The U.S. workforce is about to undergo “unprecedented job destruction” as computers and robots get smarter, billionaire Jeff Greene told CNBC on Tuesday. The founder of The Greene Institute took Treasury Secretary Steven Mnuchin to task for recently saying he’s not worried about artificial intelligence displacing jobs for at least 50 to 100 years. Greene said Mnuchin is “completely out of touch with reality.” Greene argued that AI has the potential decimate the white-collar workforce of the future in a similar way automated factories replaced blue-collar workers in recent decades. Due to technological advances, there will be less work to go around in the decades to come, Greene predicted. He said society needs to come to grips with how people are going to live in this new paradigm. “I think we will have a world with much less work. … Who says both parents have to work 40 hours a week?” he said. “We’re going to have to focus on the quality of life, which is sort of what a lot of the millennials are talking about now.” A new study backs up Greene’s view on automation. The National Bureau of Economic Research said every new robot added to a U.S. factory in recent decades reduced employment in the surrounding area by 6.2 workers. One of the ways to deal with the relentless rise of automation and machine learning, advocated by prominent futurists including billionaire entrepreneur Elon Musk, is a concept known as universal basic income — a guaranteed paycheck from the government. The idea is currently being tested in Finland. Greene said he does not agree with most of Trump’s politics, including building a wall along the Mexican border, a sign of the president’s protectionist views and desire to pull back from globalization. Greene, who made his fortune in real estate, is known for making hundreds of millions of dollars shorting subprime mortgage-backed securities before the 2008 financial crisis.