The population question

There are now 8 billion of us.

How does that affect our ability to live within planetary boundaries — and to stave off the worst climate hazards?

Actually, what matters most is not how many we are. It’s how we live.

More people doesn’t necessarily mean more emissions. More fossil fuel burning means more emissions. And more affluence has historically meant more fossil fuel burning. Take a look at the United States and India:

By 2030, India’s population is projected to be more than four times that of the United States. Yet India’s total emissions are still expected to be lower than those of the United States, and its per capita emissions still a small fraction of those of the United States.

This reflects a global fact. Countries that represent 12 percent of the population account for 50 percent of the emissions that have warmed the planet over the last 170 years.

As a recent study in the journal Nature concluded, “the affluent citizens of the world are responsible for most environmental impacts” and are central to any future prospect of a more balanced relationship with the environment.

Put another way, those of us who live in the world’s richest countries consume a lot of energy. We drive long distances in big cars. We crank up the air conditioning in our offices. We eat a lot of red meat, another huge source of emissions. We throw away a lot of food. (Hacks here on fixing food waste.)