Lecture chapter 21 - global climate change
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The document discusses global climate change, including its causes from increasing greenhouse gases, effects such as rising sea levels and changes in precipitation patterns, and ways to deal with it through mitigation and adaptation. It provides evidence that climate change is occurring, such as rising global temperatures and retreating glaciers. Predictions include ranges of plant and animal species shifting. Solutions involve reducing carbon emissions through actions like using less fossil fuels, insulating homes, and developing renewable energy.
Lecture chapter 21 - global climate change
- 2. OverviewOverview 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
- 3. Climate Change-Climate Change- Mean Annual Global Temperature 1960-2005Mean Annual Global Temperature 1960-2005
- 4. Climate Change TerminologyClimate Change Terminology o Greenhouse GasGreenhouse Gas • Gas that absorbs infrared radiationGas that absorbs infrared radiation • Ex: Carbon dioxide, methane, nitrous oxide, chlorofluorocarbonsEx: Carbon dioxide, methane, nitrous oxide, chlorofluorocarbons and tropospheric ozoneand tropospheric ozone o Positive FeedbackPositive Feedback • Change in some condition triggers a response that intensifies theChange in some condition triggers a response that intensifies the changed conditionchanged condition o Infrared RadiationInfrared Radiation • Radiation that has a wavelength that is longer than that of visibleRadiation that has a wavelength that is longer than that of visible light, but shorter than that of radio waveslight, but shorter than that of radio waves o Greenhouse EffectGreenhouse Effect • Increase of heat in a system where energy enters (often as light), isIncrease of heat in a system where energy enters (often as light), is absorbed as heat, and released sometime laterabsorbed as heat, and released sometime later
- 5. Climate ChangeClimate Change o Evidence for Climate ChangeEvidence for Climate Change • 11 of the 12 years between 1995 and 2006 were among11 of the 12 years between 1995 and 2006 were among the twelve warmest years since the mid-1800sthe twelve warmest years since the mid-1800s • Phenological spring in N. hemisphere now comes 6 daysPhenological spring in N. hemisphere now comes 6 days earlierearlier o Warming is not due to natural causesWarming is not due to natural causes • Human produced greenhouse gases are most plausibleHuman produced greenhouse gases are most plausible explanationexplanation
- 6. CausesCauses o Greenhouse gas concentrations increasingGreenhouse gas concentrations increasing
- 7. o Increased concentrationIncreased concentration of COof CO22 (right)(right) • Burning fossil fuels inBurning fossil fuels in cars, industry and homescars, industry and homes • DeforestationDeforestation • Burning of forestsBurning of forests CausesCauses
- 9. Other Pollutants Cool the AtmosphereOther Pollutants Cool the Atmosphere o Atmospheric Aerosols tend to cool the atmosphereAtmospheric Aerosols tend to cool the atmosphere • Both human and natural sourcesBoth human and natural sources • Tiny particles that remain in troposphere for weeks orTiny particles that remain in troposphere for weeks or monthsmonths • Contain many chemicals, but often contain sulfurContain many chemicals, but often contain sulfur o Complicates models of climate changeComplicates models of climate change
- 10. Climate ModelsClimate Models o Climate affected by:Climate affected by: • winds, clouds, ocean currents,winds, clouds, ocean currents, and albedoand albedo o Used to explore past climateUsed to explore past climate eventsevents o Advanced models can projectAdvanced models can project future warming eventsfuture warming events o Models are only as good as theModels are only as good as the data and law used to programdata and law used to program themthem • They have limitationsThey have limitations
- 12. Effects of Global Climate ChangeEffects of Global Climate Change o Ocean as COOcean as CO22 sink - excess COsink - excess CO22 is starting to harmis starting to harm ocean lifeocean life
- 13. Effects of Global Climate Change- Melting IceEffects of Global Climate Change- Melting Ice and Rising Sea Levelsand 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 decreases albedoIncreased melting decreases ice, which decreases albedo leading to further warmingleading to further warming
- 14. Melting Ice and Rising Sea LevelsMelting Ice and Rising Sea Levels 19571957 19981998
- 15. Case-In-Point Impacts in Fragile AreasCase-In-Point Impacts in Fragile Areas o Eskimo Inuit live traditional lifeEskimo Inuit live traditional life dictated by freezing climatedictated by freezing climate o Climate change is altering theirClimate change is altering their existenceexistence • Wildlife are smaller or displacedWildlife are smaller or displaced • Reduced snow cover and shorterReduced snow cover and shorter river ice seasonsriver ice seasons • Thawing of permafrost (right)Thawing of permafrost (right)
- 16. o Some areas will get more water, some areas willSome areas will get more water, some areas will have greater droughtshave 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
- 17. o Zooplankton in parts of California Current haveZooplankton in parts of California Current have decreased by 80% since 1951decreased 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 rangeSpecies have shifted their geographic range o Migrating birds are returning to summer homesMigrating birds are returning to summer homes earlierearlier • 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
- 18. Effects on Organisms - Coral ReefsEffects on Organisms - Coral Reefs o Coral reefs can be bleached (right) due to increaseCoral reefs can be bleached (right) due to increase in water temperaturein water temperature • Affects coral symbiotes and makes them moreAffects coral symbiotes and makes them more susceptible to diseases to which they would otherwise besusceptible to diseases to which they would otherwise be immuneimmune
- 19. Effect on Organisms - VegetationEffect on Organisms - Vegetation Beech Tree RangeBeech Tree Range
- 20. Effects on Human HealthEffects on Human Health o Increased number of heat-related illnesses andIncreased number of heat-related illnesses and deathsdeaths
- 21. Effects on AgricultureEffects on Agriculture o Difficult to anticipateDifficult to anticipate • Productivity will increase in some areas and decrease in othersProductivity will increase in some areas and decrease in others o Rise in sea level will inundate flood plains and river valleysRise in sea level will inundate flood plains and river valleys (lush farmland)(lush farmland) o Effect on pests is unknownEffect on pests is unknown o Warmer temperatures will decrease soil moisture- requiringWarmer temperatures will decrease soil moisture- requiring more irrigationmore irrigation o Location (i.e. elevation and altitude) where certain crops canLocation (i.e. elevation and altitude) where certain crops can be grown may have to changebe grown may have to change
- 22. International ImplicationsInternational Implications of Climate Changeof Climate Change o Developed vs.Developed vs. Developing countriesDeveloping countries • Differing self-interestsDiffering self-interests • Differing ability to meetDiffering ability to meet the challenges of climatethe challenges of climate changechange
- 23. Dealing with Global Climate ChangeDealing with Global Climate Change o To avoid the worst of climate change, COTo avoid the worst of climate change, CO22 levelslevels must be stabilized at 550ppmmust be stabilized at 550ppm • 50% higher than current levels50% higher than current levels o Two ways to attempt to manage climate changeTwo ways to attempt to manage climate change • MitigationMitigation • Focuses on limiting greenhouse gas emissions to moderateFocuses on limiting greenhouse gas emissions to moderate global climate changeglobal climate change • AdaptationAdaptation • Focuses on learning to live with to the environmental changesFocuses on learning to live with to the environmental changes and societal consequences brought about by global climateand societal consequences brought about by global climate changechange
- 24. Dealing with Global Climate Change-Dealing with Global Climate Change- Relationship Between Mitigation andRelationship Between Mitigation and AdaptationAdaptation
- 25. Dealing with Global ClimateDealing with Global Climate Change- MitigationChange- Mitigation o Locate/invent alternative fuels to fossil fuelsLocate/invent alternative fuels to fossil fuels o Increase efficiency of cars and trucksIncrease efficiency of cars and trucks o Sequestering carbon before it is emittedSequestering carbon before it is emitted o Plant and Maintain trees to naturally sequesterPlant and Maintain trees to naturally sequester carboncarbon
- 26. Dealing with Global Climate Change-Dealing with Global Climate Change- AdaptationAdaptation o Rising sea levels andRising sea levels and coastal populationscoastal populations • Move inlandMove inland • Construct dikesConstruct dikes and leveesand levees o Adapt to shiftingAdapt to shifting agricultural zonesagricultural zones o NYC sewer lineNYC sewer line
- 27. “There were rumors of unfathomable things, and because we could not fathom them we failed to believe them, until we had no choice it was too late.”
- 28. Ozone DepletionOzone Depletion o Stratospheric ozoneStratospheric ozone o UV lightUV light o Chemical processesChemical processes o Environmental effectsEnvironmental effects o SolutionsSolutions
- 29. AtmosphereAtmosphere o Stratospheric ozoneStratospheric ozone o 20-30 km altitude20-30 km altitude o 19 mi at equator, 9 mi at the poles19 mi at equator, 9 mi at the poles o 400 ppb400 ppb
- 30. Ozone shieldOzone shield o 99% of all UV is absorbed99% of all UV is absorbed (UVC and most UVB)(UVC and most UVB) o UVA is not affected byUVA is not affected by ozoneozone
- 31. Production of ozoneProduction of ozone
- 32. Measurement of OzoneMeasurement of Ozone o Dobson units: 1 ppbDobson units: 1 ppb ozoneozone o Survey began in 1957 overSurvey began in 1957 over the Antarcticthe Antarctic o Taken in October,Taken in October, springtimespringtime o 1957-1970: 300 DU1957-1970: 300 DU o 150 DU by 1986150 DU by 1986
- 33. Ozone and CFC’sOzone and CFC’s o Molina and Rowland in 1974Molina and Rowland in 1974 o CFC’s are stableCFC’s are stable o Long residence in lowerLong residence in lower atmosphereatmosphere o UV radiation breaks down CFCUV radiation breaks down CFC and releases Cland releases Cl o Cl reacts with OCl reacts with O33 o Increase UVB at the surfaceIncrease UVB at the surface
- 34. Formation and destruction of ozoneFormation and destruction of ozone
- 36. UsageUsage 2003
- 38. Polar Stratospheric cloudsPolar Stratospheric clouds o Polar winter formationPolar winter formation o Have polar vortexHave polar vortex o Isolated air massIsolated air mass o Nitrogen oxides held inNitrogen oxides held in clouds as nitric acidclouds as nitric acid o NONO33 particles grow and fallparticles grow and fall outout o Facilitates ozone depletingFacilitates ozone depleting reactionsreactions
- 39. Polar vortexPolar vortex In Springtime, sunlight Returns No nitrate to form CloNO2
- 40. Environmental effectsEnvironmental effects o UV damage to DNAUV damage to DNA o Skin cancerSkin cancer o CataractsCataracts o Suppression of immune systemSuppression of immune system o Ecosystem:Ecosystem: o Primary producersPrimary producers o Food chainsFood chains o Development in aquatic larvaDevelopment in aquatic larva
- 41. Managing ozone depletionManaging ozone depletion o Montreal protocol, Sept 1987–Montreal protocol, Sept 1987– Production of CFC eliminationProduction of CFC elimination o Economic gapEconomic gap o Replacements: HFC and HCFCReplacements: HFC and HCFC o Shorter lifetime, less reactiveShorter lifetime, less reactive o Collection and reuse (noCollection and reuse (no venting)venting) o Expensive replacementsExpensive replacements
- 42. Climate ChangeClimate Change o Climate SwingsClimate Swings o Greenhouse gasesGreenhouse gases o EvidenceEvidence o PredictionsPredictions o ControlControl
- 43. Historic Climate shiftsHistoric Climate shifts o Milankovitch cycles: shifts in earth‘s orbit and tiltMilankovitch cycles: shifts in earth‘s orbit and tilt o Volcanic activity: Mt. TobaVolcanic activity: Mt. Toba
- 44. El Nino/Southern OscillationEl Nino/Southern Oscillation o Trade winds keep warm water inTrade winds keep warm water in W. Pacific. La NinaW. Pacific. La Nina o El Nino: Shift in tropicalEl Nino: Shift in tropical depressiondepression o Northern Jet stream splits changesNorthern Jet stream splits changes rainfall patternsrainfall patterns o Pacific decadal oscillation: warmPacific decadal oscillation: warm water in northern pacific moveswater in northern pacific moves back and forth.back and forth. o Cool water in north help AlsakaCool water in north help Alsaka salmon runs, warm off coast andsalmon runs, warm off coast and then switches.then switches.
- 45. Human ActivitiesHuman Activities o IndustrializationIndustrialization o COCO22 increased 31%, CHincreased 31%, CH44 inc 151%, Ninc 151%, N22O inc 17% over since pre-O inc 17% over since pre- industrial times.industrial times. o 40% of excess CO40% of excess CO22 absorbed by oceansabsorbed by oceans o Methane a big problemMethane a big problem
- 46. Evidence of Climate ChangeEvidence of Climate Change o Avg global temperature has climbed 0.6Avg global temperature has climbed 0.6oo C over last centuryC over last century o Arctic sea ice is 40% thinner, Antarctic glaciers are retreating 50m/yr.Arctic sea ice is 40% thinner, Antarctic glaciers are retreating 50m/yr. o Alpine glaciers are retreatingAlpine glaciers are retreating o Ocean acidificationOcean acidification o Sea level has risenSea level has risen o Changes in animal behavior, breeding cyclesChanges in animal behavior, breeding cycles o Storm frequency and intensity are increasingStorm frequency and intensity are increasing
- 47. Larsen B ice shelf-- AntarcticaLarsen B ice shelf-- Antarctica
- 49. ConsequencesConsequences Arctic sea ice Alpine glaciers
- 50. PredictionsPredictions Sugar maple range Predicted warming with doubling of CO2
- 51. ControlsControls
- 52. Reduction of Carbon EmissionsReduction of Carbon Emissions o Burn less fossil fuel: Turn down your thermostatBurn less fossil fuel: Turn down your thermostat o Plant Trees for shade and COPlant Trees for shade and CO22 uptakeuptake o Insulate your houseInsulate your house o Replace old appliancesReplace old appliances o Use compact fluorescence light bulbsUse compact fluorescence light bulbs o Use renewable energyUse renewable energy