The eventual formation of the next supercontinent, often referred to as Pangea Ultima, could lead to conditions that are “uninhabitable to mammalian life”, according to a study led by researchers from the University of Bristol.
This dire prediction is based on models of the greenhouse gas effect and climatic changes that may occur when continents converge into a single landmass, a process that has happened multiple times in Earth’s history. The researchers argue that the formation and eventual decay of Pangea Ultima could exceed the thermal tolerances of warm-blooded, milk-producing creatures, leading to their extinction much earlier than previously estimated.
THE PANGEA ULTIMA SCENARIO
While past supercontinents, like Pangea, offer some insight into these processes, the study focused on Pangea as a case study and attempted to predict the climate changes that could accompany the formation of the next supercontinent.
The results indicate that Earth could experience significantly higher temperatures, partly due to a 2.5 percent increase in solar radiation. Additionally, the alteration of the global climate system during supercontinent formation could result in widespread drying of landmasses and a rise in atmospheric carbon dioxide levels.
RISING TEMPERATURES AND CARBON LEVELS
During the formation of the first Pangea, carbon dioxide levels increased from around 200 parts per million (ppm) to as high as 2,100 ppm, causing temperatures to rise by approximately 10°C more than the current global mean temperature. By comparison, today’s atmospheric carbon dioxide levels stand at approximately 416 ppm compared to preindustrial levels.
The study suggests that if atmospheric carbon dioxide levels were to spike past 560 ppm, even for a short period, it could trigger a mass extinction event comparable to the “Big 5” events in Earth’s history.
MAMMALIAN SURVIVAL IN PERIL
Modelling worst-case scenarios, the researchers predict that Pangea Ultima’s formation could result in a mean temperature of 46.5°C (115.7°F) during warm months. Such extreme temperatures would likely be untenable for the majority of known species, including mammals.
At 280 ppm, most tropical regions could become uninhabitable, and by 1,120 ppm, this inhospitable zone would extend through mid to high latitudes. The models suggest that at 1,120 ppm, only about 8 percent of Pangea Ultima’s landmass would remain capable of supporting mammalian life, with small high-latitude refuges being the last holdouts.
The study concludes that the likelihood of mammals evolving rapidly enough to adapt to the extreme conditions created by Pangea Ultima is low, painting a bleak picture of Earth’s future during supercontinent formation.