7 billion, and counting (more slowly)

Happy 7th billion! The United Nations Population Division has picked today as the symbolic day when the world population reaches 7 billion. Twelve years ago, we marked 6 billion. Twelve years before then, in 1987, it was 5 billion.

These two numbers alone are indicative of an important trend: The rate of increase in global population is slowing down. It's easier to add another billion if you already have 6 on the planet than with a mere 5, yet it took us as long to add the 7th as it did to add the 6th billion.

Still, for some that decrease isn't coming nearly quickly enough. They point to (over)population as the real environmental menace: If only there were fewer people, the planet would be just fine, or so they say.

There's something to this. Seven billion have a larger environmental footprint than 6 or 5. Sensible population policies—giving women the freedom, education, and means to make their own decisions about how many children they want—need to be part of the picture.

But the combined footprint of the richest billion still dwarfs that of the large rest, especially the bottom 3 or 4 billion. There's no escaping sensible climate and environmental policies.

Lastly, population raises the most fundamental of all questions: Why are we environmentalists? Is it for the love of the planet, or for the love of people? As you can gather from the picture of my 7-month-old, I have pretty much answered that question for myself.