Was Antarctica Ever Warm?
For much of the last 400 million years, Antarctica has been a temperate place, covered with forests and animals. Due to continental drift, it has moved from straddling the equator to being centered on the South Pole, where it is today. Today, Antarctica is the coldest continent on the planet, almost completely covered in a layer of ice, and entirely lacking in animals aside from visiting penguins and a few small bugs in the coastal areas.
But it wasn't always that way. Antarctica was once part of the supercontinent Gondwana, which lasted up until about 160 million years ago, when it slowly began to break up. Gondwana included most of the continents in the southern hemisphere today, including South America, Africa, Arabia, India, Australia, and New Zealand. Gondwana straddled the equator and was one of the world's two supercontinents, along with Laurasia, which included present-day North America and Asia. Fossils of some of the earliest complex life have been found in the shallow seas surrounding it.
When life first came onto the land, Antarctica was one of the continental landmasses to be covered in forests and animals. Much of the fossil record of the Antarctic landmass is under the ice, but fossils, including those of dinosaurs, can be found in the Antarctic mountains, where rocks jut out from the continent's mile-deep ice cap.
In the times of the dinosaurs, Gondwana's north-south orientation blocked currents from circulating at a certain latitude, instead directing them north and south long distances. This prevented from the temperature differentials at any given latitude from forcing the waters into a permanent hot or cold temperature, as the poles are today.
As Antarctica began to break away from the supercontinent Gondwana 160 million years ago, cooling began. It moved south, still connected to Australia and South America but separated from Africa. At this point, Antarctica was still had a tropical or subtropical climate, but was located further south, near the latitude of present-day Australia. Like today's Australia, the continent had a marsupial fauna.
Around 40 million years ago, Antarctica separated from present-day Australia and began to cool down even more, its forests dying. Ice and glaciers began to cover the continent, but the final end of Antarctica's life came only about 23 million years ago, when Antarctica separated from South America and the Drake Passage opened. This permitted the existence of a Antarctic Circumpolar Current, a frigid current that continuously encircles the continent. It resulted in the continent being covered in a mile-deep layer of ice, as snow that fell never melted. Today, Antarctica's ice sheet contains about 70% of all fresh water on Earth.
@stoneMason-- There is ongoing research about Antarctica. The study I saw was done in 2014 and they found that the temperatures in Antarctica used to be as hot as California.
I think the results of some of the earlier studies might be inaccurate because there are new technologies being used to study these things. I'm sure that we will get more accurate information about what Antarctica was like in the next several decades.
@Ana1234-- Scientist have been able to take some samples from Antarctica and they have found some plant remnants. But you are right that it's very difficult to get samples, not just because it's covered by ice but also because the ice moves and destroys sediments.
But I think that the temperature calculations of Antarctica of the past are a bit exaggerated. One scientist said hat Antarctica had some vegetation in the past, but it was not a place of lush green growth. The average temperature is suspected to be around 44 degrees Fahrenheit. That's not very warm.
Wow, I had no idea that Antartica had a hot, tropical climate once upon a time. Since it's such a cold place now, we are inclined to think that it was always that way.
@browncoat - It's true that the Earth was once warmer, but that doesn't mean that this is a natural next step. When it has gone through shifts before, they have been over thousands of years, or even longer and it has allowed fauna and flora the time they need to adjust. At the moment we are going through the same level of change in a much shorter time period.
So, if we end up with Antarctica as a temperate zone again, it would likely be barren, because it doesn't have an established ecosystem able to cope with those temperatures. I don't think we're quite at that point yet, though, thank goodness. There is so much water caught up in Antarctic ice, if it suddenly ended up in the ocean, then we'd all be in trouble.
@Ana1234 - Well, we do seem to know some things about the creatures that lived there, and even that it was temperate enough for them to live there in the first place. I think it speaks to the fact that global warming at the moment is just another step in a long process of the Earth heating up and cooling down over the eons.
With that said, I'd love to visit Antarctica one day. I've heard there are artist grants that allow writers and painters to go there with science expeditions and that's probably my best bet.
It must be amazingly inspiring. Such a different and unique place.
You've got to wonder what kinds of fossils are hidden underneath the ice of Antarctica. Sometimes it feels like we couldn't possibly discover many other ancient creatures, but that is essentially an entire continent that has never really been explored for fossils, because there is no way to reach them.
I guess when global warming increases, it's possible that fossil collectors will be able to conquer Antarctica as well.
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