Dinosaurs roamed Antarctica, a green forest

Antarctica is generally known as a frozen, free and isolated continent, although this has not always been the case.

In a geological epoch, the mbad of the great southern continent was covered with forests and dinosaurs roamed the earth. How was this once frozen continent so hot that it allowed the largest organisms on Earth to live on their own?

To find out why, we have to go back in time, especially to the Cretaceous, which began 145 million years ago and ended 66 million years ago.

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Antarctica was ice-free at that time, and it was the last time dinosaurs lived before the meteor hit Earth and bury them all.

Forests of this age were developing at the North and South Poles, where scientists discovered fossils of cold-blooded trees and reptiles that allowed them to paint a complete picture of the time that he was doing at that time .

We know that cold-blooded reptiles need the warmth of the sun to stay alive, and we can see them lying in the sun, enjoying the warmth of the light during the day.

The bipolar climate in winter, when the sun disappears, is probably hot enough to keep them alive during the dark months.

Scientists have also used fossils of organisms living in the ocean in perforated shells called "Formaneva" in order to know the nature of the weather that he was doing in the past.

By badyzing the chemical composition of the shells and determining the time scales in which different species lived, scientists were able to estimate the temperature of the ocean at that age.

Dr. Bryan Huber of the Smithsonian Museum of Natural History conducts scientific research to explore the Cretaceous period, focusing on the bottom of the Antarctic Ocean.

"Species are one of the best natural records of the evolution of life," says Huber. "We have benthic fossils that live in marine sediments and record record temperatures deep in the ocean."

"If we collect these natural archives and badyze the shells of different parts of the world's oceans, we will have a clear picture of the evolution of time," he said.

But research on the Antarctic Ocean around Antarctica led scientists to a discovery that surprised them at first, Huber said, noting that the Southern Ocean in the past , was hotter than expected.

"We found that temperatures reached 30 degrees Celsius at 58 degrees South" near the Antarctic Circle.

Temperatures were recorded during the Middle Cretaceous period, while scientists described the phenomenon as "Cretaceous global warming", caused by high concentrations of greenhouse gases in the atmosphere, such as carbon dioxide.

But what happened in the Cretaceous period did it turn Antarctica, which today looks like a barren and icy forest, into a green forest populated by trees? Trees where dinosaurs roam?

"All we know about the middle of the Cretaceous era, is that this time has seen the sea floor speed increase and that the volcanic activities have increased considerably, which has resulted in Huge amounts of carbon dioxide in the atmosphere, "says Huber.

Hopper and his colleagues are still studying the causes of Cretaceous global warming, be they mbadive volcanic eruptions, which have released huge amounts of carbon dioxide, causing global warming, and therefore warming of the planet.

Climate change has become a reality, it has changed in the past, it is changing now and will change in the future.

But what is the difference between the current climate change and the Cretaceous? Could Antarctica be soon again without ice?

"Climate change is now larger and faster than any known climate change that has caused major events in previous geological eras," Huber said.

"In dozens of years, hundreds of billions of tons of carbon dioxide are emitted into the atmosphere and these quantities can not be released by volcanic eruptions, regardless of their magnitude and in a period as short, "he said.

"In the decades or perhaps centuries to come, I predict that the number of glaciers is growing and that the West Antarctic icecap may begin to retreat, but given the current rate of glaciers, I do not I do not expect the continental ice cap to be based, "says Huber. Antarctica for decades. "

Ice experts predict that the negative effects of climate change will be exacerbated by rising sea levels and then in a vicious circle: the faster the sea level rise, the more the ice flow, which turns into sea, increases, etc. So we are already seeing signs of melting ice in Antarctica. "

We do not rule out Antarctica becoming ice-free in the future, but we do not think the dinosaurs will come back. However, we can not predict the impact of these transformations on humans because we did not live on the surface of the Earth when the poles were ice-free.

You can read the original article from BBC Earth

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