As the population grows, it becomes more difficult for Earth to meet everyone’s needs. Earth is a finite system. We cannot increase the number of oceans or mountains. None of the minerals or oil can be resupplied. And there is only so much fertile soil for growing the world’s food supply.

But our global family grows by 230,137 people every day and over 84 million every year! In fact, our family has almost seven billion (7,000,000,000) people now!

Oh! How We’ve Grown

How did our global family become so large? For most of human history, the population grew very slowly because people didn’t live as long as they do today. Our earliest ancestors relied on hunting and gathering their food to survive. Only a finite number of people could be supported on the wildlife in an area for a limited amount of time.

Until recently, birth rates and death rates were about the same, keeping the population stable. People had many children, but most died before age five.

These trends in child deaths began to change with the Industrial Revolution and many inventions that promoted longer life. These included improvements in farming, nutrition, medicine and sanitation. With modern medicine, vaccines, clean and healthy living conditions, most children survive common diseases like measles or the flu.

At the same time, birth rates stayed high. Most of the world was less industrialized, so large families were still needed to help farm the land. Still today, in many countries, parents need large families to help them.

The world population began to grow significantly. By 1930, the world population reached two billion. Just 30 years later, in 1960, the world population was three billion and is expected to hit eight billion by 2024.

What’s the Big Deal?

When it comes to population, bigger isn’t always better. Every population, whether plants, animals or people, has a carrying capacity. This is the maximum number of a species that can be supported by the finite resources available.

It may seem like there’s plenty of room to go around in this big world of ours. But when the number of people doubles, other things grow or shrink. With every new person, the need for food, shelter, clothes and fuel grows. More people need more cars, roads, schools, hospitals, and stores. But more buildings mean cutting more trees for lumber, burning more fuel for energy and using up land that may have been home to different plants and animals. There is only so much land on our planet to grow food, plant trees, build cities and still leave space for animals and plants to grow in the wild. If there are too many people, there may not be enough of some of the things we need for everyone to have a share.

Source: You’re One in Seven Billion! (2010)
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