Scientists predict a new mass extinction that will wipe out humans and all mammals

A new study illuminates the drastic climatic conditions that could lead to a mass extinction of humans and all mammals, rivaling the extinction of the dinosaurs, approximately 250 million years into the future.

This research posits that the formation of a supercontinent, merging of the world’s current continents, will create a largely inhospitable environment. Extreme temperatures will plague this new supercontinent and will severely endanger most mammal species, including humans.

Supercomputer predictions

For the first time, researchers have employed supercomputer climate models to simulate future climatic conditions, exposing the severe intensification of climate extremes as the Earth’s continents coalesce to form a singular, uninhabitable supercontinent.

The process would escalate average global temperatures, making survival for most mammals virtually impossible due to their inability to adapt to such extreme heat conditions.

Sun’s brightness and tectonic activity

Further, the research projects escalation in the sun’s brightness, which would emit more energy and increase Earth’s temperatures.

Additionally, the formation of the supercontinent will be marked by frequent volcanic eruptions due to tectonic processes within the Earth’s crust. This would release enormous amounts of carbon dioxide and exacerbate global warming.

The research team says that the increasing carbon dioxide levels, coupled with a hotter sun and extreme continentality, will create a triple threat. This, in turn, will cause temperatures to rise between 40 to 70 degrees Celsius in most areas.

Extinction of humans and mammals

Mammals, including humans, have historically evolved to endure climatic extremes, adapting to cold through features like fur and hibernation. However, their ability to tolerate high temperatures has remained relatively constant, making the survival in prolonged excessive heat almost impossible.

The climatic conditions portrayed in this study, if they come to fruition, would not be survivable for mammals due to their inability to dissipate heat through sweat and cool their bodies. This would result in the extinction of humans.

Dr Eunice Lo, a co-author of the study, emphasized the urgency to address the current climate crisis resulting from human-induced global warming and greenhouse gas emissions. Extreme heat, which is already detrimental to human health, underscores the immediate need for global efforts to achieve net-zero emissions.

Future projections and CO2 levels

To project future climatic conditions and CO2 levels, scientists simulated temperature, wind, rain, and humidity trends for the next expected supercontinent — Pangea Ultima.

The models estimate CO2 levels rising from 400 ppm today to over 600 ppm in the future, assuming humanity ceases fossil fuel consumption. Otherwise, such levels may be reached much sooner.

Professor Benjamin Mills, who led the CO2 calculations, pointed out the grim outlook for the future with potential double CO2 levels, 2.5% more radiation from the sun, and a supercontinent situated in the hot, humid tropics.

Exoplanet research and habitability

This study also emphasizes the importance of considering tectonics and continental layouts in researching exoplanets or planets beyond our solar system.

The research illustrates that being in the ‘habitable zone’ of a solar system does not guarantee a planet’s habitability for humans. The landmass layout of a distant world plays a pivotal role in determining its livability.

In summary, while the projections paint a bleak picture for life in the distant future due to extreme heat and harsh conditions, it simultaneously accentuates the urgent need for addressing current climate crises and reducing greenhouse gas emissions to preserve the planet’s habitability.

The collective endeavor to reach net-zero emissions is more critical than ever, not only to prevent human extinction, but also for the diverse mammalian species sharing this planet.

The full study by the University of Bristol was published in Nature Geoscience.

Past mass extinctions

The Earth’s geological and climatic history is punctuated by several mass extinction events, moments in time when the planet experienced abrupt shifts, leading to the substantial loss of its biodiversity.

Ordovician-Silurian Extinction (Around 443 million years ago)

In this first notable mass extinction, ice ages predominated and caused substantial marine life loss, wiping out nearly 85% of sea life. Changing sea levels and temperatures reduced habitat range and induced environmental stress, directly affecting marine biodiversity. This extinction primarily decimated marine species, since life on land was scarce during this period.

Late Devonian Extinction (Around 360 million years ago)

The Late Devonian extinction left a significant impact, with a 75% reduction in species. This extinction event extensively affected marine life, particularly reef-building organisms and fish. Volcanic activity and asteroid impacts are considered primary culprits, disrupting ecosystems and altering atmospheric conditions, leading to extensive marine anoxia.

Permian-Triassic Extinction (Around 252 million years ago)

Often referred to as “The Great Dying,” this cataclysm annihilated around 96% of marine species and 70% of terrestrial species. Massive volcanic eruptions in what is now Siberia released colossal amounts of lava, triggering severe climate change, acid rain, and ocean acidification. These environmental alterations devastated global ecosystems, transforming life on Earth.

Triassic-Jurassic Extinction (Around 200 million years ago)

This event marked the end of the Triassic and the rise of the Jurassic period, with around 50% of species perishing. Large-scale volcanic activities and resultant climate changes are believed to be the driving forces, facilitating the dominance of dinosaurs by clearing ecological niches and allowing for adaptive radiations of various species.

Cretaceous-Paleogene Extinction (Around 66 million years ago)

This well-known mass extinction event resulted from a colossal asteroid impact, creating the Chicxulub crater in present-day Mexico and obliterating approximately 75% of all species, including the non-avian dinosaurs. The impact caused wildfires, tsunamis, and released substantial quantities of sulphur, leading to a “nuclear winter” effect, causing extreme and sudden climate shifts.

Examining these extinction events, we observe the recurring themes of sudden environmental and climatic changes — often due to volcanic activity or celestial impacts — that drastically altered life on Earth.

These past events are crucial in understanding the fragility of life on our planet and underscore the importance of preserving biodiversity and maintaining ecological balance in the face of current environmental changes and challenges. They serve as poignant reminders of Earth’s dynamic history and the transitory nature of its inhabitants.

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