Asian governments are being warned to plan for the future as the region’s population ages more rapidly than ever in human history.

The Asian Development Bank says in a report Wednesday that China’s ratio of elderly to working-age people will quadruple by 2050. It says other countries with fairly younger populations, like India, Pakistan and the Philippines, have only a few years before they undergo a similar process.

The bank says regional leaders will have to find innovative ways to sustain Asia’s economic expansion. It says they will need to build or strengthen pension, health care and social security systems for the elderly.

The bank also says countries with aging populations should be more flexible about opening their doors to workers from other countries with younger populations.