Population decline is not a problem but hungry kids are

livemint.com:

The Population Bomb. But the relative number of older people will skyrocket, causing anxiety among some economists and political leaders who want more people to have more kids.

On the other side, some environmentalists argue for pushing population to drop faster to slow global warming and loss of habitat for other species (and us). At the core of the debate are big unanswered questions: Is 9.5 billion too many? Will the population subsequently fall to a number that’s too low? Is there a right number of humans? Maybe instead of focusing on the number of children people are having, policymakers should focus on the fact that too many children worldwide aren’t getting adequate nutrition, education or medical care.

Even now, though humans grow enough food to feed everyone, roughly one person in 10 is chronically undernourished —i.e., hungry all the time— and more than one child in five is stunted (too short) because of chronic hunger and infections. As demographer and mathematician Joel Cohen explains, the “right number of people" question depends on yet more questions, among them: What would be the accepted standard of material wealth? How much inequality is okay? Would it be okay to build cities in areas prone to catastrophic flooding and earthquakes? Do people prefer parking lots or parks? Cohen calls the Lancet estimate credible.

“This is really the most serious piece of work in the business about what has happened and what to expect," he said. “There are lots of connections to climate, religion, economics, politics—but the fact is that fertility has been going down and is likely to continue to go down." Fertility is usually measured by looking at the number of children born each year to women of each age, from 15 to 55.