In the early 20th century, a meteorologist named Alfred Wagner noticed striking similarities between the coasts of Africa and South America.
These observations led him to propose a controversial new theory: that perhaps these and many other continents were once connected into a single, enormous landmass.
Wagner's theory of continental drift directly contradicted the popular opinion that the Earth's continents had remained stable for thousands of years, and it took nearly 50 years for its proponents to convince the larger scientific community.
But today, we know something even more interesting—Pangaea was just the latest in a long line of continents, and it won't be the last.
Continental drift laid the foundation for our modern theory of plate tectonics, which states that the Earth's crust is made up of wide, rifting plates that partially move over a layer of molten rock called the mantle.
These plates move at a rate of only 2.5 to 10 cm per year, but these incremental movements shape the planet's surface. So to determine when a new continent will emerge, we need to predict where these plates are moving.
One approach here is to look at how they have moved in the past.
Geologists can determine the position of the continents over time by measuring changes in the Earth's magnetic field. When molten rock cools, its magnetic minerals are "frozen" at a specific point in time.
So by calculating the direction and magnitude of a rock's magnetic field, we can discover the latitude where it was located when it cooled. But this approach has serious limitations.
For one thing, the rock's magnetic field doesn't tell us the plate's longitude, and latitude can be measured north or south. Worse, this magnetic data is erased when the rock is reheated, such as during continental collision or volcanic activity.
So geologists need to use other methods to reconstruct the positions of the continents. Dating local fossils and comparing them to the global fossil record can help identify areas that were previously connected.
The same is true of cracks and other faults in the Earth's crust, which can sometimes be found in plates. Using these tools, scientists have pieced together a relatively reliable history of plate movement, and their research has revealed a pattern spanning hundreds of millions of years.
What is now known as the Wilson cycle predicts how continents move apart and reassemble. And he currently predicts that the next continent will form 50 to 250 million years from now. We're not too sure about what that landmass will look like.
This could be a new Pangea emerging from the closing of the Atlantic Ocean. Or it could result in the formation of a new pan-Asian sea. But while its shape and size remain a mystery, we know these changes will affect far beyond our national borders.
In the past, the collision of plates caused climate change.
When the Rodania supercontinent broke up about 750 million years ago, it left large terrestrial populations vulnerable to climate change.
This newly exposed rock absorbed more carbon dioxide than it rained, eventually removing so much CO2 from the atmosphere that the planet plunged into an era known as Snowball Earth.
Over time, volcanic activity released enough CO2 to melt this ice, but the process took another 4 to 6 million years. Meanwhile, when the next continent is accreted, things are more likely to heat up.
Plate migration and continental collisions can create and widen cracks in the Earth's crust, potentially releasing large amounts of carbon and methane into the atmosphere. This influx of greenhouse gases will rapidly warm the planet, possibly leading to mass extinctions.
The sheer scale of these cracks would make it nearly impossible to plug them, and even if we could, the resulting stress would only cause new cracks.
Fortunately, we have at least 50 million years to come up with a solution here, and we may already be on to something.
In Iceland, recent trials were able to store carbon in basalt,
rapidly turning these gases into rock. So it's possible that a global network of pipes could redirect vented gases into basalt emissions, reducing some of our emissions now and protecting our continental future.
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