Three hundred million years ago, our world looked very different than it does today. Instead of seven continents, we had one: Pangaea, a supercontinent surrounded by a global ocean. Due to a process called plate tectonics, continents move over time. In 250 million years, the continents will combine again to form another supercontinent called Pangaea Ultima – and it may be bad news for mammals like us.
In a recent study published in Nature Geoscience, a team of researchers built climate simulations to investigate how the formation of Pangaea Ultima will affect mammals. When supercontinents form, there is increased volcanism that leads to higher levels of carbon dioxide in the air, which in turn leads to hotter temperatures. The researchers found that most of Pangaea Ultima will consistently experience temperatures hotter than 40°C (104°F). Depending on uncertainties in their model, 8-25% of Pangaea Ultima will remain habitable to mammals, in comparison to 66% of land today. Nearly half of the supercontinent will be desert. This drastic climate upheaval and decrease in living space is likely to cause a mass extinction event.
While the study paints a bleak picture for the future habitability of Earth, all hope is not lost: life has survived five mass extinction events in the past. This work also provides interesting food for thought to scientists hoping to find habitable planets elsewhere in the universe. Astronomers often discuss the “habitable zone”, the distance from a star where a planet has a suitable temperature for life. These calculations do not account for the distribution of continents, which the researchers argue is a mistake: in their models, they found that Earth still had habitable regions, even in cases where the astrophysical calculation considered it uninhabitable. This finding implies that more planets may be habitable than previously thought.
This study was led by Dr. Alexander Farnsworth, a senior research associate in the School of Geographical Sciences at the University of Bristol.
Managing Correspondent: Emily Pass
Press Article: This is what Earth’s continents will look like in 250 million years (News from Nature)
Original Journal Article: Climate extremes likely to drive land mammal extinction during next supercontinent assembly (Nature Geoscience)
Image Credit: Pixabay/ELG21