New Study Links Volcanic CO2 to Triassic–Jurassic Marine Extinction

A groundbreaking study published in *Nature Communications* reveals that volcanic carbon dioxide (CO2) emissions played a crucial role in the extinction of marine life during the Triassic–Jurassic boundary, approximately 201 million years ago. This research, conducted by a collaborative team from the University of St Andrews and the University of Birmingham, provides new insights into the mechanisms of mass extinction and serves as a stark warning regarding current climate change threats.

The research team utilized ancient oyster fossils to reconstruct historical ocean pH levels, uncovering a significant acidification event that correlates with the extinction of diverse marine species, including coral reefs, ammonites, and large marine reptiles. Dr. James Rae, a co-author of the study and researcher at the University of St Andrews, stated, “The geological record tells us that major CO2 releases transform the face of our planet, acidifying the oceans and causing mass extinction.”

Prior to the extinction event, ocean pH levels were approximately 8.2, akin to contemporary conditions. However, the study indicates that pH levels plummeted by more than 0.3 units due to increased CO2 from extensive volcanic activity associated with the breakup of the supercontinent Pangaea. These findings emphasize the immediate and long-term impacts of ocean acidification on marine ecosystems.

Dr. Sarah Greene, an Associate Professor of Palaeoclimates at the University of Birmingham and co-author of the study, noted, “The mass extinction event during the Triassic-Jurassic period unfolded over a prolonged timeframe, whereas modern ocean acidification is occurring at a significantly accelerated pace.” The researchers warn that the current rate of carbon emissions may mirror the ancient event but compressed into a much shorter timespan, leaving marine life with insufficient time to adapt.

Historically, ocean acidification has been implicated in at least three of the five largest extinction events on Earth, suggesting a consistent pattern where disturbances in the carbon cycle precipitate widespread ecological disaster. This study provides critical evidence linking elevated CO2 levels to oceanic changes and subsequent biodiversity loss.

The implications of these findings extend beyond historical analysis; they serve as a dire reminder of the potential consequences of unchecked carbon emissions today. The oceans currently absorb nearly a third of atmospheric CO2, and the rapid influx of carbon can lead to drastic shifts in marine chemistry. Shell-forming organisms, such as corals and oysters, are particularly vulnerable, and their decline could disrupt entire marine food webs.

The urgency of addressing climate change is underscored by the historical precedent set during the Triassic–Jurassic extinction. As contemporary society grapples with rising atmospheric CO2 levels, scientists emphasize the need for immediate action to mitigate emissions to avoid repeating the ecological catastrophes of the past. The study not only sheds light on ancient extinction dynamics but also provides vital context for understanding and combating current environmental challenges.