"One in five Europeans is already at risk of living in poverty at old age," said Petra Hielkema, chief of the Frankfurt-based European Insurance and Occupational Pensions Authority.

"[That's] a ridiculously high percentage, frankly. And if you then look at women, they have a 30 percent larger risk for that," she told POLITICO in an interview.

And it's getting worse: Europe's population is aging rapidly, and within 40 years there will be only 1.5 workers for every pensioner. That's half the current ratio.

"Some countries are already there. And that’s unsustainable,"