Our first child was born at the end of August. I am not a young parent; I was born in 1974, and in the span of this one generation, global carbon levels rose by nearly twice as much as in all of human history before. I teach environmental law, so naturally people get around to asking whether my wife and I struggled with what it means to bring a child onto this troubled planet, and whether it is a good thing to do at all.

I take the point. James added his seven pounds, 10 ounces to a planet where humans and our…