For 81 years, it's been a financial safety net for retirees. But in just 18 years, Social Security could run out of money.

Current projections show in 2034, the Social Security trust funds could be broke. While the program is facing a long term funding shortfall, millions of current retirees who rely on Social Security benefits are struggling to stretch those dollars.

Next year the Social Security Administration's cost of living (COLA) increase will be just 0.3 percent. For the average senior that would increase their monthly benefits check by $4. Last year, however, there was no cost of living increase at all.

Why is the cost of living increase so small?

"The simple answer is inflation is very low," New York Times writer Neil Irwin explained to CNBC's "On the Money" in an interview. "Energy prices have been falling, food prices have fallen some," Irwin said. "Therefore there's a very low cost increase."

The COLA is based on the Consumer Price index, a basket of goods and services tracked by the federal government. Increases have ranged from more than 14 percent in 1980 to last year's zero change.

Despite relatively low fuel and food prices, The Times' Senior Economic Correspondent said there's "plenty of costs that especially seniors — especially people on Social Security receive — that are rising faster than that, health care is a big one."

But if COLA is calculated a different way, it could raise benefits and overall Social Security spending, putting even more pressure on the program's trust funds.

"If you want to increase the cost of living adjustments to use a different measure of inflation, that actually makes it more expensive, makes the financial challenges greater. It's a kind of complex set of tradeoffs," he added.

An option to saving Social Security could be raising the full retirement age from 67 to 70.

"That would definitely make the solvency issue better." Irwin tells On The Money. "That's easy for people in white collar jobs, executives who have jobs they can keep doing into their 60's and 70's to say."

The other side, Irwin explains, is "if you're in a more working class, you're working with your hands. If you're a miner, a farmer doing something that's more physically taxing, it's hard to keep working into your 65 to 70's," he said.

The last time Social Security was reformed, the retirement age was raised from 65 to 67 and that was "gradually phased in" over two decades.

"Most people didn't even notice it. It happened automatically, so it was a kind of forward- looking policy back in 1983," Irwin said. Still, he doesn't see something similar happening in the immediate future.

"There's not much evidence there's a ton of momentum towards that now."

On the Money airs on CNBC Sundays at 7:30 pm, or check listings for airtimes in local markets.