Transcript Land Pollution - Effingham County Schools

Land Pollution
Urbanization
• Urbanization is an increase in the ratio or
density of people living in urban areas rather
than in rural areas. People usually leave rural
areas for more plentiful and better paying jobs in
towns and cities.
• As urban populations have grown, many small
towns have grown together and formed large
urban areas called metropolitan areas. An
example would be Washington D.C.-Baltimore.
Urban Sprawl
• When people move
into an area, they
have to have
infrastructure to
support them.
• Infrastructure is
the basic facilities
of a country or
region, such as
roads, bridges,
sewers, and
railroads.
Urban Crisis
When more people live
in a city than its
infrastructure can
support, the living
conditions deteriorate.
This growth problem
has become so
widespread throughout
the world that the term
urban crisis was coined
to describe it
Urban Sprawl
• Urban sprawl is the rapid spread of a city
into adjoining suburbs and rural areas
Other Impacts of Urbanization
• City environments differ from rural
environments…
1. Heat island is an area in which the air
temperature is generally higher than the
temperature of surrounding rural areas.
• Roads and buildings absorb and retain
heat longer then vegetation does.
Other Impacts of Urbanization
• Scientists are beginning to see that heat islands
can affect local weather patterns. Hot air rises
over a city, cooling as it rises, and eventually
produces rain clouds.
• Reduce heat-island effect by planting trees for
shade and reflecting rooftops.
• In Atlanta, Georgia, and many other cities,
increased rainfall is a side effect of the heat
island effect.
Farmlands
• Farmland is land that is used to grow crops and
fruit. The U.S. contains more than 100 million
hectares of prime farmland.
• In 1996, the U.S. government established a
national Farmland Protection Program to help
state, county, and local governments protect
farmland in danger of being paved over or
otherwise developed.
How does Farmland add to land
pollution?
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Pesticides
Insecticides
Fertilizers
Farm Machinery
Rangelands
• Land that supports different vegetation types like
grasslands, shrublands, and deserts and that is
not used for farming or timber production is
called rangeland.
• Like farmland, rangeland is essential for
maintaining the world’s food supply. World
population growth may require a 40 percent
increase in the food production of rangeland
from 1977 to 2030.
Problems on the Range
• Overgrazing is the depletion of vegetation
due to the continuous feeding of too many
animals.
• The Public Rangelands Improvement Act
of 1978 was enacted to reverse this trend
and improve land management practices.
Forest Lands
• Land used to harvest trees. Trees provide
paper, furniture, lumber/plywood, syrup
and turpentine
• Also important for their removal of CO2
from air
Harvesting Trees
• People use enormous amounts of wood.
• The worldwide average is 1,800 cm3 of
wood used per person each day.
• However, on average, each person in the
United states uses about 3.5 times this
amount.
Harvesting Trees
– 3 Categories of Forest land:
1. Virgin forests: forests that have never been
cut.
2. Native forests: forests that are planted and
managed.
3. Tree farms: areas where trees are planted in
rows and harvested like other crops.
2 Methods of Harvesting Trees
1. Clear-cutting is the process of removing all of
the trees from and area of land. Clear-cutting
large areas destroys wildlife habitat and causes
soil erosion.
2. Selective cutting is the process of cutting and
removing only middle-aged or mature trees. It is
more expensive than clear-cutting, but is usually
much less destructive. It is usually practiced on
smaller areas owned by individuals.
Deforestation
• Deforestation is the process of clearing
forests.
Impacts of Deforestation
• 1. When forests are cleared from hillsides,
soil erosion usually results if the area is
not quickly planted with a cover crop.
Without tree roots to hold the soil in place,
it is easily washed or blown away into the
valley below.
2. Deforestation reduces wildlife habitat
3. Reduction of the amount of carbon
dioxide taken out of atmosphere
Reforestation
• Reforestation is the reestablishment and
development of trees in a forest land.
Parks and Preserves
• In the 1870s, a group of explorers approached
Congress with news of a magnificent expanse of
land in Wyoming and Montana they believed
would be damaged by the development that had
changed the northeastern United States.
• Congress agreed to protect this land by setting it
aside for the public to use and enjoy, and the
first national park, Yellowstone, was created.
• Today, the U.S. has about 50 national parks.
Wilderness
• The U.S. Wilderness Act, passed in 1964,
designated certain lands as wilderness areas.
• Wilderness is a region that is not cultivated and
that is not inhabited by humans.
• So far, 474 regions covering 32 million acres
have been designated as wilderness in the
United States. These areas are open to hiking,
fishing, and camping. Building roads or
structures and using motorized equipment is not
allowed in wilderness areas.
Benefits of Protected Areas
• Protected areas often provide the only place
where unspoiled forests, deserts, or prairies
remain.
• Wilderness areas serve as outdoor classrooms
and research labs where people can learn more
about the natural world.
• These protected areas also provide recreation,
such as hiking and camping, for many people.
Threats to Protects Areas
1.Litter and traffic jams now plague many of our
national parks.
2. Rangelands, mining and logging sites, oil and
gas operations, power plants, and urban areas
are often close enough to affect the parks.
3. In addition, preserved areas are affected by
climate change and by air and water pollution,
as are most other parts of the world.