Several billion years from now, our sun will become a red giant.
In a billion years, the Sun's increasing brightness will cause Earth's oceans to dry up, in all likelihood putting an end to life on the planet. After that, the Earth will begin to resemble Venus with an atmosphere consisting mainly of carbon dioxide, shrouded in clouds containing droplets of sulfuric acid along with compounds of chlorine. When the Sun achieves red giant stage, some 7.5 billion years from now, the atmosphere will have been driven off by the Sun's encroaching photosphere and the Earth's surface will have melted.
Sic transit gloria mundi!
