Earth’s Most Catastrophic Extinction Event: The Great Dying

The Great Dying

The 66 million-year-old extinction of the dinosaurs is frequently cited when discussing catastrophic extinctions. The Great Dying, also referred to as the Permian-Triassic extinction, took place approximately 252 million years ago and was a far more catastrophic extinction event. The worst extinction event in Earth’s history, this apocalyptic event wiped out roughly 90–96% of all marine species and 70% of terrestrial species. Numerous factors have contributed to this unprecedented loss of biodiversity, and the origin of this mass extinction is still the focus of intense philosophical debate.

The Great Dying
The Great Dying—National Geographic

The Great Dying changed the course of life on Earth by separating the Permian and Triassic eras. Life was extremely diverse prior to this catastrophe, particularly in the waters, which were filled with ammonite, brachiopod, and trilobite species. Massive woods, early reptiles, amphibians, and insect species flourished on land.

But the majority of these animals had been wiped off by the end of the Permian epoch. It took several hundred thousand to a few million years for the Great Dying catastrophe to occur. Geologically speaking, this chronology is short, yet it is long enough to provide a prolonged era of environmental instability that results in mass extinctions.

Credits: CBS News

What Caused The Great Dying?

Although there is no one explanation for the Great Dying, scientists think that it was caused by a number of interrelated factors. Some of the most prominent theories are as follows:

  1. Siberian Traps Volcanism: The most well recognized idea suggests that the Siberian Traps, a sizable area in northern Russia, has seen enormous volcanic eruptions. Massive volumes of methane and carbon dioxide (CO2) were released into the atmosphere by these eruptions, causing uncontrollably high global temperatures. According to some calculations, CO2 levels might have risen tenfold throughout this period. Extreme global warming, ocean acidification, and anoxia—the loss of oxygen in the oceans—would have resulted from this significant change in the climate. Other harmful gasses, such as sulfur dioxide, were also emitted by the volcanic activity, and this probably led to acid rain, which further destroyed life.
  2. Ocean Acidification and Anoxia: The rise in atmospheric carbon probably led to an increase in ocean temperatures, which upset circulation patterns. Less oxygen is held in warmer water, which causes extensive anoxia and dead zones that are devoid of life. A large portion of the rising CO2 levels in the atmosphere dissolved into the oceans, increasing the acidity of the water. Marine life would have had a harder time surviving as a result, particularly species with calcium carbonate shells like mollusks and corals.
  3. Methane Release: The disintegration of methane hydrates, which are ice-like substances that are present on the ocean floor, may have been another factor. Methane, a powerful greenhouse gas, is stored in enormous quantities in these hydrates. These hydrates may have contributed to global warming by releasing methane into the atmosphere when the oceans warmed. The Earth was probably made even hotter by this feedback loop.
  4. Supercontinent Pangaea: The majority of Earth’s landmasses were united to form the supercontinent Pangaea at this time. Extreme temperature differences between the interior and coastal regions were brought on by this enormous landmass, which also decreased the diversity of coastal ecosystems. Pangaea’s enormous size also played a role in the drying up of wide regions, turning many ecosystems into deserts and lowering biodiversity.

Throughout the Great Dying, the biosphere was all but destroyed. Ecosystems in the oceans needed millions of years to recover. Particularly hard-hit were species that create reefs, and coral reefs were gone for about 10 million years. The loss of huge herbivorous and carnivorous species on land was equally disastrous. The early archosaurs, the ancestors of dinosaurs and birds, and some therapsid species, which later gave rise to mammals, were the only animals to survive because they were small, adaptive, and able to survive in difficult settings.

After this catastrophe, life ultimately recovered and new evolutionary lineages, such as the earliest dinosaurs and early mammals, emerged that would rule the Mesozoic Era.

Permian–Triassic boundary at Frazer Beach in New South Wales, with the End Permian extinction event located just above the coal layer.

The Great Dying serves as a clear reminder of how delicate the ecosystems on Earth are. Even though it occurred more than 250 million years ago, the same environmental elements—ocean acidification, temperature change, and volcanic activity—remain pertinent now. The current situation of our world, with growing carbon dioxide levels and rising global temperatures, has indeed been compared by some scientists to the circumstances that led to the Permian-Triassic extinction.

Sessile filter feeders like this Carboniferous crinoid, the mushroom crinoid (Agaricocrinus americanus), were significantly less abundant after the P–Tr extinction.

We can learn more about the effects of swift environmental change and the resiliency (or vulnerability) of life by researching the Great Dying. It demonstrates that while catastrophic mass extinctions can reset the evolutionary stage, it takes millions of years for life to fully rebound.

Lystrosaurus was by far the most abundant early Triassic land vertebrate.

The Great Dying, which wiped out almost all life and altered the planet’s ecosystems, was the most devastating extinction event in Earth’s history. The evidence suggests a confluence of ocean disruption, climate change, and volcanic activity, while the precise mix of factors is still up for debate. In addition to illuminating Earth’s past, an understanding of this event offers vital insights into how current environmental concerns may impact life on Earth in the future.

You can read more about this topic here: https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event