As we have noted in previous scientific issues, humanity is at the onset of the sixth large-scale mass extinction. In the past, this phenomenon has caused the disappearance of more than 75% of all species on Earth. This piece takes a look at the progression of previous mass extinctions. With particular attention to the end-Permian extinction, celebrated for its unprecedented severity and alarming analogies to our contemporary ecological crises.
Throughout Earth’s history, five great mass extinctions have radically altered the biological landscape. These disasters, defined by large-scale biodiversity collapse, have many of the same underlying causes. Most importantly, these events are not attributed to cosmic effects such as meteors. Instead, they are most commonly linked to super-volcanic eruptions that discharged vast quantities of carbon dioxide (CO2) into the atmosphere and oceans.
The end-Permian extinction, the most severe mass extinction in earth’s history that occurred roughly 252 million years ago, has been called a “climate of unmatched evil.” The aftermath of this event was the greatest 90 million years of mass extinction that fundamentally changed Earth’s ecosystems. Climate Chaos The world experienced an unprecedented spike in temperatures. Estimates suggest that it warmed by at least 10 degrees Celsius over just a few thousand years.
Volcanic activity along mid-ocean ridges during this period was particularly important in rapidly increasing CO2 levels. Scientists have well documented that volcanoes emit carbon dioxide at least 40% of their gas output as CO2. The huge cloud of CO2 pumped out during these daylong explosions was even more disastrous. It significantly altered the atmosphere and devastated all life on Earth.
When the Earth’s carbon cycle broke down, it resulted in devastating environmental consequences. Our once-great old-growth forests and the variety of fauna they protected were massacred. The animals and plants that once populated these important ecosystems disappeared with their habitat, leaving a wasteland in their place. While all this was happening, marine life endured huge losses as oceanic conditions worsened. Organisms became brittle, unwell, with some not being able to produce shells at all.
Today, there are pressing questions about the role that industrial civilization plays in increasing CO2 emissions. Estimates suggest that if humanity collectively endeavored to extract and burn all accessible fossil fuels, it could theoretically produce around 18,000 gigatons of CO2. Even these conservatively low estimates—30,000 gigatons—again seem unimaginable and would imply a rate of carbon emissions for thousands of years to come.
The earth has long signaled the fate that humans were accelerating at an alarming rate with each eruption. In 1978, scientists made an astonishing discovery. Their resulting discovery of a 110-mile-wide crater, buried under Mexico’s Yucatán Peninsula, attributed the cataclysmic event to one of the mass extinctions.
“The burning of coal,” one scientist writes of the end-Permian extinction, “would have represented an uncontrolled and catastrophic release of energy from Earth’s planetary fuel cell.”
Modern civilization is currently wrestling with the climate crisis and environmental destruction. The role of mass extinctions in our historical context serves as a harsh reminder of the cost of inaction. Paleoclimate data show just how fragile this balance is on Earth. At the same time, they underline the sometimes catastrophic effects of human actions.