Another study by Burtless shows that education is a key factor that influences the labor market participation rates of workers in the 62 to 74 year old age group. Two-thirds of older American men with doctoral or professional degrees were still working compared with just one-third of high school graduates. For women the proportion was half versus one-quarter.

While older workers are holding their own in white collar roles, one may be tempted to think that surely younger workers have a big advantage in physically demanding blue collar jobs. The Japanese fishing industry, for one, displays a contradictory trend. According to government statistics, more than a third of Japanese fishermen are over 65 while 13 percent are even over 75. In contrast, 15 to 24-year-olds make up only 3 percent of the fishermen. Not only have older workers used skill and machinery to stay in business, but also younger workers seem to be daunted by the physical rigors of the work. The unwillingness of younger workers to take up this physically demanding job is causing serious worries about the future of the fishing industry in Japan.

So it is wrong for governments, policymakers and companies trying to sell things to view aging societies as full of unproductive retirees and medical invalids. Senior citizens are increasingly both willing and capable of participating formally in the workforce. And this is before accounting for their significant contributions in voluntary community service and other activities.

Hence, societies will need to change in many ways to accommodate these trends. For instance, rather than build ever more retirement homes, urban design will have to adapt to the needs of senior citizens who wish to continue to work.

Similarly, the education system will have to become friendlier to older students wanting to upgrade their skills. Given that people will routinely work into their 70s, it will probably be common for workers in their 40s or 50s to return to university and completely change professions.

Besides, younger people need to recognize that they will have to work a lot harder to keep up with their grandparents.

The author is the global strategist at Deutsche Bank.