We hear quite a bit about sustainability these days. Most of the “sustainable” conversation has to do with the environment. Some are concerned that our physical environment might be dramatically different in 30, 50 or 100 years. We hear much less about the sustainability of our American society as we know it today.

In “Civilization,” Niall Ferguson documents how the great societies of the past typically collapsed in a very short period of time, 10 to 20 years. In the United States today, we are living as a country in a way that is unsustainable. The only question is whether we will change the unsustainable ways before the consequences are more severe than those of the Great Depression.

Last month in this column I introduced the notion of debtism, the insistence on receiving benefits today that we do not pay for, and probably cannot afford, today. I discussed the issues of credit card debt, student loan debt, and mortgage debt that is higher than the value of a home. As serious as each of these problems is, they pale in comparison to the topic of this column, unfunded liabilities. Unfunded liabilities are financial commitments made to someone, often in the distant future, that are not being saved for along the way. One day, the commitment is due, and it costs far more than was ever dreamed, and little or nothing has been saved to pay for it.

Years ago, my neighbor, Roy Fletcher, showed me his W-2 from 1937, the first year that Social Security payroll deductions went into effect. Roy paid into Social Security $1.38 for the entire year. Prices were much lower then; the average first year payout was $58.30. So, if there are 40 people like Roy Fletcher paying in $1.50 for each beneficiary receiving about $60, then the program is sustainable. The program becomes unsustainable if there are fewer people paying in, and more people receiving benefits — exactly the situation we have today. In Social Security, Medicare and federal employee pension commitments, the federal government is on the hook for over $87 trillion of obligations that we are not saving for now.

That is such a large number that we can’t even relate to it. I thought it would be helpful to give an example we can relate closely to, the city of Lumberton. City employee James Moore was incredibly helpful in providing numbers for this column. Like most municipalities, the city of Lumberton, in 1989, established a retiree health insurance benefit. At that time, the city paid $553,000 to cover the health insurance premiums of about 283 employees and 30 retirees. A little over 20 years later, the city pays $3.1 million to cover about 360 active employees and 152 retirees. More than 140 current employees have already qualified for the retiree health care benefit. When the city calculated the unfunded liability for health care, the total was about $37.7 million. The city’s annual operating budget is about $80 million. Lumberton actually has a lower proportionate liability than most cities in the country, although it is still a hefty bill.

What can be done about Lumberton’s $20 million, the federal government’s $87 trillion and the states’ and municipalities’ $38 trillion in state and municipal unfunded liabilities? Any proposed solution will be very painful for our country and its citizens. Many people who worked a career for an employer, with the promise of financial commitments into retirement, will likely find that those promises can’t be met, or at least they will be deferred. Laws can be changed to require that obligations be funded each year. This is the situation with the U.S. Postal Service. Last year they defaulted on a legally-required payment. Part of the answer will include increasing tax revenue to begin funding liabilities. However, as tax rates are raised, people and companies shift their behaviors to result in lower tax revenue, so this strategy can only be used to a certain extent.

Nearly everything in life is uncertain. One statement we can make with certainty is that the path we are on is unsustainable. I don’t think it is too late to fix this problem, but if we do nothing, we may be doomed in as little as 10 years.

Eric B. Dent, a Lumberton resident, is a business professor at Fayetteville State University.