How Many People Can Live on Earth? (Part 2 of 2)

In part 1, I left off with the fact that the world population could feasibly reach 18 billion by the year 2100, at which point we may still inhabit roughly the same percentage of land. I'd like to take a moment to continue talking about water, though, and how we might run into serious problems relating to water when that many people are living in the same regions.

Believe it or not, Mexico City is one of the richest cities in the world. In fact, at the time of writing this article, Mexico City ranks in at No. 8 in the entire world - wealthier than Hong Kong, Washington D.C., Philadelphia and Sao Paulo. Yet, despite the city's massive wealth, it has major water problems.

For the citizens of Mexico City, water is never a sure thing. They just simply don't know when they will have water and when they won't. The problem is their infrastructure. The plumbing just can't handle the water needs of that many people. Most of the citizens resort to buying their water in large quantities from local vendors to ensure they always have enough on hand in case they need it. Just think about that for a moment, though. The eighth richest city in the entire world suffers from habitual water shortages.

What many people do not realize is that the bulk of the water we use on a daily basis is not used for drinking. It's actually used for the energy and the production of goods and services. For example, 1 cup of coffee that is only 8 ounces of liquid can take up to 120 liters of water to be produced. As I mentioned in part 1, a simple hamburger uses up 8,000 liters of water on average. Taking shorter showers and watering your lawn less often is great, but just remember that the amount of water used every time you take a trip to McDonald's is the equivalent of taking 10 baths.

If we could say that the Earth can support 20 billion or more people, then we might have at least 150 years to sort the problem out. However, when we look at all the data, it's evident that the Earth can probably not handle more than twice the amount of people we already have, which means our population could create major problems for us before the turn of the century. No one can say exactly how many people the Earth can support, but it's safe to assume it's far less than we are ready for.