Earth Will Become One Big Supercontinent Again, And It Will Probably Kill Us
Category: Health, Science & TechnologyVia: freefaller • 2 years ago • 40 comments
- G eoscientists say Earth will be home to one massive supercontinent about 200 million years from now; there are four prominent versions of this mega-continent.
- The climate might be surprisingly balmy in one of the most popular versions, but there is also the potential for an ice age.
- In the off-chance that a post- human species survives, they might have to be in a state of equilibrium with the natural ecosystem.
Pangea (or Pangaea ), the humongous landmass that joined together all seven continents into one massive continent during Earth’s prehistoric past, broke apart around 200 million years ago. In a fascinating twist of terrestrial evolution, it turns out that we’re about 200 million years away from the formation of a new, Pangea-like supercontinent , scientists say.
In the first scenario , we assume the Atlantic Ocean keeps opening up, while the Pacific Ocean keeps closing. The Pacific Ocean, for its part, is full of subduction zones , or places where oceanic plates are sinking down into continental plates and then into Earth’s mantle. (This is also why 80 percent of big earthquakes occur around the edges of the Pacific Ocean, also known as the “Ring of Fire.”)
As a result of this tectonic activity , the Americas continue to separate from Europe and Africa, which means they eventually smash into northbound Antarctica, and eventually into Africa, Europe, and Asia, which will have already been crammed together. Meanwhile, Australia will have docked to East Asia. The result is one immense mega-continent called “Novopangea” (Greco-Latin for “New Pangea”).
In the “Pangea Proxima” (or “next Pangea”) scenario , the Atlantic as well as the Indian Ocean continues to expand until new subduction zones pull the continents back again, resulting in a collision between Eurasia and the rest of the continents. To visualize the end result, picture a somewhat ring-shaped landmass with a small ocean basin at its center.
The Pacific and the Atlantic are really old—a whopping 200 million and 180 million years old , respectively. So, what if they both closed? In that case, the supercontinent of“ Aurica ” (a portmanteau word from “Australia” and “America”) would be born.
“We are assuming there are only two oceans, the Atlantic and the Pacific. But on Earth, you have more options, like the Indian Ocean,” says João C. Duarte , an assistant professor in tectonics at the University of Lisbon Portugal, who is also the creator of the Aurica hypothesis. “It’s possible to close both the Atlantic and the Pacific, because they are both at this time really old,” Duarte tells Popular Mechanics . All you need is a third ocean. It’s already there and it’s the Indian Ocean, the youngest of the bunch, “only” about 140 million years old . So, if the Indian Ocean opens in the future, and the Pacific and the Atlantic close, all seven continents will become one big Aurica around the equator .
Finally, the “Amasia” (a portmanteau from “Americas” and “Asia”) theory speculates that the Atlantic and Pacific will remain open, while the Arctic Ocean closes. In that case, all continents except Antarctica will start moving north and settle near the North Pole. “You end up with just a huge ocean around the North Pole and Antarctica on the other side,” says Duarte.
In research that was published in the journal Geochemistry, Geophysics, Geosystems in July 2021, researchers used 3D global climate models to simulate how the Aurica and Amasia land arrangements would impact our climate. If you are a fan of Netflix’s post-apocalyptic dystopian thriller series Snowpiercer , in which the entire world is frozen except for a train called Snowpiercer that is incessantly circling Earth, rejoice. If the Amasia scenario outshines the others, and all land masses around the North and South Poles, the lack of land in between will disrupt the ocean conveyor belt, a constantly-moving system of deep-ocean circulation that carries heat from the equator to the poles, making the poles not only colder, but covered in ice all year long. “All of that ice would reflect heat out into space,” Michael Way, a physical scientist at the NASA Goddard Institute for Space Studies in New York, who spearheaded the July 2021 study, tells Popular Mechanics .
Aurica, on the other hand, might turn out to be a surfer’s paradise. “This supercontinent will be near the equator, so it will probably be a little warmer, and maybe drier than today’s Earth,” says Duarte, who believes Aurica is the likeliest supercontinent scenario and Amasia the least likely. A warmer Earth (by three degrees Celsius, according to their models) could lead to a proliferation of Brazil-like coasts, with beautiful, white-sand beaches, enchanting coral reefs, and sand dune complexes, but also strong ocean currents.
There’s a catch, though. A glaciated Amasia would wipe out almost all forms of life on Earth, sparing only life in the ocean— Waterworld , anyone? But that doesn’t mean that the balmier Aurica won’t be cruel to a lot of species. “Many species will face fierce competition and fight each other for survival as continents come together. We should be expecting mass extinctions ,” says Duarte.
For Alex Pullen , an assistant professor of environmental engineering and earth sciences at Clemson University in South Carolina, we come up against certain challenges when we try to look that deep into the future. For a start, we have no idea what vegetation will look like 200 million years from now. “Plants have a profound impact on atmospheric chemistry, precipitation, clouds, and albedo (which is the fraction of light a surface reflects),” Pullen tells Popular Mechanics . “Also, once the continents reach a supercontinent state, carbon dioxide emissions from volcanic activity are a major uncertainty.”
Additionally, we have no clue what greenhouse gasses will look like in the future, nor do we know how the ocean and atmospheric circulation around Aurica and Amasia would impact these greenhouse gasses, Pullen continues. “No aerosols (microscopic solid or liquid particles suspended in the air or as a gas) were included in the models either, which are profoundly important to the climate,” he says.
But Way knows there are a host of things that are beyond our grasp of prediction, given how we abuse the planet. “We can’t really understand how climate change or filling the oceans with pollution and plastic are going to affect the planet,” he says. He is pessimistic about humans, but not about the planet. “For most of the last four billion years, our planet has had fairly temperate conditions on its surface, except for a few small periods of time. We don’t completely understand how the planet has managed that. It’s amazing, right?” he says. “The planet is probably going to recover from the abuse we’ve given it.”
Perhaps humans will survive, too, but in a more evolved fashion. Mind you, we have been conditioned to believe evolution is directional, though.
“We believe evolution is always moving in the direction of improvement. ‘Yeah, we are very intelligent,’ we say,” Duarte explains. “Maybe in the future there will be superintelligence , but that assumes intelligence is always a good thing,” Duarte continues. There are theories saying intelligent species come with a load of self-destruction baggage. “We have the ability to create nuclear weapons that can kill all humanity,” Duarte says, alluding to the ongoing Russo-Ukrainian War . For a post-human species 50 to 250 million years into the future to survive, you need more than intelligence: you need to live in harmony with the surrounding ecosystem, Duarte says.
In any case, these changes won’t come in our lifetime, or in our grandchildren’s lifetimes, or even in 1,000 grandchildren’s lifetimes, as Way puts it. They are already happening though. We cannot feel it, but everything is changing—constantly, subtly, imperceptibly.
“We have mountain building on Earth. We have new islands being generated in the Pacific from volcanism... The plates are still moving on the planet and there’s a Richter-6 earthquake everyday somewhere on the planet,” says Way. We are probably halfway through a major planetary transition, and we don’t even know it.