For more than 70 years, Geert Adriaans Boomgaard, a soldier in Napoleon’s army, held the record for the longest-lived person in Europe. He was one of only 10 people in Europe to reach 100 at that time. He died shortly before his 111th birthday. In contrast, there will be close to half a million centenarians in the EU by 2050. This is a good illustration of how quickly our world is ageing. Overall, we continue to live longer by 2.2 years for every decade since the 1800s. In other words, in the 1900s when Geert was at the end of his life, one could expect to live, on average, to 55 years. Today in Ireland, one can expect to live to one’s mid-80s – and Ireland is one of the fastest-ageing countries in Europe. At the same time as we are ageing as a country, our birth rates are dropping dramatically. A helpful statistic is the replacement level of births. This represents the number of births needed to compensate for deaths, and keep the balance of young and old. But our birth rates are below this replacement level. The replacement rate is 2.2 and our birth rate is 1.5. One hundred years ago, it was over four children per woman. This doesn’t just apply to Ireland – it is the case right across Europe.So, on the one hand we are living longer and at the same time the numbers of young people are declining. This is what is meant by an ageing society. To grow old in an ageing society is fundamentally very different from growing old in a young society. A substantial challenge is how best to accommodate this remarkable demographic shift when most of our government policies, infrastructures, societal norms and institutions were built when the structure of society was very different, and the number of older people was significantly lower than today. Our systems and infrastructures are based on a predominantly younger workforce and more youthful population. They were established at a time when life trajectories mapped neatly into three phases: education, work and retirement. Today’s life patterns are very different and are becoming even more varied given the rapid growth in new technologies, including artificial intelligence, coupled with declining numbers of young people available for the workforce. We need to rethink how our traditional systems will map with an ageing society and how best to optimise reshaping of education, employment, and retirement. What should systems, institutions and financial structures redesign to accommodate longer lives and fewer young people? [ Number of people working past age 65 rises by almost a third in three yearsOpens in new window ]One approach is likely to be the creation of more flexible patterns of both education and employment throughout the life course. This would include altering approaches to education, so that it is no longer something we do in youth but rather is a lifelong pursuit. The workplace could also provide opportunities to learn new skills and enable new opportunities for career change. Companies are already heavily invested in restructuring and evaluating the benefits and implications of an ageing workforce. More and more evidence supports the added value to a company of experienced workers and a multigenerational workforce. This has become even more evident as the working world is reshaped by artificial intelligence. The competitive advantages of a multigenerational workforce are evident from companies that top the leader board for performance. They are more agile in responding to change, more open to retraining, upskilling and redeployment of older workers. A 2024 survey by Mercers Global Workforce Longevity Practices reported that more than two-thirds of the highest-performing disrupter companies worldwide purposefully construct multigenerational teams. Younger and older workers bring varied and complementary skills. For example, younger workers have more fluid intelligence, which is characterised by the ability to solve novel reasoning problems. Fluid intelligence correlates with important skills such as comprehension, problem solving and learning – skills that depend minimally on prior experience. Conversely, older workers have predominantly crystallised intelligence, which evolves and grows over time. This is characterised by better verbal ability, reasoning, visual-spatial skills, a better capacity to tune out negativity and to instil positivity. Experienced workers bring decades of accumulated knowledge, of judgment and understanding of how organisations actually work and thrive. [ Rose Anne Kenny: Why are ages 30, 50 and 70 vital moments in determining how we grow old?Opens in new window ] At all life stages, we as humans require purpose. This has been recently well publicised by Japanese cultural observations and publications on “Ikigai”, the Japanese word for purpose. Knowing why you wake up in the morning makes you healthier, happier, and adds up to five years of extra life expectancy. The importance of purpose translates directly into both physical and mental health. Some of the common causes of death associated with low sense of purpose are heart attack and stroke. Lacking a sense of purpose causes inflammatory changes at biological levels, which trigger these cardiovascular complications. In other words, purpose matters for mind and body. Retirement, particularly forced retirement, robs people of some of their sense of purpose. So, providing choice regarding working patterns in older age, coupled with flexible retirement, may have added advantages not only for organisations but also for an individual’s health and happiness. It is important to note, nonetheless, that loss of purpose at the time of retirement is not by any means universal. There are many who relish retirement and blossom during that time, adding new purpose to their lives. We are living longer and, at the same time, birth rates are declining. These demographic changes are radically reshaping our communities. We are ageing in an ageing society. And, rather than stretching traditional systems and infrastructures – which were originally designed for a younger demographic profile – we need to rethink societal structures at many levels including how we learn, how we work and how we perceive ourselves as we age. It may be that longer lives do not equate to longer retirements for all. But the choice to continue in employment, and reframing of work environments and practices, should be an option. The businesses that have recognised this simple demographic change and repurposed their infrastructures to harness demographic advantages and talents are thriving. Rose Anne Kenny is regius professor at Trinity College Dublin and St James’s Hospital