Stephen Hawking's final warning: Leave Earth in next 200 years or face extinction

Humans must abandon Earth in next 200 years if they want to survive. It was a stark warning issued by the legendary physicist Professor Stephen Hawking months before his demise at the age of 76.

He believed that life on Earth could be wiped out by a disaster such as an asteroid strike, AI or an alien invasion.

Hawking also warned about over-population, human aggression and climate change that could cause humanity to self-destruct.

Hawking believed, if our species had any hope of survival, future generations would need to forge a new life in space.

Climate change: One of Hawking's main fears for the planet was global warming. Hawkings had warned in July that physical resources are being drained at an alarming rate. “Rising temperatures, reduction of the polar ice caps, deforestation, and decimation of animal species. We can be an ignorant, unthinking lot,” he had added to BBC.

Hawking warned that Earth will one day look like the 460°C (860°F) planet Venus if we don't cut greenhouse gas emissions.

The physicist also believed President Donald Trump's decision to withdraw from the Paris Climate Agreement has doomed our planet.

Asteroid strikes: If global warming doesn't wipe us out, Hawking believed Earth would be destroyed by an asteroid strike. 'This is not science fiction. It is guaranteed by the laws of physics and probability,' he said.

He further added that to stay on Earth risked facing annihilation.

'Spreading out into space will completely change the future of humanity. It may also determine whether we have any future at all.'

Hawking was working with Russian billionaire Yuri Milner's Breakthrough Starshot project to send a fleet of tiny 'nanocraft' carrying light sails on a four light-year journey to Alpha Centauri, the nearest star system to Earth.

Astronomers estimate that there is a reasonable chance of an Earth-like planet existing in the 'habitable zones' of Alpha Centauri's three-star system.

AI could replace humans: Hawking claimed that AI will soon reach a level where it will be a 'new form of life that will outperform humans.' Hawking went so far as to say that AI may replace humans altogether, although he didn't specify a timeline for his predictions.

He had said these during a recent interview with Wired.

He said: 'The genie is out of the bottle. I fear that AI may replace humans altogether. If people design computer viruses, someone will design AI that improves and replicates itself. This will be a new form of life that outperforms humans.”

He also he said the AI apocalypse was impending and 'some form of government' would be needed to control the technology.