Human activities can have a major impact on the world around
us. Consider the carbon-oxygen cycle. The carbon-oxygen
cycle is the transfer of carbon and oxygen—in the form of
matter and energy—within and between organisms and their
environment. The carbon-oxygen cycle is a natural process, but
human activities can alter the natural balance of carbon-oxygen
on Earth. For example, in the atmosphere, carbon takes the
form of carbon dioxide. Too much carbon dioxide released by
human activities can harm our planet in many different ways.
Carbon dioxide (CO2) is a gas created by the reaction of carbon
and oxygen atoms. Carbon, the fourth most abundant element
on Earth, is found in every organism and in everything that once
was alive. All of the carbon atoms on the planet are continually
moving between land, air, and organisms. When plants and
animals die and decompose, the carbon stored within them is
released as carbon dioxide.
Plants help reduce carbon dioxide levels in the atmosphere
through the process of photosynthesis. In this process, plants
grow by absorbing sunlight, water from the soil, and carbon
dioxide from the atmosphere. Trees are one of the
biggest absorbers of carbon dioxide.
Human activities can speed up the carbon-oxygen cycle.
When we burn fossil fuels, for example, the carbon
stored in those fuels is quickly released. Fossil fuels are
substances such as coal and oil that formed over millions
of years from the remains of organisms. We burn these
fuels to power our cars, homes, and factories. Since 1958,
scientists have been taking regular measurements of the
amount of carbon dioxide in the atmosphere. Since that
time, carbon dioxide levels have been slowly rising.
Humans have likely played a role in this increase.
Though humans can have a negative impact on the carbonoxygen cycle, we can also change our behavior to have a positive
impact. As technology becomes more advanced, people have
developed ways to release less carbon dioxide. Let's examine
some new technologies for automobiles.
Leann Ortiz
Friday, February 10, 2012 12:53:32 PM CT
70:cd:60:8b:90:56
Have you even been inside an electric car? These cars don't burn
gasoline—instead, they're powered by electricity stored in a large
battery. Even so, electric cars still release carbon dioxide, at
least indirectly. To charge an electric car's battery, we must plug
it into a power outlet. The electricity in the outlet comes from a
power plant, and the majority of power plants generate
electricity by burning coal, oil, or natural gas.
Scientists are working to create even cleaner cars. One
possibility is a car powered by a fuel cell. Fuel-cell cars are still
being developed. They are different from both gasoline-powered
and electric cars because fuel-cell cars don't require any fossil
fuel consumption. A fuel cell is a device that converts hydrogen
gas into electricity that can then be used to power the car.
Unlike burning fossil fuels, operating a fuel cell produces no air
pollution—the only output, other than electricity, is clean water.
Cars aren't the only technology becoming cleaner. Many places
are trying to lessen their reliance on fossil fuels by developing
alternative power plants. A wind power plant uses the force
of blowing wind to generate power. Wind power plants generate
this power without releasing harmful carbon dioxide. Today, the
United States generates enough wind power to supply
electricity to almost 10 million homes. Each year,
American wind plants prevent more than 60 million
tons of carbon dioxide emissions. As more places
install wind power plants, construction and operating
costs decrease, making the technology more affordable.
Many homes and businesses also rely on solar power.
Specially designed panels capture energy from
sunlight. This energy is used to power homes and
buildings. Like wind power, solar power produces no
carbon dioxide emissions.
Undoubtedly, many of our modern activities upset the natural
balance of the carbon-oxygen cycle. However, humans can also
work to restore this balance and keep the environment healthy.
Can you brainstorm other ways to reduce the amount of carbon
dioxide in the atmosphere?
Leann Ortiz
Friday, February 10, 2012 12:53:32 PM CT
70:cd:60:8b:90:56