A supercontinent is defined by geologists as a single, massive landmass comprising most or all of Earth’s continental crust. This configuration is drastically different from the seven scattered continents we know today. Throughout history, continental fragments have repeatedly assembled and broken apart, forming ancient landmasses such as Rodinia and the well-known Pangaea, which existed approximately 335 million years ago. Scientists predict this cycle is far from complete, and we are currently moving toward the next convergence. The question for geophysicists is not if another supercontinent will form, but when and what it will look like.
The Supercontinent Cycle
The formation and breakup of supercontinents are governed by a continuous geological process known as the Wilson Cycle. This cycle describes the repeated opening and closing of ocean basins over timescales of hundreds of millions of years. It begins with the rifting and separation of a continental landmass, which leads to the formation of a new ocean basin like the present-day Atlantic.
As the new ocean widens, older oceanic crust is slowly consumed beneath the continental margins in zones of subduction, a process driven by the planet’s internal heat. Mantle convection acts as the primary engine, causing large-scale movement of the tectonic plates. Eventually, the subduction zones consume enough oceanic crust to pull the continents back toward one another.
The cycle culminates in a massive continental collision, closing the ocean basin and forming a new supercontinent with immense mountain ranges along the suture zones. The current continental arrangement is merely a temporary phase in the planet’s deep history. The forces generated by the mantle’s slow-churning currents are already setting the stage for the next global landmass.
Candidate Supercontinents
Geophysicists have developed competing models for the geography of the next supercontinent, each based on a different mechanism for ocean closure. The distinction between these candidates rests on whether the Pacific Ocean or the Atlantic Ocean will close first. The Pacific is currently shrinking, surrounded by the active subduction zones of the Ring of Fire.
One leading model is Amasia, which predicts the closure of the Pacific Ocean and the Arctic Ocean. This scenario suggests that the Americas will drift northward and collide with Asia, merging near the North Pole. Australia is also expected to move north, connecting with East Asia and completing a ring of continents around the former Arctic Basin.
The alternative model is Novopangea, which anticipates the closure of the Atlantic Ocean. In this configuration, the mid-Atlantic ridge ceases spreading, and new subduction zones form along the eastern coasts of the Americas. This action would pull the Americas back toward Africa and Eurasia. This convergence would likely trap a remnant ocean basin, a large inland sea, at its center.
Projected Timeline and Formation Mechanisms
The formation of the next supercontinent will occur 200 to 300 million years in the future. The specific mechanism that dominates the current cycle will determine which candidate configuration emerges. These mechanisms are classified based on the type of ocean basin that is consumed.
The formation of Novopangea is an example of introversion, where the internal oceans close first. This process causes the continents to reassemble near the geographical location of the previous supercontinent, Pangaea. It requires the current Atlantic spreading to slow and reverse, initiating new subduction zones along its margins.
Conversely, the Amasia model is an example of extroversion, where the continents continue their outward drift to close the external Pacific Ocean. This process involves the continents converging on the opposite side of the planet from where Pangaea existed. The Pacific’s current active subduction zones, marked by the Ring of Fire, support the idea that this ancient ocean will be the first to disappear.
Environmental Impact of the Next Supercontinent
A single, massive landmass will dramatically reshape the planet’s climate and environment. The most immediate effect is the continentality effect, where the vast interior of the supercontinent becomes extremely arid, far removed from the moderating influence of the oceans. Climate models predict that temperatures over much of the interior could regularly exceed 40 to 50 degrees Celsius, making large portions of the landmass uninhabitable for mammals.
The consolidation of land will lead to significant changes in global ocean circulation patterns, disrupting the current heat distribution. The intense continental collisions will cause widespread mountain-building events and increased volcanic activity. This volcanism would release large amounts of carbon dioxide into the atmosphere, further contributing to a greenhouse climate.
A single supercontinent would reduce the total length of active mid-ocean ridges, leading to a net decrease in global sea levels. The reduction of shallow continental shelf environments would drastically diminish the available habitat for many marine species. The combination of extreme temperatures, arid interiors, and reduced coastal zones suggests a future Earth where life will face significant evolutionary pressures.