Module 16

Population ClockYouTube - Population Connection - "World Population"

I. Why is human population growth an environmental problem?

A. Causes of human population growth

1. Agricultural Revolution – people settle into communities

and more people were needed for division of labor; more

reliable food supply can support a larger population.

2. Industrial Revolution – In the early 20th century

technological advancements led to improvements in

medicine and sanitation allowing for an increased birth rate

and decreased death rate.

3. Urbanization (development of cities) leads to economic

and social development which influence human populations.

Industrial Revolution

B. Effects of human population

1. Increased pollution – air, water, and land ALL

pollution problems relate back to overpopulation. Pollutants

are produced as waste products from human activity, such

as burning fossil fuels, mining, and use of

consumer goods. Solid waste requires disposal in landfills

or incineration.

2. Decreased natural resources, especially

nonrenewable resources (available only in limited

amounts).

Ex. fossil fuels, minerals, metals

3. Increased land use – leads to loss of habitat for

other species.

C. Census Data – demographers construct histograms to use in predicting future population

growth trends (field called “demography”)

D. Solution

1. ZPG – zero population growth (birth rate = death rate).

a. Limit number of births per family by offering tax incentives

Ex. China

b. Make birth control and family planning more available.

c. Educate public and our political leaders.

2. Conservation – wise and careful use of resources through

environmental stewardship

a. Twenty percent of the world’s population uses more than

fifty percent of the world’s resources.

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b. People in developed countries (like the U.S.) can decrease

resource use by the 3 R’s:

i. Reduce – use less materials; for example, buying

products that have less packaging

ii. Reuse – use products more than once; for example,

bring lunch in Tupperware instead of one-use

containers

iii. Recycle – return products to be re-processed; for

example, old tires are used to make track surfaces

c. Sustainability – ensuring the availability of resources and a

stable environment for future generations.

II. How is North Carolina affected by human activity?

A.Global Warming

1. Cause: Excessive greenhouse gases such as CO2 and

CH4 in the atmosphere trap heat, leading to an abnormal

increase in earth’s surface temperature

a. CO2 comes from burning fossil fuels in power

plants, factories, and cars.

b. CH4 comes from bacteria in landfills and cow farts

2. Effects: With just a small increase in temperature

such as 2-4 degrees Celsius, weather patterns will

change worldwide. Polar ice caps may melt and

thermal expansion occurs, flooding coastal cities and

contaminating drinking water with saltwater.

Front: Pictures or Diagrams explaining a specific human impact (ex. Acid precipitation)

Back: Description written to yourself in the future What the problem is How it is affecting the environment What we can do to solve the problem

3. Beach Erosion in North Carolinaa. Sea level is directly related to global climate. In

North Carolina, the sea level increase is twice the global average.

b. Rising sea levels lead to beach erosion. Severe storms also increase erosion. The incidence of severe storms is increasing as a result of global climate change.

c. Coastal residents attempt to prevent beach erosion to protect property, leading to negative environmental consequences to ocean ecosystems.

C. Acid Precipitation

1. Cause: Harmful emissions from cars and factories ,

especially nitrous oxide and sulfur oxide) react with

oxygen and water to make precipitation more

acidic – with a pH less than 5.6

2. Effects: A lowered pH disrupts aquatic ecosystems,

makes soil less fertile, harms plant life, and damages

human property.

3. Acid Precipitation in North Carolina Mountainsa. Red spruce and Frasier fir trees in the

mountains are dying as a result of acid precipitation, damaging the ecosystem.

b. The mountains are greatly impacted by acid precipitation caused largely by pollutants from Tennessee. The soil has a low buffering capacity and acid fog continuously surrounds the trees making the damage more profound.

1. Cause: Sources of water pollution often

begin on land, such as oil from cars, sediments from

naked land, and fertilizers from lawns. Other sources

include illegal chemical dumping, acid rain, overheated

water from power plants, and raw sewage.

2. Effects: A lack of clean drinking water is a leading

cause of disease (such as cholera, dysentery, typhoid).

Water pollution also affects many ecosystems through

habitat destruction.

D. Water Quality

3. Waste Lagoons on North Carolina Hog Farmsa. There are approximately 7 million hogs on

industrial farms in NC, most in eastern NC which is a flood-prone coastal plain.

b. Industrial farms raise thousands of animals in a small space, producing TONS of waste. The waste is stored in lagoons, but may run-off, leak or spill into surface water with rainfall.

c. The sewage in the surface water leads to high levels of disease-causing bacteria such as E. coli, oxygen-depleting organic matter, and hormones/antibiotics used in feed

d. Also, nitrogen run-off from the waste may contribute to outbreaks of Pfisteria, a single-celled alga that produces a deadly neurotoxin. Massive fish kills have resulted, along with health problems in fishermen and others exposed.

III. How do humans negatively impact other species?

A. Biodiversity – the number of different species of organisms that exist within an area and the genetic diversity within each species

B. Causes of Biodiversity Loss: 1. Habitat Destruction such as deforestation , fragmentation, and pollution of aquatic ecosystems leads to loss of biodiversity. In NC, urban development in the Piedmont has led to biodiversity loss due to:

 a. Forests are fragmented – breaking up a large

forested area into smaller zones due to construction.

b. Clearing land for development leads to soil erosion which ultimately leads to water pollution

c. An increase in impervious surfaces such as asphalt and concrete lead to increased water run-off and pollution.

2. Introduction of non-native species, “invasive species”a. Kudzu, aka “The Vine That Ate The South”

i. Kudzu vines are native to Japan. The vines were brought to the US during the Great Depression to plant in order to stabilize hillsides, minimizing erosion.

ii. Kudzu vines have no natural predators in the US. The vines can grow up to 1 foot per day in our climate.

iii. Excessive growth has engulfed forests, outcompeting native species for sunlight and soil nutrients, leading

to loss of native biodiversity.

b. Dutch Elm Disease

i. Dutch Elm Disease is a fungus that spread to NorthAmerica on crates made from Elm wood.

ii. The disease easily spreads by insects or root to root

iii. Dutch Elm Disease leads to the death of trees, impacting the environment and economy.

3. Biomagnification of Pesticides

a. Bioaccumulation is the build up of certain pesticides in the tissues of organisms (Ex. DDT in fish)

b. Biomagnification is the increasing concentration as pesticides move up the food chain (Ex. DDT in bald eagles)

C. Effects of Biodiversity Loss:

1. Endangerment/Extinction of Species

a. Endangered species are at risk of

becoming extinct. Extinction refers to the

loss of a particular species (image shows

extinct Carolina Parakeet)

b. The Endangered Species Act provides

protection for species recognized and listed by the government. This Act does

not, however, provide adequate protection

of the habitat.

2. Loss of valuable medicinal or crop plants, and

other species that may be potentially useful to

humanity

3. Lack of genetic variety makes crops more

susceptible to disease, pests, and environmental

changes

IV. What can you do to protect the environment?A. Awareness –each human impacts the

environment, and because our population is large we have an ENORMOUS impact at the global level. “We cannot all do everything, but we can all do

something”

B. Specific suggestions:

1. Reduce dependence on fossil fuels

(Example – car pool, support

“green power”)

2. Recycle whenever possible

3. Limit use of chemicals at home

4. Consumer choices – support

“green” businesses / products