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Environmental Science: Toward a Sustainable Future Richard T. Wright

Feb 24, 2016

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Environmental Science: Toward a Sustainable Future Richard T. Wright. Chapter 20. The Atmosphere: Climate, Climate Change, and Ozone Depletion PPT by Clark E. Adams. El Niño: What Happened?. Jet streams shifted from normal course Cause unknown. April. May. June. El Niño: What Happened?. - PowerPoint PPT Presentation

WFSC 420 Chapter 21

Environmental Science: Toward a Sustainable Future Richard T. WrightThe Atmosphere: Climate, Climate Change, and Ozone Depletion PPT by Clark E. AdamsChapter 20El Nio: What Happened?Jet streams shifted from normal courseCause unknown

AprilMayJune

El Nio: What Happened?Development of warm water in the eastern Pacific over timeReversal in trade winds that normally blow from an easterly directionEl Nio: What Happened?Warm water spread to the eastGlobal patterns in moisture and evaporation changed = climate shiftsThe El Nio Effects: Fig. 20-1Landslides on the California coastMildest hurricane season in many yearsRain five times normal in an East Africa drought regionRecord crop harvests in India, Australia, and ArgentinaLa Nia: What Happened?Easterly trade winds reestablished with greater intensityUpwelling of colder water from ocean depthsJet streams are weakenedGlobal patterns in moisture and evaporation return to normalThe Atmosphere: Climate, Climate Change, and Ozone DepletionAtmosphere and weatherClimateGlobal climate changeResponse to climate changeDepletion of the ozone layerAtmosphere and WeatherAtmospheric structureWeatherAtmospheric Structure

Weather: Solar Energy BalanceMost solar energy absorbed by atmosphere, oceans, and landWeather: Convection Cell

TornadoesCold low-pressure air mass collides with a warm high-pressure air mass

http://www.photolib.noaa.gov/nssl/nssl0065.htmFujita Scale Measures the Intensity of TornadoesF-0: 4072 mph, chimney damage, tree branches brokenF-1: 73112 mph, mobile homes pushed off foundations or overturnedF-2: 113157 mph, considerable damage, mobile homes demolished, trees uprooted

Fujita Scale Measures the Intensity of TornadoesF-3: 158205 mph, roofs and walls torn down, trains overturned, cars thrownF-4: 207260 mph, well-constructed walls leveledF-5: 261318 mph, homes lifted off foundation and carried considerable distances, autos thrown as far as 100 metersClimateOcean and atmosphereClimates in the pastClimateDefined as the average trend in temperature and rainfall that produces a unique assemblage of plants and animalsOn the next slide identify climates A to E, e.g., low average rainfall and high average temperature = hot desertIdentify Climates A to EPrecipitationTemperatureLowHighHighABCDEClimates in the Past

Past Climates

Ocean and AtmosphereCovers 75% of the Earths surfaceMajor source of water to hydrologic cycleMajor source of heat to atmosphereStores and conveys heatThe Ocean Conveyor System

The Ocean Conveyor SystemThermohaline circulation: effects that temperature and salinity have on density of waterConveyor system moves water masses from the surface to deep oceans and back againCool northern waters more dense and sink to depths of 4,000 m = North Atlantic Deep Water (NADW)

The Ocean Conveyor SystemDeep water spreads southward to south Africa and joined by cold Antarctic watersSpread northward into Indian and Pacific oceans as deep currentsCurrent slows down, warms up, becomes less dense, rises to the surface, and moves back to North AtlanticProduces a warm climate in Europe

The Ocean Conveyor SystemFactors that could alter the conveyor systemAppearance of unusually large quantities of freshwater melting icebergsGlobal warmingGlobal Climate ChangeThe Earth as a greenhouseThe greenhouse gasesEvidence of climate changeThe Earth as a Greenhouse

Factors Affecting Global TemperaturesCloud cover: coolingChanges in Suns intensity: cooling or warmingVolcanic activity: coolingSulfate aerosols: cooling

Greenhouse Gases: CO2 Emissions from Fossil Fuel Burning35% higher than before industrial revolutionOceans = CO2 sinkForests = CO2 source24 billion metric tons CO2 added each yearOther Greenhouse Gases and SourcesWater vaporMethaneNitrous oxideCFCs and other halocarbonsHydrologic cycleAnimal husbandryChemical fertilizers*Refrigerants** = Long residence times and contribute toozone depletion

Atmospheric CO2 Concentrations

Global Surface TemperaturesGlobal Carbon Cycle

Impacts of Global WarmingMelting of polar ice capsFlooding of coastal areasMassive migrations of people inlandImpacts of Global WarmingAlteration of rainfall patternsDeserts becoming farmland and farmland becoming desertsSignificant losses in crop yieldsEvidences of Climatic Change17 of the hottest years on record have occurred since 1980 (Fig. 20-5)Wide-scale recession of glaciersSea level risingPredicted mean global temperature changeby 2100 is between 1.5 and 4.5oCReducing CO2 Emissions (True or False)Reducing use of fossil fuelsAdopt a wait-and-see attitudeDevelop alternative energy sourcesPlant treesExamine other possible causes of global warming

Reducing CO2 Emissions (True or False)Make and enforce energy conservation rulesRely on the governmentAdopt the precautionary principleRaise the minimum driving age to 18 yearsKey Findings of the 2000 U.S. Climate Change Assessment (Table 20-3)Increased warmingDiffering regional impactsVulnerable ecosystemsWidespread water concernsAgriculture largely unaffectedForest growth to increaseCoastlines rising sea levelsResponses to Climate ChangeResponse 1: mitigation = reduce CO2 emissionsResponse 2: adaptation = accepting and learning to live with the consequences of climate changeFramework Convention on Climate Change (FCC)Relied on voluntary approach to reduce CO2 emissionsDeveloping countries continue toward developed nation status using fossil fuelsFramework Convention on Climate Change (FCC)To achieve a 7% reduction by 2010 requires a 25% reduction of present useBy 2010 CO2 emissions will have increased by 30%Framework Convention on Climate Change (FCC)Bottom line: need 60% reduction (144 ppm) in CO2 emission worldwide NOW to stabilize greenhouse gas concentrations at todays levels

Depletion of Ozone LayerRadiation and importance of the shieldFormation and breakdown of the shieldComing to grips with ozone depletion

Good Ozone!Bad Ozone!Electromagnetic Spectrum

Radiation and Importance of the ShieldSkin cancer (700,000 new cases each year)Premature skin agingEye damageCataractsBlindnessFormation of the Ozone ShieldReaction #1: UV light + O2O + OReaction #2: Free O + O2 O3Reaction #3: Free O + O3O2 + O2Reaction #4: UV light + O3O + O2Chlorofluorocarbons (CFCs)Organic molecules in which both chlorine and fluorine atoms replace some of the hydrogen atomsSources:refrigerators and air conditionersproduction of plastic foamcleaner for electronic partspressurizing agent in aerosol cansBreakdown of Ozone ShieldReaction #5: CFCl3 + UV Cl + CFCl2Reaction #6: Cl + O3ClO + O2Reaction #7: ClO + ClO 2 Cl + O2Which reaction releases Cl from CFCs?Which reaction generates more Cl?Chlorine is a catalyst that destroys the production of ________?Montreal Protocol1987 scale back CFC production by 50% by 2000Coming to Grips with Ozone Depletion: Montreal Protocol1990 amendment to completely phase out ozone-destroying chemicals by 20001992 amendment to completely phase out ozone-destroying chemicals by 1996Why the rush?

Ozone Hole: 11 million sq.mi.The Clean Air Act of 1990: Title IVRestricts production, use, emissions, and disposal of ozone-depleting chemicalsRegulates the servicing of refrigeration and air-conditioning unitsProtecting Stratospheric OzoneEnd of Chapter 20

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