Climate Change
Chapter 19
An Enormous Cloud of Air Pollutants and Ash from
Mt. Pinatubo
 June 1991: Mount Pinatubo
(Philippines) exploded
 Airborne pollutants, deaths, and
damage
 Affected climate temperature
 James Hansen(NASA) cooled the
temp of the earth by )0.5* over a
19th month period. Then the earth
would warm
Earth’s Future Temperature and Climate Change
• The overwhelming scientific consensus is that the earth’s atmosphere is
warming rapidly, mostly because of human activities, and that this will
lead to significant climate change during this century.
Global Warming and Global Cooling
Are Not New
• Over the past 4.7 billion years the climate has been
altered by
• Volcanic emissions
• Changes in solar input
• Movement of the continents
• Impacts by meteors
• Over the past 900,000 years
• Glacial and interglacial periods
Global Warming and Global Cooling
Are Not New
 Over the past 10,000 years
◦ Interglacial period, fairly stable climate and steady
average global surface temperature
 Over the past 1,000 years
◦ Temperature stable but began to rise during the
last century when forests cleared, fossil fuel
burned
 Over the past 100 years
◦ Temperature changes mostly since 1975
Different techniques……..
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Analysis of radioisotopes in rocks and fossils
Plankton and radioisotopes in ocean sediments
Tiny bubbles of ancient air found in ice cores from glaciers
Temperature measurements taken at different depths from bore holes
drilled deep into the earth’s surface
 Pollen from lake/bog bottoms
 Tree rings
 Historical records - 1861
Estimated Changes in the Average Global
Temperature of the Atmosphere
Our Climate, Lives, Economies Depend on the
Natural Greenhouse Effect ( Arrhenius)
• Without
the natural greenhouse effect, warms the earth’s
lower atmosphere and surface.
• Solar energy absorbed by the earth radiates into the
atmosphere as infrared radiation(heat)
• 1% of earth’s lower atmosphere is compressed of
greenhouse gases- water vapor, carbon dioxide, methane,
and nitrous oxide
• Cold, uninhabitable earth
Human Activities Emit Large Quantities of
Greenhouses Gases
• Since the Industrial Revolution (275 years ago)
• CO2, CH4, and N2O emissions higher
• Main sources: agriculture, deforestation, and burning of
fossil fuels
• Correlation of rising CO2 and CH4 with rising global
temperatures, during past 400,000 years
• Countries with the largest CO2 emissions- US, China, EU-27
contries, Indonesia, Russia, Japan, India
Human Activities Emit Large Quantities of
Greenhouses Gases
 Per capita emissions of CO2
Scientific and economic studies
◦ 2007: Field and Marland
560 ppm by 2050 – 1390 by 2100
Tipping point 450 ppm
◦ 2008: Aufhammer and Carson
 China’s CO2 emission growth may be underestimated
 Ice core analysis – 60% of methane emissions
◦ human impact – landfills, raising live stock, extracting fossil fuels
◦ Nitrous oxide – nitrogen fertilizers
Atmospheric Levels of CO2 and CH4, Global
Temperatures, and Sea Levels
The Atmosphere Is Warming Mostly Because of
Human Activities
• Intergovernmental Panel on Climate Change (IPCC)
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90–99% likely that lower atmosphere is warming
1906–2005: Ave. temp increased about 0.74˚C
1970–2005: Annual greenhouse emissions up 70%
Past 50 years: Arctic temp rising almost twice as fast as the rest of the earth
Melting of glaciers and floating sea ice
Prolonged droughts: increasing
Last 100 years: sea levels rose 10–20 cm
Alaska’s Muir Glacier
• Al Gore and the IPCC :
Nobel Peace Prize
• Natural and humaninfluenced factors
could have an effect
on temperature
changes
The Big Melt: Some of the Floating Sea Ice in
the Arctic Sea
Drop in average cover of summer arctic ice
Scientific Consensus about Future Temperature
Change?
• Mathematical models used for predictions
• Global warming: rapid rate
• Human factors are the major cause of temperature
rise since 1950
• Human factors will become a greater risk factor
Model of Some Major Processes That Interact
to Determine Climate
Comparison of
Measured
Temperature
from 1860–2007
and Projected
Changes
Is a Hotter Sun the Culprit?
• Since 1975- satellite and balloon measurements
• Troposphere has warmed
• Stratosphere has cooled
• Scientists have concluded that the rapid rise in global mean
temperature could not be the result of increased solar output
Can the Oceans Save Us?
• Solubility of CO2 in ocean water – removes 25-30% of the carbon dioxide
pumped into the lower atmosphere by human activities. Some of it converted to
insoluble carbonate salts that are buried in the bottom sediments
• Warmer oceans
• Solubility decreases increases atmospheric CO2
• Coral reefs destroyed
• Increased acidity –less carbon dioxide absorbed, increases growth
of some algae
• drop in populations of phytoplankton,
• Antarctica’s Southern Ocean and the North Atlantic Ocean –decrease in carbon
dioxide uptake
There Is Uncertainty about the Effects of Cloud
Cover on Global Warming
• Warmer temperatures create more clouds by increased evaporation of
surface water
• Thick, light-colored low altitude clouds: decrease surface temperature
• Thin, cirrus clouds at high altitudes: increase surface temperature
• Effect of jet contrails on climate temperature – they expand and turn
into cirrus clouds that release heat into the upper troposphere
Outdoor Air Pollution Can Temporarily Slow
Global Warming
• Aerosol and soot pollutants
• light colored sulfate particles, reflect sunlight and
cool atmosphere
• sulfate particles also cool the lower atmosphere by
forming condensation nuclei that form cooling clouds
Some Possible Effects of a Warmer
Atmosphere……………
• The projected rapid change in the atmosphere's temperature during this
century is very likely to
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Increase drought and flooding,
shift areas where food can be grown,
raise sea levels,
result in intense heat waves,
cause the premature extinction of many species.
Enhanced Global Warming Could Have Severe
Consequences
• Very rapid, global change in climate – projected rapid increase in average
temperature in the lower atmosphere
• Worst-case scenarios
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Ecosystems collapsing
Low-lying cities flooded
Wildfires in forests
Prolonged droughts: grasslands become dust bowls
More destructive storms
Glaciers shrinking; rivers drying up
Stepped Art
Fig. 19-7, p. 507
Severe Drought Is Increasing from 15-30%
• less moisture in the soil – NPP will decrease
• stream flows and available water will decline
• Biodiversity will decrease
• growth of plants/trees will slow
• forest and grassland fires will increase
• some lakes/seas will shrink and disappear, rivers will fail
to reach the sea
• 1-3 billion people will face water shortage
• dry climate biomes will increase – savannas,
chapparal,deserts
Ice and Snow Are Melting
• global warming be worse in the polar regions – exposure
of darker land, absorb more solar radiation
• floating sea ice disappearing – could affect the average
rate of precipitation in certain areas
• Mountain glaciers affected by
• Average snowfall, adds to mass in winter
• Average warm temperatures- apur their melting during
the summer
Ice and Snow Are Melting
• Europe’s Alps
• Glaciers are
disappearing
• South America
• Glaciers are
disappearing
• Greenland
• Warmer
temperatures
Areas of Glacial Ice Melting
in Greenland
Melting Ice in Greenland
• Largest island: 80% composed of glaciers
• 10% of the world’s fresh water
• 1996–2007: net loss of ice doubled
• Effect on sea level if melting continues
Sea Levels Are Rising – 90-99% certainity
• Expansion of warm water and
melting of land based ice–
• Water will rise 18-59 cm (0.6-1.9
feet) during this century
• storm surges of 6 meters (20 feet)
• accompanying tropical cyclones
and tsunamis
• Degradation and loss of 1/3 of coastal
estuaries, wetlands, and coral reefs
• Disruption of coastal fisheries
• Flooding of
Sea Levels Rising
• Low-lying barrier islands and coastal areas
• Agricultural lowlands and deltas
• Contamination of freshwater aquifers
• Submergence of low-lying islands in the
Pacific and Indian Oceans and the
Caribbean
Maldives- Indian Ocean
Projected Decline in Arctic Tundra in Portions of
Russia from 2004 - 2100
Melting of permafrost in tundra soils releases methane and
carbon di oxide
Loss of arctic tundra-reduce grazing lands for caribou
Boreal vegetation would replace tundra
Ocean Currents Are Changing but the Threat Is
Unknown
• Melting glaciers, particularly in Greenland
• Increased rain in the North Atlantic
• Could add enough fresh water to disrupt the flow of deep and shallow ocean
currents
• Could climate of Northern Europe. N. America and Japan
• Not thought to be an immediate problem on the ocean currents
Extreme Weather Will Increase in Some Areas
• Heat waves and droughts in some areas- kill people, reduce crop production,
expand deserts
• Prolonged rains and flooding(flash floods) from heavy and prolonged
precipitation
• Will storms get worse?
• More studies needed – Saunders and Lea (2008)
• Hurricanes Katrina and Rita – lost 320 million big trees
Global Warming Is a Major Threat to
Biodiversity
• Most susceptible ecosystems
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Coral reefs
Polar seas
Coastal wetland
High-elevation mountaintops
Alpine and arctic tundra
Changes in water temperature, relative to coral bleaching
threshold
• 30% of land –based plants and
animals will disappear (temp
change 1.5-2.5*C)
• What about
Global Warming Is a
Major Threat to
Biodiversity
• Migratory animals
• Forests
• Some organisms will increase
• Insects, Fungi, Microbes
Exploding populations of mountain
pine beetles
Destroy lodge pole pine forests
Climate Change Will Shift Areas Where Crops
Can Be Grown
• Regions of farming may shift
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Decrease in tropical and subtropical areas
Increase in northern latitudes
Overall food productivity would decrease because of less productivity soil
Decrease in food production in farm regions dependent on rivers fed by snow
melt
• Genetically engineered crops more tolerant to drought
Climate Change Will Threaten the Health of
Many People
• Deaths from heat waves will increase
• Deaths from cold weather will decrease
• Higher temperatures can cause
• Increased flooding
• Increase in some forms of air pollution, more O3
• More insects, microbes, toxic molds, and fungi
Norman Myers – 150 to 200 million environmental refugees in
this century
What Can We Do to Slow Climate
Change……………..
• To slow the rate of global warming and climate change, we can
• increase energy efficiency,
• sharply reduce greenhouse gas emissions,
• rely more on renewable energy resources
• slow population growth.
What Can We Do to Slow Climate Change?
• Governments can
• subsidize energy efficiency and renewable energy use,
• tax greenhouse gas emissions,
• set up cap-and-trade emission reduction systems,
• help to slow population growth.
Dealing with Climate Change Is Difficult
 Global problem
 Long-lasting effects
 Long-term political problem
 Harmful and beneficial impacts of climate change unevenly spread
 Many proposed actions disrupt economies and lifestyles
What Are Our Options?
• Two approaches
• Drastically reduce the amount of greenhouse gas emissions
• Recognize that some warming is unavoidable and devise strategies to reduce
the harmful effects of global warming
• Will we reach a political tipping point before we reach irreversible
climate change tipping points?
We Can Reduce the Threat of Climate Change
• Input or prevention strategies
• Improve energy efficiency to reduce fossil fuel use
• Shift from non-renewable carbon-based fossil fuels to a mix of carbon-free
renewable energy resources
• Stop cutting down tropical forests
• Output strategy
• Capture and store CO2 -
Avoiding Catastrophe: We Can Reduce the Threat
of Climate Change
• Socolow and Pacala
• Climate stabilization wedges
• Keep CO2 emissions to 2007 levels by 2057
• Brown: need to do more
• Cut CO2 emissions by 80% by 2020
• 2008 book: Plan B 3.0: Mobilizing to Save Civilization
We Can Reduce the Threat of Climate Change
• Output solutions
• Massive global tree planting – 4 billion need to be planted
• Wangari Maathai
• Great Wall of Trees: China and Africa
• Plant fast-growing perennials such as switch grass on degraded land which takes
carbon dioxide from the air and stores it in the soil. Can be used to produce
ethanol
SOLUTIONS
Global Warming
Prevention
Cleanup
Cut fossil fuel use
(especially coal)
Remove CO2 from
smokestack and vehicle
emissions
Store (sequester) CO2 by
planting trees
Sequester CO2 deep
underground (with no leaks
allowed)
Sequester CO2 in soil by
using no-till cultivation and
taking cropland out of
production
Sequester CO2 in the deep
ocean (with no leaks
allowed)
Repair leaky natural gas
pipelines and facilities
Use animal feeds that
reduce CH4 emissions from
cows (belching)
Shift from coal to natural gas
Improve energy efficiency
Shift to renewable energy
resources
Transfer energy efficiency
and renewable energy
technologies to
developing countries
Reduce deforestation
Use more sustainable
agriculture and forestry
Limit urban sprawl
Reduce poverty
Slow population growth
Fig. 19-13, p. 515
Fifteen Ways to Cut CO2 Emissions
Stepped Art
Fig. 19-14, p. 515
Some Output Methods for Removing CO2 from the Atmosphere
and storing it
Oil rig
Tanker delivers
CO2 from plant Coal power
to rig
plant
CO2 is pumped
down from rig for
disposal in deep
ocean or under
seafloor sediments
Abandoned
oil field
Tree plantation
Switchgrass
Crop field
CO2 is
pumped
underground
Spent oil or
natural gas
reservoir
Spent coal
bed cavern
Deep, saltwater-filled cavern
= CO2 pumping
= CO2 deposit
Fig. 19-15, p. 516
Is Capturing and Storing CO2 the Answer?
• Carbon capture and storage (CCS) – involves removing carbon dioxide
from the smoke stacks of coal- burning power and industrial plants and
storing them somewhere
• Several problems with this approach
• Power plants using CCS
• More expensive to build
• None exist
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Unproven technology
Large inputs of energy to work
promotes continued use of coal
Effect of government subsidies and tax breaks
Stored CO2 would have to remain sealed forever: no leaking
Use Geo-Engineering Schemes to Help Slow
Climate Change……..
• CCS – large scale geo engineering scheme opposed by scientists because
long term effects on earth’s energy flow, chemical cycling processes and vital
biodiversity are unknown
• Injection of sulfate particles into the stratosphere by balloons, large jet
planes, giant cannons
• Huge amounts of sulfur dioxide injected into the atmosphere every 2 years
• Would it have a cooling effect?
• Would it accelerate O3 depletion?
Use Geo-Engineering Schemes to Help Slow
Climate Change……
• Remove HCl from seawater – reduce ocean acidity. How would it affect the
ecology ?
• Pump up nutrient-rich deep ocean water and cause algal blooms, remove
carbon dioxide and emit dimethyl sulfide which will contribute to the
formation of low clouds that would reflect sunlight
• Re-ice the Arctic – 8,000 ice making barges
• Wrap large areas of the glaciers with insulating blankets
Cost to Slow Climate Change….
• Short-term costs lower
• Local and global economies may be boosted
• Provide jobs because of new technology associated with alternative
energy
• Less expenses for remediation
Governments Can Help Reduce the Threat of
Climate Change
• Strictly regulate CO2 and CH4 as pollutants
• Cap-and-trade approach-political advantage
• carbon taxes - levy energy taxes on each unit of fossil fuel that is burned – tax
pollution, not payrolls
• Increase subsidies to encourage use of energy-efficient technology
• Technology transfer-fund the transfer of green technologies to phase out
older, energy wasting technologies
Governments Can Enter into International
Climate Negotiations: The Kyoto Protocol
• 1997: Treaty to slow climate change -2200 delegates from161 nations
• 1st phase – 174 of the world’s 194 countries (but not US) ratifying the
agreement by mid -2008.
• The Kyoto Protocol
• Reduce emissions of CO2, CH4, and N2O by 2012 to levels of 1990
• Trading greenhouse gas emissions among countries
• Not signed by theUS.(2001) 67% of ppublic upset
• President G.W. Bush’s reasons-would harm US economy
Cap and Trade systems need to have the caps set low to increase value of the tradable allowances
Move Beyond the Kyoto Protocol
 2004: Stewart and Wiener
◦ New treaty needed
 Should be led by the U.S.
 Include China, India, Brazil and other developing countries that are
getting industrialized and will be soon emitting the more than 50% of
the world’s greenhouse gases
 Cap-and-trade emissions program
 Set up achievable 10 year goals – to reduce greenhouse gases over the
next 40 years
Governments Are Leading the Way are……
• Costa Rica: goal to be carbon neutral by 2030 – 78% from hydroelectric,18%
from wind and geothermal
• Norway: aims to be carbon neutral by 2050
• China and India must change energy habits
• U.S. cities and states (27+ DC: solar and wind) taking initiatives to reduce
carbon emissions
• 650 cities around the world, including 453 US cities reduce greenhouse gases
• Portland, Oregon – 1993-2005 greenhouse gases at 1990 levels
Reducing Greenhouse Gas Emissions in California
(12th largest producer of greenhouse gases)
• Use of energy-efficient appliances and buildings
• Incentives for consumers to use less energy
Has saved California from building 24 new power plants
• California sued the EPA so that they and 17 other states can set tougher
emission standards
Some Companies and Schools Are Reducing
Their Carbon Footprints
• Major global companies reducing greenhouse gas emissions- reduce 1065% below 1990 levels by 2010
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Alcoa
DuPont
IBM
Toyota
GE
Wal-Mart $12 million /year saved by using LED’s
• Fluorescent light bulbs
• Auxiliary power units on truck fleets – no idling
• Carbon Disclosure Project
Some Companies and Schools Are Reducing
Their Carbon Footprints
• Colleges and universities reducing greenhouse gas emissions
• Oberlin College, Ohio, U.S.
• 25 Colleges in Pennsylvania, U.S.
• Yale University, CT, U.S.
• Largest teach-In Feb 2008-1500 colleges, climate change and
sustainability
What Can You Do? Reducing CO2 Emissions
Prepare for the Harmful Effects of Climate
Change
• Reduce greenhouse gas emissions as much as possible (50-85% cut in by
2050) to prevent the planet from heating up by 2*C
• Move people from low-lying coastal areas
• Limit coastal building
• Remove hazardous material storage tanks away from the coast
Prepare for the Harmful Effects of Climate
Change
• Genetically engineer crops more tolerant to drought
• Stockpile 1–5 years of key foods
• Waste less water
• Connect wildlife reserves with corridors
Which do you think is the most
important ?
Develop crops that
need less water
Waste less water
Connect wildlife
reserves with corridors
Move hazardous material
storage tanks away from coast
Move people away
from low-lying
coastal areas
Stockpile 1- to 5-year
supply of key foods
Prohibit new construction
on low-lying coastal areas
or build houses on stilts
Expand existing
wildlife reserves
toward poles
Fig. 19-17, p. 522