robot workers Staff program a robot arm by Nachi Robotic Systems at the International Robot Exhibition in Tokyo, Japan December 2, 2015. Reuters/Thomas Peter

In just 30 years, intelligent machines could replace about half of the global workforce.

That was the message Moshe Vardi, a computer science professor at Rice University and Guggenheim fellow, shared during a presentation at the American Association for the Advancement of Science annual meeting on Saturday in Washington D.C.

"We are approaching the time when machines will be able to outperform humans at almost any task," Vadri said, according to a report from The Guardian. "Society needs to confront this question before it is upon us: if machines are capable of doing almost any work humans can do, what will humans do?"

From drivers to sex workers, no job is safe, Vardi and other scientists warned.

"Are you going to bet against sex robots? I would not," Vardi added.

Vardi, of course, is not the first to warn of the loss of middle class jobs because of a rise in automation.

In fact, according to research published by McKinsey last year, as much as 45% of current jobs could be replaced using technology that already exists.

And in an Oxford University study published in 2013, researchers predicted that it could only take 10 to 20 years before almost 50% of jobs in the US are computerized.

Robot bear nurse robobear YouTube/ Plastic Pals

Wendell Wallach, a consultant, ethicist, and scholar at the Yale University Interdisciplinary Center for Bioethics, told Tech Insider last year that we had reached a tipping point where technology is now destroying more jobs than it creates. And if the trend continues, Wallach warned we could face a serious crisis in the US and abroad.

"When people no longer receive the money from wages they need to support their families, it is hard to know what they will do, but in the past and in other countries this has been thought of as a situation ripe for a revolution," Wallach told Tech Insider.

Vadri had a similar message when he spoke over the weekend.

Vadri said that political leaders have largely ignored the reality that automation will continue to up end the employment landscape in the United States.

"We are in a presidential election year and this issue is just nowhere on the radar screen," he said.

He added that as machines replace humans in more occupations, they will ultimately be forced to confront their greatest challenge yet, which is finding meaning in life without the purpose of work.

"We need to rise to the occasion and meet this challenge," he said.