Living to 100 today is not unheard of, but is still rare.Life expectancies in developed and developing countries are increasing, with the UN stating that the number of centenarians would hit 573,000 in 2021. Japan has the highest rate of centenarians, with 0.06% of the population 100 or older. Should the latest efforts to prolong life reach their potential, living to see your 100th birthday could become the norm; making it to 120 could become a perfectly reasonable aspiration.

More exciting still, those extra years would be healthy. What progress has been made in expanding lifespans has so far come by countering the causes of death, especially infectious disease. The process of ageing itself, with its attendant ills such as dementia, has not yet been slowed. This time, that is the intention.

Any development that causes people to live healthily for longer, and to take fuller advantage of what the world has to offer, is cause for cheer. The fact that many people living much longer would have wide ramifications. For example, working lives will be extended, as they have already as life expectancies have lengthened, and possibly even more so for women, who will lose less of their careers to having children, perhaps narrowing inequality in the workplace.

What are the other implications of this potential demographic shift? We will discuss:

• What technologies and treatments are being used?
• What will the impact be on inequality?
• Will people think about future threats, such as climate change, even more, as they might live to experience the downsides of these threats?
• What will the family structure look like?
• Will a surfeit of centenarians marginalise the young, create a cult of youth—or both?