Earth Science 4.3 Water, Air, Land Resources Water, Air, Land
Resources
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Key Concepts Why is fresh water a vital resource? Why is the
chemical composition of the atmosphere important? What are Earths
important land resources?
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The Water Planet Water covers nearly 71% of Earths surface Most
of this water is salt water, not fresh water While salt water
oceans are important for our climate and are an important part of
our ecosystem; fresh water is what we as humans need to live. Every
day we use fresh water for drinking, cooking, bathing and growing
food Less than 1% of the water on the planet is usable fresh
water
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Freshwater Pollution Contamination of our freshwater supply is
an important issue. There are two types of water pollution Point
Source Pollution Nonpoint Source Pollution
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Point Source Pollution Point source pollution is pollution that
comes from a known and specific location
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Nonpoint Source Pollution Nonpoint source pollution does not
have a specific point of origin. Runoff, the water that flows over
the land rather than seeping into the ground, often carries
nonpoint source pollution Runoff can carry waste oil from streets,
sediment from construction sites, or pesticides from farm soils
Water filtering through piles of waste rock can carry sulfuric acid
into rivers and streams killing fish Pollutants from eating
contaminated fish can damage our bodies major organs and systems,
cause birth defects and cause certain types of cancers
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Earths Blanket of Air Earths atmosphere is a blanket of
nitrogen, oxygen, water vapor and other gases The chemical
composition of the atmosphere helps maintain life on Earth First
and foremost, people and animals need oxygen to breath The
atmosphere is also part of other cycles
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Earths Blanket of Air The carbon cycle of Earths atmosphere
makes vital nutrients available to many life forms The atmosphere
also makes life on land possible by shielding Earth from harmful
solar radiation
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Earths Blanket of Air Earths ozone layer high in the atmosphere
helps protect us from solar radiation Ozone is a three-atom form of
oxygen that protects Earth from 95% of the suns harmful ultraviolet
radiation Certain greenhouse gases in the atmosphere help maintain
a warm temperature near earths surface
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Pollution in the Air Pollution can change the chemical
composition of the atmosphere and disrupt its natural cycles and
functions Fossil-fuel combustion is the major source of air
pollution. Most of this pollution comes from motor vehicles and
coal or oil burning power plants
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Pollution in the Air Power plants release sulfur dioxide and
nitrogen oxide. These pollutants combine with water vapor to create
acid precipitation The burning of fossil fuels also produces carbon
dioxide, an important greenhouse gas.
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Pollution in the Air The amount of carbon dioxide in the
atmosphere has increased dramatically in the past 100 years with
the industrial revolution This increase has altered the carbon
cycle and contributed to global warming. Global warming could lead
to huge changes in the Earths climate such as the melting of polar
ice caps.
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Pollution in the Air Chlorofluorocarbons (CFCs) destroy ozone
in the upper atmosphere. A significant loss of ozone has resulted
in the increased risk of health problems related to too much UV
radiation exposure such as skin cancer and cataracts. Because of a
growing hole in the Earths ozone layer, we now are unable to spend
time outdoors without being conscious of the affects of sun- damage
to our skin
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Pollution in the Air Air pollution is a major public health
problem Long term health effects include asthma, bronchitis,
emphysema, and lung cancer The US EPA estimates 200,000 deaths each
year are associated with the outdoor air pollution
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Land Resources Earths land provides soil and forests, as well
as mineral and energy resources Removing and using resources from
earths crust can take a heavy environmental toll.
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Land Resources There are essentially 500,000 mines in the
United States. While mines are essential to our economy and energy
usage, mining tears up Earths surface and often destroys the
landscape. Mining also causes soil erosion, creates pollution
through runoff, and contaminates surrounding water supplies as well
as destroys entire ecosystems
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Affects of Agriculture Agriculture and farming have heavy
affects on the land as well While many dry areas are now being
farmed thanks to irrigation, this heavy pumping and water use is
depleting groundwater supplies in areas Over time, irrigation
causes salinization ( the buildup of salts). Eventually the soil
becomes useless for plant growth. With the loss of plant growth
soil deteriorates and becomes a dust bowl.