Carrying Capacity Reached: The Need for Population Stability

by Joshua on June 27, 2009 · 16 comments

Too Many People Harms Us All

Too Many People Harms Us All

We all want to have long, peaceful, and prosperous lives – to do this we need fresh water, healthy cropland for food, and materials for shelter and security. However, being that we live in a finite world, there are limits on everything needed for a long, healthy human life.

There is a limit to size of the pie. If more people eat from this proverbial pie, each piece must shrink to accommodate the growing number of people at the table. Historically the Earth’s resources have provided amply for the population. We always had more then enough pie to feed new people at the table, and more people were a welcomed sign of continued prosperity (generally).

Today we have almost 7 billion people on our planet and we have taken up nearly every square inch of usable land as our populace has grown. Continuing to grow will make it harder and harder to sustain our population comfortably. We are adding more and more people to the table but no longer have more pie and our pieces are beginning to shrink.

As our global pie of resources continues to diminish, our increasing population begins to be harmful to all of us. At our current growth rate we will have over 10 billion people on earth by 2050. If the world moves quickly to stabilize population growth, the UN estimates we will peak around 8 billion people in 2041 and then decline. Let’s assume the best possible case of 8 billion. (Brown, Plan B 3.0)

Carrying Capacity

“If you haven’t witnessed it yourself, common sense will tell you that a certain forest can carry on a certain amount of deer.” – Brian Czech, Shoveling Fuel…

Carrying capacity is defined as the maximum population of a given species that an area can support without reducing its ability to support more of the same species in the future. Biologist have studied the effects of different populations on their ecosystems as they grow. As they grow, there are two routes a populace can take, regardless of whether it is a community of beavers or a community of people.

Carrying Capacity vs Growth Outcomes

Carrying Capacity vs Growth Outcomes

The first route is a population explosion as resources are abundant (food, shelter, et cetera). As these resources begin to decrease the population eventually reaches the carrying capacity. At this point the area cannot sustain continued growth and the population levels out. This means that birth and death rates in the future are relatively equal.

The second scenario entails a population explosion that rockets past the carrying capacity and does not slow as resources begin to decrease. The resources dwindle faster than they can be replenished. You can see that in the long run, this scenario ends with a massive die-off, because there are no longer enough resources for the bloated population to thrive on. Worse yet, the population has taken the reserves needed to sustain the original carrying capacty and after a mass die-off a much smaller carrying capacity exists.

Humans have highly variable consumption habits and as such the carrying capacity of our area (Earth) can vary. Regardless of our these habits, there’s always a maximum. We have the ability to adapt if we do go over the Earth’s carrying capacity, there are indications that we have done so already, but our ability to mitigate the damages to our environment will only go so far. Before we hit that critical point we need to stabilize our growth.

The Population Limit

How many people can the Earth support? Our carrying capacity varies depending on our how much we consume. How much each person consumes will determine how many people can live on Earth. The question is: what standard of living do we want and how much are we willing to compromise?

For instance, if everyone ate as much as Americans we would only be able to support 2.5 billion people. The Italians, on the other hand, live healthier lives with a much more varied diet, consuming half as much grain as Americans. They have longer life expectancies and at their level of consumption we could support roughly 5 billion people. (Brown, Plan B 3.0)

In order to meet that 8 billion people from our previous estimate we would have to eat somewhere between the average resident of India and the average Italian. This means a significant change in the American diet and a more efficient distribution of the available food on the planet. Basically: Eat enough, not too much, mostly fruits and vegetables.

It’s important to realize a “healthy 8 billion” would not be an extravagant 8 billion. Our diet would be significantly cut here in America, while increased around most of the rest of the world. Our diet would not necessarily be beans and rice every night, but there would definitely not be as many steak dinners. One way or another, it is essential for us to stabilize our population so this 8 billion doesn’t become 10 or 12 billion – making life on Earth incredibly harder to sustain in peace and prosperity.

Personal and Public Challenge

Population stabilization is a sensitive topic in our society. Many hear the term and, incorrectly, associate it with abortions, childless families, and strict birth control mandates from the government. There are family-friendly, politically safer ways to support a stable population. Most of the work can be done by educating women and improving public health. Food and jobs also help to stabilize population; as well as more obvious measures like free condoms, birth control, and sexual education.

Ecological Economists, architects of the steady state economy, would prefer a method that is strict on a macro-level (governmental scale) with a minimum sacrifice of micro-level (personal scale) freedom and variability. Herman Daly and Joshua Farley describe this in their textbook Ecological Economics:

“Population stability requires the average of 2.1 children per couple. But it is not necessary (or even possible in this case) for each family to have the required average number of children corresponding to generational replacement. Macro-control is compatible with varying degrees of micro-variability around the average.”

One proposed policy is to create a two-child limit but allow trade of child-bearing privileges. This allows people who do not want to have kids to give those who wish to have more than 2 children the ability to do so. Other ideas are to employ economic incentives to have no more than two children, such as tax deductions for the first two only. This might make it more difficult for poorer families who have more children regardless. While every option has its pitfalls, something needs to be done.

I challenge you in your personal life to make a positive change and set an example for the rest of the world by having no more than two children. If you choose to have less, even better, but having a child in your life is an amazing part of human growth and should never be taken away from anyone. However, having three, four, or more children begins to take resources from other families that need them for their one or two children!

Publicly I challenge us to push for basic, universal health care, free education for everyone (K-12 and college), and easy access to birth control methods. Perhaps more importantly, I challenge us to place a social stigma on families that bloat over two children. They consume a more than stable, fair amount of our collective pie, burdening the rest of the world in order to bring even more people into it.

Here are some other good places to learn more about population stabilization, policies, and actions we can take:

Every resource on Earth is constrained by the consumption of the human race. When we increase our population we make those resources even more constrained and decrease the collective standard of living worldwide. We need to cut the extravagant consumption of the industrialized countries, but we also need to stabilize our population to ensure we can maintain a good standard of life on Earth for everyone.

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