Environmental Science
Name __________________________________ Period __________ Date ________________
13-3, Global Warming - Notes
Objectives
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Explain why Earth’s atmosphere is like the glass in a greenhouse.
Explain why carbon dioxide in the atmosphere appears to be increasing.
Explain why many scientists think that the Earth’s climate may be becoming
increasingly warmer.
Describe what a warmer Earth might be like.
The Greenhouse Effect
• The Earth is ____________________________________________. The Earth’s
atmosphere acts like the glass in a greenhouse.
• Sunlight streams through the atmosphere and heats the Earth. ____________________
_________________________ up from Earth’s surface, some of it escapes into space.
The rest of the heat is absorbed by gases in the troposphere and warms the air.
• This process of heat absorption is called the ________________________________.
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Not ____________________________________ atmosphere absorbs heat in this way.
A greenhouse gas is a ______________________________________________ that
absorb and radiate infrared radiation from the sun.
_____________________________________________ are water vapor, carbon dioxide,
CFCs, methane, and nitrous oxide. Of these, water vapor and carbon dioxide account for
most of the absorption of that occurs in the atmosphere.
Measuring Carbon Dioxide in the Atmosphere
• In 1985, a ______________________________________________________ installed
an instrument at the top of a tall tower on the volcano Mauna Loa in Hawaii. He wanted
to precisely measure the _____________________________________________ in the
air, far away from forests and cities.
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In a forest, carbon dioxide levels rise and ______________________________________
of photosynthesis. Near cities, carbon dioxide from traffic and industrial pollution raises
the local concentration of gas.
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The winds that blow steadily over Mauna Loa __________________________________
___________________ across the Pacific Ocean, far from most forests and human
activities, swirling and mixing as they traveled.
Keeling reasoned that at Mauna Loa, the ______________________________________
levels for the entire Earth could be measured.
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Keeling’s _______________________________________, in March of 1958, was
0.0314 percent, and the levels rose slightly the next month. By summer the levels were
falling, but in the winter, _______________________________________.
During the summer, __________________________________________ carbon dioxide
for photosynthesis than they release in respiration, causing the levels to drop.
In the winter, dying grasses and fallen leaves decay and release the carbon that was stored
in them, ___________________________________________.
Rising Carbon Dioxide Levels
• After a few years of measurement, it was obvious that the levels were undergoing
________________________________________________ seasonal fluctuations.
• Each year, the _____________________________________________ of winter were
higher, and each year, the summer levels did not fall as low.
• In 42 years, carbon dioxide has gone from 314 to 386 __________________________,
and increase of 54 parts per million. This increase may be due to the burning of fossil
fuels.
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Greenhouse Gases and the Earth’s Temperature
• Many scientists think that ________________________
trap heat near the Earth’s surface, more greenhouse gases
in the atmosphere will result in an increase in global
temperature.
• A comparison of carbon dioxide in the atmosphere and
average global temperatures ______________________
_____________________________________________.
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Today, we are _________________________________
than any other greenhouse gas into the atmosphere.
Millions of tons of carbon dioxide are released into the
_____________________________________ from power
plants that burn coal or oil, and cars that burn gasoline.
Millions of trees are burned in tropical rainforest to clear
the ___________________________________.
_____________________________________ other
greenhouse gases, such as CFCs, methane, and nitrous
oxide, in significant amounts.
How Certain is Global Warming?
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Global warming is a
gradual increase in the
_______________________
___________ that is due to a
higher concentration of gases
such as carbon dioxide in the
atmosphere.
_______________________
______________________
temperature increased during
the 20th century and many
scientists predict that this
warming trend will continue throughout the 21st century.
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However, not all scientists ___________________________________________ global
warming is due to greenhouse gases.
Some scientists believe that the warming ______________________________________
variability.
They point out that widespread fluctuations in temperature have occurred throughout
____________________________________________.
Modeling Global Warming
• Scientists are currently ___________________________________________ predictions
about the rate of global warming because climatic patterns are too complex and too many
variables _____________________________________________ into account to be
solved, even using today’s fastest computers.
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Predictions about climate change are based on ________________________________
that predict how phenomena such as temperature, rainfall patterns, and sea level will be
affected.
Computer modeling is complicated by the Earth’s ______________________________
that sometimes make it necessary to use different equations under changing simulated
environments.
These feedback __________________________________________________ such as
clouds, water vapor, ice, changes in ocean chemistry, and changes in vegetation.
Computer models are __________________________________________ as more data
are available, additional factors are considered, and faster computers are built.
The Consequences of a Warmer Earth
• The impacts of global warming could include a number of potentially serious
___________________________________________.
• These problems range from the ___________________________________________
patterns and a global rise in sea level to adverse impacts on human health, agriculture,
and animal and plant populations.
• _______________________________________ environment that could not be predicted
by computer models might also arise.
Melting Ice and Rising Sea Levels
• If the global temperature increased, the ________________________________________
at the poles would decrease, causing sea levels around the world to rise.
• Coastal wetlands, and other __________________________________________ could be
flooded. People who live near coastlines _______________________________________
and sources of income.
• The salinity of bays and estuaries ________________________________, adversely
affecting marine fisheries. Also, freshwater aquifers could become too salty to be used as
sources of fresh water.
Global Weather Patterns
• If the Earth __________________________________________, the surface of the
oceans will absorb more heat, which may make hurricanes and typhoons more common.
• Some scientists are concerned that global warming will also cause a change in ocean
current patterns, __________________________________________________.
• Such a change could significantly affect the world’s weather. Severe flooding could
______________________________________________ at the same time droughts
devastate other regions.
Human Health Problems
• Greater numbers of heat related deaths could occur. __________________________ and
very old people would have the greatest risk of heat exhaustion.
• Concentrations of ground level ozone could increase as __________________________,
causing respiratory illnesses, especially in urban areas, to increase.
• Warmer temperatures might _____________________________________, which carry
diseases such as malaria and encephalitis, to greatly increase in number.
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Agriculture
• Agriculture would be _________________________________________ by global
warming if extreme weather events, such as drought, became more frequent.
• Higher temperatures could result in _______________________________________.
• As a result, the demand for irrigation could increase, which would further deplete
aquifers that _________________________________________________________.
Effects on Plants
• Climate change could alter the __________________________________________ and
could change the composition of plant communities.
• A warmer climate _______________________________________________ to colonize
northward into cooler areas.
• ________________________________________ in areas in the southern part of their
range and lose diversity.
Effects on Animals
• Global warming could cause a __________________________________________ of
some animals. For example, Northern birds ______________________________ as far
south during the winter.
• Warming of surface waters of the ocean might cause a __________________________,
tiny shrimp-like animals, that many marine animals depend on for food.
• Warming tropical waters _____________________________________________ that
nourish corals, thus destroying coral reefs.
Recent Findings
• The International Panel on Climate Change (IPCC) issued its Third Assessment Report
(TAR) in 2001 _____________________________________________ currently known
about about the global climate system and provided future estimates about the state of the
__________________________________________.
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The IPCC reported that the _______________________________________ temperature
increased by 0.6ºC during the 20th century, snow and ice cover has dropped, and the
global sea level has risen.
The IPCC also reported that ________________________________________________
have continued to increase as a result of human activities.
It has also predicted that ______________________________________________ will
continue to change the composition of the Earth’s atmosphere and continue to warm the
Earth __________________________________________________.
Reducing the Risk
• The Kyoto Protocol is an international treaty according to _______________________
_______________ that signed the treaty agree to reduce their emissions of carbon
dioxide and other gases that may contribute to global warming by the _______________.
• In March of 2001, the United States decided not to ratify the Kyoto Protocol. However,
most other developed nations are going _______________________________________.
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The need to slow global warming ________________________________________ by
the global community. Some nations and organizations have engaged in reforestation
projects to _____________________________________________________.
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However, the attempt to slow global warming is _______________________________
the economic, political, and social factors faced by different countries.
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Conflict has already arisen between ______________________________________
countries over future CO2 emissions.
_________________________________________________ projected to make up half
of all CO2 emissions by 2035.
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Questions
_____ 1. Which of the following will require most developed countries to decrease
emissions of carbon dioxide and other greenhouse gases?
a. Montreal Protocol
c. Emissions Reduction Act
b. Kyoto Protocol
d. Reforestation Project
_____ 2. Most of the warming that has been observed over the 20th century can be
attributed to
a. human activity.
c. glacial melting.
b. plant growth.
d. droughts.
_____ 3. The attempt to slow global warming is made difficult by
a .economic factors.
c. social factors.
b. political factors.
d. All of the above
_____ 4. Which of the following is not a major greenhouse gas?
a. water vapor
c. sulfur
b. carbon dioxide
d. methane
_____ 5. In an area away from forests and cities, geochemist Charles David Keeling
measured the amount of
a. ozone in the air.
c. nitrous oxide in the air.
b. oxygen in the air.
d. carbon dioxide in the air.
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