Dinosaurs thrived after Ice

by | December 1, 2024, 7:33 PM | Earth Science

Archaeopteryx Credit: Peter Montgomery

Jupiter’s moon Io is the most volcanic object in our solar system today, but our planet gave Io a run for its money more than 200 million years ago. At that point in our planet’s history, our world was dominated by the Triassic period’s great reptiles, amphibians and earliest dinosaurs. This was a time when the Earth had a single continent – Pangea – and life was wildly evolving. But the break up of Pangea into the continents we see today was one of violence and mass extinction. It has long been known that the Triassic – Jurassic boundary marks a great extinction and a period of massive volcanic eruptions that are linked to the continents splitting apart. From earlier research we thought this volcanism may have spanned long periods of time and resulted in the earth getting too hot to support life due to carbon dioxide-related global warming. 

New research, appearing in the Proceedings of the National Academy of Sciences and led by Dennis Kent, finds that the continent-rending volcanic upheavals likely occurred over very brief periods, lasting less than a century each. These events released so many sunlight-reflecting sulfate particles into the atmosphere that our planet underwent a massive cooling. Basically, if the sunlight can’t reach the surface of our world, the world grows cold.

And a cold earth was not a good place for cold-blooded reptiles… but it did lead to the age of the dinosaurs. Their research finds the small feathered dinosaurs survived and went on to get much larger. Smaller turtles, lizards, and mammals also made it through, potentially because they could burrow to escape the cold. 

What I love about this story is how much our understanding of dinosaurs has changed since I was a 5 year old who could identify every skeleton in a museum. We now know these great beasts evolved into birds, were warm blooded, and in some cases tended their eggs and possibly their young. And they were warm blooded and that let them survive the volcanoes.

Unfortunately, when that asteroid struck the Yucatan peninsula at the Crettaceous period, everything on the surface that wasn’t washed away in tsunamis was baked by the planet’s super heated air. For dinosaurs at least, Fire and Ice are not equally nice.