Chapter 21Chapter 21Global Climate ChangeGlobal Climate Change

Climate Change Climate Change TerminologyTerminology Greenhouse GasGreenhouse Gas

Gas that absorbs infrared radiationGas that absorbs infrared radiation Positive FeedbackPositive Feedback

Change in some condition triggers a response Change in some condition triggers a response that intensifies the changed condition that intensifies the changed condition

Infrared RadiationInfrared Radiation Radiation that has a wavelength that is longer Radiation that has a wavelength that is longer

than that of visible light, but shorter than that of than that of visible light, but shorter than that of radio waves radio waves

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 Introduction to Climate ChangeChange "Scientific evidence for warming of "Scientific evidence for warming of

the climate system is unequivocal." the climate system is unequivocal." - - Intergovernmental Panel on Climate Intergovernmental Panel on Climate ChangeChange

Evidence of Climate Change

Spring in N. hemisphere now begins 6 Spring in N. hemisphere now begins 6 days earlierdays earlier

Evidence of Climate Change

Sea level rise

Evidence of Climate Change Global

temperature rise

Evidence of Climate Change Warming oceans

Evidence of Climate Change

Shrinking ice sheets The Greenland and

Antarctic ice sheets have decreased in mass. Data from NASA show Greenland lost 150 - 250 km3/year between 2002-2006, while Antarctica lost about 152 km3 of ice between 2002-2005.

Flowing meltwater from the Greenland ice sheet

Evidence of Climate Change

Declining Arctic sea ice Both the extent and thickness of

Arctic sea ice has declined rapidly over the last several decades. 9

Evidence of Climate Change

Glacial retreat Glaciers are

retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska and Africa.10

Evidence of Climate Change Extreme events The number of record high

temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.11

Evidence of Climate Change Ocean acidification The carbon dioxide content of the

Earth’s oceans has been increasing since 1750, and is currently increasing about 2 billion tons/year. This has increased ocean acidity by about 30%. 12

Introduction to Climate Introduction to Climate Change: Mean Annual Change: Mean Annual Global Temperature 1960–Global Temperature 1960–20072007

Causes of Climate ChangeCauses of Climate Change

Greenhouse gas concentrations Greenhouse gas concentrations increasingincreasing

Causes of Climate ChangeCauses of Climate Change

Increased Increased concentration of concentration of COCO22 Burning fossil fuels Burning fossil fuels

in cars, industry in cars, industry and homesand homes

DeforestationDeforestation Burning of forestsBurning of forests

Greenhouse EffectGreenhouse Effect

Pollutants That Cool the Pollutants That Cool the AtmosphereAtmosphere

Atmospheric Aerosols Atmospheric Aerosols 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 Often contain sulfurOften contain sulfur

Complicates models of climate Complicates models of climate changechange

Climate ModelsClimate Models

Climate affected by:Climate affected by: winds, clouds, ocean currents, and winds, clouds, ocean currents, and

albedo albedo Advanced models can project future Advanced models can project future

warming eventswarming events Models have limitationsModels have limitations

Effects of Global Climate Effects of Global Climate ChangeChange Wildfire in CaliforniaWildfire in California

Effects of Global Climate Effects of Global Climate Change: Change: 1. Melting Ice and 1. Melting Ice and Rising Sea LevelsRising Sea LevelsSea level rise caused in 2 waysSea level rise caused in 2 ways

1.1. Thermal ExpansionThermal Expansion

2.2. Melting of land iceMelting of land ice

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

19519577

19919988

Glacier National ParkGlacier National Park

Melting Ice and Rising Sea Melting Ice and Rising Sea LevelsLevels

 

                                                                 

                                                                 

 

                                                                 

                                                                 

Impacts in Fragile AreasImpacts in Fragile Areas

Eskimo InuitEskimo Inuit Climate change isClimate change is altering their altering their

existenceexistence Wildlife displacedWildlife displaced Reduced snow cover and shorter river ice Reduced snow cover and shorter river ice

seasonsseasons Thawing of permafrost (right)Thawing of permafrost (right)

Tuvalu- threatened by permanent Tuvalu- threatened by permanent flooding on their island flooding on their island

Effects of Global Climate Effects of Global Climate Change: 2. Changing Change: 2. Changing Precipitation PatternsPrecipitation Patterns Some areas will get more water, Some areas will get more water,

some areas will have greater some areas will have greater droughtsdroughts

Effects of Global Climate Effects of Global Climate Change: 3. Effects on Change: 3. Effects on OrganismsOrganisms Zooplankton in parts of CA have Zooplankton in parts of CA have

decreased by 80% since 1951decreased by 80% since 1951 Effecting entire food chainEffecting entire food chain

Decline in krill around AntarcticaDecline in krill around Antarctica Species have shifted their Species have shifted their

geographic rangegeographic range Migrating birds are returning to Migrating birds are returning to

summer homes earliersummer homes earlier

Effects on Organisms: Coral Effects on Organisms: Coral ReefsReefs Coral reefs can be bleached (right) Coral reefs can be bleached (right)

due to increase in water temperaturedue to increase in water temperature Affects coral symbiotes and makes them Affects coral symbiotes and makes them

more susceptible to diseasesmore susceptible to diseases

Effect on Organisms: Effect on Organisms: VegetationVegetation

4. Effects on Human Health4. Effects on Human Health Increased number of heat-related Increased number of heat-related

illnesses and deathsillnesses and deaths

5. Effects on Agriculture5. Effects on Agriculture Difficult to anticipateDifficult to anticipate

Productivity will increase in some areas and Productivity will increase in some areas and decrease in othersdecrease in others

Rise in sea level will inundate farmlandRise in sea level will inundate farmland Effect on pests is unknownEffect on pests is unknown Warmer temperatures will decrease soil Warmer temperatures will decrease soil

moisture- requiring more irrigationmoisture- requiring more irrigation Location where certain crops can be grown Location where certain crops can be grown

may changemay change

International Implications of International Implications of Climate ChangeClimate Change Developed vs. Developed vs.

Developing Developing countriescountries Differing self-Differing self-

interestsinterests Differing Differing

ability to meet ability to meet the challenges the challenges of climate of climate changechange

Dealing with Global Climate Dealing with Global Climate ChangeChange

Two ways to manage climate Two ways to manage climate changechange

1.1. Mitigation:Mitigation: Limiting greenhouse gas Limiting greenhouse gas emissions to moderate global climate emissions to moderate global climate changechange

2.2. Adaptation:Adaptation: Learning to live with Learning to live with environmental changes and societal environmental changes and societal consequences brought about by global consequences brought about by global climate change climate change

Relationship Between Relationship Between Mitigation and AdaptationMitigation and Adaptation

Dealing with Global Climate Dealing with Global Climate Change: MitigationChange: Mitigation

Locate/invent alternative fuels to Locate/invent alternative fuels to fossil fuelsfossil fuels

Increase efficiency of cars and trucksIncrease efficiency of cars and trucks Carbon Capture and StorageCarbon Capture and Storage Plant and Maintain trees to naturally Plant and Maintain trees to naturally

sequester carbonsequester carbon

Dealing with Global Climate Dealing with Global Climate Change: AdaptationChange: Adaptation Rising sea levels and coastal Rising sea levels and coastal

populationspopulations Move inlandMove inland Construct dikes and leveesConstruct dikes and levees

Adapt to shifting agricultural zonesAdapt to shifting agricultural zones NYC sewer lineNYC sewer line

International Efforts to International Efforts to Reduce Greenhouse Gas Reduce Greenhouse Gas EmissionEmission Kyoto ProtocolKyoto Protocol

Legally bindingLegally binding Provides rules on reducing greenhouse Provides rules on reducing greenhouse

gasesgases US and Australia have not sign it - it will US and Australia have not sign it - it will

be difficult to implement without US be difficult to implement without US backingbacking

Chapter 21: Global Climate Change Climate Crisis Networkhttp://www.climatecrisis.net/takeaction/

Goddard Institute for Space Studies: Surface Temperature Analysishttp://data.giss.nasa.gov/gistemp/

United Nations Intergovernmental Panel on Climate Changehttp://www.ipcc.ch/

US Global Change Research Programhttp://www.globalchange.gov/

Pew Center on Global Climate Changehttp://www.pewclimate.org/

World View of Global Warming - The Photographic Documentation of Climate Changehttp://www.worldviewofglobalwarming.org/pages/glaciers.html