New research in South America links dinosaur diversification with a sudden climate change event. How does “sudden” climate change in the Triassic geologic time, over 230 million years ago, compare with modern climate change?
“The main evidence for this climate change, this Carnian Pluvial Episode, is actually a couple of million years before the first skeletons of dinosaurs. But we know because of the evolutionary relationships of the different dinosaurs that they had to have had an ancestor, common ancestor prior to that time," said Randall Irmis, the chief curator at the Natural History Museum of Utah.
Irmis is working with a research team in Argentina to learn more about the origin of dinosaurs. About the time the earliest dinosaur fossils appear, Irmis said scientists have also found evidence of a sudden climate shift in Europe and Asia to warmer and wetter.
The team’s findings in Argentina are the first reported evidence of this shift in the southern hemisphere.
“So, what we ultimately discovered was evidence that things got warmer and more humid in this part of Argentina at about the right time for being the Carnian Pluvial Episode,” said Irmis. “We can say that it does look like it was a very widespread climate event that happened during a time when dinosaurs or their close relatives were leaving their footprints along this lake margin.”
Rocks from the late Triassic time period are found in Utah, but Irmis said they are several million years younger than the Carnian Pluvial Episode climate event. He also said during the Triassic period, the world’s climate was very different.
“This is what we call a greenhouse world where there's no polar icecaps and carbon dioxide levels are higher than they are today.”
Learning about these past climate events and how species responded is something Irmis said is useful in understanding our planet today.
“What's cool is that we can use these sudden climate events in the geologic record to ask questions," Irmis said. "They're still very useful analogues for understanding where our Earth might be headed.”