The extinction of the dinosaurs 66 million years ago came during a tumultuous time in Earth’s history, with some of the largest known volcanic eruptions and a 10-15km wide asteroid crashing into the planet.
The role these events played in the dinosaurs’ fate has been fiercely debated over several decades, but new research published in the journal Science Advances suggests the asteroid impact was the primary driver of the end-Cretaceous mass extinction.
A research team, including scientists from the University of Plymouth, analysed samples of ancient peats collected during fieldwork in Colorado and North Dakota.
This enabled them to reconstruct the mean annual air temperatures in the 100,000 years leading up to the extinction, which revealed that volcanic CO₂ emissions caused a slow warming of about 3°C across this period.
There was also a short cold “snap” — a cooling of about 5°C — that coincided with a major volcanic eruption 30,000 years before the extinction event that was likely due to volcanic sulphur emissions blocking out sunlight.
However, the temperatures returned to stable pre-cooling temperatures around 20,000 years before the mass extinction of dinosaurs, suggesting the climate disruptions from the volcanic eruptions weren’t catastrophic enough to kill off the dinosaurs.
The findings are the result of the Equable Earth project, funded by a grant of over £580,000 from the Natural Environment Research Council, and involving researchers from the University of Manchester, University of Plymouth, Utrecht University in the Netherlands, and Denver Museum of Nature and Science in the USA.
Professor Gregory Price
