The World Health Organization says it's bracing itself for a significant increase in the number of senior citizens around the world. At nearly 1.4 billion people, China has the world's largest population, but the country is about to experience demographic changes like it's never seen before. Hou Na has more.

Diminished vision, reduced mobility, I have the chance to feel the effects of aging.

"This is me when I'm eighty years old."

But for these seniors, there's still a lot more to life. Just ask 92-year-old Xiong Douyin. He's been in this nursing home for three years. Though it's still a bit of a shock to him.

XIONG DOUYIN "I never never thought that I could spend my later years in a nursing home because I came from a wealthy family and my children treat me really well."

Xiong says he loves the old days when he spent quality family time with his son and grand-daughter. But his son's family moved abroad for work and education, which left the old man with a problem that money can't solve.

XIONG DOUYIN "Of course I felt a little uncomfortable when I first moved here. But the more friends I make, the more I like it here."

There are more and more families like Xiong's who will face the same dilemma: Where to live when you get old.

OLD MAN'S DAUGHTER "Many of the younger generation like us have become global citizens. We travel around the world. Putting our parents in a nursing home gives us feel a sense of security."

According to the World Health Organization, nearly two billion people across the world are expected to be over 60 years old by 2050, more than triple the number in 2000. Some of the world's largest economies are already having to deal with increased health-care costs and higher pension costs.

Professor Zheng Zhenzhen has been studying China's population issues for decades.

PROFESSOR ZHENG ZHENZHEN INSTITUTE OF POPULATION & LABOR ECONOMICS CHINESE ACADEMY OF SOCIAL SCIENCES "I think we should put the population issue into our social and economic planning."

She points out that an aging population also means an aging labor force.

China may have the biggest population of any country in the world, but it isn't having enough babies. The decades-old One-Child Policy was amended in early 2016 to allow all couples to have two children.

At the same time, the government's population plan warns against too great an increase. The environmental carrying capacity, food and water supplies, energy production, and medical and public services couldn't handle the strain.

HOU NA BEIJING "China is getting old. According to the United Nations, it's aging more rapidly than almost any other country in recent history. The UN says it will take China just 20 years for the proportion of the elderly population to double from 10% to 20%. The next closest is Japan, where it took 23 years. By comparison, it took 61 years in Germany and 64 years in Sweden. Last year in Russia, for the first time since the collapse of the Soviet Union, the birth rate was higher than the death rate."