Researchers from the University of Lisbon explored a future in which the Atlantic Ocean might transition from expanding to contracting. Their study, published in Geology, outlines a scenario where subduction—the process of one tectonic plate sliding beneath another—could gradually encroach on the Atlantic Basin. This marks a first detailed model showing how an oceanic contraction might begin, offering a new perspective on the long-term evolution of coastlines and basins around the world.
Oceans appear expansive to observers, yet their histories unfold across cycles spanning hundreds of millions of years. The Atlantic is believed to have opened about 180 million years ago when the supercontinent Pangea split, creating new seaways and reshaping global boundaries. In this framework, the Mediterranean region represents the remnant of the ancient Tethys Ocean, a vast marine gap that once lay between Africa and Eurasia. These histories remind readers that today’s blue expanse results from a lengthy, dynamic geological narrative rather than a fixed feature of Earth’s surface.
For the Atlantic to stop widening and start retreating, zones of subduction must form where a tectonic plate sinks beneath another. Such zones require extreme bending and fracturing of the lithosphere and are not easy to establish. Yet the Lisbon team notes that subduction zones may migrate over time, shifting positions as the forces driving plate tectonics reorganize the crust. Their analysis emphasizes that oceanic geodynamics are not static, but capable of relocation over deep time, with wide-reaching implications for regional sea levels, volcanic activity, and seismic risk.
The researchers’ model presents a plausible pathway for how an invading subduction system could evolve. Their three-dimensional computational framework suggests that the current subduction feature beneath the Strait of Gibraltar might extend its reach further into the Atlantic Ocean. Such movement would contribute to a process they describe as the Atlantic Ring of Fire, a subduction-related system within the Atlantic that bears some resemblance to the Pacific’s well-known ring of fire. The projection is more than theoretical; it reframes expectations about future tectonic interactions in the region and their potential effects on oceanography, climate interactions, and coastal hazards.
From a geological standpoint, this transition would unfold gradually over millions of years rather than decades. The analysis indicates that meaningful shifts could begin to become detectable on a timeline of roughly 20 million years from now, a horizon that encourages ongoing observation and refinement of models as more data become available from sea-floor surveys, seismic monitoring, and paleogeographic reconstructions. The study also contributes to a broader discussion about how large-scale ocean circulation, including currents and heat transport, might be altered by evolving plate movements, with possible consequences for regional climates, precipitation patterns, and ecosystems across North America, Europe, and North Africa.
Earlier research warned of potential climate and hydrological impacts tied to changes in Atlantic currents, including effects on European weather systems. The new findings complement these viewpoints by offering a tectonic mechanism that could influence long-term climate dynamics, ocean chemistry, and marine habitats. In sum, the Lisbon investigation adds a key piece to the global puzzle of how Earth’s lithospheric plates continually sculpt the planet’s oceans, continents, and climate over deep time, shaping the environments and risks communities may face far into the future.