it is about 250 million years After reptile-like animals evolved into mammals. Now, a team of scientists predicts that mammals may only have 250 million years left.
The researchers built a virtual simulation of the future world, similar to models that predicted human-induced global warming over the next century. A new study used data on the movement of Earth’s continents and changes in the chemical composition of the atmosphere to make predictions even further into the future.
Alexander Farnsworth, a paleoclimate scientist at the University of Bristol who led the team, said the Earth may become too hot for mammals, including us, to survive on land. Researchers found that three factors make the climate deadly: the brightness of the sun, changes in continental geography, and increased carbon dioxide levels.
“This is a triple whammy that makes it non-viable,” Dr. Farnsworth said. he and his colleagues study It was published Monday in the journal Nature Geoscience.
Scientists have been trying to predict the fate of life on Earth for decades. Astronomers predict that the sun will steadily get brighter and could engulf Earth in about 7.6 billion years.
But life probably won’t last that long. As the sun gives Earth more energy, the Earth’s atmosphere heats up and more water evaporates from the oceans and continents. Water vapor is a powerful greenhouse gas, so even more heat is trapped. In 2 billion years, the oceans may become hot enough to boil.
In 2020, Dr. Farnsworth turned his attention to the future of the planet as a way to distract from the pandemic.he met something study Predict how continents will move around the Earth in the distant future.
Over the course of Earth’s history, its continents have collided to form supercontinents, and then parts have broken apart. The last supercontinent, Pangea, existed from 330 million years ago to 170 million years ago. The study predicted that a new supercontinent called Pangea Ultima will form along the equator 250 million years from now.
Dr. Farnsworth’s main research involves building models of ancient Earth to reconstruct past climates. But he thought it would be interesting to use his own model of Pangea to see what life would be like on his Ultima. He was surprised by the climate that finally arrived.
“This world was so warm,” he said.
Dr. Farnsworth enlisted former University of Texas geophysicist Christopher Scotese, who created the Pangea Ultima model, and other experts to run more detailed simulations of that distant future, including oceans, supercontinents, and It tracked the atmosphere as it moved above. Mountain.
“They’ve done a tremendous amount, and I’m very impressed with it,” said Hannah Davis, an Earth system scientist at the GFZ German Geoscience Research Center. He was not involved in this study.
The researchers found that under a variety of possible geological and atmospheric conditions, Pangea Ultima would be much hotter than the modern continent. One of the causes of rapid changes is the sun. Every 110 million years, the energy emitted by the Sun increases by 1%.
But a supercontinent would make things even worse. First, land warms faster than the ocean. If the continents were squeezed into her one giant landmass, there would be vast inland areas where temperatures could soar.
Pangea Ultima will also have an impact on climate thanks to its topography, which includes vast flatlands far from the ocean. On Earth today, rainwater and carbon dioxide react with minerals on the slopes of mountains and hills, are transported to the ocean, and fall to the ocean floor. As a result, carbon dioxide is steadily removed from the atmosphere. But once Earth becomes home to Pangea Ultima, that conveyor belt will slow down.
If Pangea Ultima behaves like previous supercontinents, it would be studded with carbon dioxide-spewing volcanoes, the model found. Thanks to the turbulent movements of molten rock deep within the Earth, volcanoes can emit huge amounts of carbon dioxide over thousands of years, creating a burst of greenhouse gases that rapidly raise temperatures. is.
Currently, humans are heating the earth through emissions. Over 40 billion tons of carbon each year from fossil fuels. Biologists fear that if global warming continues unabated, many species will become extinct and humans will no longer be able to tolerate high temperatures and humidity across large areas of the planet.
For Pangea Ultima, Dr. Farnsworth and his colleagues concluded that the situation will probably get even worse for mammals like us. Researchers have found that nearly all of Pangea Ultima can become hot enough for mammals to survive. They may disappear in a mass extinction.
Farnsworth acknowledged that a small number of mammals may survive in refugia on the fringes of Pangea Ultima. “Some areas on the north and south sides may survive,” he said.
Still, he was convinced that mammals would lose the advantage they had enjoyed for the past 65 million years. They may be replaced by cold-blooded reptiles that can tolerate the heat.
Wolfgang Kiesling, a climatologist at the University of Erlangen-Nuremberg in Germany who was not involved in the study, said the model was able to predict a factor that could have major implications for mammal survival: a slow global decline. He said he had not considered it. Heat escaping from the Earth’s interior. This reduction could result in fewer volcanic eruptions and less carbon dioxide being released into the atmosphere.
“Mammals may live somewhat longer than what has been modeled,” he says – perhaps more or less 200 million years.
Eric Wolf, a planetary climate scientist at the University of Colorado who was not involved in the study, said the work could one day help discover life on other planets. As scientists begin to use powerful space telescopes to observe planets in other solar systems, they may be able to measure the placement of continents and infer what kind of life might live there. I don’t know.
“We’re trying to prepare for a lot of the world we’re going to see,” Dr. Wolf said.