Someday, life on Earth will cease, with our society’s grandest structures becoming mere ruins over time, and every mammal will eventually vanish – scientists have an idea of when this might happen.
For the four-billion-year history of life on Earth, it won’t be a catastrophic asteroid that erases life, akin to the event that led to the dinosaurs’ extinction and wiped out 75 percent of all species.
Instead, life forms are expected to encounter a ‘triple whammy’ of extinction events that will render Earth unlivable, according to a study in Nature Geoscience conducted using a supercomputer.
Fortunately, despite the significant threats posed by climate change due to fossil fuel combustion, there are likely several hundred million years before the planet faces three simultaneous life-ending events.
Researchers from the University of Bristol predict that all mammals may be extinct in 250 million years due to a combination of three significant and unavoidable factors.
The study suggests that the first major extinction event will occur following the creation of a final supercontinent, as all land masses eventually merge into ‘Pangaea Ultima’ through plate tectonics.
This process will lead to more frequent volcanic eruptions and an influx of greenhouse gases into the atmosphere, causing global temperatures to soar between 40C and 50C.
This increase would far surpass the effects of burning all fossil fuels, which would raise global temperatures by 12C.
At these extreme temperatures, no mammal could survive.
The study’s authors stated: “Coupled with tectonic–geographic variations in atmospheric CO2 and enhanced continentality effect for supercontinents, Earth could reach a tipping point rendering it uninhabitable to mammalian life.”
This could then be followed by a significant temperature drop, similar to what occurred during previous supercontinent formations, the last of which took place 200 million years ago.
This dramatic temperature decrease could trigger another extinction event, ischemic necrosis, which would eliminate any humans or other mammals that managed to endure temperatures reaching 50C as CO2 levels surged.
Ischemic necrosis occurs when freezing temperatures cause severe contraction of blood vessels, effectively mummifying the remaining warm-blooded creatures on Earth.
These intense temperature fluctuations, along with the increasingly CO2-rich atmosphere, constitute the ‘triple whammy’ of extinction events that will make our planet inhospitable to life.
Rather than interpreting this information as reassurance that all is well at present, the research team aimed to alert people to how close we are to potentially triggering our own mass extinction event.
Dr. Eunice Lo, Research Fellow in Climate Change at the University of Bristol and co-author of the study, emphasized: “It is vitally important not to lose sight of our current climate crisis, which is a result of human emissions of greenhouse gases.
“While we are predicting an uninhabitable planet in 250 million years, today we are already experiencing extreme heat that is detrimental to human health. This is why it is crucial to reach net-zero emissions as soon as possible.”