In the history of Earth, the ice age refers to a long period when global temperature is lower than average resulting in the widespread formation of ice sheets and glaciers. Here, we gathered information about how long the ice age lasted. What defines an ice age? Difference between the ice age and the glacial period.
How Long Did The Ice Age Last
In Earth’s history, the term Ice Age refers to a prolonged period of cooler global temperatures. During this period, large sheets of ice cover parts of the Earth’s surface. Our Earth has experienced five significant ice ages throughout its history. The most recent Ice Age is known as the Quaternary Ice Age. It started about 2.6 million years ago and is technically ongoing because our Earth still has large ice caps on the polar regions.
Within the Ice Age, individual phases of cold climates are called glacial periods, and intermittent phases of warm periods are called interglacial periods. About 11,700 years ago, the Last Glacial Period ended and marked the start of the current interglacial period called the Holocene Epoch.
So the Ice Age that started about 2.6 million years ago is still ongoing, but the last glacial period ended about 11,700 years ago.
What Defines An Ice Age?
In Earth’s history, the term Ice Age refers to a long period when global temperatures significantly reduced. It led to the formation and expansion of continental and polar ice sheets and glaciers. During the Ice Age, large portions of continents were covered with ice and involved cyclic patterns of colder and warmer periods. Currently, our Earth is in the Ice Age known as Quaternary Glaciation.
Scientific Criteria For Classifying An Ice Age
An Ice Age is based on several geological and climatological criteria, which include:
- Global Temperature
The average temperature of the Earth must be much lower than usual to result in a cooler climate across most parts of the Earth.
- Formation Of Ice Sheets
Due to cooler climates, ice sheets are formed, and expand to cover most parts of the continents. The ice sheets should remain for thousands or millions of years.
- Presence Of Polar Ice Caps
The continuous presence of polar ice caps marks the ice ages. Ice caps reflect solar radiations and further contribute to the cooling effect.
- Sea-Level Changes
The existence of large volumes of water in the form of ice during the ice ages caused a lowering of the global sea level. It led to the exposure of continental shelves.
- Isotopic And Geological Evidence
The conditions of the ice ages are confirmed from evidence such as;
- Isotopic ratios (oxygen isotopes in marine sediments), and
- Geological markers, like glacial till (unsorted glacial sediments) and moraines (debris or material left behind by moving glaciers).
When Did The Most Recent Ice Age Started And Ended
The most recent Ice Age is the Last Glacial Period (LGP) or the Last Glacial Cycle. It started at the end of the Last Interglacial about 115,000 years ago and ended at the beginning of the Holocene, about 11,700 years ago. Therefore, it covers most of the Late Pleistocene. During this era, alternative periods of glacial (cooler, during which ice sheets advanced) and interglacial (warmer, during which ice sheets retreated) occurred across parts of Asia, Europe, and North America.
What Are The Different Phases Of Ice Age
The Ice Ages alternated between the following two main phases that shaped the climate and landscapes of the Earth:
- The Glacial Periods
Ice age refers to a long period of millions of years when the climate of Earth is cold enough to allow the formation of large ice sheets on continents. Ice ages have alternative phases of glacial (colder) and interglacial (warmer) periods.
- The Interglacial Periods
During the interglacial periods, the temperature rose and the Earth’s climate was milder. The ice sheets melted and retreated, and the sea level rose.
Timeline Of The Ice Ages
Scientists say that our Earth experienced five significant ice ages throughout its history:
- Huronian lasted from 2.4 to 2.1 billion years ago
- Cryogenian lasted from 850 to 635 million years ago
- Andean-Saharan lasted from 460 to 430 million years ago
- The Karoo lasted from 360 to 260 million years ago
- Quaternary, from 2.6 million years ago to the present
What Is The Difference Between Ice Ages And Glacial Periods?
An ice age and a glacial period are related to each other, but both are different terms:
- Ice Age
Ice age refers to a long period of millions of years when the climate of Earth is too cold to allow the expansion of large ice sheets on continents. Ice ages have alternative phases of glacial (colder) and interglacial (warmer) periods.
- Glacial Period
The glacial period refers to a colder phase within an ice age. In this phase, ice sheets advance and cover large parts of the continents, temperature drop, and the sea level falls. The last glacial period is known as the “Last Glacial Maximum”, and peaked about 20,000 years ago.
How Long Was The Longest Ice Age?
The Huronian ice age was the longest ice age that lasted for a total of 300 million years.
Did Humans Live During The Ice Age?
Yes, people live in the ice age. It is believed that our species Homo Sapiens came into being about 300, 000 years ago in the African continent and then spread throughout the world. The Quaternary Ice Age started about 2.6 million years ago and is technically still going on.
Will Ice Age Happen Again?
According to NASA, the ice age will not happen again. The reason is that humans have emitted so many greenhouse gasses that even decreased radiation from the sun (as it happened before) would not be enough to counteract the impacts of global warming.
Are We Currently Living In An Ice Age?
Yes, we are living in the Quaternary ice age that started around 2.6 million years ago. But, it is the interglacial period of the ice age and the climate is mild.
Will There Be A Mini Ice Age In 2030?
No, there is no “mini ice age” or impending ice age in 2030. The energy output from our sun naturally changes through its lifetime when its magnetic pole flips. Some of these happen in a regular 11-year cycle, with periods of high activity (many sunspots) and low activity (few sunspots), which are easy to predict. The current cycle started in 2019 and its peak is predicted in 2024 or 2025. After that, the sun will return to the low activity (few sunspots) period in the early 2030s.
