As we reach the middle of the 21st century, half the population of the world will lose their job to a machine. Yes, this is another ‘ robots will take our jobs ’ story.The latest comes from Moshe Vardi, professor at Rice University , Houston, who delivered a talk to the American Association for the Advancement of Science , exploring the question: “If machines are capable of doing almost any work humans can do, what will humans do?”Vardi reckons that half of workers across the globe will be replaced by machines within the next 30 years, wiping out middle-class jobs and “exacerbating inequality”. He noted that robots would take over in many spheres of life, including automated driving and sex robots. As the Guardian reports, he also observed that this future is likely to mean humans have much more leisure time — indeed we may only work a handful of hours per week.However, this might not be the utopia we imagine. Vardi warned: “I do not find this a promising future, as I do not find the prospect of leisure-only life appealing. I believe that work is essential to human wellbeing.” Of course, if you don’t have to do a job, life doesn’t become ‘leisure-only’ — you can go for voluntary work for example. Perhaps Vardi is worried that many won’t see it like that, though.It’s clear that over the next few decades there are going to be big leaps in AI and robots, and these will have major repercussions on our society. Previous research has indicated that 20 years from now, 35 per cent of UK jobs are at high risk of replacement by automation and robotics.