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Chapter 21Chapter 21Global Climate ChangeGlobal Climate Change
Overview of Chapter 21Overview of Chapter 21
o Introduction to Climate ChangeIntroduction to Climate Change• Causes of Global Climate ChangeCauses of Global Climate Change
o Effects of Climate ChangeEffects of Climate Change• Melting Ice and Rising Sea LevelMelting Ice and Rising Sea Level• Changes in Precipitation PatternsChanges in Precipitation Patterns• Effects on OrganismsEffects on Organisms• Effects on Human HealthEffects on Human Health• Effects on AgricultureEffects on Agriculture
o Dealing with Global Climate ChangeDealing with Global Climate Change
Introduction to Climate Change-Introduction to Climate Change-Mean Annual Global Temperature 1960-Mean Annual Global Temperature 1960-
20052005
Climate Change TerminologyClimate Change Terminology
o Greenhouse GasGreenhouse Gas• Gas that absorbs infrared radiationGas that absorbs infrared radiation• Ex: Carbon dioxide, methane, nitrous oxide, Ex: Carbon dioxide, methane, nitrous oxide,
chlorofluorocarbons and tropospheric ozonechlorofluorocarbons and tropospheric ozoneo Positive FeedbackPositive Feedback
• Change in some condition triggers a response that Change in some condition triggers a response that intensifies the changed condition intensifies the changed condition
o Infrared RadiationInfrared Radiation• Radiation that has a wavelength that is longer than Radiation that has a wavelength that is longer than
that of visible light, but shorter than that of radio that of visible light, but shorter than that of radio waves waves
o Greenhouse EffectGreenhouse Effect• Increase of heat in a system where energy enters Increase of heat in a system where energy enters
(often as light), is absorbed as heat, and released (often as light), is absorbed as heat, and released sometime later sometime later
Introduction to Climate ChangeIntroduction to Climate Change
o Evidence for Climate ChangeEvidence for Climate Change• 11 of the 12 years between 1995 and 2006 11 of the 12 years between 1995 and 2006
were among the twelve warmest years were among the twelve warmest years since the mid-1800s since the mid-1800s
• Phenological spring in N. hemisphere now Phenological spring in N. hemisphere now comes 6 days earliercomes 6 days earlier
o Warming is not due to natural causesWarming is not due to natural causes• Human produced greenhouse gases are Human produced greenhouse gases are
most plausible explanationmost plausible explanation
Causes of Climate ChangeCauses of Climate Change
o Greenhouse gas concentrations Greenhouse gas concentrations increasingincreasing
Causes of Climate ChangeCauses of Climate Change
o Increased Increased concentration of concentration of COCO22 (right) (right)• Burning fossil fuels Burning fossil fuels
in cars, industry in cars, industry and homesand homes
• DeforestationDeforestation• Burning of forestsBurning of forests
Greenhouse EffectGreenhouse Effect
Other Pollutants Cool the Other Pollutants Cool the AtmosphereAtmosphere
o Atmospheric Aerosols tend to cool the Atmospheric Aerosols tend to cool the atmosphereatmosphere• Both human and natural sourcesBoth human and natural sources• Tiny particles that remain in troposphere Tiny particles that remain in troposphere
for weeks or monthsfor weeks or months• Contain many chemicals, but often contain Contain many chemicals, but often contain
sulfursulfur
o Complicates models of climate changeComplicates models of climate change
Climate ModelsClimate Models
o Climate affected by:Climate affected by:• winds, clouds, ocean currents, and albedo winds, clouds, ocean currents, and albedo
o Used to explore past climate eventsUsed to explore past climate eventso Advanced models can project future Advanced models can project future
warming eventswarming eventso Models are only as good as the data Models are only as good as the data
and law used to program themand law used to program them• They have limitationsThey have limitations
Climate ModelsClimate Models
Effects of Global Climate ChangeEffects of Global Climate Changeo Ocean as COOcean as CO22 sink - excess CO sink - excess CO22 is starting to is starting to
harm ocean lifeharm ocean life
Effects of Global Climate Change- Effects of Global Climate Change- Melting Ice and Rising Sea LevelsMelting Ice and Rising Sea Levels
o Sea level rise caused in 2 waysSea level rise caused in 2 ways• Thermal ExpansionThermal Expansion
• Water expands as it warmsWater expands as it warms• Melting of land iceMelting of land ice
• Retreat of glacier and thinning of ice at the polesRetreat of glacier and thinning of ice at the poles
o Melting has positive feedbackMelting has positive feedback• Increased melting decreases ice, which Increased melting decreases ice, which
decreases albedo leading to further decreases albedo leading to further warmingwarming
Melting Ice and Rising Sea Melting Ice and Rising Sea LevelsLevels
19519577
19919988
Case-In-Point Impacts in Fragile Case-In-Point Impacts in Fragile AreasAreas
o Eskimo Inuit live Eskimo Inuit live traditional life dictated traditional life dictated by freezing climateby freezing climate
o Climate change is Climate change is altering their existencealtering their existence• Wildlife are smaller or Wildlife are smaller or
displaceddisplaced• Reduced snow cover and Reduced snow cover and
shorter river ice seasonsshorter river ice seasons• Thawing of permafrost Thawing of permafrost
(right)(right)
o Some areas will get more water, some Some areas will get more water, some areas will have greater droughtsareas will have greater droughts• Ex: Hurricanes will likely get strongerEx: Hurricanes will likely get stronger
Effects of Global Climate Change- Effects of Global Climate Change- Changing Precipitation PatternsChanging Precipitation Patterns
o Zooplankton in parts of California Current Zooplankton in parts of California Current have decreased by 80% since 1951have decreased by 80% since 1951• Effecting entire food chainEffecting entire food chain
o Decline in krill around AntarcticaDecline in krill around Antarctica• Caused decrease in penguin populationsCaused decrease in penguin populations
o Species have shifted their geographic Species have shifted their geographic rangerange
o Migrating birds are returning to summer Migrating birds are returning to summer homes earlierhomes earlier• Food is not available at this timeFood is not available at this time
Effects of Global Climate Change- Effects of Global Climate Change- Effects on OrganismsEffects on Organisms
Effects on Organisms - Coral Effects on Organisms - Coral ReefsReefs
o Coral reefs can be bleached (right) due Coral reefs can be bleached (right) due to increase in water temperatureto increase in water temperature• Affects coral symbiotes and makes them Affects coral symbiotes and makes them
more susceptible to diseases to which they more susceptible to diseases to which they would otherwise be immunewould otherwise be immune
Effect on Organisms - VegetationEffect on Organisms - VegetationBeech Tree RangeBeech Tree Range
Effects on Human HealthEffects on Human Health
o Increased number of heat-related Increased number of heat-related illnesses and deathsillnesses and deaths
Effects on AgricultureEffects on Agriculture
o Difficult to anticipateDifficult to anticipate• Productivity will increase in some areas and Productivity will increase in some areas and
decrease in othersdecrease in others
o Rise in sea level will inundate flood plains and Rise in sea level will inundate flood plains and river valleys (lush farmland)river valleys (lush farmland)
o Effect on pests is unknownEffect on pests is unknowno Warmer temperatures will decrease soil Warmer temperatures will decrease soil
moisture- requiring more irrigationmoisture- requiring more irrigationo Location (i.e. elevation and altitude) where Location (i.e. elevation and altitude) where
certain crops can be grown may have to certain crops can be grown may have to changechange
International ImplicationsInternational Implicationsof Climate Changeof Climate Change
o Developed vs. Developed vs. Developing Developing countriescountries• Differing self-Differing self-
interestsinterests• Differing ability to Differing ability to
meet the meet the challenges of challenges of climate changeclimate change
Dealing with Global Climate Dealing with Global Climate ChangeChange
o To avoid the worst of climate change, To avoid the worst of climate change, COCO22 levels must be stabilized at 550ppm levels must be stabilized at 550ppm• 50% higher than current levels50% higher than current levels
o Two ways to attempt to manage climate Two ways to attempt to manage climate changechange• MitigationMitigation
• Focuses on limiting greenhouse gas emissions to Focuses on limiting greenhouse gas emissions to moderate global climate changemoderate global climate change
• AdaptationAdaptation• Focuses on learning to live with to the Focuses on learning to live with to the
environmental changes and societal environmental changes and societal consequences brought about by global climate consequences brought about by global climate change change
Dealing with Global Climate Change- Dealing with Global Climate Change- Relationship Between Mitigation and Relationship Between Mitigation and
AdaptationAdaptation
Dealing with Global Climate Change- Dealing with Global Climate Change- MitigationMitigation
o Locate/invent alternative fuels to fossil Locate/invent alternative fuels to fossil fuelsfuels
o Increase efficiency of cars and trucksIncrease efficiency of cars and truckso Sequestering carbon before it is Sequestering carbon before it is
emittedemittedo Plant and Maintain trees to naturally Plant and Maintain trees to naturally
sequester carbonsequester carbon
Dealing with Global Climate Change- Dealing with Global Climate Change- AdaptationAdaptation
o Rising sea levels and coastal Rising sea levels and coastal populationspopulations• Move inlandMove inland• Construct dikes and leveesConstruct dikes and levees
o Adapt to shifting agricultural zonesAdapt to shifting agricultural zoneso NYC sewer lineNYC sewer line
International Efforts to Reduce International Efforts to Reduce Greenhouse Gas EmissionGreenhouse Gas Emission
o Kyoto ProtocolKyoto Protocol• Legally bindingLegally binding• Provides operational rules on reducing Provides operational rules on reducing
greenhouse gasesgreenhouse gases• US and Australia have not signed it- it will US and Australia have not signed it- it will
be difficult to implement without US be difficult to implement without US backingbacking
