20 hostile prehistoric environments that should have led to the extinction of our species

About 74,000 years ago, the Toba supereruption, in what is now Indonesia, spewed ash over parts of Asia and may have affected the climate for years. Earlier theories claimed that it nearly led to the extinction of humanity, although archaeological findings in India indicate that people were living and making tools both before and after the ashfall.

About 26,000 to 19,000 years ago, the ice caps reached their greatest extent in recent history in North America, Northern Europe, and parts of Asia. People lived near cold, open landscapes where animals migrated with the seasons.

A major genetic study suggests that human ancestors experienced a severe demographic bottleneck approximately 930,000 to 813,000 years ago. This phenomenon is believed to have been caused by severe climate change, and human history was affected by it for nearly 120,000 years. 

About 70,000 years ago, enormous quantities of icebergs broke off in the North Atlantic and released freshwater as they melted. Such a phenomenon could have disrupted ocean circulation and the regional climate, forcing human communities to cope with colder periods, changes in rainfall patterns, and animal migrations.

This mass extinction occurred about 445 million years ago, long before the appearance of humans, mammals, or any other life forms similar to us. It is, however, part of a broader history, as life on Earth had to survive enormous changes in sea level and climate before the evolutionary chain took shape.

About 252 million years ago, Earth experienced its most severe mass extinction event. Known as the “Great Extinction,” this catastrophe was caused by massive volcanic eruptions in what is now Siberia. It led to the extinction of more than 90% of marine life and 70% of terrestrial life. Fortunately, small, mammal-like reptiles survived, which explains why we are here today.

About 12,900 years ago, the warming that followed the Ice Age was interrupted by a sudden return to cold weather across much of the Northern Hemisphere. In just three years, the Earth’s temperature dropped by 3 °C (5 °F) in North America alone, and even more dramatic temperature fluctuations were observed in Europe and Greenland. While humans were able to adapt, researchers agree that the population experienced a significant decline.

Between about 50,000 and 10,000 years ago, mammoths, giant ground sloths, saber-toothed tigers, and other large animals disappeared from many regions. More than 65% of all megafauna species became extinct, but some believe this extinction was caused by overhunting by early humans.

About 1.2 million to 700,000 years ago, the Earth’s glacial cycles shifted from shorter phases to longer and more severe glacial periods. Human ancestors had to survive periods of cold that lasted tens of thousands of years, during which grasslands, forests, coastlines, and migration routes were constantly changing.

About 71,000 to 59,000 years ago, the world entered a colder glacial period, and some regions of Africa became less hospitable for humans. In certain areas, the drier climate made water, vegetation, and wildlife less abundant and less accessible.

Humans reached Australia tens of thousands of years ago and discovered a continent dotted with arid regions, habitats shaped by fire, and populated by animals of unusual size. The extinction of Australia’s megafauna is still a subject of debate, but survival in this hostile region required a great deal of adaptability on the part of our ancestors.

More than two billion years ago, oxygen began to accumulate in Earth’s atmosphere and oceans, posing a crisis for many organisms that could not tolerate it. This catastrophe gave rise to our ozone layer, but it also led to a mass extinction of organisms.

As the glaciers of the Ice Age melted, sea levels rose and low-lying coastlines changed. People living near the coast must have watched as farmland, transportation routes, and foraging grounds disappeared under 20 meters of water in just 500 years.

About 130,000 to 115,000 years ago, the last interglacial period brought warming to the Northern Hemisphere, to such an extent that forests extended as far as the Arctic Circle. It is possible that, in addition to demographic bottlenecks, early humans also resorted to cannibalism simply to survive.

Thousands of years ago, certain regions of the Sahara were home to lakes, grasslands, livestock herds, fishing activities, and human communities. As this wetter period came to an end, approximately 6,000 to 5,000 years ago, people migrated to more reliable water sources, including the Nile Valley and other corridors conducive to life.

About 13,000 years ago, the Laach Lake volcano, located in what is now western Germany, erupted and blanketed part of Europe with ash. The most severe consequences were local and regional, but neighboring communities had to cope with the degradation of their hunting grounds, changes in the flora, and years of environmental stress.

During the last ice age, Europe experienced a succession of colder periods and others that were slightly milder. Neanderthals and early modern humans had to hunt animals, adapt to changes in vegetation, and survive in increasingly limited habitable areas as the climate around them changed.

Between approximately 191,000 and 130,000 years ago, a major glacial phase caused sea levels to drop and transformed African environments. The earliest Homo sapiens survived this period, likely by taking advantage of scattered refuges, coastal resources, inland waterways, and all the viable habitats available to them.

About 39,000 years ago, the Campanian ignimbrite eruption, which occurred in the Phlegraean Fields volcanic region near present-day Naples, blanketed vast regions of Europe with ash. While its role in the decline of the Neanderthals is a matter of debate, it nonetheless constituted another major environmental shock during an already difficult period.

The Toba eruption blanketed parts of South Asia with ash, including areas where stone tools provide evidence of human presence both before and after the event. This does not mean, however, that the period that followed was easy; it simply means that humans managed to survive despite devastated landscapes, disrupted food sources, and massive volcanic fallout.