Planet Earth has been around for 4.5 billion years, give or take, and it has changed a lot in that time. What began as a ball of molten, swirling magma eventually cooled to form several small tectonic plates; some billion years later, the planet was adorned with various supercontinent formations and teeming with life.
But the Earth is still young from a cosmological point of view. We’re barely more than a third of the way through its likely lifespan, and there’s still a lot of change ahead of us.
Unfortunately, it seems unlikely that we will survive them. According to a study published last year that used supercomputers to model the climate for the next 250 million years, the world of the future will once again be dominated by a single supercontinent – and virtually uninhabitable by any mammal.
“The outlook for the distant future looks very bleak,” confirmed Alexander Farnsworth, senior research fellow at the University of Bristol’s Cabot Institute for the Environment and lead author of the study.
“The carbon dioxide levels could be double that,” he explained. “Given that the Sun is expected to emit 2.5 percent more radiation and the supercontinent is located primarily in the hot and humid tropics, much of the planet could face temperatures between 40 and 70 degrees Celsius. [104 to 158 °F].”
The new supercontinent — known as Pangea Ultima, in reference to the ancient supercontinent Pangea — would create a “triple whammy,” Farnsworth said: not only would the world deal with about 50 percent more CO.2 in the atmosphere than current levels; Not only would the Sun be hotter than it is today—this happens to all stars as they age, due to the developing push and pull between gravity and the fusion going on in the core—but the sheer size of the supercontinent itself would make it almost completely uninhabitable. This is due to the continentality effect – the fact that coastal areas are cooler and wetter than inland areas, and the reason why summer and winter temperatures are much more extreme in, say, Lawrence, KS than in Baltimore.
“The result is a mostly hostile environment with no food and water sources for mammals,” Farnsworth said. “Widespread temperatures between 40 and 50 degrees Celsius and even greater daily extremes coupled with high humidity levels would ultimately seal our fate. Humans – along with many other species – would die out due to their inability to release this heat through sweat and cool their bodies.”
And here’s the kicker: that’s kind of the best case scenario. “We think CO2 could increase from around 400 ppm today to more than 600 ppm many millions of years into the future,” explained Benjamin Mills, Professor of Earth System Evolution at the University of Leeds, who led the study’s calculations. “Of course, this assumes that people stop burning fossil fuels, otherwise we will see these numbers much, much sooner.”
So while the study paints a picture of Earth many millions of years from now, the authors caution us not to forget the problems just around the corner. “It is vital not to lose sight of our current climate crisis, which is the result of human emissions of greenhouse gases,” warned Eunice Lo, a climate change and health researcher at the University of Bristol and co-author of the study. paper.
“We are already experiencing extreme heat that is harmful to human health,” she emphasized. “This is why it is crucial to reach net zero emissions as soon as possible.”
The study is published in the journal Nature Geoscience.