Ancient volcanic eruptions linked to mass extinction and climate change

The End Triassic Extinction, one of Earth’s most significant mass extinctions, reshaped life on the planet 201.6 million years ago. Three-quarters of species vanished, signaling the transition from the Triassic to the Jurassic era.

This shift coincided with massive volcanic eruptions that tore apart the supercontinent Pangaea, separating what we now know as the Americas, Europe, and North Africa. As lava surged for around 600,000 years, the planet became unrecognizable, setting the stage for dinosaurs to thrive in the ensuing Jurassic period.

Traditionally, scientists believed the extinction was triggered by rising temperatures and ocean acidification, driven by high levels of carbon dioxide released by these eruptions. However, recent research proposes a different cause: a sudden cold spell resulting from massive amounts of sulfate particles launched into the atmosphere.

According to the study, led by Dennis Kent of the Columbia Climate School’s Lamont-Doherty Earth Observatory, the first waves of lava erupted in powerful pulses, each lasting less than a century. These bursts produced sulfate aerosols that reflected sunlight and plunged the world into rapid volcanic winters. While carbon dioxide effects build slowly, taking centuries to heat the atmosphere, sulfate aerosols have immediate cooling effects.

“Carbon dioxide and sulfates act not just in opposite ways, but opposite time frames,” Kent noted. “It brings us into the realm of what humans can grasp. These events happened in the span of a lifetime.”

Published in the Proceedings of the National Academy of Sciences, Kent’s findings offer a fresh perspective on what ended the Triassic era. The research team drew from Central Atlantic Magmatic Province (CAMP) deposits, a volcanic region that emerged during Pangaea’s split.

Over decades, scientists like Kent have connected CAMP's eruptions to the extinction event, but this study narrows the timing of volcanic pulses down to specific decades, showing how sulfur-driven cooling likely outpaced carbon-induced warming.

Kent’s team compared volcanic rock formations across Morocco’s Atlas Mountains, Nova Scotia’s Bay of Fundy, and New Jersey’s Newark Basin. They analyzed magnetic particles within these rocks to track Earth's historical magnetic pole shifts, a technique vital to their conclusions. Magnetic particles embedded in lava align with Earth’s magnetic field at the time of eruption.

Over millennia, the pole gradually shifts position, so particles trapped in lava from the same eruption will point in one direction. If the lava erupts thousands of years apart, the magnetic alignment shifts due to Earth’s pole drift. In these layers, the particles aligned identically, suggesting eruptions spanned decades rather than millennia.

These repeated volcanic pulses, lasting less than a century each, released staggering amounts of sulfate particles, reflecting sunlight and cooling the planet. Paul Olsen, study coauthor and Lamont-Doherty paleontologist, observed, “The magnitude of the environmental effects is related to how concentrated the events are.”

Olsen pointed out that small eruptions spread over thousands of years produce fewer environmental impacts, but when concentrated in a short time frame, their effects become devastating. These volcanic winters devastated ecosystems, freezing animals and disrupting habitats. CAMP's eruptions dwarfed historical eruptions, such as Iceland’s Laki eruption in 1783, which led to crop failures; CAMP’s impact was hundreds of times greater.

Pre-eruption Triassic fossils tell a story of diverse life, from crocodile-like creatures and flat-headed amphibians to tropical plants. These species disappeared in the eruption’s wake. In contrast, small feathered dinosaurs, which had already been around for tens of millions of years, managed to survive—perhaps due to their burrowing habits, which shielded them from sudden climatic shifts. These dinosaurs would later grow in size and dominate the Jurassic era.

The volcanic activity that marked the end of the Triassic era wasn’t an isolated event. Paul Olsen has studied this boundary for decades, working to connect the timing of CAMP’s eruptions with Earth’s magnetic and sedimentary records. His work aligns sediment layers with Earth’s precession cycle—a predictable change in Earth’s axial tilt over 20,000 years. This alignment further narrows down the timing of the extinction to less than 20,000 years, likely far shorter.

Many scientists today believe mega-volcanism has triggered multiple extinctions throughout history. The exact mechanisms are complex, but Kent’s findings strengthen the link between rapid volcanic events and mass extinction. The massive lava flows from CAMP generated not only rapid cooling from sulfate aerosols but also sustained warming due to carbon dioxide.

Following each volcanic winter, carbon dioxide trapped in the atmosphere created millennia of warming, impacting species unable to adapt. Olsen’s team, studying samples from New Jersey to North Africa, found fossils of eel-like fish, early crocodiles, and lush plants in the sediment just below the CAMP layers. Above, these species vanish.

Previous studies have suggested that the extinction event could have been influenced by a meteorite impact, although this theory remains unconfirmed. The extinction of dinosaurs 135 million years later has stronger evidence for a meteorite-triggered end, alongside a simultaneous volcanic event. The Triassic-Jurassic extinction, however, remains firmly linked to volcanism, with the new findings showing that concentrated eruptions had a profound, nearly instant effect on Earth’s climate.

Scientists today see similarities between the conditions of the End Triassic Extinction and our current climate crisis. Since the Industrial Revolution, human activities have increased atmospheric carbon dioxide by over 40% in just 200 years. Such rapid rises mirror past volcanic events and could lead to similar consequences. The rise in CO₂ is now altering ecosystems, with ocean acidification happening at a pace that rivals historical volcanic impacts.

Terence Blackburn, a geochronologist and study coauthor, believes that examining events like the End Triassic could inform our understanding of today’s climate issues. “Much insight on the possible future impact of doubling atmospheric CO₂ on global temperatures, ocean acidity, and life on earth may be gained by studying the geologic record,” he said. For instance, while carbon dioxide has a slow warming effect, sulfates bring immediate cooling, suggesting that even quick, temporary interventions in atmospheric composition can lead to dramatic climate shifts.

Paul Renne, a geochronologist at the Berkeley Geochronology Center, sees Kent’s work as a major advancement in our understanding of extinction events. Renne commented, “The pendulum continues to swing in favor of that idea,” noting that while carbon dioxide is commonly seen as a driver of extinction events, exactly how it acted during the End Triassic Extinction remains uncertain. Renne added that understanding past events better might someday allow us to project outcomes more precisely and take targeted action against climate change.

Today, some scientists argue that human activities may be pushing Earth into a sixth mass extinction. Human-driven factors, including rapid industrialization, rising population, and fossil fuel consumption, may be moving at a pace rivaling natural cataclysms like the End Triassic.

With rising temperatures and ongoing ocean acidification, lessons from these ancient die-offs remind us of Earth’s fragile equilibrium and the profound impacts sudden climate shifts can have on life.

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