Warren Buffett doesn't think the rich in America are paying enough in taxes. "The wealthy are definitely undertaxed relative to the general population," he told CNBC's Becky Quick during an interview on "Squawk Box" on Monday.

As industries become more specific and as workers develop more specialized skill sets, Buffett said, it's the wealthy who benefit.

Back in the 1800s, for example, when most people worked on farms, those who were stronger and worked harder still earned more, Buffett explained, but "the top person working on that farm would be worth one-and-a-half to two times what the bottom person was."

However, that disparity has grown. Today, the richest 10 percent of people worldwide own 85 percent of global wealth, according to Credit Suisse's 2018 Global Wealth Report. And as the market system continues to become increasingly specialized, "the rich will get even richer," Buffett said.

To Buffett, that means the next step should be figuring how to take care of people like "a guy who is a wonderful citizen" but "just doesn't have market skills."

His solution: Expand the earned income tax credit, which benefits people with low incomes. Even though "that probably means more taxes for guys like me," Buffet said, "I'm fine with it."

Fellow billionaire Bill Gates has made similar comments. "There's no doubt that what we want government to do in terms of better education and better health care means that we need to collect more in taxes," he said during a recent conversation in New York City. "And there's no doubt that as we raise taxes, we can have most of that additional money come from those who are better off."

Gates, like Buffett, acknowledges that he's among those whose taxes should go up. "I need to pay higher taxes," he told CNN's Fareed Zakaria during a 2018 interview. "I've paid more taxes, over $10 billion, than anyone else, but the government should require people in my position to pay significantly higher taxes."