The New York Times "Room for Debate" series brings together a half-dozen or so experts to offer diverse opinions on the news. I was asked to contribute to the conversation about the new UN report claiming a global population of 10 billion people by 2100, and my piece is now up.

Population projections 90 years out – even 40 years out – are risky. There are big challenges to human civilization already under way this century, such as climate disruption and food sustainability, and more on the horizon. If any of them hit as hard as we fear, or if our responses are insufficient, there’s little likelihood that Earth’s population would get to 10 billion people. In a way, getting there would be a sign of successful navigation of this century’s problems.

It goes on from there.

I'm particularly pleased with the point made in the last sentence of that paragraph -- it's a reframing of the issue that I haven't seen elsewhere. But it's true: given the scale of the challenges we'll face this century, if we do end up with a planet of 10 billion people in 2100, it can only be because we've successfully managed the cascading crises. Ten billion in 2100 is a positive sign, not a negative one.