When changes in climate made Antarctica one of the most comfortable continents
Antarctica is getting green again. For the last 50 years, moss has been making inroads along the Antarctic Peninsula thanks to global climate change, although it’s certainly not the first time this continent has seen non-winterized flora and fauna. In fact, Antarctica’s milder periods may have made it a haven for species having a hard time when the rest of the world’s climate was being a bit less hospitable. That’s not to say that it’s a place to buy real estate though, since for starters, Antarctica used to be in a different location altogether.
600 million years ago, before creatures like dinosaurs were even close to being a thing, Antarctica was part of the single super-continent, Gondwana. Life at that point would have been happy in a petri dish, and so nothing was going to discriminate against Antarctica or it’s neighbors Australia and India. The fact that all the world’s continents were sort of centered along the equator meant that no place was especially colder than another, and the six-month winter that helps keep modern Antarctica frosty wasn’t an issue.
From the Great Dying to dinosaurs
At the end of the Permian Period, around 250 million years ago, Antarctica got to differentiate itself a bit. A lack of oxygen in the Earth’s oceans and spike in carbon dioxide levels was wreaked havoc across ecosystems, wiping out an estimated 96 percent of life forms on the planet. Average global temperatures also rose, which turned most of Gondwana into a harsh, parched wasteland, except in Antarctica. Being on the cooler end of the global climate, even just a bit, helped the southern end of the super-continent remain a bit more habitable, and home to various plants, reptiles, synapsids and more. By the Jurassic Period, Antarctica was in full bloom, complete with conifer trees, cycads, pterosaurs and some decently-sized dinosaurs.
One such dinosaur was a theropod named Cryolophosaurus ellioti. Walking on two tall legs with arms long enough to make a T. rex jealous, this predator also sported a pretty neat head crest, probably used in either species or sex identification. In the large scheme of things, at around 21 feet long, Cryolophosaurus was a larger theropod than many of its contemporaries on other continents. It’s not clear why this larger size evolved early but these species didn’t really keep pace. A herbivorous sauropod found in Antarctica was notably shorter, or “wimpier,” than it’s long-necked kin elsewhere, but by the Cretaceous period it was becoming clear that this southern continent’s role as a habitat was being pushed to the margins.
Around 145 million years ago, the Cretaceous period began, marking the birth of a modern Antarctica. The super-continent of Gondwana was breaking apart, and continents were migrating to their modern positions on the globe. For Antarctica, this of course meant heading to the Earth’s south pole, and being geographically isolated from other land masses. For a time, Australia stayed with Antarctica, but that union would eventually end as well. Dinosaurs stuck things out at long as they could, although even the south pole wasn’t safe from the asteroid impact that famously caused the extinction of non-avian dinosaurs, pterosaurs and marine reptiles around the world.
Warming as a warning?
As Antarctica warms once again, we will likely be able to uncover more of its history that’s been hidden beneath layers of ice and snow. Unfortunately, it looks like other parts of our planet’s history may also be repeating, with more northern climates heating up faster than life can adapt. As great as it would be to find more fossils in Antarctica, nobody wants life to have to retreat to this elusive continent all over again.
Source: The Mysterious World of Prehistoric Antarctica by Charles Owen-Jackson, Earthly Universe
