The little bright spot: It won’t happen for another 250 million years.

In about 250 million years, the continents as we know them will no longer exist, but will have merged into a single supercontinent (see box). This will likely lead to the extinction of many species. Things also don’t look good for mammals, which also includes humans, the researchers wrote in the journal. Natural earth sciences.

Great continents
Over the past billions of years, the continents have not always been in their current position. In fact, land masses have wandered around a bit and come together again and again into so-called supercontinents. The last time this supercontinent formed was about 336 million years ago. This giant continent – called Pangea – broke up again 175 million years ago, after which the continents as we know them came into existence. But researchers say those continents are doomed to come together again and form a supercontinent. That supercontinent – also called Pangea Ultima – is expected to form in about 250 million years.

too hot
However, it won’t be so comfortable on the yet-to-form supercontinent, as the researchers now predict in their new study. It is expected to be very hot there. So hot that almost all mammals will become extinct.

Climate models
The researchers base this conclusion on the first climate models of the very distant future, run using supercomputers. These models depict a less favorable climate on the supercontinent. For example, temperatures in large parts of the supercontinent range between 40 and 70 degrees Celsius. “Add to that high humidity, and our fate seems sealed: humans and many other species will die because they are unable to dissipate their body heat through sweat and thus cool their bodies,” says researcher Alexander Farnsworth.

Causes of heat
The extreme heat that would ultimately prove fatal to many can be traced back to three processes that people have nothing to do with – for a change. “Once you change the position of the continents and rearrange the continents, the surface temperature changes dramatically,” Farnsworth says. Scientias.nl. “This is mainly because most of the Earth’s surface will then be in the equatorial region.” But there is more to it than that. “In addition, the Sun will be 2.5% brighter in 250 million years than it is now, which will also warm the Earth a little more.” Finally, there is also expected to be more volcanic activity on the supercontinent (see box), which will release a lot of carbon dioxide. This, in turn, causes the Earth’s temperature to rise further.

Volcanoes
Volcanoes – with the exception of so-called hotspots – usually arise in places where tectonic plates collide with each other. When a supercontinent forms, several land masses rub against each other, increasing the number of places where tectonic plates meet. This also increases the chance of volcanic activity.

Scraps of the habitable zone
Overall, the researchers expect that only 8 to 16 percent of the supercontinent that will be formed will remain somewhat habitable for mammals. That may not sound so bad, but it means up to 94% of the supercontinent is uninhabitable for mammals. The habitable parts are not expected to be contiguous, but are distributed across the supercontinent. The researchers expect that only small, vulnerable populations can survive in these viable “fragments.” As a result, the chance of species extinction also increases sharply in those habitable areas.

pile
So it doesn’t look good for us. But Farnsworth still has some courage. “Of course, such a world would not be very comfortable for people. But given the technological progress that humanity is constantly making, such a supercontinent might remain habitable, for example, through cooling systems or geoengineering aimed at reducing the amount of carbon dioxide in the atmosphere.” Atmospheric energy or the amount of solar energy that reaches the Earth.

Uncertainty
In addition, it is important to emphasize that Farnsworth and colleagues’ predictions are not yet set in stone. Predicting what will happen in 250 million years is not easy, and requires a number of assumptions. For example, about the precise rearrangement of the continents, and therefore also the associated volcanic activity in Pangea Ultima. There is also still some uncertainty about the location of the supercontinent – which is also very important. “We expect that it originates at the equator. This is in line with previous research that has shown that this is the most likely scenario. The core of many previous supercontinents was also located at the equator. But the latest reconstruction – also referred to as amazea – ​​predicts that “The heart of the next supercontinent is in the Arctic. Such a supercontinent would be more suitable for mammals to survive, because temperatures there are lower. But Asia is controversial.”

Ramifications
You can of course wonder – even with these uncertainties in mind – why scientists are going to all this trouble to put together a picture of something that won’t happen for another 250 million years. There are several reasons for this, Farnsworth explains Scientias.nl Outside. For example, the research provides more knowledge about the long-term impact of plate tectonics on our climate. “Plate tectonics is really important, it is crucial to the direction of climate over long time scales, and it has the potential to hit the reset button when it comes to life and evolution. Our study highlights that species do not always remain dominant; mass extinctions associated with the formation of supercontinents have significantly affected It is recurrent on the number and types of species that have occurred on our planet throughout Earth’s history. But the impact of this study extends far beyond Earth (and its history and future) alone. The research also has implications for our search for life on other planets. Now, the first thing that is often examined is Whether the planet lies in the so-called “habitable zone” and is therefore capable of accommodating liquid water (which is crucial for the emergence and maintenance of life as we know it).But Farnsworth and his colleagues’ research now suggests that the arrangement of continents on such a planet is likely to… Being habitable is also important, simply because it has a huge impact on the climate, and therefore on the planet’s habitability. For example, after 250 million years, the Earth will still be in the habitable zone, but – based on scientists’ models – will not be habitable at all. . “Plate tectonics can also greatly affect the habitability of other planets in other solar systems, simply because habitability also depends on the location of the continents and whether or not they together form a supercontinent.”

Finally, the research also clearly shows how dependent we are on the Earth’s climate for our survival. This, in turn, has implications for the climate crisis we are experiencing today, says researcher Eunice Lu. “Although we expect that the Earth will be unlivable in 250 million years, today we are already seeing extreme heat that is having a devastating impact on human health. That’s why it’s so important to move to net-zero emissions as quickly as possible. It’s a big undertaking, But the good news is that we can still do something about this climate crisis. Things may be different in 250 million years, because we will no longer appear to be the driving force behind global warming, but merely an unfortunate plaything of tectonic plates.