Researchers from the University of Bristol in the United Kingdom have released a striking study projecting the planet’s future based on advanced climate models. Published in the journal Nature Geoscience, the research suggests that the formation of a new supercontinent, dubbed Pangea Ultima, could occur in roughly 250 million years, triggering extreme conditions that threaten the survival of mammals, including humans. Using supercomputers, scientists simulated trends in temperature, wind, rainfall, and humidity, pointing to a scenario of intense heat and inhospitable environments. Rising carbon dioxide levels, combined with increased solar radiation, are expected to push global temperatures to between 40°C and 70°C, rendering vast regions of the planet nearly unlivable for life as we know it. According to the experts, this event would mark a new mass extinction, akin to the five already recorded in Earth’s geological history.
The study emphasizes that the merging of current continents, driven by tectonic plate movements, will have profound impacts on the global climate. Beyond extreme heat, the supercontinent’s formation could amplify volcanic activity, releasing massive amounts of greenhouse gases into the atmosphere. This phenomenon, paired with forecasts that the Sun will emit about 2.5% more radiation in the distant future, creates what Alexander Farnsworth, one of the study’s authors, described as a “triple whammy” of climatic challenges.
Mammals, which have historically shown resilience through adaptations like fur for cold climates or hibernation in warmer ones, would face unprecedented obstacles. The predicted conditions exceed biological adaptation limits, particularly due to the difficulty of dissipating heat in high-humidity environments, impairing mechanisms like sweating, which is vital for humans and other animals.
Climatic impacts of the Pangea Ultima supercontinent
The emergence of Pangea Ultima, expected in 250 million years, goes beyond mere geographic rearrangement. It will bring drastic shifts in global climate patterns, as outlined by the Bristol team’s models. The concentration of landmasses into a single supercontinent, largely positioned in the hot and humid tropics, will heighten the continentality effect, resulting in extreme temperatures and a significant reduction in habitable areas. This tectonic process is also likely to alter wind and rainfall patterns, creating vast deserts and prolonged drought zones in regions that currently support rich ecosystems.
To estimate future carbon dioxide levels, researchers examined interactions between tectonic movements, ocean chemistry, and biological processes. Their findings suggest that CO₂ concentrations could double compared to today’s already elevated levels, driven by human emissions. This rise, combined with the Sun’s natural warming over millions of years, would transform the planet into a hostile environment with scarce water and food sources for mammals.
Another critical factor highlighted in the study is the potential surge in volcanic activity. During the formation of past supercontinents, such as the original Pangea around 300 million years ago, massive eruptions released gases that altered the global climate. A similar scenario is anticipated with Pangea Ultima, further worsening conditions for life.
History of mass extinctions on Earth
Earth has experienced five major mass extinction events over its 4.5-billion-year history, each triggered by distinct natural phenomena. The most well-known occurred 66 million years ago when an asteroid struck what is now the Yucatán Peninsula in Mexico, wiping out the dinosaurs and about 75% of existing species. Known as the Cretaceous-Paleogene extinction, it left behind evidence like the Chicxulub crater and a global iridium-rich layer. Prior to that, the largest recorded extinction, dubbed “The Great Dying,” took place 252 million years ago at the end of the Permian period, eliminating roughly 95% of marine species and 70% of terrestrial ones due to massive volcanic eruptions in Siberia.
Other events include the Ordovician-Silurian extinction, 443 million years ago, which decimated 85% of marine species due to glaciations and falling sea levels, and the Late Devonian extinction, 375 million years ago, marked by climate shifts and ocean oxygen depletion. Some 201 million years ago, the Triassic-Jurassic extinction, linked to the breakup of Pangea and volcanism, paved the way for dinosaurs to rise. These episodes demonstrate that Earth has faced catastrophic transformations before, and the current study suggests the next event could follow a similar yet unique pattern, driven by global warming and tectonics.
Unlike previous extinctions, researchers note that the future event won’t stem from a sudden impact like an asteroid but from a gradual, cumulative shift in environmental conditions. Nevertheless, its impact on biodiversity could be comparable, particularly for mammals, which dominate today’s terrestrial ecosystems.
Timeline of major extinctions and what lies ahead
Understanding Earth’s geological past provides context for future predictions. Below is a timeline of the major mass extinction events recorded so far:
- Ordovician-Silurian (443 million years ago): Loss of 85% of marine species due to glaciations and sea level changes.
- Late Devonian (375 million years ago): Extinction of 70% to 80% of species, tied to climate shifts and ocean anoxia.
- Permian-Triassic (252 million years ago): The largest extinction, wiping out 95% of marine and 70% of terrestrial species via volcanism.
- Triassic-Jurassic (201 million years ago): About 75% of species vanished with Pangea’s breakup and volcanic eruptions.
- Cretaceous-Paleogene (66 million years ago): End of dinosaurs and 75% of species due to an asteroid impact.
The next event, projected for 250 million years from now, would be the sixth in Earth’s history. Though distant, scientists warn that current climate change impacts could hasten the deterioration of living conditions well before then, especially if carbon emissions remain unchecked.
Limits of mammal adaptation to extreme heat
Mammals, including humans, have natural mechanisms to cope with climate variations, such as sweating and hibernation. However, the temperatures forecasted with Pangea Ultima, ranging from 40°C to 70°C, combined with high humidity, surpass the physiological limits of these adaptations. In such hot, humid conditions, sweat evaporation becomes inefficient, preventing effective body temperature regulation. This would lead to metabolic collapse in species reliant on this process, like humans.
Complementary studies show that mammals thrived over the past 66 million years thanks to their ability to adjust to diverse climates. During cold periods like ice ages, they developed thick fur and hibernation strategies. In warmer eras like the Paleocene, they adapted with smaller bodies and nocturnal habits. Yet, the future scenario poses an unprecedented challenge, offering little chance of survival in a world dominated by extreme heat and resource scarcity.
The research also suggests that some species might seek refuge in polar or mountainous regions, where temperatures could be slightly milder. Even so, the limited extent of these areas and competition for space and food would make survival unlikely for most.
Factors worsening the future scenario
Beyond the supercontinent’s formation, other elements contribute to the grim picture painted by scientists. The natural increase in solar radiation as the Sun ages is an unavoidable factor. Estimates indicate that in 250 million years, the star will emit 2.5% more energy, intensifying global warming regardless of human actions. This process, paired with projected high carbon dioxide levels, creates a cascading effect that heightens adverse conditions.
The redistribution of rainfall and wind patterns, another consequence of Pangea Ultima, is expected to turn large areas into deserts. Regions currently home to tropical rainforests, like the Amazon, could vanish, sharply reducing the planet’s capacity to sustain life. Ocean acidification, driven by excess CO₂, would also harm marine ecosystems, disrupting vital food chains.
Finally, intensified volcanism linked to tectonic shifts could release toxic gases like sulfur, alongside more carbon, mirroring conditions seen in past extinctions like the Permian. Together, these factors form an environment that challenges even the most resilient species, hinting at a future of biodiversity decline.
Fascinating facts about supercontinents and extinctions
Here are some intriguing insights to grasp the scale of what’s to come:
- The original Pangea existed about 300 million years ago, and its breakup shaped today’s continents.
- Supercontinents influence climate by altering ocean currents and atmospheric patterns.
- The Permian extinction, the most devastating, was driven by Siberian eruptions lasting thousands of years.
- Mammals survived past events due to their small size and adaptability, but extreme heat may prove insurmountable.
These points highlight how Earth’s geological history intertwines with the cycles of life and death of its species.
