45.5 Human Population Growth

Scientists now know that the age-specific mortality of populations is very important.

By the end of this section, you will be able to discuss exponential human population growth, explain how humans have expanded the carrying capacity of their habitat, and discuss the long-term implications of economic development in different countries.

Some worry about the ability of the earth's environment to sustain the rapidly growing population.
The risks of famine, disease, and large-scale death are associated with long-term exponential growth.

Although humans have increased the carrying capacity of their environment, the technologies used to achieve this transformation have caused unprecedented changes to Earth's environment, altering it to the point where some may be in danger of collapse.

Human activities are to blame for the decline of the ozone layer, erosion due to acid rain, and damage from global climate change.
The effect of these changes on our carrying capacity is not known.
The world's carrying capacity for human beings might actually decrease due to the negative effects of increasing carrying capacity.

Even though human reproduction is far below its biotic potential, the human population is experiencing exponential growth.

All females have to become pregnant every nine months during their reproductive years to reach its biotic potential.
The environment would support such growth.
The human population is still growing.

While the population in Asia is growing rapidly, the population in Europe is growing slowly.

A reduction in time it takes to add a certain number of humans to the Earth is a consequence of exponential human population growth.

Our ability to increase our carrying capacity indefinitely is limited.
The human growth rate is predicted to slow in the future without new technological advances.

The population will continue to increase and the threat of overpopulation remains.

Over time, the time between the addition of each billion humans to Earth decreases.

Humans have a unique ability to change their environment to increase carrying capacity.

This ability is responsible for human population growth and a way of overcoming density- dependent growth regulation.
Human intelligence, society, and communication are all related to this ability.
Humans can build shelter to protect them from the elements and have domesticated animals to increase their food supplies.
Humans use language to communicate with new generations, allowing them to improve upon previous accomplishments.

migration and public health are some of the factors that affect population growth.

Humans have migrated to almost all of the Earth's land.
The use of antibiotics and vaccines has reduced the ability of infectious disease to limit human population growth.
Between 30 and 60 percent of Europe's population were killed by diseases such as the bubonic plaque in the 14th century, which reduced the world population by as many as 100 million people.
The threat of infectious disease is less severe today.
According to the Institute for Health Metrics and Evaluation in Seattle, the global death from infectious disease declined from 1990 to 2017: Between 1993 and 2002 the percentage of the world's population killed decreased from 0.30 percent to 0.14 percent.
Human population growth is becoming less influenced by infectious disease.

The ability to associate population growth with economic development in the region is a result of age structure.
The age structure diagrams of countries with rapid growth show a lot of younger people, many of whom are of reproductive age or will be soon.
A pyramidal structure still exists in areas with slow growth, but with fewer young and reproductive-aged individuals and a greater proportion of older individuals.
Italy has no population growth.
Middle-aged and older individuals make up a greater percentage of these populations.

The diagram shows that the number of individuals decreases with age.
Stable population diagrams show that the number of individuals per age group decreases gradually, and then increases for the older part of the population.

Stages 1 through 3 show age structure diagrams for rapidly growing, slow growing, and stable populations.

Hundreds of millions of people will starve to death in the 1970s, even if crash programs are implemented now.
The world death rate will increase at this late date.
The laws of exponential population growth are still in effect, even though many experts think this statement is incorrect.

Policies aimed at influencing population have been instituted by several nations.

National and regional populations are implemented by India to encourage family planning.
Japan, Spain, Russia, Iran, and other countries have made efforts to increase their population.