Environmental Science (2+1)

Essential Concepts

Essential Concepts

• Overpopulation is a leading environmental problem,
• exponential population growth and development leads to faster depletion of resources,
• population grows exponentially,
• why population prediction is difficult,
• Population is not evenly distributed throughout the world.

Lifestyle affects resource use

• The characterization of overpopulation as the cause of many environmental problems may be an oversimplification. Consumption of natural resources also plays an important role in straining the environment. On a global scale, it is probably pretty intuitive to students that the presence of more people in the world causes a bigger strain on natural resources. What may not be intuitive is the concept of sustainability. What does sustainability mean?


• Sustainability "the simple principle of taking from the earth only what it can provide indefinitely, thus leaving future generations no less than we have access to ourselves." Many other organizations define it in differently; however, the crux of the definition is the same. Sustainability involves living within the limits of the resources of the Earth, understanding connections among economy, society, and environment, and equitable distribution of resources and opportunities.


• It is the last part of the definition that joins population growth, particularly in developed countries, and resource use. Developed countries, in general, have and use more of the Earth's resources. Population growth in developed countries puts a greater strain on global resources and the environment than growth in less developed nations. For example, in 1997, the U.S. generated 27.5% of the world's total CO2 emissions; more than five times that of India (5% of the world's total), a country with 4-5 times the population of that U.S (Texas A&M's LABB). In fact, the way of life in the United States, on average, requires approximately 5 times the resources available on Earth today (Earthday Network). Some of the factors that may modify the birth and death rates in a region are

Age structure of the population - the number of women of child bearing age affects the rate of population growth.


• Total fertility rate - Total fertility rate (TFR) is the average number of children that each woman will have in her lifetime and affects the birth rate.


• Health care - the quality and availability of health care in an area can affect both death rate (by increasing average life expectancy) and birth rate (babies are more likely to survive past childhood). Access to immunizations, family planning and birth control are also important to the overall picture of population growth.


• Education - Birth rates tend to fall in countries where the population has access to education.


• Jobs - Birth rates also fall off when unemployment is low.Standard of living - Birth rates are lower where standards of living and quality of life are high. Unfortunately, standards of living are difficult to raise in areas where population growth is high - this creates a negative feedback loop that is difficult for some countries to get out of.


• Immigration/emigration - the number of people entering or leaving a country (area) actually changes the N0 and changes population in a more complex way than by altering birth rate or death rate.


• Development and industrialization - these two factors alter population growth in complex ways. They can affect an area's income and, thus, its access to many of the factors listed above. Higher income/more developed countries have lower birth and death rates


• Disease - in a given year (or even decade) epidemics of infectious diseases can increase death rate dramatically, particularly for a specific area. For example, the bubonic plague decimated Europe in the 14th century - the population of Europe was cut nearly in half by 1400.War/political upheaval - War and political upheaval can also increase death rates.


• Climate - Natural disasters such as drought or flooding can affect food resources and the population will be affected accordingly.