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Chapter 19 Review questions and answers
Climate Disruption
Suggested Answers to End of Chapter Questions
Review Questions
1. Core Case Study. Summarize the story of Greenland’s melting glaciers (Core Case Study) and the
possible effects of this process. Explain how it fits into the IPCC projections about climate change.
Satellite measurements and computer modeling confirm that the Greenland ice sheet has been losing
mass at an accelerating rate since the 1990s. Climate scientists hypothesize that a key factor in the
melting is atmospheric warming. The IPCC projects that global sea level will rise 18 to 59
centimeters by the end of this century. They estimate that Greenland’s ice loss will make up more
than half of the sea level rise.
2. Section 19-1. What is the key concept for this section? Explain why weather and climate are not the
same. Summarize the trends in atmospheric warming and cooling over the past 900,000 years and
during the last century. How do scientists get information about past temperatures and climates? List
five pieces of evidence that indicate that the atmosphere has been warming since 1975.
 Key concept: Considerable scientific evidence indicates that the earth’s atmosphere is warming at
a rapid rate that is likely to lead to significant climate disruption during this century.
 Weather refers to short-term changes in wind, temperature, precipitation, and barometric pressure
in a given area, while climate refers to the average weather conditions in a given area over a long
period of time.
 Over the past 900,000 years, the atmosphere has experienced prolonged periods of global cooling
and global warming. These alternating cycles of freezing and thawing are known as glacial and
interglacial (between ice ages) periods. For roughly 10,000 years, we have had the good fortune
to live in an interglacial period characterized by a fairly stable climate and a fairly steady average
global surface temperature.
 Five pieces of evidence:
 Between 1906 and 2012, the average global surface temperature has risen by about 0.
8C° (1.4F°), and over land, the average rise has been 1.4C° (2.5F°). (Land warms more
than ocean waters do because heat can stay concentrated near the land surface while
waves mix ocean water and transfer some of the heat to deeper water.) Most of this
increase has taken place since 1975 (Figure 19-3).
 The first decade in this century (2000–2009) was the warmest decade since 1881, and
2012 was the warmest year on record. Of the 12 hottest years on record, 11 have
occurred since 2000, and the twelfth was 1998.• In some parts of the world, glaciers are
melting at increasing rates (Figure 19-5).
 Floating arctic sea ice is shrinking. In 2012, it had shrunk to the smallest area ever
recorded in 34 years of satellite measurements, according to NASA scientists.
 During the 20th century, the world’s average sea level rose by 19 centimeters (7.6
inches)—an average of 1.9 cm (0.76 inches) per decade—mostly because of the
expansion of ocean water as its temperature increased and to a lesser extent by runoff
from melting land-based ice. By comparison, sea levels rose about 2 centimeters (threeInstructor's Manual: Chapter 19
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quarters of an inch) in the 18th century and 6 centimeters (2 inches) in the 19th
century.
Past temperature changes are estimated by analysis of a number of types of evidence,
including radioisotopes in rocks and fossils; tiny bubbles of ancient air found in ice cores
from glaciers; tree rings; and temperature measurements taken regularly since 1861.
3. Section 19-2. What is the key concept for this section? What is the greenhouse effect and why is it so
important to life on the earth? What are greenhouse gases and how do they affect the atmosphere?
What are three key greenhouse gases and how do they differ in atmospheric lifetimes and warming
potentials? What is the role of water vapor in the atmosphere and how does it relate to other
greenhouse gases in the warming process?
 Key concept: Scientific evidence strongly indicates that the earth’s atmosphere has been warming
at a rapid rate since 1975 and that human activities, especially the burning of fossil fuels and
deforestation, have played a major role in this warming.
 The greenhouse effect warms the earth’s lower atmosphere. About 1% of the earth’s lower
atmosphere is composed of greenhouse gases. Heat radiated into the atmosphere by the earth
causes molecules of these greenhouse gases to vibrate and release infrared radiation into the
lower atmosphere. This warms the lower atmosphere and the earth’s surface.
 Life on the earth and the world’s economies are totally dependent on the natural greenhouse
effect. Without this natural greenhouse effect, the world would be too cold to support the forms of
life we find here today.
 Greenhouse gases trap heat in the lower atmosphere.
 Three key greenhouse gases are carbon dioxide, methane, and nitrous oxide. Carbon dioxide is
added to the atmosphere primarily from burning fossil fuels. Methane is added as a result of
human activities such as raising cattle and sheep, extracting fossil fuels, creating landfills, and
flooding land to create reservoirs. Nitrous oxide accumulation is largely the result of using
nitrogen fertilizers.
 Water vapor is also a greenhouse gas. It only stays in the atmosphere about 1 to 3 weeks, so it is
less of a factor in the ongoing greenhouse effect.
4. How have human activities affected atmospheric greenhouse gas levels during the last 275 years and
especially in the last 30 years? List the major human activities that add CO2, CH4, and N2O to the
atmosphere. How do scientists use models to make projections about future temperature changes?
What do a number of climate models project about temperature changes during this century? Explain
how each of the following might contribute to projected atmospheric warming and resulting global
climate disruption: (a) a hotter sun, (b) the oceans, (c) cloud cover, and (d) air pollution.
 There is general agreement that the climate has warmed by 0.6 degrees C and that human
activities played a major role and are likely to continue to impact the climate.
 Carbon dioxide is added to the atmosphere primarily from burning fossil fuels. Methane is added
as a result of human activities such as raising cattle and sheep, extracting fossil fuels, creating
landfills, and flooding land to create reservoirs. Nitrous oxide accumulation is largely the result
of using nitrogen fertilizers.
 Mathematical models simulate interactions among the earth’s sunlight, clouds, landmasses,
oceans, ocean currents, concentrations of greenhouse gases and pollutants, and positive and
negative feedback loops.
 Climate models project that it is very likely that the earth’s mean surface temperature will
increase by 2–4.5 C (3.6–8.1 F) between 2005 and 2100, with about 3 C (5.4 F) being the most
likely rise, unless the world halts deforestation and makes drastic cuts in greenhouse gas
emissions from fossil fuel–burning power plants, factories, and cars.
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Positive feedback loops could amplify the projected changes in the average temperature of the
atmosphere shown.
A hotter sun would warm that stratosphere before warming the lower atmosphere.
Oceans absorb carbon dioxide and heat from the lower atmosphere.
Warmer temperatures increase evaporation of surface water and create more clouds. Depending
on their content and reflectivity, these additional clouds can cool or warm the atmosphere. An
increase in thick and continuous light-colored clouds at low altitudes could decrease surface
warming by reflecting more sunlight back into space. But an increase in thin and discontinuous
cirrus clouds at high altitudes could increase the warming of the lower atmosphere by preventing
more heat from escaping into space.
Aerosols (suspended microscopic droplets and solid particles) of various air pollutants can either
warm or cool the air and hinder or enhance cloud formation depending on factors such as their
size and reflectivity.
5. Section 19-3. What is the key concept for this section? What makes the current atmospheric warming
problem urgent? Define climate change tipping points and give three examples. Briefly describe the
possible effects of a warmer atmosphere on sea ice and land-based ice, permafrost, and sea levels.
Define ocean acidification and explain how and why it is occurring. Explain how atmospheric
warming, global drought, extreme weather, and an intensified water cycle are related. What are the
possible effects of climate disruption on biodiversity, food production, and human health and
economies? Pick three of these effects and describe how each can become part of a positive feedback
loop leading to increased climate disruption. Summarize the science community’s discussion of
whether or not the IPCC scientists were too conservative in their projections.
 Key concept: The projected rapid change in the atmosphere’s temperature could have severe and
long-lasting consequences, including increased drought and flooding, rising sea levels, and shifts
in the locations of croplands and wildlife habitats.
 Current atmospheric warming is an urgent problem because effects will be felt during the coming
century.
 Climate change tipping points are thresholds beyond which natural systems cannot repair
themselves. Three tipping points are:
1. Atmospheric carbon level of 450 ppm
2. Melting of all Arctic summer sea ice
3. Collapse and melting of the Greenland ice sheet
 Atmospheric warming will likely cause all forms of ice to melt, thereby increasing sea level.
 Ocean acidification is the increasing acidity of ocean waters caused by the absorption of CO2.
 Intensifying the water cycle adds water to the atmosphere, which could cause severe droughts in
some areas of the globe.
 The projected change in the earth’s climate due to global warming could cause increased drought
and flooding, decreased polar ice cover, rising sea levels, melting permafrost, shifts in ocean
currents, increased extreme weather, loss of biodiversity, and shifts in locations of agriculture and
wildlife habitats, and increases in a variety of human health problems.
 Student answers will vary.
 Considering the speed with which climate effects are taking place, some scientists think the IPCC
was too conservative in their estimates of global climate change.
6. Section 19-4. What is the key concept for this section? What are five factors that make it difficult to
deal with the problem of projected climate disruption? What are two basic approaches to dealing
with the projected harmful effects of global climate disruption? List four major prevention strategies
for reducing greenhouse gas emissions. Why do some scientists argue for focusing on reducing
greenhouse gases other than carbon dioxide? List seven strategies for trying to clean up carbon
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emissions. What is carbon capture and storage (CCS)? Describe three problems associated with
capturing and storing carbon dioxide emissions. What are geoengineering schemes (give two
examples) and what is the major problem with most of them?
 Key concept: We can reduce greenhouse gas emissions and the threat of climate disruption while
saving money and improving human health if we cut energy waste and rely more on cleaner
renewable energy resources.
 The problem of climate change is difficult to tackle because:
o The problem is global. Dealing with this threat will require unprecedented and prolonged
international cooperation.
o The effects will last a long time.
o The problem is a long-term political issue. Voters and elected officials generally respond well
to short-term problems but have difficulty acknowledging and coping with long-term threats.
o The harmful and beneficial impacts of climate change are not spread evenly. There will be
winners and losers in the event of moderate climate.
o Many proposed actions that might reduce the threat of climate change are controversial
because they would disrupt economies and lifestyles.
 The two basic approaches are adaptation and mitigation.
 Prevention strategies include cutting fossil fuel use, improving energy efficiency, and shifting to
renewable energy resources. Cleanup strategies include removing carbon dioxide from
emissions, planting trees, and sequestering carbon underground.
 Some scientists want to focus on other greenhouse gases such as methane because they also
contribute greatly to global warming.
 Strategies for cleaning up carbon emissions:
o Cut fossil fuel use
o Shift from coal to natural gas
o Sequester carbon using biochar
o Reduce deforestation
o Shift to renewable energy sources
o Remove carbon dioxide from smokestack and car emissions
o Sequester carbon in the deep oceans
 Carbon capture and storage (CCS) is the removal of some of the CO2 from smokestacks to pump
it deep underground into abandoned coal beds and oil and gas fields, or to liquefy it and inject it
into sediments under the sea floor.
 CCS problems include:
o Power plants using CCS are much more expensive to build and operate than conventional
coal-burning plants and thus would sharply raise the price of electricity for consumers.
o CCS is an unproven technology that would remove only part of the CO2 from smokestack
emissions. No plants using CCS exist, and building and testing them could take 20–30
years and huge amounts of money with no guaranteed successes.
o CCS requires large inputs of energy, which could increase CO2 emissions.
o CCS promotes the continued use of coal, which should probably be phased out. Coal is by far
the world’s dirtiest fuel to dig up and burn.
o Providing huge government subsidies and tax breaks for developing and testing CCS
technology would divert or reduce the huge subsidies and tax breaks needed for the rapid
development of solar, wind, geothermal, and other forms of renewable energy.
o With CCS no leaks are allowed. Any large-scale leaks due to earthquakes, other geological
events, or wars, as well as any number of smaller continuous leaks from storage sites
around the world, could dramatically increase global warming and the resulting climate
change in a very short time.
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Geoengineering is an attempt to manipulate certain natural conditions to help counter an
enhanced greenhouse effect. Two examples are launching sulfates into the stratosphere and
bringing nutrient rich water from the deep oceans to the surface to stimulate algal growth. The
major problems are that they require large investments of energy and materials and there is no
guarantee they will work.
7. Summarize the argument for regulating greenhouse gases as pollutants. List two ways to put a price
on carbon emissions. What are the advantages and disadvantages of using taxes on carbon emissions
or energy use to help reduce greenhouse gas emissions? What is cap and trade and what are the
advantages and disadvantages of using it to help reduce greenhouse gas emissions? What is the Kyoto
Protocol and how has it progressed? What are three ways in which governments can cooperate
internationally to deal with projected climate change?
 A pollutant is a chemical or other agent such as noise or heat in the environment that proves
harmful to the health, survival, or activities of humans or other organisms. Carbon dioxide is
considered a pollutant when it is present in high concentrations because it causes warming which
is harmful to the biosphere.
 Two ways to price emissions include taxes, and cap and trade.
 The advantages of carbon taxes are that they are simple to administer, there is a clear price on
carbon, the taxes would cover all emitters, and they would generate predictable revenues. The
disadvantages are that tax laws can be complex, the taxes could be vulnerable to loopholes, they
don’t guarantee lower emissions, and they are politically unpopular.
 Cap-and-trade means that governments would place a cap on total human-generated CO2 and
CH4 emissions in a country or region, issue permits to emit these pollutants, and then let polluters
trade their permits in the marketplace. The advantages are that there would be a clear legal limit
on emissions, they would reward cuts in emissions, there would be a Record of success, and the
expense would be low for consumers. The disadvantages are that revenues would not be
predictable, the system is vulnerable to cheating, rich polluters can keep polluting, and it puts a
variable price on carbon.
 The Kyoto Protocol is an international treaty designed to attempt to slow projected climate
change. However, they are often seen as weak, slow and ineffective responses to an urgent global
problem.
 Governments can:
o Strictly regulate carbon dioxide (CO2) and methane (CH4) as climate-changing pollutants.
o Impose carbon taxes or fees
o Place a cap on total emissions and institute cap-and-trade
o Increase subsidies to energy efficient technologies
o Fund the transfer of green technologies from more-developed to less-developed countries
o Create programs to help curb population growth
8. Give two examples of what some countries are doing on their own to deal with climate change. Give
two examples of what some companies are doing and two examples of what some colleges and
universities have done to reduce their carbon footprints. List five ways in which you can reduce your
carbon footprint.
 The first major U. S. city to establish programs to reduce greenhouse gas emissions was Portland,
Oregon. Between 1993 and 2005, the city cut its greenhouse gas emissions back to 1990 levels,
while national levels rose by 16%. The city promotes energy-efficient buildings and the use of
electricity from wind and solar sources. It has also built bicycle trails and has greatly expanded its
mass transit system. Far from hurting Portland’s economy, these strategies have produced an
economic boom and have saved the city $2 million a year on its energy bills.
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China has the most intensive energy efficiency program in the world. Chinese automobile fuelefficiency standards are higher than U.S. standards. China’s government is working with the
country’s top 1,000 industries to implement tough energy efficiency goals. China is also rapidly
becoming the world’s leader in developing and selling solar cells, solar water heaters, wind
turbines, advanced batteries, and plug-in hybrid electric cars. China may become the world leader
in developing and selling these low-carbon technologies.
In 2009, 30 U.S. states had set goals for reducing greenhouse gas emissions and more than 450
U.S. cities have established programs for doing so.
A number of major global companies, including Alcoa, DuPont, IBM, Toyota, General Electric,
and British Petroleum (BP), have set goals for seriously reducing their greenhouse gas emissions.
In 2006, DuPont slashed its energy usage and cut its greenhouse gas emissions by 72% and saved
$3 billion, while the company increased its business by almost a third. Some colleges and
universities are also taking action. Students and faculty at Oberlin College in the U.S. state of
Ohio have asked their board of trustees to reduce the college’s CO2 emissions to zero by 2020 by
buying or producing renewable energy. In the U.S. state of Pennsylvania, 25 colleges have joined
to purchase wind power and other forms of mostly carbon-free renewable energy.
You can reduce your annual emissions of CO2:
o Drive a fuel-efficient car, walk, bike, carpool, and use mass transit.
o Use energy-efficient windows.
o Use energy-efficient appliances and lights.
o Heavily insulate your house and seal all air leaks.
o Reduce garbage by recycling and reusing more items.
o Insulate your hot water heater.
o Use compact fluorescent light bulbs.
o Plant trees to shade your house during summer.
o Set your water heater no higher than 49°C (120°F).
o Wash laundry in warm or cold water.
o Use a low-flow showerhead.
o Buy products from, or invest in, companies that are trying to reduce their impact on climate.
9. Section 19-5. What is the key concept for this section? List five ways in which we can prepare for the
possible long-term harmful effects of climate disruption. Describe the no-regrets strategy for dealing
with the problems associated with energy waste and fossil fuel use, regardless of climate change.
 Key concept: While we can prepare for some climate change that is now inevitable, we could
realize important economic, ecological, and health benefits by drastically reducing greenhouse
gas emissions with the goal of slowing projected climate disruption.
 Ways to prepare for the possible long-term harmful effects of climate change include:
o Developing crops that need less water
o Wasting less water
o Moving people away from low-lying coastal areas
o Stockpiling a one- to five-year supply of key foods
o Moving hazardous material storage tanks away from coast
 The no-regrets strategy is based on the idea that efforts to deal with climate disruption lead to
other very important environmental, health, and economic benefits.
10. What are this chapter’s three big ideas? Describe how we can apply the six principles of
sustainability to the problem of projected climate disruption.
 The three big ideas are
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Considerable scientific evidence indicates that the earth’s atmosphere is warming, mostly
because of human activities, and that this is likely to lead to significant climate disruption
during this century that could have severe and long-lasting harmful consequences.
o Reducing the projected harmful effects of rapid climate disruption during this century
requires emergency action to increase energy efficiency, sharply reduce greenhouse gas
emissions, rely more on renewable energy resources, and slow population growth.
o We need to continue phasing out the use of chemicals that have reduced ozone levels in
the stratosphere and allowed more harmful ultraviolet radiation to reach the earth’s
surface.
The scientific principles of sustainability can be applied to help reduce the harmful effects of air
pollution, projected climate change, and stratospheric ozone depletion. We can reduce inputs of
air pollutants, greenhouse gases, and ozone-depleting chemicals into the atmosphere by relying
more on direct and indirect forms of solar energy than on fossil fuels; reducing the waste of
matter and energy resources and recycling and reusing matter resources; and mimicking
biodiversity by using a variety of carbon-free renewable energy resources, especially those that
are available regionally and locally. We can enhance these strategies by finding substitutes for
ozone-depleting chemicals, emphasizing pollution prevention, and reducing human population
growth.
o
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