In a billion years: Earth's fate under a changing Sun

Researchers from NASA and Japan's Toho University forecast that Earth will no longer be able to sustain life in about a billion years. According to a study published in "Nature Geoscience", Earth's oxygen-rich atmosphere will change to one dominated by methane, which will destroy life as we currently understand it.

Calculations from a supercomputer suggest this shift will happen in the year 1,000,002,021. The study warns that even the most resilient organisms won't be able to live on the planet's surface then.

Christopher T. Reinhard and Kazumi Ozaki, the study's authors, predict that the Sun will evolve into a red giant, possibly engulfing Mercury and Venus. For Earth, two scenarios are possible: sharing the fate of its neighbouring planets or being pushed into a more distant orbit. Over a billion years, Earth's oxygen concentration could fall to less than 10 percent of today's level.

The study, partly funded by NASA's Astrobiology program, suggests that the Sun's increasing temperature may cause solar flares that will disrupt Earth's atmosphere and magnetosphere. "The atmosphere will return to a state similar to before the Great Oxidation Event, which happened about 2.4 billion years ago," explains Christopher Reinhard. Scientists recommend that humanity prepare for these changes by developing enclosed life support systems or seeking new planets to inhabit.

Kazumi Ozaki and Christopher Reinhard used a supercomputer to develop a model of Earth to simulate its climate and biochemical processes. They caution that even the most resilient organisms won't be able to live on the planet's surface then. The study utilized a complex model combining biogeochemical and climate data to forecast atmospheric changes.