Earth is a rocky planet orbiting a G-type main sequence star known as the Sun. The planet is the third in order from its star, home to the human species and assorted varieties of flora and fauna.
In the middle of the 21st century, the planet suffered the Blight which threatened to destroy all lifeforms on the planet. However, NASA launched the Endurance spacecraft toward a mysterious wormhole in a bid to relocate humanity to other planets.
The planet was saved by the actions of the crew of the Endurance, especially Murphy Cooper.
With the blight ravaging Earth in the 21st century and no immediate solution being found to eliminate it, it is safe to speculate that Earth did not in fact recover and essentially died. One could presume that the doctor on Cooper Station saying that Murph was transferring from another station and a nurse stating that she had been in hypersleep for 2 years hints that she was on a space station orbiting Earth because the planet can no longer sustain human or any life.
In the year 2320, Cooper returns to the Earth and lands a Chinese spacecraft near his old house, the planet is essentially a dead ice planet, he lets the Fractal Lifeform loose on the world where it thrives. Cooper then realizes that the entire mission was not to save humanity but to save these fractal alien creatures because their planet was going to be destroyed by Gargantua. He finds his way back to the Chinese spacecraft only to lose consciousness and then awaken aboard a space station orbiting Earth called Space Station Joseph A. Cooper.