Add BlackRock CEO Larry Fink to those warning that America is facing a retirement crisis.

Huge numbers of aging Baby Boomers have saved far too little for retirement and mistakenly expect to rely on Social Security, he tells CNBC, saying the government program is meant to be a secondary income source after private savings.

Many people are either not saving for retirement or don't bother to start saving until late in their lives, a mistake that puts them at a disadvantage.

Building an adequate retirement fund requires saving throughout life, Fink advises. The later you begin saving, the more difficulty you'll have accumulating enough to live "in dignity" in your later years.

Plenty of research says Americans have inadequate retirement savings. For instance, the Census Bureau reports that 36 percent of Americans don't save for retirement and 35 percent of those older than 65 rely entirely on Social Security, CNBC reports.

Employers share some of the blame for not educating employees about the importance of saving for retirement, he says. "We have to be noisier in the private sector. The business community is at risk for not educating their employees."

People typically live for today, without thinking about what will happen in 30 or 40 years, but a long-term, buy-and-hold strategy is the best action, he advises, saying investors can expect returns of 6 to 8 percent, including compounding, from equities over the long-term.

"One of the fundamental problems with individuals is they watch the news—whether it's Ebola, whether it's the volatility in the world, whether it's ISIS—they become frightened, and they pull back their investments to, maybe, more in cash."

Some commentators say Baby Boomers will simply have to work longer. But being forced to work in old age is not a solution, counters Teresa Ghilarducci, an economics professor at The New School for Social Research, in an article for The Huffington Post.

It's a "retirement crisis."

"The shocking fact" is that work has become more physically and mentally demanding for older workers, writes Ghilarducci. At the same time, their bargaining power is falling and their pay is stagnating.

"Living longer doesn't mean people can work longer. Longer lives aren't necessarily healthier or more productive lives," she notes.

"After age 68, chronic conditions begin to limit the body and mind. Our employment policies should prioritize getting the prime-aged population working, not insisting the elderly have no other choice."
 

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