Blog Post by Karun Tyagi

What if human civilization faced mass extinction? This intriguing hypothesis raises issues regarding the interconnectivity of Earth’s geological past, Climate changes, and human-induced climate change. This blog article will examine the complex connection between these causes and their potential effects on human civilisation.

Geologic History of the Planet

To understand the broader context, we must first explore Earth’s geological history. Volcanic eruptions, tectonic activity, and solar radiation have caused climate change cycles over millions of years. Long-term geological processes have shaped Earth’s climate and ecosystems and still affect environmental conditions today.

Geological periods have had a major impact on the ecosystem. These times have diverse climates, ecosystem alterations, and species extinctions. Some important times and their environmental impacts:

The Precambrian Era (4.6 billion–541 million years ago) covers most of Earth’s history. Early life and atmospheric development occurred during this time. Photosynthetic organisms like cyanobacteria raised oxygen levels, enabling more complex living forms.

Paleozoic Era (541–252 Ma): Plants and animals colonised land and diversified during the Paleozoic Era. During the Cambrian explosion, many complex marine species appeared quickly. Fish, amphibians, reptiles, and forests appeared in the late Paleozoic. The Permian-Triassic mass extinction, Earth’s worst, killed 96% of marine species and 70% of terrestrial vertebrates at the end of the Paleozoic Era.

Mesozoic (252–66 million years ago): The Mesozoic Era is called the “Age of Reptiles” or “Dinosaur Age.” Triassic, Jurassic, and Cretaceous are its periods. Dinosaurs, birds, flowering plants, and marine reptiles dominated the Mesozoic Era. The Cretaceous-Paleogene extinction catastrophe wiped off non-avian dinosaurs and many other species.

Cenozoic Era (66 million years ago – present): Paleogene and Neogene are Cenozoic Era eras. Due to the increase and diversification of mammalian species, it is called the “Age of Mammals”. The Paleogene was warmer, and monkeys, rodents, and ungulates emerged and spread across continents. Horses and elephants evolved from grasslands in the Neogene. Humans also appeared.

Quaternary (2.6 million years ago–present): The most recent period, the Quaternary, has glaciations and interglacial periods. It includes the glaciated Pleistocene and the interglacial Holocene, which began 11,700 years ago. The Quaternary Period saw the emergence of modern humans, the extinction of megafauna like mammoths, and the global spread of human civilizations.

There have been instances of civilization extinctions that can be attributed, at least in part, to Earth’s geological history. One notable example is the extinction of the Minoan civilization on the island of Crete around 1450 BCE.While the exact cause is still debated among scholars, one theory suggests that a cataclysmic event contributed to its downfall.

The Minoan civilization may have declined due to the eruption of the Aegean Sea volcano Thera (Santorini) near Crete. One of the most major volcanic eruptions in human history occurred approximately 1600 BCE. It released massive volumes of volcanic ash, gases, and tsunamis, which affected Crete.

Climate Variation

Earth’s climate fluctuates naturally. Volcanic activity, orbital variations, and solar radiation have affected Earth’s temperature, rainfall, and climate. Long-term climate changes lasting hundreds or millions of years shape ecosystems and surroundings that civilizations depend on.

Environments shape civilizations. They create climate-adapted agricultural, settlement, and economic systems. Civilizations can struggle when Earth’s climate changes. Droughts, changing rainfall patterns, extreme weather events, and temperature changes can destabilise communities by reducing agricultural production, water supplies, and resource scarcity.

Historical Examples:

a. Indus Valley Civilization: The decline of the Harappan civilization in the Indus Valley, around 1900 BCE, coincided with changes in the monsoon patterns and shifts in river courses. These environmental changes likely impacted agricultural productivity and trade routes, contributing to the decline of the civilization.

b. Mayan Civilization: The Classic Maya civilization, between 200 and 900 CE, experienced a collapse attributed, in part, to a combination of droughts and changes in rainfall patterns. These climate changes disrupted the agricultural system, leading to food shortages, social unrest, and the eventual abandonment of many Maya cities.

It is vital to emphasise that climate change is not the exclusive cause of civilization extinction. Political insecurity, social disputes, economic obstacles, resource depletion, and external forces all interact to determine the fate of civilizations. These elements can increase the vulnerabilities caused by climate change, resulting in a chain reaction of events that can lead to the extinction or decline of a civilization.

Human activities alter the climate

Human actions have substantially affected the Earth’s climate in recent millennia, generating concerns about the doom of human civilization. Human-caused climate change is caused by activities such as the use of fossil fuels, deforestation, industrialization, and the emission of greenhouse gases into the atmosphere. These activities have resulted in a significant increase in atmospheric CO2 levels, trapping heat and amplifying the greenhouse effect.

Climate change caused by humans can set off feedback loops that intensify the warming process. For example, melting polar ice caps lowers the Earth’s albedo, allowing more sunlight to be absorbed and contributing to additional warming. The rate of climate change is accelerated by this positive feedback loop. Climate change caused by humans poses a serious existential threat to human civilization. Rising sea levels, harsh weather events, environmental changes, and resource scarcity all necessitate immediate response.

Conclusion

The possibility of mass extinction of human civilizations as a result of Earth’s geological history, climate changes, and human-induced climate changes is a major issue in the modern age. Understanding the complex relationship of these factors is critical for designing comprehensive solutions for mitigating and adapting to climate change concerns. We may endeavour to preserve the long-term survival and well-being of human civilizations in the face of an uncertain future by recognising the relevance of our geological history, understanding the impact of human actions, and adopting collective action.

Image by brgfx on Freepik