Supercontinent induced climate change: Extreme heat will kill all humans in about 200 million years

Scientists for decades have known that all of Earth's continents would one day again join together to form a new supercontinent. We started from Pangea and will go back to it again. There are several scenarios that could unfold, and one of them will most definitely spell doom for all mammals, including humans.

Studies have shown that Pangea started breaking apart 200 million years ago, and will come together again in the same amount of time. A research article published in Geological Magazine in 2018 proposes four ways this could go.

1. Novopangaea

The Pacific Ocean will close, and the Atlantic Ocean will expand. The Americas will collide with East Asia and Antarctica, resulting in a landmass which would be centred primarily in the Northern Hemisphere. The portions near the equator will be hot and arid. The coastal regions will witness heavy precipitation, but the inner land would be mainly dry. But since the land would extend towards the colder latitudes, moderate global ocean circulation and polar ice dynamics would continue to exist.

2. Aurica

The Pacific and Atlantic Oceans will close, creating the supercontinent of Aurica. Since they are 200 million and 180 million years old, older than the Indian Ocean, which is 140 million years old, the former two will close up. The interior of the continents will rift apart, reassembling Earth's landmasses into a ring around the equator. Since the continent would be near the equator, "it will probably be a little warmer, and maybe drier than today’s Earth," João C. Duarte, an assistant professor in tectonics at the University of Lisbon, Portugal, who created the Aurica hypothesis, told Popular Mechanics.

3. Amasia

In this scenario, the Arctic Ocean will close and all continents, except Antarctica, will move towards the North Pole. With every landmass in the North, the Southern Hemisphere will be nothing but one vast ocean, with the exception of Antarctica. In the absence of land in between, the ocean conveyor belt that carries heat from the equator to the poles would be disrupted. The poles will become colder and remain covered in ice all year long.

4. Pangea Ultima / Próxima

The Atlantic Ocean will close entirely as new subduction zones form. The Indian Ocean will also close and become an inland sea. The Americas will collide with Asia. All continents merge around the equator to form Pangea Ultima. It will be like a large landmass shaped like a ring around the equator.

Which supercontinent will most likely kill all humans?

While both Aurica and Amasia will mean the end of specific species on land and sea, it is the Pangea Ultima that will kill all humans on Earth. Interior land areas will be thousands of miles away from the ocean breezes, meaning 90 per cent of the land will be hot and dry desert. The Sun is also getting brighter, which will make things even hotter for the planet, especially in inner regions in Pangea Ultima. The atmosphere would be filled with high levels of carbon dioxide from the several volcanic explosions caused by tectonic movement.

Temperatures will reach between 40°C and 70°C, with only 8 per cent to 16 per cent of Earth's land area remaining hospitable to mammals. With no breeze and high heat, the human body would not be able to shed the heat. It would push Earth past the physiological thermal limit for mammalian life, triggering a mass extinction.

The good news is that none of us would be here when this happens in over 200 million years. However, a new life cycle might have started by that time with species that may be able to adapt to the new world.