“People are everywhere. Some People say that there are too Many of us, but no one Wants to leave.”

According to your book, There are over 6 billion people In the world. (2000) World Population Clock As we’ve said before, many Scientists think that this rapid Growth is a fundamental cause Of many environmental problems.

Usually, an organism can Produce many more offspring Than can survive to grow up And reproduce. For example, a herring may lay Up to eggs a year. But each population has a Characteristic maximum Growth rate.

This maximum growth rate, Also known as biotic potential, Is the rate at which a population Would grow if every new Individual survived to adulthood And reproduced at its Maximum capacity. Given the right conditions, any Population can grow Exponentially.

An exponential curve, or A “J” curve.

The biotic potential for humans Is around 6% per year, but For rats it is 1.5 % per day, And for bacteria it is 250% Per hour! However, these are under the Right conditions, there are Limits on how a population Can grow.

As a population grows, it Consumes greater amounts Of resources. Eventually a resource will run Out. The resource that limits A population from growing Is called a limiting resource.

Limiting resources for animals Include food, water, shelter, And nesting sites. For plants; water, sunlight, And certain nutrients are Limiting resources.

When a population increases, Its individuals compete for These limiting resources. The combined effect of all the Factors that limit population Size is called Environmental resistance.

The population eventually Ceases to grow as it reaches, And often exceeds, its Carrying capacity. The carrying capacity is the Maximum population size An environment can support For a long time.

The earth’s human population Is increasing by about 149 People per minute, 8956 each Hour, each day, And 78 million each year!

Like a single ecosystem, The earth has a carrying capacity. The issue is that no one knows What that carrying capacity is Because of advancements in Technology and society.

Throughout about 99% of our History, humans were hunter- Gatherers. Or people who obtain food by Hunting, fishing, and Gathering wild plants. Today, very few people survive That way.

It is estimated that only about 1 million people were on the The entire earth when humans Were hunter-gatherers.

Then the agricultural revolution Took care of all that and The population grew to about 1 billion around 1800 AD.

Agriculture allowed people To produce more food than they Could ever get by gathering it. So farming increased the Carrying capacity of the land. So after thousands of years of Slow growth, the population of The earth doubled by 1930.

Then add another billion by 1960, Another in 1975, another in 1987 And yet another in Why so fast? Simple, people were living longer Because of sanitation, Nutrition, and medicine.

Although it seems that there Is an explosion (and there is In certain places), in industrial countries, it has slowed. This is because birth rates have Slowed since there is no need for extra kids to work the farms.

There is a theory to support this… It is the theory of demographic Transition by Frank Notestein. This states that the economic And social progress of the Industrial revolution affects Population growth in 3 stages.

1.Both birth and death rates Are high in preindustrial Societies, and the population Grows slowly, if at all.

2. When health care improves, The population size increases. The birth rate stays high, and People are living longer, so The population grows by 3% Each year.

3. Birth rates fall until they are Roughly equal to death rates, And population growth Slows and stops. Why do birth rates fall? Women usually get a better Education, and parents see kids Not as workers, but as a huge Financial responsibility.

Some countries are still In the second stage.

Population pyramids

The Death Clock – When Am I Going To Die?

The united nations and the World bank have determined That fuel wood is a Limiting resource in many Developing countries. Without the ability to have a Fire to cook their food, Many people suffer from Malnutrition or even starvation.

People in industrialized Countries feel safe drinking Water from the tap, However many people in Underdeveloped countries Die from parasites by drinking Unboiled water! Each year about 10 million people Die of diseases contracted From dirty water.

As a country’s population grows, More and more people move Toward The cities searching for work. The united nations projects that Up to ¼ of the world’s Population will be homeless By 2020.

Environmental refugees are People who are driven from Their homes by severe Environmental damage. The millions of people who left Their homes in Kenya, Somalia, And Ethiopia in search of Food are also environmental Refugees.

Slowing the growth of the Human population is considered Vital to future peace and Prosperity throughout the world. In order to be rich… SEE THE SIGN ON THE WALL!

Developed countries contain Only 21% of the world’s Population, but they consume 75% Of its energy, produce 70% of The global CO2, and 90% Of the global hazardous waste.

To achieve a sustainable future, The problems of overpopulation And overconsumption must be Solved.