Half of humans could be hounded by unemployment in 30 years’ time as machines fill job vacancies, warned a scientist in an expert panel that sounded the alarm on the threat of increasing use of autonomous systems on jobs.

Robots and smart machines such as self-driving car and intelligent drones are fast taking over traditional jobs, possibly resulting in this unprecedented rate of unemployment, according to computational engineering professor Moshe Vardi from Rice University in Texas.

“I do believe that, by 2045, machines will be able to do a very significant fraction of the work a man can do,” said Vardi, presenting at the annual meeting of the American Association for the Advancement of Science (AAAS) in Washington.

“[I]f machines are capable of doing almost any work humans can do, what will humans do?” he continued.

Artificial intelligence experts predicted at the Feb. 13 news briefing during the annual meeting that these autonomous systems will “march into society” in the next two or three years. Driving is expected to be completely automated in 25 years.

With over a billion dollars allocated in 2015 for AI research – the biggest in the entire history of the field – experts agreed that these advances may threaten job security as well as unleash a number of ethical, legal, and regulatory challenges.

With the advent of self-driving cars, for instance, car accident rates will likely be reduced; the labor market can be seriously wounded and courts would have to determine liability given computers’ involvement in accidents.

Automation, said Vardi, has already slashed the number of jobs in the American manufacturing sector, whose jobs have now dropped below 1950 figures. The country now has more than 250,000 industrial robots, with a double-digit growth rate.

The scientist harped on what’s called “job polarization,” where jobs in the middle – in terms of skill requirements and cost efficiency – will be the easiest target for automation. “Great inequality” will result from the job disappearance, Vardi said, adding that the issue should be on the radar of U.S. presidential candidates.

"We need to start thinking very seriously: What will humans do when machines can do almost everything?" urged Vardi.

It is not too late, however, for policymakers to act on potential legal and ethical concerns surrounding AI machines.

"There's a need for concerted action to keep technology a good servant and not let it become a dangerous master,” said ethicist Wendell Wallach of Yale University, calling for “strong, meaningful human control” of the rapidly growing technology.

Wallace proposed the devotion of 10 percent of AI research funding to studying the machines’ societal effects.