Discovery of 40-million-year-old river system in Antarctica is a warning sign for humans

A massive ancient river system once existed beneath the Antarctic ice sheets, geologists have discovered. While digging into the massive ice sheet of West Antarctica, they found that this river flowed for a thousand miles. But what happened to this river? Researchers say that climate change likely played a role and the finding shows that we are at risk of enduring a similar fate in the future if the temperatures continue to rise at the current rate. 

Johann Klages, study co-author and a sedimentologist at the Alfred Wegener Institute Helmholtz Center for Polar and Marine Research in Germany, and his team in 2017 drilled into the western part of Antarctica to collect samples from soft sediments and hard rocks set within the frozen seabed. They found sediments with layers from two different periods. The lower part contained fossils, spores and pollens, indicating that a temperate rainforest existed during the mid-Cretaceous period, about 85 million years ago. 

The upper part of the sediment contained mostly sand. As the scientists delved into these samples from the mid-to-late Eocene epoch, about 30 million to 40 million years ago, they found a strongly stratified pattern which resembled something that would normally come from a river delta. More research concluded that an ancient river once flowed in the Antarctic region.

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The Earth has witnessed periods when carbon dioxide levels were more than double what we are seeing today. Between 34 million to 44 million years ago, during the middle-to-late Eocene epoch, the atmosphere on our planet saw a drastic change. Carbon dioxide levels plummeted, and the resultant cooling led to the formation of glaciers. However, during the late Eocene period, CO2 was at levels that Earth is predicted to reach in another 150 to 200 years, Klages told Live Science.

Scientists have been trying to understand how that happened, but vast swathes of West Antarctica are covered in ice, making it difficult to access sedimentary rocks that can offer clues to how the change unfolded.