Scientists have predicted when and why humanity will become extinct.

New research suggests that extreme heat in the distant future could lead to mass extinctions of humans and other mammals. This is possible if all continents merge into a single supercontinent, according to Earth.

Scientists warn that these conditions will be the most severe since the extinction of the dinosaurs.

New data on the supercontinent Pangea Ultima

Researchers used powerful climate models to understand how the future supercontinent, dubbed Pangea Ultima, would change conditions on Earth. They took into account plate movements, changes in solar activity, and greenhouse gas levels.

The work was published in the journal Nature Geoscience and was led by Dr Alexander Farnsworth, a senior research fellow at the University of Bristol.

Geologists have long believed that the continents are slowly shifting. Pangea Ultima could emerge in millions of years. In this case, most territories would be far from the cooling influence of the oceans. This phenomenon is called the continental effect.

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"A new supercontinent will create a triple whammy: continentality, a hotter sun, and increased atmospheric CO₂. All of this will lead to increased heat across much of the planet," Dr. Farnsworth explained.

Three factors of possible extinction

1. A vast land area. Its interior regions will become particularly hot.
2. Increased solar radiation. The sun will shine brighter over time.
3. Increased CO₂ emissions due to volcanic activity will enhance the greenhouse effect.

"Temperatures of 40 to 50°C (104 to 122°F) and even higher daytime peaks, combined with high humidity, will be lethal. Humans and other species will be unable to sweat off this heat to cool their bodies," Dr. Farnsworth added.

According to forecasts, the Sun will emit 2,5% more energy, and the supercontinent will be located predominantly in the hot tropics. This could lead to temperatures ranging from 40 to 70°C.

Effects on mammals

In the past, mammals survived climate fluctuations by adapting to thick fur or hibernation. But prolonged heat is more difficult to survive, as cooling the body relies directly on sweating and access to water.

The study shows that only 8%–16% of the supercontinent's territory will remain habitable.

A severe drought will pose an additional threat. Water will become scarce. Vegetation will decline.

Finding food and moisture will become extremely difficult.

Modern climate risks

"It's crucial not to lose sight of the current climate crisis caused by greenhouse gas emissions. We're talking about an uninhabitable Earth in 250 million years. But we're already experiencing extreme heat today, which is dangerous to health. Therefore, it's vital to reach net-zero emissions as quickly as possible," said study co-author Dr. Eunice Lo, a research fellow in climate and health at the University of Bristol.

Temperatures have been rising in recent decades. Heat waves threaten crops, disrupt power grids, and put many communities at risk.

Experts are calling for accelerated emissions reductions to prevent worst-case scenarios.

Future carbon dioxide levels

Scientists used plate motion and ocean chemistry models to estimate how CO₂ levels will change. Volcanic processes could increase them to more than 600 ppm in the future.

Elevated greenhouse gas concentrations will trap more heat, creating a vicious cycle of increasing warming on a planet where oceanic influence is minimal.

"We think CO₂ could increase from the current 400 ppm to over 600 ppm over many millions of years. Of course, that's assuming humans stop burning fossil fuels. Otherwise, we'll see these figures much sooner," explained Professor Benjamin Mills of the University of Leeds.

Previous mass extinctions

The Earth's history has already experienced periods when significant parts of the biosphere disappeared:

• 443 million years ago, the Ordovician–Silurian extinction event occurred, killing about 85% of marine life;
• 360 million years ago, the Late Devonian extinction event wiped out up to 75% of species;
• 252 million years ago, the Permian-Triassic extinction event wiped out more than 90% of marine species and 70% of land species;
• 200 million years ago, the Triassic-Jurassic extinction event reduced the number of species by about half;
• 66 million years ago, an asteroid caused a catastrophe that wiped out the dinosaurs and about 75% of all species.

Implications for the Search for Life on Other Planets

The analysis helps us understand how conditions on exoplanets can change dramatically. Even if a planet is in the habitable zone, the coalescence of continents can lead to a sharp increase in temperature.

Scientists believe similar processes could occur on other planets. Plate movement, solar radiation, rotation rate, and atmospheric chemistry could significantly alter conditions for life.

"This work shows that a planet in the habitable zone may not be the most hospitable to humans if the continents are either united or separated, as they are today. Understanding such configurations helps scientists search for life-friendly environments beyond Earth," Dr. Farnsworth concluded.

Scientists warn that climate stress is already affecting health and resources.

Rising temperatures and more frequent extreme weather events could become the norm if emissions are left unchecked.

While the prospect of a hot supercontinent seems distant, it highlights the need to take action today.