Sep 26, 2023 20:00:00

Scientists warn that the future supercontinent ``Pangaea Ultima'' may cause mass extinction of mammals on Earth

The Earth's surface is made up of hard rock called

plates , and it is thought that continents move or new continents are created as various plates move relative to each other. Scientists have announced that when a supercontinent called Pangea Ultima forms in about 250 million years, most of the mammals on Earth may become extinct.

Climate extremes likely to drive land mammal extinction during next supercontinent assembly | Nature Geoscience
https://www.nature.com/articles/s41561-023-01259-3

Mammals may be driven to extinction by volcanic new supercontinent Pangaea Ultima | Live Science
https://www.livescience.com/planet-earth/mammals-may-be-driven-to-extinction-by-volcanic-new-supercontinent-pangaea-ultima

The Next Supercontinent Formation Could Wipe Out Most Mammal Life : ScienceAlert
https://www.sciencealert.com/the-next-supercontinent-formation-could-wipe-out-most-mammal-life

'Supercontinent' could make Earth uninhabitable in 250m years, study predicts | Geology | The Guardian
https://www.theguardian.com/science/2023/sep/25/supercontinent-could-make-earth-uninhabitable-in-250m-years-study-predicts

Over the past several billion years on Earth, continents have repeatedly broken up and coalesced as plates move due to magma convection, sometimes forming extremely vast continents called supercontinents . It is known that there was a supercontinent called Pangea about 300 million years ago, and about 250 million years later, multiple continents collided near the equator, forming a new supercontinent called Pangea and Ultima. expected to be formed.

The formation of new supercontinents is thought to greatly change the Earth's environment, but little is known about how supercontinents specifically affect the climate. Therefore, an international research team from the United States, the United Kingdom, China, and Switzerland conducted research to examine what would happen to the climate due to the formation of the Pangea/Ultima continent, using the past continent of Pangea as a case study.

The research team used a climate model from the Met Office and a supercomputer from the University of Bristol to predict changes in land surface temperature on the continent of Pangea Ultima. We also studied what the future climate would be like by taking into account factors such as the amount of radiation from the sun and rising carbon dioxide concentrations.

From about 334 million years ago to about 255 million years ago, when the Pangea continent existed, the carbon dioxide concentration on earth rose to a maximum of 2100 ppm.

The current carbon dioxide concentration on Earth is approximately 416 ppm , an increase of nearly 49% since before the industrial revolution, but it is still overwhelmingly lower than it was when the Pangea continent existed. Due to this environment, in particular, the average temperature during the Cretaceous period from about 145 million to 65 million years ago was about 10 degrees Celsius higher than it is today, and it is thought that there was no ice in the North and South poles.

The research team reports that similar climate changes will likely occur when the continent of Pangea Ultima is formed in the distant future, causing average temperatures to rise significantly. While the humidity along the coasts of the supercontinent will be higher than it is today, most of the inland areas will become very dry desert areas, and the average temperature is expected to rise by nearly 15 degrees Celsius compared to pre-industrial revolution levels.

The figure below predicts the ground surface temperature of the Pangea Ultima continent in a scenario where the carbon dioxide concentration reaches 1120 ppm. In some inland areas, the ground surface temperature exceeds 50 degrees, indicating an extremely hot climate. When modeling the worst-case scenario, the average temperature on the continent of Pangea Ultima could reach 46.5 degrees Celsius in hot months.

Mammals living on the earth today have the ability to cope with high temperatures, but when the temperature exceeds 40 degrees Celsius in dry conditions and 35 degrees Celsius in humid conditions, the body's temperature regulation function becomes difficult. It will stop working. Therefore, it is possible that many mammals will become extinct on Earth when the Pangea Ultima continent is formed.

The figure below shows in green the places where mammals can live on the Pangea Ultima continent in a scenario where the carbon dioxide concentration is 1120 ppm. It is almost impossible for mammals to survive in low- and mid-latitude zones, and it is estimated that mammals can only survive in less than 8% of the area of high latitude regions.

The animals that can survive on the extremely hot continent of Pangea Ultima are ``nocturnal mammals that spend the day in holes dug in the ground'' and ``mammals that migrate depending on the season.'' . However, high temperatures not only cause direct heat damage, but also have a significant impact on the vegetation that they feed on, which may cause food supply problems.

'Supercontinents seem to create the conditions that lead to mass extinctions,' said Alexander Farnsworth , a geoscientist at the University of Bristol and lead author of the paper. It is pointed out that it is often formed.

Furthermore, this research shows that when astronomers look for extrasolar planets that have the potential for human habitation, in addition to factors such as water and distance from stars, which have long been attracting attention, they also consider the presence or absence of supercontinents. suggests that it may be possible. Farnsworth said, ``If NASA could only send the space shuttle to a single planet, I would choose a planet without supercontinents. That's fine.''