There's been a lot of fear about the future of artificial intelligence.

Stephen Hawking and Elon Musk worry that AI-powered computers might one day become uncontrollable super-intelligent demons. So does Bill Gates.

But Baidu chief scientist Andrew Ng—one of the world's best-known AI researchers and a guy who's building out what is likely one of the world's largest applied AI projects—says we really ought to worry more about robot truck drivers than the Terminator.

In fact, he's irritated by the discussion about scientists somehow building an apocalyptic super-intelligence. "I think it's a distraction from the conversation about...serious issues," Ng said at the RE:WORK Deep Learning Summit, an A.I. conference held in San Francisco last week.

Ng isn't alone in thinking this way. A select group of AI luminaries met recently at a closed door retreat in Puerto Rico to discuss ethics and AI. WIRED interviewed some of them, and the consensus was that there are short-term and long-term AI issues to worry about. But it's the long-term questions getting all the press.

Artificial intelligence is likely to start having an important effect on society over the next five to 10 years, according to Murray Shanahan, a professor of cognitive robotics with Imperial College, Professor of Cognitive Robotics. "It's hard to predict exactly what's going on," he told WIRED a few weeks ago, "but we can be pretty sure that these technologies are going to impact and society quite a bit. "

The way Ng sees it, it took the US about 200 years to switch from an agricultural economy where 90 percent of the country worked on farms, to our current economy, where the number is closer to 2 percent. The AI switchover promises to come must faster, and that could make it a bigger problem.

That's an idea echoed in two MIT academics, Erik Brynjolfsson and Andrew McAfee, who argue that we're entering a "second machine age," where the accelerating rate of change brought on by digital technologies could leave millions of medium-and-low skilled workers behind.

Some AI technologies, such as the self-driving car, could be extremely disruptive, but over a much shorter period of time than the industrial revolution. There are three million truck drivers in the US, according to the American Trucking Association. What happens if self-driving vehicles put them all out of a job in a matter of years?

With recent advances in perception, the range of things that machines can do is getting a boost. Computers are better at understanding what we say and analyzing data in a way that used to be the exclusive domain of humans.

Last month, Audi's self-driving car took WIRED's Alex Davies for a 500 mile ride. In Cupertino, California's Aloft Hotel a robot butler can deliver you a toothbrush. Paralegals are now finding their work performed by data-sifting computers. And just last year, Google told us about a group of workers who were doing mundane image recognition work for the search giant—jobs like figuring out the difference between telephone numbers and street addresses on building walls. Google figured out how to do this by machine, and so they've now moved onto other things.

Ng, who also co-founded the online learning company Coursera, says that if AI really starts taking jobs, retraining all of those workers could present a major challenge. When it comes to retraining workers, he said, "our education system has historically found it very difficult."