Former Federal Reserve Chief Alan Greenspan warned that "abnormally low" interest rates will pop a bubble in the bond markets.

"The current level of interest rates is abnormally low and there's only one direction in which they can go, and when they start they will be rather rapid," Greenspan told CNBC.

Since December 2015, the Fed has approved four rate hikes, but government bond yields remained mired near record lows, CNBC explained.

"I have no time frame on the forecast," he said. "I have a chart which goes back to the 1800s and I can tell you that this particular period sticks out. But you have no way of knowing in advance when it will actually trigger," he said.

"It looks stronger just before it isn't stronger," he said. Anyone who thinks they can forecast when the bubble will break is "in for a disastrous" experience."

Greenspan also is known for the "irrational exuberance" speech he gave at the American Enterprise Institute in 1996. The speech warned about asset prices and said it is difficult to tell when a bubble is about to burst, CNBC explained.

"You can never be quite sure when irrational exuberance arises," he told CNBC. "I was doing it as part of a much broader speech and talking about the analysis of the markets and the like, and I wasn't trying to focus short-term. But the press loved that term."

Greenspan made a similar prediction earlier this week in a Bloomberg interview.

While the consensus of Wall Street forecasters is still for low rates to persist, Greenspan isn’t alone in warning they will break higher quickly as the era of global central-bank monetary accommodation ends.

Deutsche Bank AG’s Binky Chadha told Bloomberg that real Treasury yields sit far below where actual growth levels suggest they should be. Tom Porcelli, chief U.S. economist at RBC Capital Markets, says it’s only a matter of time before inflationary pressures hit the bond market.

If rates start rising quickly, investors would be advised to abandon stocks apace, Greenspan’s argument holds. Goldman Sachs Group Inc. Chief Economist David Kostin names the threat of rising inflation as one reason he isn’t joining Wall Street bulls in upping year-end estimates for the S&P 500.

While persistently low inflation would imply a fair value of 2,650 on the benchmark gauge, the more likely case is a narrowing of the gap between earnings and bond yields, Kostin told Bloomberg.

He is sticking to his estimate that the index will finish the year at 2,400, implying a drop of about 3 percent from current levels.

(Newsmax wires services contributed to this report).

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