Throughout history, our planet has experienced five major glaciations.
The first glaciation occurred approximately 2.4 billion years ago. It is known as the Huronian glaciation, and some studies suggest it was linked to the activity of photosynthetic bacterial organisms, especially in regions like the Huronian, which dramatically increased atmospheric oxygen.
The second glaciation took place during the Cryogenian period and is considered one of the most extreme, with episodes during which much of the planet may have been covered in ice.
The third glaciation, known as the Andean-Saharan glaciation, began about 460 million years ago and affected large areas of the Southern Hemisphere.
The fourth glaciation is commonly called the Karoo glaciation; it occurred between 360 and 260 million years ago and was characterized by abundant sharks in the oceans, giant insects, and the earliest forests of primitive trees.
The fifth and final glaciation began about 2 million years ago, during the Pleistocene, and is the only one humanity has experienced.
We are currently in an interglacial period—the Holocene—characterized by a relatively stable climate.
The Würm Glaciation: The Last Known Ice Age
This era was marked by heavy snowfall, severe droughts, scarce vegetation, and the mass displacement of animals migrating toward more hospitable territories in search of food.
The Würm glaciation is the name given to Earth’s last glaciation in classic Alpine terminology.
In Earth’s early history, the Sun emitted 30% less energy, yet Earth remained warm due to its atmospheric radiation balance. Greenhouse gases regulate surface temperatures and cause variations in Earth’s climate. In Earth’s early stages, carbon dioxide levels were higher; as CO₂ concentrations declined through weathering and erosion, the first continents took shape.
The degree of cooling that began 115,000 years ago varied by latitude. In polar regions, average temperatures fell by as much as 27°F — and up to 41°F in Antarctica.
Of course, in tropical zones, the drop was at most around 9°F, though it was accompanied by a significant decrease in precipitation. As a result, rainforests were replaced by savannas.
The period of greatest temperature decline during this glaciation occurred 22,000 years ago and is known as the Last Glacial Maximum (LGM).
Evidence of these temperature drops can be seen in changes in faunal distribution, as reflected in the cave art we find today.
For example, the inhabitants of the Cosquer caves in southern France painted penguin-like birds on their walls, including the Great Auk (Pinguinus impennis) — a species that, by the Holocene, had retreated much farther north before its extinction in the 19th century.
Even more direct evidence comes from the discovery of fossil remains of these cold-weather animals in temperate locations. For instance, remains of this same Great Auk appear among the fauna consumed by prehistoric inhabitants of the Nerja Cave in southern Spain, dated to 30,000 years ago.
Additionally, alongside these fossil bones in Nerja Cave, bones of Phoca vitulina were found — a seal species that today inhabits the North Atlantic.
Toward the end of the last pleniglacial, around 40,000 to 30,000 years ago, woolly mammoth (Mammuthus primigenius) remains have been documented at the Padul peat bog site in Granada, south of the Sierra Nevada in Spain.
As a consequence of ice accumulation on the continents, sea levels dropped considerably, exposing continental shelves and creating land bridges — including the Bering Strait, the Persian Gulf, and connections linking the Philippine Islands, Borneo, and Java to the Asian continent, as well as northern France to southern Great Britain.
As a consequence of ice accumulation on the continents, sea levels dropped considerably, exposing continental shelves and creating land bridges — including the Bering Strait, the Persian Gulf, and connections linking the Philippine Islands, Borneo, and Java to the Asian continent, as well as northern France to southern Great Britain.
This allowed both animals and humans to move more easily from one point to another.
The Ice Age was probably one of the harshest periods for human beings; however, we developed great abilities to survive. We did not need our bodies to change or evolve — rather, our behaviors, tools, and skills had to adapt.
The Ice Age was probably one of the harshest periods for human beings; however, we developed great abilities to survive. We did not need our bodies to change or evolve — rather, our behaviors, tools, and skills had to adapt.
The key to surviving the Ice Age was conserving energy. At that time, it was essential to find new ways to stay warm and reduce any unnecessary effort.
It was then that ingenuity led us to invent tools such as the bone needle — an advancement that allowed us to sew animal hides and wear them as clothing to better retain body heat.
Humanity survived the last glaciation thanks to ingenuity and cooperation, showing us once again that when we stand united and work together, we can overcome even the harshest of conditions.
Cooperative hunting was also a major advancement, as it required planning, task division, and improved communication. This cooperation strengthened social bonds and fostered the development of symbolic language, the earliest artistic expressions (such as cave art), and cultural transmission.
Humanity survived the last glaciation thanks to ingenuity and cooperation, showing us once again that when we stand united and work together, we can overcome even the harshest of conditions.
