The planet Earth has existed for approximately 4.5 billion years, more or less, undergoing significant transformations during that time. Initially a molten, churning mass, it eventually cooled down, forming several small tectonic plates; a few billion years later, the planet was covered with various supercontinents and teeming with life.
However, in a cosmological context, Earth is still relatively young. We are just over a third of the way through its expected lifespan, with many changes yet to come.
Regrettably, it appears unlikely that we will survive these future changes. A study published last year, which utilized supercomputers to simulate the climate over the next 250 million years, suggests that the future world will be dominated by a single supercontinent – and it will be nearly uninhabitable for mammals.
“The outlook in the distant future appears very bleak,” confirmed Alexander Farnsworth, Senior Research Associate at the Cabot Institute for the Environment at the University of Bristol and lead author of the study, in a statement.
“Carbon dioxide levels could be double current levels,” he elaborated. “With the Sun also expected to emit about 2.5 percent more radiation and the supercontinent situated mainly in the hot, humid tropics, much of the planet could experience temperatures between 40 to 70 °C [104 to 158 °F].”
The new supercontinent, named Pangea Ultima in reference to the ancient supercontinent Pangea, would create a “triple whammy,” Farnsworth said: not only would the world be dealing with around 50 percent more CO2 in the atmosphere than current levels; not only would the sun be hotter than it currently is – a phenomenon that occurs with all stars as they age due to the dynamic balance between gravity and fusion within their cores – but the sheer size of the supercontinent itself would render it nearly uninhabitable. This is due to the continentality effect – the phenomenon where coastal areas are cooler and wetter than inland areas, explaining why summer and winter temperatures are far more extreme in, say, Lawrence, KS, than in Baltimore.
“The result is a predominantly hostile environment lacking food and water sources for mammals,” Farnsworth stated. “Widespread temperatures ranging from 40 to 50 degrees Celsius, with even greater daily extremes, compounded by high humidity levels would ultimately be our downfall. Humans – along with many other species – would perish due to their inability to dissipate this heat through sweating, thereby cooling their bodies.”
And here’s the stark reality: that’s actually a relatively optimistic scenario. “We think CO2 could increase from around 400 parts per million (ppm) today to more than 600 ppm in many millions of years,” explained Benjamin Mills, a Professor of Earth System Evolution at the University of Leeds, who conducted the calculations for the study. “Of course, this presumes that humans will cease burning fossil fuels; otherwise, we will see those numbers much sooner.”
Thus, while the study offers a grim vision of Earth millions of years from now, the authors emphasize the importance of addressing the immediate problems. “It is crucial not to lose sight of our current Climate Crisis, which is a result of human greenhouse gas emissions,” warned Eunice Lo, a Research Fellow in Climate Change and Health at the University of Bristol and co-author of the paper.
“We are already experiencing extreme heat that is harmful to human health,” she noted. “This is why achieving net-zero emissions as soon as possible is critical.”
The study is published in the journal Nature Geoscience.
