Pangaea Ultima: could the Atlantic close?
Pangaea Ultima is a future supercontinent scenario, not a world map discovered ahead of time. Its defining idea is closure of the Atlantic. The Americas would approach Africa and Eurasia again, although the result would not reproduce ancient Pangaea.
Open the Pangaea Ultima scenario 250 million years ahead. This is the endpoint of the version used here. It is a model parameter, rather than an event date established by measurement. The animation traces consequences of specified assumptions.
A growing ocean would have to change course
New oceanic crust forms at the Mid-Atlantic Ridge. USGS explains this process as part of plate divergence. For the whole basin to shrink, consumption of its lithosphere at subduction zones would have to outweigh production.
Subduction is the descent of one plate beneath another. Saying that oceans must eventually reverse is not enough. A scenario must specify where boundaries that consume the floor develop, how plate motions change and what happens to the oceanic ridge. These changes are central assumptions of this future.
What does our animation assume?
In the version by Davies, Green and Duarte (2018), expanding subduction systems reverse the Atlantic's history. Continents converge, while remnants of former basins may survive as an interior sea. Our map shows the grids the authors published in 2020, built from those maps.
The map shows land and shelves in frames 20 million years apart. It does not calculate the height of a new mountain range where continents collide, or how continental area changes as the crust shortens and thickens.
Does this mean the end of life on land?
Farnsworth and colleagues (2023) investigate extreme climate in a Pangaea Ultima configuration, including the effects of continental arrangement, future solar brightness and carbon dioxide scenarios. Their simulations suggest severe limits on conditions suitable for mammals.
This does not demonstrate that the geography must occur, or independently predict humanity's fate. The climate result depends on assumed conditions. Our map does not display that climate, only land and shelves in successive model frames.
Comparing this future with others
Novopangea offers the clearest contrast, with the Pacific as the main closing ocean. Aurica closes both major basins. The difference concerns mechanisms and pathways, not merely the final outline of a landmass.
Compare the scenarios at the same time, such as 100 million years ahead, before looking at their endpoints. Ancient Pangaea has geological evidence for an actual assembly. Ultima is a way to explore a possible next history, without an assigned probability of occurrence.