He is a brilliant physicist so I would definitely listen to his opinion in that specialist area. But he is not an expert on climate change, artificial intelligence or global extinction events. There are experts in those other areas that are worth listening to but just because Mr Hawking says something in those areas does not mean it is gold dust. If you want to know the possible dangers of AI then talk to Andrew Ng but Stephen Hawking is not your man. Would be listen to Kim Kardashian's opinion on climate change? I hope not as she is not qualified in that area, being well known does not mean you have expertise. Just an opinion and that opinion might be no better than the general public.
/RantOver
Getting on Mars is our best bet for now, as human race. If we can colonize Mars, this will double our chances of survival.