When the self-driving-car revolution firmly takes hold, there will be carnage, according to Wolf Richter of the Wolf Street blog. Not the car-crash kind — though that is a prevalent fear — but on the employment front.

“The magnitude of this problem is breathtaking,” he wrote. Citing government figures, he says that 4.1 million jobs (the stat of the day in our daily Need to Know before-the-bell column) are at risk, including chauffeurs and drivers of trucks, cabs and ride-share vehicles.

“ ‘There will be delays, setbacks, and gruesome accidents. Some people will call for putting an end to this. And others will refuse to get into those cars. But this is happening.’ ” — Wolf Richter

“These people can’t easily switch to writing software. There’s no room for them in manufacturing. Even the fast-food sector is getting automated, as are many other jobs, including writing stories for the major wire and news services,” Richter said. “It all might be happening faster than society is prepared to deal with it. And we’re not even talking about it!”

Read:Mobileye chairman questions safety of Tesla’s Autopilot.

The potential savings will outweigh the human cost, as companies fight for profit margins, he explained. Drivers are one of the biggest expenses for transportation companies. And they have to sleep and take vacation. Not so their autonomous replacements.

Read:Ford rolls out plans for autonomous-car services.

But Uber, a company expected to benefit from the advancements in a big way, said recently that it wouldn’t be phasing out drivers entirely. “We believe ride-sharing will be a mix — with services provided by both drivers and self-driving Ubers,” according to the Uber blog.

Nevertheless, it’s clearly a concern of Uber drivers, who aren’t exactly thrilled about the notion of losing their jobs to some software.

“We don’t expect Uber to move to driverless cars in New York City anytime soon, but they can expect we would launch an aggressive campaign, the likes of which they have yet to see, to halt such a move,” Jim Conigliaro Jr., founder of the Independent Drivers Guild, which represents 35,000 Uber drivers in the New York City area, said in an email. Read the full story.

Uber started its self-driving pilot program in Pittsburgh this week, outfitting Ford F, -1.31% Fusions for its “most loyal” users when they request an UberX ride. The car comes with a human sitting in the front seat to take over if something goes wrong.

Read:Watch Uber’s self-driving cars hit the road in Pittsburgh.

Still, the naysayers — and there are plenty — just aren’t buying it.

“Right now it is ALL HYPE and false hope to raise funds, billions and billions of funds,” writes one of the blog’s commenters, echoing a popular refrain.

But Richter stood by his stance.

“There will be delays, setbacks, and gruesome accidents,” Richter wrote. “Some people will call for putting an end to this. And others will refuse to get into those cars. But this is happening.”