Scientists have a new theory for when all mammals – humans included – will be wiped out.
Yes, as bleak as it sounds, a supercomputer simulation of the distant future has projected how much global temperatures will change – and we will have an “uninhabitable planet in 250 million years”, according to study co-author Eunice Lo.
The researchers predict the sun will get brighter and hotter over the years while the Earth’s tectonic plates shift.
That means more volcanic eruptions, more CO2 emissions and a hotter planet.
The research, published in the journal Nature Geoscience this week, suggested that the world’s continents will also merge to create Pangea Ultima – an ultra-hot, uninhabitable supercontinent.
That wouldn’t be the first time the Earth was primarily made up a one large landmass – the original supercontinent of Pangea split up around 200 million years ago.
Using models to recreate humidity, temperature, rain and wind trends we might see over the next 250 millions, scientists expect the continents to come together again in the future.
This giant supercontinent will not exactly be welcoming, though – it’ll be incredibly hot and arid.
While fur and hibernation have helped animals survive Earth’s extreme cold in the past, scientists don’t expect mammals will be able to survive extreme heat just through sweating.
And even after millions of years of evolution, mammals’ upper-temperature tolerance has remained stable for millions of years.
So the Earth would become “mostly hostile” with little food or water for mammals, and average temperatures of around 40C to 50C – and, just to make things even worse, very high humidity.
The study’s lead author, Alexander Farnsworth, from the University of Bristol said: “The newly emerged supercontinent would effectively create a triple whammy, comprising the continentality effect, hotter sun and more CO2 in the atmosphere, of increasing heat for much of the planet.”
He added: “Humans – along with many other species – would expire due to their inability to shed this heat through sweat, cooling their bodies.”
Of course, 250 million years is a long way away, but the study suggested just eight to 16% of the Earth’s land will still be habitable for mammals.
The scientists also highlighted how humanity is accelerating global warming by burning fossil fuels and pumping carbon emissions into the atmosphere.
Fellow study author, Benjamin Mills, said: “We think CO2 could rise from around 400 parts per million (ppm) today to more than 600 ppm many millions of years in the future.
“Of course, this assumes that humans will stop burning fossil fuels, otherwise we will see those numbers much, much sooner.”
“The outlook in the distant future appears very bleak. Carbon dioxide levels could be double current levels,” Dr Farnsworth said.
A geologist at the GFZ German Research Centre for Geosciences, Hannah Davies who was not involved in the study, told Nature News that the findings were a “bit depressing”.
However, she added: “There have been extinction events in the past and will be extinction events in the future. I think life will make it through this one. It’s just kind of a grim period.”