100,000 years.
20. The most recent glacial phase in our current Ice Age ended only 10,000 years ago and today we are in interglacial phase which will last for at least 30,000 years that follow.
Interesting Ice Age Facts: 21-25
21. The last glacial phase of the Quatemary Glaciation reached its peak somewhere about 18,000 years. That is when massive areas of the continents in the northern half of the planet went under sheets of ice.
22. The CIS and the LIS were the two major ice sheets that covered vast expanses of northern land.
23. CIS is abbreviated form of Cordilleran Ice Sheet and LIS is abbreviated form of Laurentide Ice Sheet. CIS covered the western side while the LIS covered the midwestern and eastern sides.
24. According to scientists, at least 50 glacial and interglacial cycles have taken place with 12 of them being major glacial cycles.
25. The most massive glacial cycle in the last 1 million years started some 650,000 years ago and lasted for nearly 50,000 years.
Interesting Ice Age Facts: 26-30
26. The biggest and the most recent glacial cycle happened some 18,000 years ago. It is this recent glacial cycle that we colloquially call as ICE AGE of our times.
27. During the peak of the last glacial cycle, ice sheets swept across Russia, South America, Scandinavia and Canada. The ice sheets during this glacial period reached about 12,000 feet in thickness.
28. During this glacial cycle, there was a 10 degrees Fahrenheit average temperature drop globally with some areas experiencing drop of about 40 degrees Fahrenheit. At the same time, the sea levels also dropped by a staggering 400 feet.
29. There are several factors that can lead to an Ice Age. Scientific community has figured out that when warm water which is known to be flowing from equator towards earth’s poles is obstructed by the positioning of the continents, the conditions become ripe enough for the formation of ice sheets.
30. The scientists also argue that once the ice sheets start forming, much of sun’s radiation is reflected back by the ice sheets instead of being absorbed by the earth’s surface. This further propels cooling and Ice Age advances.
Interesting Ice Age Facts: 31-35
31. The question is, ‘exactly where do these continents need to sit in order to block warm water flow to the poles from the equator?’ Actually, there are three possible scenarios as mentioned by scientists:
- Geological conditions arise where almost complete land-locking of a polar sea takes place. In today’s date, Arctic Ocean is a nice example.
- A continent drifts over times and eventually comes to halt when it sits right on the top of one of the poles of Earth. In today’s date Antarctica is a nice example.
- Almost all of the equator gets covered under a super continent. Unfortunately we don’t have a live example today but in the Cryogenian Period, there was one such super continent – the Rodinia.
32. A group of scientists actually blame Ice Age on the mighty Himalayas. They hold the view that when the Himalayas were formed, earth was exposed to greater amounts of rainfall. The resulting increase in rainfall lead to washing away of CO2 – a greenhouse gas that is known for trapping sun‘s heat. The argument provided here is that reduction in greenhouse gas eventually led to decrease in global temperature of earth some 40 mya during the mid-Eocene. Even today, the Himalayas are growing at the speed of 5mm every single year.
33. There is an alternative aspect too when it comes to blaming Himalayas. Some say that once the Himalayas came out because of the collision between Asia and India, the stones that laid deep beneath the surface of earth were suddenly exposed to natural elements. This is when the chemical erosion of the rocks started during which CO2 was consumed and the sheer volume of CO2 used up during the erosion process was just enough to directly trigger an Ice Age.
34. When it comes to the role of CO2 in Ice Age, it is unanimously agreed that when CO2 concentration in atmosphere decreases, temperatures fall and when CO2 increases, the greenhouse effect leads to increase in temperature. However carbon dioxide is not alone when it comes to greenhouse effect. Even methane is blamed.
35. In 2012, a group of scientists conducted a nice study in which it was found that 150 million years ago when the earth was literally ruled by dinosaurs, a massive amount of methane was released into the atmosphere because of the digestive process of the dinosaurs, leading to a significant greenhouse effect, which in turn led to a warm climate. Today, those scientist say, humans emit similar amounts of methane by several activities like burning or fossil fuels. Together with CO2, this released methane leads to greenhouse effect, which is causing global warming and hence, rapid melting of polar ice and glaciers, which is turn is actually stalling glaciation (remember that we are in interglacial phase).
Interesting Ice Age Facts: 36-40
36. So, human activities can actually postpone glacial phases of the glacial-interglacial cycles. However, humans should not be blamed for all the postponing business. Natural causes are there too! For example, greenhouse gases are released in atmosphere when continents drift (which is actually happening currently) and also when some volcanoes go boom!
37. Ice Ages can lead to interesting effects. Talking of the ice sheets, they grow so big and heavy that they can actually deform the crust as well as the mantle of earth. However, the mantle rock has high viscosity. This means that when the ice sheets melt, the deformed land actually rebounds back at the rate of maximum of 1 cm in one year.
38. When ice sheets form, they actually use up water from water bodies like seas and oceans. This leads to drop in sea level and exposes continental shelves. When this happens, land bridges form. Such land bridges actually help migration of animals.
39. When ice sheets melt, sea levels rise up again, many land masses are submerged under water. This can lead to profound impact on life. Many life forms may be wiped out simply because of rising sea levels. It can also lead to overcrowding to land masses that do not get submerged. Ocean currents can change. Deglaciation can also lead to formation of ice dams, which can lead to formation of large fresh water lakes. These fresh water lakes can suddenly become saline when ice dams collapse, allowing salt water to mix up with fresh water, thereby eliminating freshwater life forms.
40. Even gravity and earth’s rotation can be affected by Ice Ages. Ice sheet formation and even deglaciation changes the flow of mantle rock, which leads to changes in earth’s gravitational fields. When ice melts, the ice water is redistributed, which in turn redistributes earth’s moment of inertia, leading to changes in axis, angular velocity and overall rotation.
Bonus Ice Age fact:
Formation of ice sheets puts enormous pressure on the lithosphere and restricts the movement of the faults underneath. When the ice sheets melt, that pressure is released, allowing quicker than usual movement of the faults, triggering massive earthquakes.