Microbes Will be the Only Survivors on Earth After 2.8 Billion Years

In about 2.8 billion years from now, microbes would be the dominant life-form on earth due to their ability to survive on a hotter Earth that has very little carbon dioxide.

"The far-future Earth will be very hostile to life by this point. All living things require liquid water, so any remaining life will be restricted to pockets of liquid water, perhaps at cooler, higher altitudes or in caves or underground. This life will need to cope with many extremes like high temperatures and intense ultraviolet radiation and only a few microbial species known on Earth today could cope with this," said Jack O'Malley James of the University of St Andrews, who proposed the idea at the National Astronomy Meeting.

Life on Earth can't continue like the way it is now. The Sun's advancing age will mean that it will get hotter and expand, engulfing nearby planets. According to this site, all these changes will occur in about 1.1 billion years from now. Then, about 3.5 billion years later, the Earth will look more like Venus - an inferno or molten rock. Another few billion years and there would be no Earth and the Sun would be a large, orange star heating up the frigid Pluto.

In the present research, Jack O'Malley James and colleagues show how Earth will look in about 2.8 billion years. According to them, rise in the rate of evaporation would lead to loss of carbon dioxide. With no carbon dioxide to fix, the plants would die and life on earth would constitute microbes that can live on very little carbon dioxide and even these microbes called extremophiles would find Earth an uninhabitable place with its relentlessly increasing surface temperature.

The research isn't just fixed on showing how Earth would end; rather, it focuses on the clues that we are missing when we try to find life on other planets. According to researchers, we currently look for life like we have been used to seeing- higher life-forms. But, life on other planets must have occurred billions of years ago and is now unrecognizable to us. "Life in the Earth's far future will be very different to this, which means, to detect life like this on other planets we need to search for a whole new set of clues," O'Malley James said in a news release. 

"We have now simulated a dying biosphere composed of populations of the species that are most likely to survive to determine what types of gases they would release to the atmosphere. By the point at which all life disappears from the planet, we're left with a nitrogen:carbon-dioxide atmosphere with methane being the only sign of active life," O'Malley James said.