One of the toughest problems retirees face is making sure their money lasts as long as they do.

From the U.S. to Europe, Japan and Australia, retirement account balances aren’t increasing fast enough to cover rising life expectancy, the World Economic Forum warns in a report published Thursday. The result could be workers outliving their savings by as much as a decade or more.

“The size of the gap is such that it requires action” from policymakers, employers and individuals, said report co-author Han Yik, head of institutional investors at the World Economic Forum. Unless more is done, older people will either need to get by on less or postpone retirement, he said. “You either spend less or you make more.”

Most of the world’s retirees are doing better than those in Japan, where the retirement savings gap is 15 years for men and almost 20 years for women.

While Japanese workers save no less than others, they tend to invest in very safe assets that produce few gains over time, Yik said. As a result, average savings in Japan are only enough to cover 4.5 years of retirement.

Meanwhile, life expectancy at birth for Japanese women is 87.1 years — the highest in the world, according to the Organisation for Economic Co-operation and Development — and 81 years for men.

The forum assumed retirees would need enough income to cover 70% of their pre-retirement pay, and didn’t include Social Security or other government welfare payments in the total.

In the U.S., the forum calculates that 65-year-olds have enough savings to cover just 9.7 years of retirement income. That leaves the average American man with a gap of 8.3 years. Women, who live longer, face a 10.9-year gap.

The retirement savings gap is about 10 years for men in the U.K., Australia, Canada, and the Netherlands, the forum says. Longer-living women in those countries face an extra two to three years of financial uncertainty.