From Pyramid To Rectangle

She showed a pyramid in the shape of a triangle, which she said represented population. The bottom represented many young people and the winnowing at the peak depicted the small number of survivors, she said, explaining that 25 percent of babies died before 1900, and many more before the age of 12. She added that death in these times was common at all ages and not associated with old age.

Out of concern, our ancestors collectively began to invest in building a world so that babies would have longer lives. “They discover causes of diseases and how they were spread, and they put in place inoculations, community-wide vaccinations, so that diseases would not spread,” she said.

They didn’t stop there. They also began to pasteurize milk, purify water and use agricultural technology that provided a steady food supply. And they put public education in place so all children could learn to read and write.

“Today, education is a better predictor of life and age. That’s a stunning observation,” Carstensen said, explaining that the population triangle has now reshaped into a rectangle.

“It changes the family and the entire population,” she said. “Here we are where four and five generations routinely will be living at the same time. Education will change, financial planning will change, the nature of work will change. All of these things will change because of these numbers. Completely novel.”

Carstensen pointed out that fertility fell by half at the same time we gained 30 years, and that’s why we have an aging society, she said. A hundred years ago, only 4 percent of the U.S. population was over 65. Now that number will rise to 20 percent in a couple of years. And this is a global trend. For example, in Japan, 27 percent of the population is over 65 and by 2050 that figure is estimated to reach 36 to 41 percent depending on fertility, she said.

By 2035, there will be more people over 65 in the U.S. than people under 18, she added.

For men, 68 is the new 59: Men reached the point of 2 percent mortality risk at age 59 in 1970 and that’s up to age 68 today, Carstensen said. For women, 73 is the new 65. Women hit that 2 percent mortality risk at 65 in 1970 and it’s at 73 today.

Carstensen offers four key things that people need to do: