Another opponent of Musk’s Mars plans emerged recently was former US President Barack Obama.
Speaking at a renewable energy conference in Paris, Obama raised similar concerns to Mr Rees.
He said: “But when I hear some of the people talk about the plan to colonize Mars because the [Earth’s] environment may become so degraded that it becomes unliveable, I look at them like, what are you talking about?
“I would rather us invest in taking care of this planet here.”
The former president suggested that space exploration should be confined to “gathering knowledge and discovery.”
