It's a small world after all, and as we continue to grow and grow our population on Earth, many have wondered how much it takes a toll on the environment and on all the natural resources.
Throughout the entire history of the existence of modern humans spread across the Earth until about 10,000 BCE, Nature has kept us well under a million and many times, close to extinction. But we certainly never came near 1 billion. Until 1804. But then Nature kept us within the 1 billion mark. Until 1927. And so Nature kept us within the 2 billion mark. Until 1959. And then we hit 4 billion in 1974. 5 billion in 1987. 6 billion in 1999. And now we're well over 7 billion (7.6 as of this writing). And we're projected to hit 11 billion in 2088. Good lord, what happened?
Outside of the bubonic plague, the world population had been slowly rising in the last 1,000 years. Then, about two centuries ago, our hygiene and medicine advanced, and in Europe and North America the mortality rate (death) began declining as the birth rate increased (currently, our birth to mortality ratio is 3:1). Then, the global socioeconomic state of most other countries began to progress and so their population increased, as well. The overall global population growth peaked in the 1950's at about 2% with an average of 5 children per woman but today, the average global growth rate is around 1.1% with an average of 2.5 children per woman. All countries are currently experiencing a plateau in their growth rate, except for Africa. Regardless of their current AIDS epidemic, Africa's population is actually quickly growing with 1 in 6 people today living in Africa, and will be 1 in 3 by 2100.
Whether or not Earth can sustain our current population is still a debated topic. Some believe there are not enough natural resources or land to provide these resources for everyone, and others believe there are with the right implications. This "max amount" of a population is what is called the carrying capacity.
the carrying capacity
The carrying capacity of a population is defined as the maximum amount of beings within an area that can sustain itself and its environment with enough allowance for the extracted resources to renew themselves. So for example, let's say a lion only needs to eat two hyenas a day and one acre to roam for survival (omitting water, a mate, shelter and other factors). If you put 3 lions on 3 acres that has a cackle of 6 hyenas, these lions have gone beyond their carrying capacity because there are no longer any hyenas left to create offspring. Similarly, we have to consider the carrying capacity of humans with how we live today so that we don't just have enough to eat, drink, and have enough space and material for a roof over our heads; but we are still able to commute to our jobs and our in-laws' on Thanksgiving. That we have enough to produce medicine and build hospitals and restaurants, to make clothing and computers, and so on.
But it gets a little more complex than this because not everyone lives the same way. A 2-bedroom house in the Philippians is an average of 164 square feet, whereas in Dallas, Texas it's 1,030 square feet. And in developing countries, many people use very little material and will reuse what they do have, in contrast to more affluent countries. Then, consider differentiating diets throughout different regions and cultures. Finally, understanding Earth's carrying capacity for humans goes even further with what is called ecosystem services, and the amount of them for supply. These services are what we need to survive but are usually supplied for us automatically from their own ecosystems, that we take for granted. Take bees that pollinate flowers, for example, or trees that supply oxygen (among other things).
But even though most of us are plateauing our growth, the birth rate is still much higher than the mortality and thus, we're still increasing. Regardless of whether or not we have already reached (or will be soon) our carrying capacity for our Earth, the general consensus is that the resources are struggling to sustain us, especially since we went from less than a billion two hundred years ago, to nearly 8 billion today and not allowing for Nature to catch up with evolution. This will only get worse and become more strained for all resources, and for other beings, in the future as our numbers continue to rise.
Options for slowing the growth
China, as well as other places, have implemented a one-child policy for families to help combat a population crisis (China has since increased this to a two-child policy), which appears effective as a valid remedy to this situation. But a government telling adults how many children they're aloud to produce can be controversial because some may view it as immoral. Furthermore, depending on the country's economy, this may become a sudden dilemma if there are not enough workers to supply the demand of jobs when a generation of limited children grows up. As attractive as this quick-fix appears, there are too many loop holes, unfortunately.
When considering how to morally lower the birth rate to ensure sustainability, we must look at how the majority of our countries' population growth is slowing down. It was not long ago that a vast majority of people lived on farms and needed extra help to maintain it; thus more children. Also, further education was usually not thought of for the sake of the farm or from the effects of the Depression, and so they had more time to stay at home and have more children. But then as time went on and culture progressed, certain milestones occurred and life began to change more. More and more people left agricultural life and moved into cities with 9-5 work schedules. More young adults decided to advance their studies and receive college educations, consuming more of their time. Women received rights and joined the work force. Contraceptives became more readily available with various options and much more accepted in society. And child rearing today can be very expensive and a handful, especially if most adults become parents at a later age than they did a hundred years ago.
So if we continue along this path, we may have a chance. However, we are an industrialized country; Africa is still exploding in their population, after all. So, what we've done to this society needs to be expanded elsewhere, especially where rape is not as punishable, contraceptives are not available, and women may have no public voice- in areas of Africa or elsewhere.With this, we may overcome our overpopulation crisis and begin to see a future of a sustainable population with a better respect for our carrying capacity.