All around the world, birthdates have gone down. The so-called "population explosion" is receding -- and quite rapidly in most places.

Now, this does not mean that our planet won't ultimately house more people than its population today. Even a lower growth rate still yields some growth until and unless it reaches zero. But what is also apparent is that those nightmare scenarios of ever more nonstop billions of starving people packed like sardines will not come to pass.

A brief look at data from the 20 most populous countries -- containing 75 percent of the world's population -- provides a flavor of what's going on. (The numbers were compiled by the U.S. Census Bureau's International Demographic Data Center.)

Seven of the 20 biggests nations are categorized by the United Nations as "more developed." They are the United States, the Soviet Union, Japan, Great Britian, West Germany, France and Italy. In six of these seven nations, fertility levels have already sunk so low that, if continued, such rates would lead to actual declines in population in years to come. The Soviets are only a smidgen away from such a rate.

But the biggest demographic question marks in recent years have concerned the major nations of the "less developed" world. A quick tour of these poor nations shows declines in birthrates everywhere, although a very different speeds.

Begin at mainland China. In the early 1950s, the mainland Chinese had an annual birthrate of 40 children per thousand people. By the late 1970s, just a quarter of a century later, that rate had fallen to 22.

India is No. 2 in the world in population. It has been thought of as a demographic basket case. India has had a much more moderate drop in birthrate than has China. In the 1950s, India recorded 43 births per thousand; today the rate is about 35. But that drop is more significant than it may seem. A nation only has to achieve rates in the mid-teens to get to population stability over time. That means that in the past 20 years India got about a third of the way to rates that will produce zero population growth.

Even greater declines in birthrates are apparent in the two next-largest poor countries, Indonesia and Brazil. Indonesia's birthrate was 46; now it's about 36. Brazil's was 44; today it's about 30.

On the other hand, Bangladash, Pakistan and Nigeria have all shown much smaller declines. Each had birthrates of around 50 in the 1950s and are only down to the mid-to-upper 40s today.

The remaining six big nations in the less developed world break down this way; the birthrates of Thailand, Turkey and Mexico have dropped about 10 per thousand; that's a bigger decline than India's, but not as sharp as China's. The Philippines and Egypt have lost about five per thousand. Data for Vietnam do not exist. (For good measure, South Korea, the world's 21st largest nation, has seen a stunning drop in its birthrate from 45 to 22, in only the past 20 years.)

The leverage of these sorts of declining rates is incredible. Thus, the often-bizarre "Global 2000 Study" cites a harum-scarum projection dealing with a world population of almost 30 billion in the next 120 years. But today, looking at the most recent birthrates, mainstream projections come in at about 10 billion to 12 billion, while the low-ball demographers are talking about a maximum of 8 billion before we level off and perhaps go to a global decline.

Lessons. First is this: there are no immutable projections. When some big out-of-town jasper with a pocket calculator comes up to you and says, "If present trends continue . . ." -- hold onto your wallet.

"Present trends" involving people typically don't continue, particularly if the trends are unfavorable. They change -- because, unlike pocket calculators, people have some control of their own destiny.

Second, what is seen as bad news drives out what is seen as good news. The alleged "population explosion" dominated our consciousness for a quarter of a century. Its recessional march now attracks little attention.

Third, what's seen as bad news may not be. The "population explosion" was regarded as "bad news" because the fellow with the calculator said that if you split a pie among more people, each person has less. That's an argument that may never be settled. A famous demographer has noted that every baby comes equipped not only with a mouth but also with hands. People not only consume but also produce. That makes the pie grow. Isn't it odd that just about every nation in the world raised its standard of living while the "population explosion" was going on?

Finally, science and statistics have become ideological handmaidens. Thus, the (distorted) perception of the population explosion yields corollaries: we're running out of resources, it's an era of limits, the rich are unfair to the poor, we need a new world economic order. Not surprisingly, the fellows with the hot calculators will also be happy to tell you how to fix things. All you have to do is follow a handy little 17-point government program that happens to be already typeset and at the printer's.

What we see, then, is a pattern that is observable elsewhere in our society:

we trumpet and politicize bad trends that may not be bad and may not be trends. w

That's bad. As for me, a political man, I trumpet only the idea that the projections of doom will not survive. Certainly not if present trends continue.