Q&A: Retirement in America is broken. Here's why and what needs to be done.

We are living in a precarious time for those nearing retirement as well as those already scrambling to patch together funds to meet their living costs in their 60s, 70s, and beyond.

"The past few decades have not been kind to older people, whether they are ‘retiring’ in poverty or working to survive," according to Teresa Ghilarducci, a labor economist and professor at the New School for Social Research, an expert on retirement security, and the author of a new book, "Work, Retire, Repeat: The Uncertainty of Retirement in the New Economy."

"The myth of the happy, healthy older worker obscures a glaring reality: millions of Americans must toil through their elder years just to stay afloat," she writes. "Needing to work in old age marks our times."

Nearly half of all families in the United States have no retirement savings, she adds. "This humanitarian and economic crisis is on the boil."

Read more: Retirement planning: A step-by-step guide

Here's what she had to say about the broken US retirement system and why working longer is not the solution to financial security at older ages. Edited excerpts:

Kerry Hannon: Teresa, one thing I’ve always loved about your work is that you look at the world from the bottom up. Can you discuss?

Teresa Ghilarducci: I think it’s because I grew up on the bottom. I grew up with a single mother who worked all of my childhood. When you care about working-class life and the security of a household, you land on what people are going to do when they retire. I've always looked from the point of view of workers and from the poor because of my personal experience.

In what way is our retirement system broken?

The 40-year experiment with a do-it-yourself model for the American pension system is failing. For instance, the median holding in a retirement account for all workers aged 55–64 is only $15,000, but the average worker needs $600,000 to supplement Social Security and maintain their standard of living. The bottom 50% have nothing but need $300,000; the next 40% have $60,000 but need $600,000; and the top 10% need at least $1 million but have $200,000.

The do-it-yourself model means that workers and their employers can decide whether or not to have a retirement account at work. It’s up to the employer to sponsor a 401(k), and it’s up to the worker to participate in the 401(k).

The worker makes all the decisions, which means they bear all the risk that they haven’t put in enough and when the financial markets don’t give them the returns that they expect.