I was appalled that Christine Emba wrote in her May 23 Wednesday Opinion essay, “Where are the babies?,” “The overpopulation doomsday scenarios have long since failed to pan out.”

Indeed? Where? Planet B? Well, there is no Planet B.

Does Ms. Emba read the newspaper? Accounts of extraordinary ocean pollution. The increase in salt pollution of our fresh waters. A large unknown source of ozone-layer-destroying chemical emissions. Threats of pandemics. Widespread use of chemicals that threaten alteration of human genes.

Just a beginning.

Add extinction of wildlife, destruction of habitat, and the killing of animals and people.

The ultimate threat of global warming and 2 billion sea-level refugees.

“Long since” is the time it has taken to threaten the habitability of our world.

Russell R. Brown, Ashburn

Christine Emba lamented that American women are having fewer babies, raising the specter of a declining U.S. population. But she used a particular measure of fertility (births per 1,000 women in a given year) that differs from the standard one used by demographers to describe the “replacement rate” that will maintain a stable population. The standard measure is the total fertility rate, which is the number of children a woman will have during the course of her childbearing years. The replacement level rate is about 2.1 per woman in today’s world. In the United States, this rate is now about 1.8.

Our total population today is 327 million. When I was born in 1941, the population of the United States was 133 million. We could again approximately triple our population in the next roughly 75 years to 1 billion, about the size of China and India today. Would that make us a better country with less poverty and a greater sense of well-being? In a world of global warming driven by the activity of 7 billion people on our planet?  

Maybe we should applaud the women who decide to have one or no children instead of making them feel irresponsible. What is missing is a serious discussion about optimum population size and sensible policies to achieve that level.

Lex Rieffel, Washington