2023-09-30 14:33:45
Illustration of the appearance of Pangea, the supercontinent which brought together almost all of the land surface, 290 million years ago.
Photo : NASA
In their study, paleoclimatologist Alexander Farnsworth and his colleagues present the first-ever climate model of the distant future made with the help of a supercomputer. They simulated the trends in temperature, wind, rain and humidity that will prevail when the world’s continents merge to form the next supercontinent, Pangea Ultima.
Thus, according to their model, the formation of Pangea Ultima will lead to volcanic eruptions associated with more frequent movements of tectonic plates, which will lead to a sharp increase in carbon dioxide (CO2) in the atmosphere.
Representation of the layout of the landmass in 250 million years.
Photo : Wikipedia
In addition, solar radiation will increase by 2.5%, which will have an effect on the surface temperature of the supercontinent, whose land will be located mainly in the warm tropical zones.
Result: Pangea Ultima will be an extremely hot supercontinent, of which only 8 to 16% of the surface will be habitable for mammals.
The arrival of Pangea Ultima will create a triple shock including the continental effect, a hotter sun and more CO2 in the atmosphere, notes Alexander Farnsworthde.
Average temperatures between 40 and 70 degrees Celsius and even higher daily extremes, coupled with high levels of humidity, will seal the fate of humans and mammals who will become extinct due to their inability to lose heat through transpiration. A quote from Alexander Farnsworth, University of Bristol
In fact, prolonged periods of heat above 40°C will exceed the tolerance thresholds of many life forms, including the vast majority of plant species. This reality will create an environment devoid of food and water sources for mammals.
Vegetation will be rare on the surface of Pangea Ultima.
Photo : iStock
Landmarks
The Earth was formed 4.6 billion years ago (at the same time as the solar system); Several supercontinents were formed during the evolution of the Earth: Rodinia, Columbia, Pannotia and Pangea. The planet has already experienced periods of intense heat. The last dates back to the Permian-Triassic era, 260 million years ago, when more than 90% of species were eradicated (new window). Since the first traces of fossil life on Earth, species have experienced five severe extinction crises, during which more than 75% of them became extinct. The last mass extinction occurred about 66 million years ago, when an asteroid hit Earth and killed dinosaurs and most forms of life on the planet. The Earth has entered the sixth great extinction of species in its history for several decades.
The human mammal
The first hominids, the ancestors of humans, appeared about 7 million years ago, which is relatively recent in Earth’s evolution. At that time, the planet was much colder than during the time of the dinosaurs.
In fact, throughout evolution, mammals have survived due to their ability to adapt to extreme weather conditions, particularly cold weather (fur and hibernation).
However, although they have evolved to better resist the cold, the tolerance of mammals to high temperatures has remained rather constant.
Although our species has developed remarkably rapidly, we will face enormous challenges in the Age of Pangea Ultima… If we can overcome the current climate crisis, which we ourselves caused, and the mass extinction of other species will follow. A quote from Alexander Farnsworth, University of Bristol
Gray areas
The authors of the work are not without recognizing that their gloomy forecasts are accompanied by great uncertainties, since they concern a future that is at least distant.
Regardless, for Alexander Farnsworth, this study still represents a stark reminder of the ephemeral nature of Earth’s climatic conditions.
The Earth’s environment is very changeable. Humans have been very lucky so far. If we are the dominant species, we must not forget that it is the planet and its climate which will decide the duration of this domination, recalls Alexander Farnsworth in a press release.
In another world
Humanity’s quest for habitable exoplanets is often associated with its distance from a star and the presence of water. This study also illustrates the importance of plate tectonics and the configuration of continents in this research.
Although Earth will still be in the habitable zone in 250 million years, for mammals, the formation of a high-CO2 supercontinent will make most of the planet uninhabitable, the researchers note.
Therefore, the configuration of the continental mass of an exoplanet also represents, according to them, a key factor in determining whether it is livable for humans.
One supercontinent, several scenarios
In addition to Pangea Proxima, other scenarios – and other names – have been put forward in recent years to project the earth’s surface into the future. According to some, Amasia will form in 200 to 300 million years, when the Pacific Ocean closes (new window).
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