In a study published in Nature Geoscience, scientists warn that humans and other mammals could face extinction when Earth’s landmasses eventually merge into a giant supercontinent known as Pangea Ultima. As reported by Earth.com, researchers modeled what conditions would look like hundreds of millions of years from now and found that planetary heat could rise to levels that mammals simply cannot survive.
The idea may sound far-fetched, but the findings show a future Earth shaped by an extreme combination of climate factors. According to lead author Dr. Alexander Farnsworth from the University of Bristol, the planet’s continents are expected to merge into a single landmass. When that happens, most territory would sit far inland, away from cooling oceans. Scientists call this the continentality effect, and it would trap regions in brutal heat.
This is only one part of what Dr. Farnsworth described as a triple threat. The sun will emit stronger radiation in the distant future, and increased volcanic activity would pump more carbon dioxide into the atmosphere. Higher CO2 means thicker heat-trapping greenhouse gases, reinforcing global temperature increases.
Researchers project widespread surface temperatures ranging between 40 and 50 degrees Celsius, with peaks even higher in humid areas. Under those conditions, humans would lose their ability to cool themselves through sweating. That stress affects other mammals as well, since most cannot regulate heat beyond limited thresholds without shade, water, and cooler air.
The team estimates that only around ten percent of land on the supercontinent would remain within tolerable temperature ranges. The rest would be too hot, too dry, or both. Severe dryness would worsen the crisis, creating water scarcity and damaging vegetation. Without access to consistent food and hydration, survival becomes nearly impossible.
Scientists also say that this scenario adds context to why mammals exist as they do today. In cold periods, animals adapt by hibernating or growing thicker fur. In extreme heat, however, biology provides fewer survival strategies. Sweating, panting, and shade-seeking only work up to certain limits before overheating becomes fatal.
Past mass extinction events have followed dramatic environmental shifts, from volcanic eruptions to asteroid impacts. This time, the danger would come from tectonic evolution and climate systems converging over millions of years.
Researchers note that the findings also matter beyond Earth. A planet can fall inside a “habitable zone” of its star and still be unlivable. If continents merge, heat patterns change dramatically, offering a new way to evaluate which planets can truly support life.
While this scenario unfolds far into the future, scientists point out that current warming already affects resources and human health. Today’s rising temperatures, extreme weather, and strained ecosystems highlight how heat threatens life long before any supercontinent appears.