Download Ch 18 Global Climate Change

CHAPTER 18
Global Climate
Change
© 2011 Pearson Education, Inc.
An introduction to global climate
change
• On August 29, 2005, Hurricane Katrina landed east of
New Orleans
• The costliest ($134 billion in damage) storm ever
• The deadliest storm (killing 1,800) since 1928
• Leaving mountains of debris, ruined homes and lives
• A month later, Hurricane Rita hit Louisiana and Texas
• 2005 had a record 27 named storms
• 2007 had 15 and 2008 had 18 named storms
• There is a link between hurricanes and global warming
• Warmer oceans create humid air, leading to hurricanes
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Number of category 4 and 5 hurricanes
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The atmosphere
• Atmosphere: a collection of gases held by gravity
around the Earth
• Troposphere: the lowest level
• Gases moderate the flow of energy to Earth
• Gases are involved with biogeochemical cycling of
elements
• Ranges from 5 to 10 miles thick
• Contains almost all the water vapor and clouds
• Gets colder with altitude
• Mixed air allows pollutants to reach the top of the
layer
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Other atmospheric layers
• Tropopause: caps the troposphere
• Air shifts from cooling with height and begins to warm
• Stratosphere: temperature increases with altitude
• To 40 miles above Earth’s surface
• Ozone (O3) absorbs the Sun’s high-energy radiation
• Due to little mixing and no precipitation, substances
remain for long periods of time
• Mesosphere and thermosphere: declining ozone
levels
• Only small amounts of oxygen and nitrogen
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Structure and temperature of the
atmosphere
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Weather
• Weather: day-to-day variations in temperature, air
pressure, wind, humidity, precipitation
• Climate: the result of long-term regional weather
patterns
• Meteorology: the study of the atmosphere (weather and
climate)
• The atmosphere-ocean-land system is a huge weather
engine
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Driven by the Sun and affected by Earth’s rotation and tilt
Solar energy is reflected (29%) or absorbed by Earth
Absorbed energy heats the ocean, land, and atmosphere
Evaporation, convection, and reradiation of infrared energy
release energy
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Solar-energy balance
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Flowing air
• Some energy released from Earth goes to the
atmosphere
• Warmer air expands and rises, creating vertical air
currents
• Convection currents: large-scale vertical air
movement
• Horizontal air currents (wind) result from sinking cool
air replacing rising warm air
• Hadley cell: combination of rising warm air and
sinking cool air
• Creates regions of high rainfall (equator), deserts, and
trade winds (horizontal winds)
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Convection
• Convection currents: bring day-to-day weather
changes
• They move from west to east
• Solar-heated rising air creates atmospheric high
pressure
• Leaving behind lower pressure closer to Earth
• Moist high-pressure air cools (through reradiation
and condensation)
• Flowing horizontally to sinking cool, dry air regions of
lower pressure
• The air is warmed and creates a region of higher
pressure
• Differences in air pressure lead to airflows (winds)
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A convection cell
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Jet streams
• Larger-scale air movements of Hadley cells are
influenced by Earth’s rotation from west to east
• Creating trade winds over oceans and the west-toeast flow of weather
• Jet streams: rivers of air created higher in the
troposphere from Earth’s rotation and air-pressure
gradients
• Move faster than 300 mph
• Meander considerably
• Can steer major air masses in the lower troposphere
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Put together …
• Fronts: boundaries where air masses of different
temperatures and pressures meet
• Regions of rapid weather change
• Other movements of air masses due to different
pressures and temperatures: hurricanes, typhoons,
tornadoes
• Monsoons: major seasonal airflows
• A reversal of previous wind patterns
• Created by major differences in cooling and heating
between oceans and continents
• India’s summer monsoons bring rains and floods
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Climate is …
• Climate: the general patterns of weather that
characterize different regions of the world
• Climate results from all the combined elements of
• General atmospheric circulation patterns and
precipitation
• Wind and weather systems
• Rotation and tilt of Earth, which creates seasons
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Climate change science
• Biomes: reflect plant, animal, and microbe
adaptations to the prevailing weather patterns
(climate) of a region
• Humans can adjust to almost any climate
• But other organisms can’t
• A major change in the climate represents a serious
threat to the structure and function of existing
ecosystems
• Because humans depend on ecosystems for vital
goods and services, we need functioning
ecosystems
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Synopsis of global climate change
• In 2007, scientists from the Intergovernmental Panel
on Climate Change (IPCC) sifted through thousands
of studies and published the Fourth Assessment
Report (AR4)
• The report concluded that warming of the climate is
unequivocal
• The atmosphere and oceans are warmer
• Sea levels are rising and glaciers are melting
• There are more extreme weather events
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Annual mean global surface
temperature anomalies
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The IPCC’s report
• The report concluded that it is very likely (90%
probability) that warming is caused by human factors
• Increased greenhouse gases (GHGs) trap infrared
radiation
• GHGs come from burning fossil fuels
• Along with deforestation
• The major GHG: CO2
• Responses to climate change
• Mitigation: reducing GHG emissions
• Adaptation: adjusting to climate change
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Atmospheric carbon dioxide
concentrations
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IPCC
• Founded in 1988 by the UN Environmental Program and
the World Meteorological Society to provide accurate
and relevant information leading to understanding
human-induced climate change
• Working Group I: assesses scientific issues of climate
change
• Working Group II: evaluates impacts and adaptation to it
• Working Group III: investigates ways to mitigate its
effects
• The AR4 report had over 2,000 experts from 154
countries
• Risk assessment: is the climate changing?
• Risk management: how do we adapt and mitigate
effects?
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Third assessment
• The IPCC’s 2001 report showed
• Increasing information shows a warming world
• Humans are changing the atmosphere, which will
affect climate
• We have increased confidence in models of future
climate change
• Stronger evidence that most recent warming is
human-caused
• Human influences will continue to change the
atmosphere
• Temperature and sea levels are rising
• We need more information and understanding
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A Nobel Effort
• AR4 produced Climate Change 2007: Synthesis
Report
• Contained key findings of the working groups
• The 2007 Nobel Peace Prize went to the IPCC and
former Vice President Al Gore: the leading advocate
of the need to take action on climate change
• For their efforts to disseminate knowledge about manmade climate change and to lay groundwork to
counter it
• Gore also was awarded the Academy Award for his
film An Inconvenient Truth
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Climates in the past
• It is harder to find evidence of climate change the
further into the past we search
• Records of temperature, precipitation, storms have
been kept for only 100 years
• Since 1880, especially since 1976, our climate
warmed
• Proxies: records providing information on climate
• Using temperature, ice cover, precipitation, tree rings,
pollen, landscapes, marine sediments, corals, etc.
• Earth warmed from 1100 to 1300 A.D.
• Little Ice Age: 1400–1850
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Ice cores
• Analyzing ice cores from Greenland and the Antarctic
shows global climate can change within decades
• Uses CO2 and CH4 (methane) and isotopes of O and H
• Climate oscillates between ice ages and warm
periods
• Ice ages tie up water in glaciers, lowering sea levels
• 8 glacial periods occurred over the past 800,000 years
• Ice ages have lower GHGs and temperatures
• CO2 levels ranged between 150 and 280 ppm
• Milanovitch cycles: climate oscillations due to Earth’s
orbit
• Periodic intervals of 100,000, 41,000, and 23,000 years
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Past climates, as determined from ice
cores
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Rapid changes
• Rapid climatic fluctuations are superimposed on the
major oscillations during glaciation and warmer
times
• The Younger Dryas event: 11,700 years ago
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Dryas: a genus of arctic flower
Arctic temperatures rose 7ºC in 50 years
Caused enormous impact on living systems
Warming was not caused by changing solar output
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Climate fluctuations
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Oceans and climate
• Oceans play a dominant role in determining climate
• They are a major source of water and heat
• Evaporation: supplies water vapor to the atmosphere
• Condensation: supplies heat to the atmosphere
• Heat capacity: oceans absorb energy with heated
water
• Oceans convey heat through currents
• Thermohaline circulation pattern: the effects of
temperature and salinity on the density of seawater
• This giant, complex conveyor belt moves water from
the surface to deep oceans and back
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Thermohaline circulation
• High-latitude North Atlantic ocean flows from the
Gulf Stream north on the surface and is cooled by
Arctic air
• North Atlantic Deep Water (NADW): the cool water
increases in density, so it sinks (up to 4,000 m)
• The current spreads to Africa’s southern tip
• It is joined by cold Antarctic waters
• The two streams spread north into the Indian and
Pacific Oceans as deep currents
• The currents slow and warm and rise to the surface
• Move back to the North Atlantic
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The oceanic conveyor system
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Thermohaline circulation affects
climate
• The movement of warm water toward the North
Atlantic transfers enormous amounts of heat toward
Europe, providing a much warmer than expected
climate
• The circulation pattern cycles over 1,000 years
• It is vital to maintaining current climate conditions
• In the past, the conveyor system has been interrupted
• Abruptly changing the climate
• Large amounts of fresh water lower water’s density
• Preventing the sinking of surface waters
• Slowing the northern movement of warmer, saltier
water
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Heinrich events
• Heinrich events: fresh water from melting icebergs
from the polar ice cap dilutes salt water
• Six times in the past 75,000 years
• Diluted water doesn’t sink
• The conveyor system is shifted southward to
Bermuda (instead of Greenland)
• The climate cools in a few decades
• Return of the normal pattern abruptly warms the
climate
• The Younger Dryas event involved dammed-up water
from glacial Lake Agassiz entering the St. Lawrence
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What if …?
• Extended global warming will
• Increase precipitation over the North Atlantic
• Melt sea ice and ice caps
• The conveyor will decrease over the 21st century
• The Achilles’ heel of our climate system: weakening
of the conveyor and a changed climate
• Especially in the northern latitudes
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Ocean-atmosphere oscillations
• These processes produce globally erratic climates
• The North Atlantic Oscillation (NAO): atmospheric
pressure centers switch back and forth across the
Atlantic
• Switching wind and storms
• El Niño/La Niña Southern Oscillation (ENSO): shifts
in atmospheric pressure over central equatorial
Pacific Ocean
• Dominates global climate for over a year at a time
• 1997–2000 ENSO cost $36 billion and killed
thousands
• Interdecadal Pacific Oscillation (IPO): a warm-cool
cycle that swings over the Pacific over several
decades
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More ocean-atmosphere oscillations
• Understanding these processes helps clarify some
puzzling developments
• A global warming trend was stopped in the mid-1940s
• But resumed 30 years later
• This mid-century cooling resulted from shifting ocean
circulation linked to the NAO
• Ocean-atmosphere oscillations can offset global
warming
• But greenhouse warming will overcome them and
intensify by the end of this decade
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The Earth as a greenhouse
• Factors that influence climate
• Internal components: oceans, atmosphere, snow, ice
• External factors: solar radiation, Earth’s rotation and
orbit, gaseous makeup of the atmosphere
• Radiative forcing: the influence of any factor on the
energy balance of the atmosphere-ocean-land
system
• Positive (negative) forcing: leads to warming (cooling)
• Forcing is measured in Watts/m2
• Solar radiation entering the atmosphere = 340 W/m2
• Radiation is acted on by forcing factors
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Warming processes
• Greenhouse gases (GHGs): water vapor, CO2, other
gases
• Light energy goes through the atmosphere to Earth
• Earth absorbs and converts energy to heat
• Infrared heat energy radiates back to space
• GHGs (but not N2 and O2) in the troposphere absorb
some infrared radiation
• Direct it back to Earth’s surface
• The greenhouse effect was first recognized in 1827
• It is now firmly established
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GHGs insulate Earth
• GHGs delay the loss of infrared heat (energy)
• Without insulation, Earth would be -19°C instead of
+14°C
• Life would be impossible
• Earth’s global climate depends on the concentration
of GHGs
• Changing amounts of GHGs change positive forcing
agents, which would change the climate
• Tropospheric ozone has a positive forcing effect
• Varying with time and location
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The greenhouse effect
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Cooling processes
• Planetary albedo: sunlight reflected by clouds
• Contributes to overall cooling by preventing warming
• Low-flying clouds have a negative forcing effect
• High-flying, wispy clouds have a positive forcing
effect
• Absorb solar radiation and emit infrared radiation
• Snow and ice contribute to albedo by reflecting
sunlight
• Black carbon soot darkens snow and ice
• Dark snow/ice absorbs radiant energy instead of
reflecting it
• Reduces albedo
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Volcanoes and aerosols
• Volcanic activity can lead to planetary cooling
• Reflects radiation from particles and aerosols
• Aerosols: microscopic liquid or solid particles from
land or water
• Industrial aerosols (pollution) cancel some GHG
warming
• Sulfates, nitrates, dust, soot from industry and forest
fires
• Sooty aerosols (from fires): warming effect
• Sulfate aerosols create cooling through more clouds
• Reduced pollution in the U.S. and Europe decreased
aerosols
• China’s and India’s pollution has increased aerosols
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Global warming and cooling
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Solar variability
• Variation in the Sun’s radiation influences the climate
• Changes in solar radiation occur on 11-year cycles
• Solar radiation increases during high sunspot activity
• Sunspots block cosmic ray intensity
• Reduce cloud cover and increase solar radiation
• Solar output declined in 1985 and continued for 20
years
• But global temperatures rose rapidly
• The IPCC AR4 concluded that GHGs were 13 times
more responsible for warming temperatures than
solar changes
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Thus …
• Global atmospheric temperatures are a balance
between positive and negative forcing from natural
causes (volcanoes, clouds, natural GHGs, solar
irradiance) and forcing from anthropogenic causes
(sulfate aerosols, soot, ozone, increased GHGs)
• Forcing agents result in climate fluctuations
• It is hard to say any one event or extreme season is
due to humans
• But climate has shifted enough to generate
international attention
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Evidence of climate change
• Weather varies naturally year to year
• Local temperatures may not follow global averages
• But the 10 warmest years on record were 1997–2008
• 2005 set a record high—the warmest since the late
1800s
• The average global temperature has risen 0.6°C since
the mid-1970s (0.2°C/decade)
• Warming is happening everywhere
• Most rapidly at high latitudes of the Northern
Hemisphere
• The warming is a consequence of an “enhanced
greenhouse effect”
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Satellites
• Measurements of tropospheric temperatures by 13
satellites over 20 years did not show temperature
increases
• Skeptics made much of this discrepancy
• The Climate Change Science Program (CCSP)
• Created in 2002 to address unresolved questions
about climate change
• Its 2006 report stated that errors caused the
discrepancy
• Corrected and new data agree that surface and
tropospheric temperatures are rising
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Ocean warming
• Recently, the upper 3,000 meters of the ocean have
warmed
• Dwarfing warming of the atmosphere
• 90% of the heat increase of Earth’s systems
• Over the last decade, oceans have absorbed most
of the non-atmospheric heat
• A long-term consequence: the impact of this stored
heat as it comes into equilibrium with the
atmosphere
• It will increase atmospheric and land heat even more
• A short-term consequence: unprecedented rising
sea levels
• Thermal expansion and melting glaciers and ice caps
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Heat capture by the oceans
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The rise in global mean sea level
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Other observed changes by the IPCC
AR4
• Changes are consistent with GHG-caused climate
change
• Increased warm temperature extremes
• Decreased cold temperature extremes
• Spring comes earlier, fall later, in the Northern
Hemisphere
• Ecosystems are out of sync
• Tree deaths and insect damage
• Heat waves are increasing in intensity and frequency
• Droughts are increasing in intensity and frequency
• 60% of the U.S. is in a drought that started in the
1990s
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More changes reported by the IPCC
• Rising Arctic temperatures have caused major
shrinkage of Arctic sea ice (11.7% in 10 years)
• Alaska, Siberia, Canada have warmed 5°F in
summer, 10°F in winter
• Spring comes 2 weeks earlier than 10 years ago
• The polar ice cap has lost 20% of its volume in 20
years
• Permafrost is melting
• Unprecedented melting of the Greenland Ice Sheet
can raise ocean levels 23 feet
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Decline of Arctic sea ice
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Other changes reported by the IPCC
• Antarctica temperatures have risen 0.5°–0.85°C
• The West Antarctic Ice Sheet (WAIS) is shrinking and
can raise sea levels by 16–20 feet
• Accelerating glacier melting since 1990
• Changing patterns of precipitation and flooding
• Greater amounts from 30° N and S poleward
• More intense and frequent tropical hurricanes
• Marine fish populations have shifted northward
• Ocean acidification: decreased pH due to CO2
absorption
• The surface ocean’s chemistry is actually changing
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Shrinkage of the Muir glacier
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Rising greenhouse gases
• The IPCC AR4 report states that global GHG
emissions from humans have grown 70% between
1970 and 2004
• The most important GHG is carbon dioxide (CO2)
• Carbon dioxide:
• Over 100 years ago, Swedish scientist Arrhenius
suggested that burning fossil fuels may increase CO2
• But he was not concerned about the impacts
• Carbon dioxide monitoring: CO2 levels have been
monitored on Mauna Loa, Hawaii since 1958
• Atmospheric CO2 levels have increased 1.5–2 ppm/yr
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Carbon dioxide levels
• CO2 levels oscillate 5–7 ppm, reflecting seasonal
changes in photosynthesis and respiration
• Fall through spring: respiration increases CO2 levels
• Spring through fall: photosynthesis decreases CO2
• By 2009, atmospheric CO2 levels = 338 ppm
• 39% higher than before the Industrial Revolution
• Higher than in the past 800,000 years
• Fossil fuels increase CO2 levels
• 1 kg of fossil fuel burned releases 3 kg CO2
• Eight billion tons (gigatons, Gt) of fossil fuel
carbon/year
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Global carbon emissions from fossil
fuels
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Sources of carbon dioxide
• Half of fossil fuel carbon comes from industrialized
nations
• Burning forests adds 1.6 Gtc/year
• Over the past 50 years, release of carbon has tripled
• Half of the carbon is removed by sinks
• Sinks: burning fossil fuels should add 8 GtC/year to
the air
• But only 3.3 GtC/year are actually added
• Carbon sinks (the ocean, biota) absorb CO2
• Oceans take up CO2 by phytoplankton or
undersaturation
• But there are limitations to uptake
• Forests are valuable for their ability to sequester
carbon
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Sources of carbon dioxide emissions
from fossil fuels
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Global carbon cycle
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Other gases
• Other gases absorb infrared radiation
• Adding to the insulating effect of carbon dioxide
• Most are anthropogenic sources and are increasing
• Water vapor: the most abundant GHG
• Its tropospheric concentration varies, but is rising
• Higher temperatures increase evaporation and water
vapor (humidity)
• Higher humidity traps more heat, causing more
warming (positive feedback)
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Other GHGs
• Methane: 20 times more effective than CO2 in
heating
• From microbial fermentation (in wetlands), green plants
• Two-thirds of emissions are from human sources:
livestock, landfills, coal mines, natural gas, rice cultivation,
manure
• Rising at 0.8 ppb/year, it is more abundant than in the past
800,000 years
• Nitrous oxide: has increased 18% over the last 200
years
• From agriculture, oceans, biomass burning, fossil fuel
burning, industry, anaerobic denitrification (fertilizers)
• Warms the troposphere and destroys stratospheric ozone
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Ozone and CFCs
• Ozone: a short-lived but potent GHG in the
troposphere
• From sunlight acting on pollutants
• Has increased 36% since 1750
• From traffic, forest fires, agricultural wastes
• CFC and other halocarbons are entirely
anthropogenic
• Long-lived GHGs causing warming and ozone
destruction
• From refrigerants, solvents, fire retardants
• They absorb 10,000 times more infrared energy than
CO2
• Levels are slowly declining but will remain for decades
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Radiative forcing
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Future changes in climate
• Happening now: higher temperatures, rising seas,
heat waves, droughts, intense storms, season shifts,
melting ice
• GHG levels are rising
• Along with fossil fuel demand and population
• Emissions will rise 35% (2030) and 100% (2050)
• Modeling global climate: computing power has
increased
• Can explore the potential future impacts of rising
GHGs
• Atmospheric-ocean general circulation models
(AOGCMs)
• Simulate long-term climatic conditions
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Modeled vs. actual data on temperature
anomalies (1900–2000)
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Testing AOGCMs
• The best test: how well they simulate present-day
climate
• The most recent models have unprecedented realism
• Assumptions about GHG emissions are combined
with climate responses to GHGs (climate sensitivity)
• Every scenario showed increased CO2 and
temperature
• Future temperature increases will be due to released
energy from the oceans (0.1°C/decade)
• The AR4 report and the models show that increasing
GHGs will increase temperatures
• Leading to regional climate changes and rising sea
levels
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Model projections of global mean
warming
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Significant findings of climate models
• Equilibrium climate sensitivity: if atmospheric CO2
stays at 550 ppm (double preindustrial values),
temperature will rise 3°C (2°–4.5°C) by 2050
• Warming will be due to GHG emissions
(0.2°C/decade)
• Higher latitudes and continental interiors will warm
most
• But it will be warmer everywhere
• Snow cover and sea ice will decrease, opening up the
Arctic Ocean by 2100
• Shrinking glaciers and ice caps will increase sea levels
• 90% of upper permafrost will thaw
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More findings
• Warmer, dilute upper layers of the North Atlantic
Ocean will lead to decreased (but not collapsed)
thermohaline circulation
• Increased storm intensities, higher wind speeds and
waves, more intense precipitation
• More frequent, longer-lasting heat waves
• Longer growing seasons, shorter frost days
• Dry areas will get dryer, wet areas will get wetter
• Extreme droughts will affect up to 30% of the world
• Ecosystems (polar ecosystems, coral reefs,
rainforests) will be profoundly affected, increasing
species extinctions
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Global warming impacts on biological
systems
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The “business as usual” approach
• Predicts 3–5°C temperature increase
• 5°C: difference between an ice age and warm period
• Earth’s climate will change dramatically if nothing is
done
• Responding will involve unprecedented and costly
adjustments
• The agricultural community does not know what to
expect
• Farmers already lose one in five crops due to weather
• How far will sea levels rise?
• 0.5 m: people will abandon flooded coastal areas
• 1 m: tens of millions of refugees, lost rice lands,
obliterated low islands
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What about the Antarctic?
• The Antarctic could be a huge factor in rising sea
levels
• The WAIS is shrinking
• Greenland and Antarctic ice sheets hold enough
water to raise sea levels 230 feet
• Snowfall has not changed in the past 50 years
• 87% of the 244 glaciers are melting
• The melting ice sheet is raising sea levels 0.4
mm/year
• Higher continental temperatures (3°C)
• Models project a 5% snowfall increase for each 1°C
temperature rise
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Climate change in the U.S.
• The 2002 Global Change Research Program
(GCRP)
• Integrates efforts of federal agencies to understand
climate change
• Communicates scientific findings to policy makers and
the public
• These reports are well done
• Global Climate Change Impacts in the United States
• Is designated the United Synthesis Product (USP)
• Looks at impacts of climate change on sectors
(health, etc.) and regions (Northwest, Alaska, etc.)
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Climate change in the U.S.
• All impacts are expected to continue and/or increase
• Impacts are greater in Alaska than any other U.S.
region
• Changes in the U.S. over the past 50–100 years
include
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Average temperature has risen 2°F
Wetter areas are wetter, dryer areas are dryer
Heavy downpours and storms have increased
More extreme and frequent weather events
Stronger Atlantic hurricanes
Sea levels have risen 2–5 inches
Arctic sea ice is declining rapidly
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Climate on the move in the Midwest
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Response to climate change
• Industries and transportation network are locked into
using fossil fuels
• Massive emissions of GHGs will continue
• Adaptation: anticipate harm and plan adaptive
responses to decrease vulnerability of people,
property, and the biosphere
• Mitigation: take action to prevent emissions
• Skeptics about global warming exist
• Fossil fuel industry, Rush Limbaugh, conservative
think tanks, some scientists
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Stages of climate change skeptics
• Stage I: you’re wrong about climate change and we
can prove it
• But there are no other plausible arguments for climate
change
• Stage II: OK, the climate is changing, but it isn’t
changing that much
• The threat is overplayed
• Why take costly steps to prevent it?
• Stage III: it will do damage, but it’s too late or too
costly to do anything about it
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Skeptics and ethical principles
• Climate change skeptics are on talk radio, on the
Internet, in Congress, in the media
• Unfounded skepticism is regrettable, dangerous, and
unethical
• Precautionary principle: the 1992 Rio Declaration
states that lack of scientific certainty should not
prevent action
• Polluter pays principle: polluters should pay for the
damage they cause
• Equity principle: the rich and privileged should care
about the poor
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Mitigation
• It will be costly to mitigate and adapt to climate
change
• But inaction will be far more costly
• Every country will be affected, but especially the
poorest
• Hundreds of millions of climate refugees
• Radicalized people will turn to conflict and terrorism
• The Natural Resources Defense Council estimates
inaction will cost the U.S. 3.6% of GDP ($3.8 trillion)
• Worldwide costs will equal 5%–20% of GDP/year
• We must reduce emissions of GHGs
• What should we target?
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Achieving stabilization
• The Framework Convention on Climate Change
(FCCC)
• We must stabilize GHG levels on a time scale that
prevents interfering with climate
• 3°C rise: rising sea levels of 80 feet
• 2°C rise: irreversible melting of the Greenland Ice
Sheet
• We have a target of 1–1.5°C more warming
• CO2 = 400–500 ppm
• Al Gore’s inconvenient truth: carbon emissions must
fall from 8 GtC/year to 2 GtC/year
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CO2 emissions and temperature
increases for a range of stabilization
levels
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What has been done?
• The Framework Convention on Climate Change
(FCCC) agreed to stabilize GHG emissions to 1990
levels by 2000 in all industrialized nations
• This voluntary approach failed
• All developed countries (except the EU) increased
GHG emissions by 7%–9%
• Developing countries increased theirs by 25%!
• Kyoto Protocol: the third Conference of Parties to the
FCCC met in 1997 in Japan to craft a binding
agreement on reducing emissions
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The Kyoto Protocol
• 38 industrial nations agreed to reduce GHG
emissions 5% below 1990 levels
• Annex I parties: signatories to this agreement
• Non-Annex I parties: developing countries
• Developing nations refused any reductions
• They said they have the right to develop using fossil
fuels, just as developed nations had
• FCC principle of “common but different
responsibilities”
• Each nation must address climate change
• But its priorities and efforts could differ
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Ratifying the Kyoto Protocol
• At least 55 nations must ratify it; 180 parties have
• The U.S. is the only Annex I party that has not
• Signers of the protocol have flexibility in how they
will achieve their GHG reductions
• Renewable fuels, nuclear, conservation, planting trees
• Emissions trading, helping other nations
• There are penalties for failing to meet commitments
• Many Annex I countries are on target
• But not the U.S., Australia, Canada, Japan
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Weaknesses of the Kyoto Protocol
• The protocol’s targeted reductions will not stabilize
GHGs
• It would take immediate reductions of 60% globally
• There is no chance of this happening, so emissions will
continue to rise
• The world’s largest GHG emitters are not participating
• India, China, the U.S.
• A 2007 UN-sponsored climate conference occurred in
Bali
• The U.S. and some developing countries opposed
emission cuts and targets
• Negotiations on emissions occurred in Copenhagen
(2009)
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U.S. policy: the Bush years
• President G. W. Bush opposed the Kyoto Protocol
• It exempts developing countries
• It would seriously harm the U.S. economy
• There was incomplete scientific knowledge
• The U.S. formally withdrew from the Kyoto
agreement
• Global Climate Change Initiative (GCCI)
• Reduces emissions intensity: the ratio of emissions to
economic output (GDP)
• GHG emissions actually rose 17%
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U.S. greenhouse gas emissions,
1990–2007
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Other Bush actions on climate change
• Climate Change Science Program (CCSP/GCRP)
• $37 billion since 2001 to research climate change
• But Bush’s administration hampered science and
policy
• The EPA did not act on a Supreme Court decision
ordering it to consider GHG pollution as a threat
• It stifled communications from climate scientists
• It heavily edited reports from federal agencies to
emphasize uncertainties
• In 2008, Bush called for limiting GHGs by 2025
• Allowing emissions to rise 10% more
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A sea change
• The Democratically controlled 110th and 111th
Congress addressed climate change issues
• The House Select Committee on Energy
Independence and Global Warming
• Research, cap-and-trade, emissions taxes
• President Obama has made climate change a
priority
• Appointed climate scientists to key positions
• Nobel Prize-winning physicist Steven Chu heads the
Department of Energy
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States and corporations
• Many states are acting to address climate change
• Renewable portfolio standards, emission reporting
• Cap-and-trade programs, reducing emissions
• Regional, state, local initiatives will pressure the
federal government to act
• The U.S. Climate Action Partnership: corporations
are joining environmental groups urging Congress to
act
• Cap-and-trade programs: government sets GHG
limits
• A company emitting less can sell its unused permits
• Already used in the EU and by Annex I parties
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Mitigation tools
• Reducing GHG emissions (several are already in place)
• Cap-and-trade, renewable energy, carbon capture and
storage, nuclear, reforestation, efficiency
• Mileage standards, subsidies, carbon tax
• Stabilization triangle: carbon savings by reducing
GHGs
• It is broken into seven wedges (mitigation strategies)
• Each wedge reduces 1 billion tons of carbon emissions
• 15 wedge strategies in four categories: efficiency/
conservation, fossil fuels, nuclear, renewables
• Only seven are needed to bring about the desired
future
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Stabilization wedges
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Adaptation
• Adaptation: making adjustments in anticipation of
changes caused by rising sea levels and
temperatures
• Reducing vulnerability to impacts
• Hard to anticipate what to do and is not cost free
• Examples of adaptation strategies
• Agriculture: climate-resistant crops, irrigation
• Structures: seawalls, reservoirs, revegetation of
coasts
• Emergency preparedness: early-warning systems
• Reducing risks: financial safety nets, proper insurance
• Development, controlling diseases, economic
progress
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New funds
• Climate change will impact developing nations the
most
• The FCCC established funding sources to help
developing countries
• Least Developed Countries Fund: advises countries
on national adaptation strategies
• Special Climate Change Fund: provides financial
assistance to countries affected by climate change
• Adaptation Fund
• Climate Investment Funds: sponsored by the World
Bank
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Poverty and climate change
• Poverty and Climate Change: Reducing the
Vulnerability of the Poor through Adaptation—a
World Bank report
• The poor will suffer disproportionately
• Climate changes will be superimposed on other
problems
• Water, food security, health, life in coastal areas
• Countries with the fewest resources will bear the
greatest burden
• Ecosystem goods and services will be disrupted
• 96% of disaster-related deaths occur in developing
nations
• Adaptation must also reduce poverty and achieve
MDGs
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Strategies
• Adaptation strategies will vary with different
circumstances
• The best way to address impacts on the poor:
integrating adaptation into development and poverty
reduction strategies
• Adaptations have “no regrets” benefits
• These measures foster desirable social benefits,
regardless of whether climate change is occurring
• Improved governance, assessing vulnerability,
accurate information, including economic processes
• Many adaptation strategies are common to all
countries
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Geoengineering
• Futuristic schemes to fight climate change may not
work
• Fertilizing oceans with iron to stimulate
photosynthesis
• Scrubbers to remove and store CO2
• Sulfate particles or satellites to block solar radiation
• These schemes have huge costs and unintended
consequences
• We are conducting an enormous global experiment
in geoengineering
• Our children and their descendants will have to live
with the consequences
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CHAPTER 18
Global Climate
Change
Active Lecture Questions
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Review Question-1
The layer of the atmosphere that is closest to the
Earth’s surface is the
a. troposphere.
b. stratosphere.
c. mesosphere.
d. thermosphere.
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Review Question-1 Answer
The layer of the atmosphere that is closest to the
Earth’s surface is the
a. troposphere.
b. stratosphere.
c. mesosphere.
d. thermosphere.
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Review Question-2
The Nobel Committee awarded the 2007 Nobel Peace
Prize to the IPCC and to
a.
b.
c.
d.
President Bill Clinton.
President Jimmy Carter.
Vice President Al Gore.
Vice President Dick Cheney.
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Review Question-2 Answer
The Nobel Committee awarded the 2007 Nobel Peace
Prize to the IPCC and to
a.
b.
c.
d.
President Bill Clinton.
President Jimmy Carter.
Vice President Al Gore.
Vice President Dick Cheney.
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Review Question-3
______ is the influence any particular factor has on the
energy balance of the atmosphere-ocean-land system.
a.
b.
c.
d.
Global warming
Radiative forcing
Greenhouse warming
Planetary albedo
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Review Question-3 Answer
______ is the influence any particular factor has on the
energy balance of the atmosphere-ocean-land system.
a.
b.
c.
d.
Global warming
Radiative forcing
Greenhouse warming
Planetary albedo
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Review Question-4
Which of the following is an observed change that
supports the concept of climate change?
a.
b.
c.
d.
shrinkage of Arctic sea ice
patterns of precipitation are changing
marine fish species are shifting northward
all of the above
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Review Question-4 Answer
Which of the following is an observed change that
supports the concept of climate change?
a.
b.
c.
d.
shrinkage of Arctic sea ice
patterns of precipitation are changing
marine fish species are shifting northward
all of the above
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Review Question-5
All of the following are anthropogenic greenhouse
gases except
a.
b.
c.
d.
carbon dioxide.
molecular oxygen.
chlorofluorocarbons (CFCs).
methane.
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Review Question-5 Answer
All of the following are anthropogenic greenhouse
gases except
a.
b.
c.
d.
carbon dioxide.
molecular oxygen.
chlorofluorocarbons (CFCs).
methane.
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Interpreting Graphs and Data-1
According to Fig. 18-16, which world region is the
greatest source of carbon dioxide emissions from fossil
fuel burning?
a.
b.
c.
d.
Africa
Middle East
Asia/Pacific
North America
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Interpreting Graphs and Data-1 Answer
According to Fig. 18-16, which world region is the
greatest source of carbon dioxide emissions from fossil
fuel burning?
a.
b.
c.
d.
Africa
Middle East
Asia/Pacific
North America
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Interpreting Graphs and Data-2
According to Fig. 18-22, if
we meet the higher emissions
scenario for climate change,
then Illinois will have summer
temperatures similar to ______
by ______.
a. Louisiana; the mid-century
b. Texas; the mid-century
c. Louisiana; the end of
the century
d. Texas; the end of
the century
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Interpreting Graphs and Data-2 Answer
According to Fig. 18-22, if
we meet the higher emissions
scenario for climate change,
then Illinois will have summer
temperatures similar to ______
by ______.
a. Louisiana; the mid-century
b. Texas; the mid-century
c. Louisiana; the end of
the century
d. Texas; the end of
the century
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Thinking Environmentally-1
Under the ______, the government imposes strict
limits on emissions from a group of industries and
then grants permits for emissions.
a. Climate Change Science Program
b. Global Climate Change Initiative
c. Cap and Trade Program
d. Framework Convention on Climate
Change
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Thinking Environmentally-1 Answer
Under the ______, the government imposes strict
limits on emissions from a group of industries and
then grants permits for emissions.
a. Climate Change Science Program
b. Global Climate Change Initiative
c. Cap and Trade Program
d. Framework Convention on Climate
Change
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Thinking Environmentally-2
All of the following are strategies that developed
countries can use to better cope with climate
change except
a. emergency preparedness.
b. have farmers shift to climate-resistant
crops.
c. establish a financial safety net and
discourage poor choices.
d. increase deforestation.
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Thinking Environmentally-2 Answer
All of the following are strategies that developed
countries can use to better cope with climate
change except
a. emergency preparedness.
b. have farmers shift to climate-resistant
crops.
c. establish a financial safety net and
discourage poor choices.
d. increase deforestation.
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