And just so, we age gracefully

What do these numbers mean? Well, one thing is that with a change like that, it should be no surprise that India’s population increased faster in 1950 than it does today. Sure enough, our numbers grew by about 2.21% in 1950, and by an average of 2.26% per year through the 1950s. Compare with 1.37% in 2011, 0.8% in 2021, and an average of 1.3% through the 2010s.

Remember that these are growth rates. In absolute numbers, we added about 8 million people in 1950, but 11 million in 2020. And if that’s already too many figures for you, I’m on your side.

So, back to the average Indian woman. The figure I referred to above—the average number of children she will have in her lifetime—is called the Total Fertility Rate (TFR), and our TFR was 6.18 in 1950. Think of it this way: if this woman and the man in her life produce six kids before they die, they will have increased our country’s population by four.

If that TFR prevails from generation to generation, you can see that the population will keep increasing without ever slowing down. Naturally, that’s not something we want to see happen. So, we want to reduce the TFR.

Suppose it reduces to four, as India’s did. Our average woman and her man now produce four kids before they die. This increases our population by only two. If the TFR remains steady at four, the population will still keep increasing, if not at the same rate as when it was six.

Going further: Suppose the TFR reduces still more, to two—about where it is these days. Now our average couple produces only two kids before they die, increasing our population by...zero. In effect, their presence in the population has been taken over by their two offspring. They have been replaced. This is why a TFR of two is known as “replacement level". A population whose TFR is two will stop growing, because every couple is merely replacing themselves.

In reality, replacement level is considered to be a TFR of 2.1, to account for babies who die, or are infertile when they reach maturity. Anyway, if the figures are right, India’s TFR dropped below replacement level in about 2021.

What if the TFR continues to fall, as has been predicted for India over the next couple of decades? As, in fact, is a reality for several “developed" countries? Far from increasing the population, couples will no longer even be replacing themselves. Eventually, inevitably, the population will start falling.

Not just that, either. With fewer babies, and increasing life spans, the population will also change character. A rising fraction will be older folks, with everything that implies. This is a stark reality for countries such as Japan, the US and Sweden—countries that have steadily ageing populations with steadily fewer young people.

That means funding welfare programmes such as social security is now a concern. Health care for older people is now a concern. Naturally, this is the prospect facing India, too, over the next few decades. We have touted our “demographic dividend" for several years now. But just like those other countries did as they “developed", India, too, will age.

But leave that aside for a bit. Somewhere above, I wrote that once the TFR dips below replacement level, “eventually, inevitably" the population will drop. The key word there is “eventually". For it takes time. You might wonder why. That is, why doesn’t a population start declining as soon as the TFR is less than 2.1?

The idea to keep in mind here, strangely enough, is momentum, that almost intangible quality of objects in motion.

Think of the ship that destroyed a bridge in Baltimore this week. It lost power, but it still kept moving forward until it smashed into a pylon. Think of Usain Bolt crossing the finish line in a 100m race at the Olympics. Even the best sprinter in history does not come to a halt right there at the line; instead, he runs on, slowing down till he stops. Both Bolt and the ship have momentum because they move. Momentum that keeps them going, that’s hard to halt, that cannot dissipate in an instant.

If that makes sense to you, here’s a thought: Analogously, growing populations have momentum, too. Think of a TFR of 2.1 like Usain Bolt’s finish line: A country crosses that replacement “line", but its effect on the country’s population takes time to appear. The growth of a population, after all, is due not only to the number of children women have on average—the TFR—but also to the number of women in the population who can produce children. We may have arrived at that moment when the TFR is down to replacement level, but there are plenty of Indian women of reproductive age who are still giving birth to babies.

There are also Indian girls reaching puberty who will also give birth in the future. So the count of fertile Indian women will keep increasing for a while. So the population of India will keep increasing for a while.

That’s the intangible sense in which a population has momentum.

India’s population will increase for at least a few more decades. In fact, projections suggest that it won’t level off and then decline till at least the middle of this century, if not later. We can also expect India’s population to grow steadily older. Thus the prospect that we are staring at: a population that ages, that will grow before it starts shrinking.

What do we do about this? We make plans to cater to and care for larger numbers of the elderly who make up an increasing fraction of us all. No lip-service, but actual plans. We encourage immigration, because we are going to need people to fill the jobs our youth perform today but that will fall vacant as India ages.

We’ve crossed a major TFR milestone. Now we focus on the implications.

Once a computer scientist, Dilip D’Souza now lives in Mumbai and writes for his dinners. His Twitter handle is @DeathEndsFun.

PS: This is my last column in this space. It's been a fabulous ride. Thank you!