Key Takeways:
- Continents are constantly moving and are expected to collide again in 200 million years to form a new supercontinent.
- There are four main theories about how the continents will collide, each resulting in a differently shaped supercontinent with a unique name.
- The formation of a supercontinent could have drastic climate effects, with some scenarios leading to an ice age and others to a warmer, more tropical Earth.
- The future of life on the new supercontinent is uncertain, with potential for mass extinctions but also for adaptation and evolution.
- These changes are far in the future, but the movement of continents is a constant process happening on Earth right now.
Pangea (or Pangaea), the massive landmass that joined all seven continents into a single continent during Earth’s prehistoric past, broke apart around 200 million years ago. In an intriguing twist of terrestrial evolution, scientists believe we are about 200 million years away from the formation of a new, Pangea-like supercontinent.
According to a research article published in Geological Magazine, there are four major theories about how this supercontinent will evolve.
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 rich in subduction zones, which occur when oceanic plates sink into continental plates and then into the Earth’s mantle. (This is also why 80 percent of large earthquakes occur along the Pacific Ocean’s edges, also known as the “Ring of Fire.”)
As a result of this tectonic activity, the Americas continue to separate from Europe and Africa, causing them to collide with northbound Antarctica and eventually with Africa, Europe, and Asia, which will already be crammed together. Meanwhile, Australia will have docked in East Asia. The result is one enormous mega-continent named “Novopangea” (Greco-Latin for “New Pangea”).
In the “Pangea Proxima” (or “next Pangea”) scenario, the Atlantic and Indian Oceans continue to expand until new subduction zones pull the continents back together, resulting in a collision between Eurasia and the other continents. Imagine a ring-shaped landmass with a small ocean basin in the center.
The Pacific and Atlantic oceans are extremely old, dating back 200 million and 180 million years, respectively. So, what happens if they both close? In that case, the supercontinent “Aurica” (a portmanteau of “Australia” and “America”) would be created.
“We assume there are only two oceans: the Atlantic and Pacific. According to João C. Duarte, an assistant professor in tectonics at the University of Lisbon in Portugal and creator of the Aurica hypothesis, there are more options on Earth, such as the Indian Ocean. “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 at “only” 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 of “Americas” and “Asia”) theory proposes that the Atlantic and Pacific Oceans 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,” Duarte says.
“Once the continents reach a supercontinent state, carbon dioxide emissions from volcanic activity are a major uncertainty.”
In a study published in the journal Geochemistry, Geophysics, Geosystems, researchers used 3D global climate models to simulate how the Aurica and Amasia land arrangements would affect the climate. If you enjoy Netflix’s post-apocalyptic dystopian thriller series Snowpiercer, in which the entire world is frozen except for a train named Snowpiercer that constantly circles Earth, rejoice.
If the Amasia scenario wins out over 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 transports heat from the equator to the poles, making the poles not only colder but also covered in ice all year. “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, may 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 result in the spread of Brazil-like coasts, complete with beautiful white-sand beaches, enchanting coral reefs, and sand dune complexes, as well as strong ocean currents.
There’s a catch, however. A glaciated Amasia would wipe out almost all forms of life on Earth, leaving only life in the ocean—Waterworld, anyone? However, this does not guarantee that the balmier Aurica will not be cruel on numerous species. “Many species will face fierce competition and fight each other for survival as continents come together. “We should expect mass extinctions,” says Duarte.
Alex Pullen, an assistant professor of environmental engineering and earth sciences at Clemson University in South Carolina, believes that looking so far into the future presents certain challenges. 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 told Popular Mechanics. “Also, once the continents reach a supercontinent state, carbon dioxide emissions from volcanic activity are a major uncertainty.”
Furthermore, we have no idea what greenhouse gases will look like in the future, nor do we know how the ocean and atmospheric circulation around Aurica and Amasia will affect these greenhouse gases, Pullen says. “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,” according to him.
However, given how we abuse the planet, Way understands that there are many things that are beyond our ability to predict. “We can’t really understand how climate change or filling the oceans with pollution and plastic are going to affect the planet,” according to him. He is pessimistic about humans but not 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 asks. “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 will not occur in our lifetime, our grandchildren’s lifetimes, or even 1,000 grandchildren’s lifetimes, as Way suggests. However, they are already happening. We can’t feel it, but everything is changing—constantly, subtly, and imperceptibly.
“We have mountain-building on Earth. Volcanic activity is forming new islands in the Pacific. 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.
