by The Pacific Ocean’s days are numbered, according to a new supercomputer simulation of Earth’s ever-drifting tectonic plates.
The good news? The oldest ocean on our planet still has 300 million years to go. If the Pacific is lucky, it may even celebrate its billionth birthday before finally disappearing.
But researchers at Curtin University in Australia believe the ocean is likely to be swallowed before that.
In its final years, the Pacific will hardly resemble the vast expanse of blue it does today. Every year, the ocean shrinks a few centimeters, as it has been doing since it was a superocean surrounding the last supercontinent of Pangaea.
This ancient ocean is home to many subduction zones. places where tectonic plates collide and slide over each other. These sites, known colloquially in the Pacific as the “Ring of Fire,” act almost like bathtub drains for the ocean floor.
Every year, a few centimeters of the Pacific plate slips under the Eurasian plate and the Indo-Australian plate, collapsing the distance between North America, Asia and Australia.
Not all scientists agree about what the next supercontinent will look like or form, but in many simulations, the Pacific Ocean is doomed.
While some studies suggest that the Atlantic Ocean, which is expanding today, may begin to shrink in the future, creating a supercontinent surrounded by a super Pacific ocean, researchers at Curtin University disagree.
Instead of a second Pangea-like continent (aka Pangea Proxima) formation, argue that the world is moving toward a supercontinent where North America collides with Asia, called Amasia.
Poor Australia is left out of this “cute couple” moniker, but in 4D geodynamic models, the Southern Hemisphere continent appears to play an important role in connecting what’s left of the Pacific.
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Recent simulations by researchers in Australia are based on realistic slab and mantle parameters from the present and past, which are then used by a supercomputer to predict the future.
“Over the past two billion years, Earth’s continents have collided with each other to form a supercontinent every 600 million years, known as a supercontinent cycle,” says Earth scientist and lead author Chuan Huang.
“By simulating how Earth’s tectonic plates are expected to evolve using a supercomputer, we were able to show that in less than 300 million years the Pacific Ocean is likely to close, allowing the formation of Amasia, debunking some previous scientific theories ».
Unlike some other supercontinent simulations, this news suggests that the Pacific Ocean, and not the Atlantic Ocean or the Caribbean Sea, will be destroyed when Amasia forms.
In today’s model, Amasia occurs when the Pacific closes due to the weakening of the upper layer of the oceanic crust.
“Earth as we know it will be drastically different when Amasia forms. Sea levels are expected to be lower and the vast interior of the supercontinent will be very arid with high daily temperatures,” says geoscientist Zheng-Xiang Li.
But this is just the latest study in a long line of supercontinent simulations, all of which have tried to predict what our planet will look like in the future.
One more model is unlikely to end the debate, but this is not the only one predicting the death of the Pacific.
In a scenario where a supercontinent called Novopangaea forms, the Americas collide with Antarctica before crashing into Eurasia and Africa. This cuts across the Pacific in a different way but with similar results.
In another supercontinent scenario, called Aurica, both the Pacific and Atlantic oceans close permanently and a new ocean basin forms in their place.
Whatever the outcome, one thing is certain: Earth and its oceans will never be the same again.
The study was published in National Science Review.
