Transcript 5-2 Human_Impact PPT LESSONx

Module 16
HUMAN IMPACT ON THE ENVIRONMENT
Population Clock
YouTube - 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 anRevolution
increased birth rate
Industrial
and decreased death rate.
3. Urbanization (development of cities) leads to economic
and social development which influence human populations.
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.
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.
3.
Beach Erosion in North Carolina
a. 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 Mountains
a. 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.
D. Water Quality
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.
3. Waste Lagoons on North Carolina Hog Farms
a.
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