Humans will go extinct on Earth in 250 million years – but that’s if we were to stop burning fossil fuels right now, a bleak new study reveals. 

Computer simulations suggest our planet will face a mass extinction that wipes out all mammals, University of Bristol experts report.

Any lifeforms still alive on Earth by this time would have to cope with temperatures of between 104°F to 158°F (40°C to 70°C), they say. 

But their calculations don’t account for greenhouse gases emitted by the burning of fossil fuels and other human-caused sources – so the date of our demise will likely be even sooner. 

It would be the first mass extinction since the dinosaurs died out, around 66 million years ago, when the Earth was catastrophically hit by a massive space rock. 

Extreme heat is likely to wipe out humans and mammals in the distant future even without the influence of CO2-belching fossil fuels (artist’s impression) 

The new study was led by Dr Alexander Farnsworth, senior research associate at the University of Bristol’s School of Geographical Sciences. 

‘The outlook in the distant future appears very bleak,’ Dr Farnsworth said.

‘Carbon dioxide levels could be double current levels. 

‘Humans – along with many other species – would expire due to their inability to shed this heat through sweat, cooling their bodies.’ 

In 250 million years’ time, all of Earth’s continents will have moved together to form a supercontinent known as Pangea Ultima, according to the researchers. 

Earth’s land would form a doughnut-shape with an inland sea in the middle – all that’s left of the once-mighty Atlantic Ocean. 

The surrounding Pacific Ocean, meanwhile, would take up the majority of Earth’s surface. 

Pangea Ultima is just one possible projection of what Earth’s supercontinent could look like once the plate tectonics come together. 

Whatever the exact alignment, scientists are sure Earth’s continents will slowly merge to form one hot, dry and largely uninhabitable mass. 

Image shows the geography of today’s Earth (left) and the expected geography of Earth in 250 million years, when all the continents converge into one supercontinent (Pangea Ultima)

Image shows the warmest month average temperature (degrees Celsius) for Earth and the projected supercontinent (Pangea Ultima) in 250 million years, when it would be difficult for almost any mammals to survive

Tectonic processes in Earth’s crust that brought the continents together would lead to more frequent volcanic eruptions, which would produce huge releases of carbon dioxide (CO2) into the atmosphere, further warming the planet.

Adding to this is another less well-known form of global warming – the natural brightening of the sun, which is steadily making the planets hotter and hotter. 

‘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,’ said Dr Farnsworth. 

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‘The result is a mostly hostile environment devoid of food and water sources for mammals.

‘Widespread temperatures of between 40 to 50 degrees Celsius, and even greater daily extremes, compounded by high levels of humidity would ultimately seal our fate.’ 

For the study, the scientists used computerised climate models to simulate temperature, wind, rain, and humidity trends for Pangea Ultima.

To estimate the future level of CO2 the team used models of tectonic plate movement, ocean chemistry and more to map out inputs and outputs of CO2. 

Researchers stress that they didn’t factor in the contribution of CO2 emissions from burning fossil fuels, commonly cited as the largest cause of climate change today. 

Pictured, average monthly surface air temperature for Earth in 250 million years in the future if all the continents come together to form Pangea Ultima 

The new calculations don’t account for greenhouse gases emitted by the burning of fossil fuels and other human-caused sources – the date we go extinct will likely be even sooner (file photo)

They estimated that 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,’ said co-author Professor Benjamin Mills at the University of Leeds. 

Findings indicate only somewhere between 8 per cent and 16 per cent of land would be habitable for mammals, but likely all mammal species will be wiped out. 

To make things worse, the supercontinent would be located primarily in the hot, humid tropics, so much of the planet could be facing hotter temperatures than many mammal species will be used to. 

‘We can’t predict how long humans will exist for, however, should we assume that we do last that long such a future world would be inhospitable for us,’ Dr Farnsworth told MailOnline. 

The academic said we might be able to survive if we built ‘environmentally-controlled shelters with air conditioning’. 

‘But we would likely have to build other facilities to house food production as well,’ he said. 

Another hope for humanity is forming civilisations on other planets in other solar systems, but this is currently only the stuff of science fiction.  

‘[Survival] will all depend on whether we can escape this planet, and if not, do we have the capacity to use geoengineering solutions to manage the climate,’ Dr Farnsworth said. 

The study has been published today in Nature Geoscience.