Have you ever wondered how many people could fit on Earth? Likely there’s more now than at any other time in Earth’s history, almost 8 billion. Yet what of the future? The World Bank predicts a peak of about 11 billion sometime this century. Or, there’s talk of a human population crash with the total dropping greatly. Yet, the population might just keep climbing to some, eventual maximum. That is, we don’t yet know how many people could possibly fit.

Let’s say the population remains the same as today. If so, then we certainly know the problems and for the most part the solutions. Such as, we’re on track to addressing climate change. We understand the importance of biodiversity and the value in preserving it. And, we realize that finite fossil fuels need be replaced by renewable energy sources. That is, the Earth might sustain the current population.

However, what of a population that continues to climb? A consequence is increasing pressures on Earth systems as people demand more energy, more food, more resources. That is, instead of solving problems, we’re exacerbating them. Climate change is quicker and greater. People use more land for themselves thus allocating less for biodiversity. And, we need all sources of energy even those not sustainable. This lack of sustainability means that Earth systems fail and eventually fewer people could fit on Earth.

Is there value in setting a maximum to the number of people on Earth? How would you calculate this value? And more important, how would you enforce this value?