In an essay for the Jan. 15 issue of Time magazine, the chairman of the insurance and investment company Berkshire Hathaway Inc (>> Berkshire Hathaway) tried to allay concerns that innovation and improved productivity might cost jobs and disrupt lives.

Saying the U.S. "game of economic miracles" was in its "early innings," Buffett, 87, downplayed polls suggesting broad pessimism for the futures of American children, saying rapid economic growth would not be necessary for people to thrive.

He said that if the economy grew at just 2 percent annually after adjusting for inflation, roughly its pace since the 2008 financial crisis, while population increased 0.8 percent a year, then gross domestic product per capita would increase to $79,000 (£58,324) by 2043 from $59,000 now.

"This $20,000 increase guarantees a far better life for our children," Buffett wrote.

The essay is part of an issue titled "The Optimists" edited by Bill Gates, the Microsoft Corp (>> Microsoft Corporation) co-founder and philanthropist.

Gates, also a Berkshire director and a longtime friend of Buffett, is Time's first guest editor in the magazine's 94-year history.

Buffett maintained that most American children will live "far better" than their parents did, but urged the country to focus on closing the gap between the rich and less-rich.

While the wealth of the 400 richest Americans rose to $2.7 trillion last year from $93 billion in 1982, as computed by Forbes magazine Buffett said millions of people were left behind, "stuck on an economic treadmill."

He said this can be fixed.

"A rich family takes care of all its children, not just those with talents valued by the marketplace," Buffett wrote.

"In the years of growth that certainly lie ahead, I have no doubt that America can both deliver riches to many and a decent life to all. We must not settle for less."

Buffett ranked third on Forbes' list on Thursday with an $85.8 billion fortune, trailing only Amazon.com Inc's (>> Amazon.com) Jeff Bezos and Gates.

He might have ranked higher had he not donated roughly $27.6 billion of Berkshire stock to charity since 2006, including $30 million to an unnamed charity on Wednesday.

(Reporting by Jonathan Stempel in New York; Editing by David Gregorio)

By Jonathan Stempel

Stocks treated in this article : Microsoft Corporation, Berkshire Hathaway, Amazon.com, Time Inc