Human impacts on the environment

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Human impacts on the environment

• SC.912.L.17.16

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Impact of Human Activities
Deforestation is the permanent destruction of
indigenous forests and woodlands
(biosphere). Often the land is cleared for
conversion into agricultural land to feed growing
numbers of people, cattle ranching, or to obtain
firewood or building materials. Forests and
woodlands act as major carbon stores. Removing
these stores means that carbon dioxide levels in
the atmosphere will climb. Trees also help to
circulate water in the local ecosystem
(hydrosphere), removing them leads to the
possibility of a drier climate.
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Impact of Human Activities
Air pollution (atmosphere) comes from a number of
sources. These include industrial sites, home
heating, transportation vehicles, and even
outdoor burning. Human activities can release
substances into the air, some of which cause
problems for humans, plants, and animals. People
(biosphere) with health problems such as asthma,
heart, and lung disease may also suffer more when
the air is polluted.
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Impact of Human Activities
Coral reefs are stony structures built by a
symbiotic relationship between coral, an animal
(biosphere), and single-celled algae -- a plant
(biosphere). The coral houses the algae, which
use photosynthesis to make sugar that helps feed
the coral. The coral's waste products, including
nitrogen and phosphorus compounds, fertilize the
algae. Live coral polyps grow on the dead bodies
of their ancestors, allowing coral to build up to
tremendous depths if left alone. Coral reef
destruction can occur when seawater (hydrosphere)
warms up. The coral expels the algae, losing its
major source of food. The algae give the reefs
its color, so bleaching occurs.
Overfertilization is another problem.
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Impact of Human Activities
The ozone layer (located in the stratosphere) is
made up of molecules containing three oxygen
atoms (O3). Even though ozone only exists in
about 3 molecules out of every 10 million air
molecules, it plays an important role. Ozone
absorbs a portion of the ultraviolet (some UV-B
and all UV-C rays) radiation that is sent from
the sun. The UV-B light that is absorbed has
been linked to many harmful effects (such as
certain types of skin cancer, cataracts, and
harming crops and certain types of marine
life). Ozone concentrations vary naturally with
sunspots, seasons, and latitude. However, human
activities have been linked to a depletion of our
ozone shield well beyond changes due to natural
processes.
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Impact of Human Activities
Humans have released chlorofluorocarbons (CFCs),
halons, and methyl bromides into the atmosphere
causing ozone depletion by breaking up O3
molecules. CFCs have been used in many
applications, including refrigeration, air
conditioning, aerosol propellant, and cleaners
for metals and electronic components. Halons are
used to extinguish fires where large computers,
military hardware, and commercial aircraft
engines are found. Methyl bromides are used in
agricultural fumigants. The use of CFCs has been
greatly reduced thanks to international
agreements on production and consumption of
halogen-containing gases.
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Now lets watch the production of a consumer
product

• and the waste it creates

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Resources
Corn flakes require farmers to grow corn. The
growing of the corn will require the farmer to
prepare the soil and plant the seeds. As the
corn grows it will require fertilizer and lots of
water. Eventually, the corn will have to be
harvested.
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Production
Once the corn is brought into the factory, it
must be dried, baked, and turned into flakes. Of
course, additional energy must be used during
these steps to transform the corn.
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Packaging
Once the corn flakes have been prepared, they
must be packaged for the consumer to buy.
Packaging today includes an inner bag which
contains the corn flakes, and a cardboard box
(now 100 recycled paperboard).
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Transportation
Transportation occurs in two separate parts of
the corn flakes product cycle. First, the corn
must be transported from the farm area to the
cereal factory. Second, the finished corn flakes
must be transported to the local supermarkets for
sale to the public. Third, you and I transport
the corn flakes home.
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Disposal
Once we are finished eating up our box of corn
flakes, we have two parts that need to be
disposed of. The inner bag the contained the corn
flakes gets thrown out with the trash. This part
will eventually end up in the local landfill. The
outer box can be recycled. It can be separated
out from the other trash and sent to a recycling
center for processing.
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Pollution
On the farm, pollution may occur when fertilizers
are washed away. Farm equipment (during planting
and harvest) as well as the trucks that transport
the corn all contribute to air pollution. The
cereal factory itself may produce some pollution
as well as the transportation to get the corn
flakes to the supermarket. If we drive to the
supermarket, our vehicle creates some air
pollution also.
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Impact of Human Activities
Think of all the materials that go into the
building of a single automobile. Millions of
automobiles are produced each year all around the
world. Once an automobile is built it must be
transported to a dealer where you can buy
it. Eventually your new car will be an old car
that no one wants to own.
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Impact of Human Activities
Eventually your one-time new car will end up in
an automotive junk yard or salvage yard. Many
car components, including tires, may end up piled
up someplace, or even squeezed down to a rough
pile of scrap metal. More materials are being
recycled, but some may still cause pollution
problems. Old used oil and other automotive
fluids may leak into the ground, batteries may
leak, tires might catch fire and pollute the
air. A variety of hazards must be monitored for
each car left sitting in the junk yard or salvage
yard.