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Chapter 18 Study Guide

Chapter 18 Study Guide and Case Studies: Anthropogenic Changes - The Atmosphere

Key Concepts

• Theglobalaveragetemperatureroseby1.3°Cbetween1860and2017.• Whilesomesmallerfluctuationsinthe20thcenturymayhavebeencausedby

moresolaractivityandalackofglobalvolcanism.Thesharpincreaseinthelast30yearshasnonaturalcause.

• Globalwarmingcausesmountainglaciersandcontinentalicesheetstomelt.Thismeltraisesglobalsealevel.

• TheVEI61991eruptionofMt.Pinatubo,Philippines temporarily loweredglobalaveragetemperatureby0.5°C,therebyoffsettingglobalwarming

• The current warming is caused primarily by the increase in atmosphericcarbon dioxidewhich is a greenhouse gas and currently has no significantnaturalsource.

• Anthropogenic increase of atmospheric CO2 comes from fossil fuel burning(80%),deforestation(17.3%)andcementproduction(2.7%).

• Secondary contributors are increasing amounts of methane that also hasincreaseexponentially.This increasehasnaturalandwellasanthropogenicsources.

• Anthropogenic increase of atmospheric CH4 comes from cattle farming(29%), waste disposal (28%%), fossil fuel production (27%) and ricepaddies(16%).

• Other contributors are nitrous oxides, ozone and CFCs. The latter isexclusivelyanthropogenic.

• CO2 levels in the atmosphere has been measured directly since 1958 onMauna Loa, Hawaii (Keeling curve). For times prior to that, CO2 levels areestimatedfromicecoresinGreenlandandAntarctica.

• Sincethebeginningoftheindustrialageattheendofthe1700s,atmosphericCO2hasincreasedbymorethan40%from280ppmto400ppmin2016.

• Seasonal variations of atmospheric CO2 are only a few ppm and so muchsmallerthantheoverallincrease.

• Between1958and2016,atmosphericCO2has increasedby26% from318ppmto400ppm.ThismeansthattheincreaseinCO2hasaccelerated6-foldfrom0.24ppm/yrbefore1958to1.41ppm/yrsince1958.

• Until2009,theU.S.wastheworld’slargestcontributortoanthropogenicCO2with25%ofallemissions. In2009,ChinasurpassedtheU.S.as theworld’stop emitter. In 2014, Indonesia was the 3rd top contributor throughdeforestation.

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Chapter 10 Study Guide

• Natural causes of temperature fluctuations are millennial warming, solarwarmingandvolcanism.Allofthesecannotexplainthecurrentwarming.

• Themeltingofglaciersandicesheetsinawarmingclimateleadstosealevelrise.

• Inthelast100years,globalsealevelhasrisenby15cm• Contributorstoglobalsealevelrisearemeltingofglaciers(20%),meltingof

Greenlandicesheet(20%)andthermalexpansionofwarmingoceans(30%).TheimpactofthemeltingAntarcticicesheetisstillanareaofresearchanddebated.Icebergsandseaice(e.g.theArcticseaice)donotcontributetosealevelrise.

• Variousclimatescenariosincluding‘businessasusual’todrasticallyreducinganthropogenicCO2predictatemperatureincreaseof2–5°Candasealevelriseby40–100cmby2100.

• Asealevelriseontheorderof1maffectsmanycountriesaroundtheworld.• The1997KyotoProtocolaimedtostabilizeatmosphericCO2at450ppm.To

achieve this goal, anthropogenic emission would have to fall below 1990levelsby2012.Theprotocolneeded toberatifiedbymore thanhalfof theemitters to be effective. Thiswas the case in 2004 after Russia joined theprotocol.

• TheKyotoProtocolwas opposedby oil-producing countries, the fossil fuelindustryandmajorfossilfuelusers(U.S.,China).

• The U.S. never joined the Kyoto Protocol and was the only industrializednation not to do so. The argument was that a ratification of the KyotoProtocolwouldhurttheU.S.economy.

• The successor to theKyotoProtocol is the2015ParisAgreement. TheU.S.hasannouncedtoleavetheParisAgreement.

• OzoneinthestratosphereinteractswithincomingUVsunlightsothatEarth’ssurfaceisprotectedfromthisharmfulUVradiation.

• Inthe1980s,athinningoftheozonelayerwasdetectedduringtheAntarcticspring. The associated reduction in ozone came from the destruction byanthropogenicCFCsthatareusedinrefrigeratorsandairconditioners.

• In1987,theMontrealProtocolwasestablishedtophaseoutCFCs.Theozonehole has slowly recovered but other agents that replaced the CFCs stilldestroyozoneandaregreenhousegases.

Key Terms

• Globalaveragetemperature• Mountainglaciers• Icesheets• Anthropogenicgreenhouse• Fossilfuels• deforestation• Industrialera

• Keelingcurve• SeasonalCO2variations• World’stopCO2emitters• Sealevelrise• Thermalexpansion• KyotoProtocol• ParisAgreement

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Chapter 18 Study Guide

• Ozonehole• Stratosphere• UVradiation

• Antarcticspring• CFCs• MontrealProtocol

Questions for Review

1. Byhowmuchhastheaverageglobaltemperaturechangedbetween1860and2017?

2. Howhasthetrendchangedinthelastfewdecades?

3. Whichnaturalprocessescausedminimaltemperaturefluctuations?

4. Discusstheinterplaybetweentemperaturefluctuationsandsealevelchange.

5. Whatisthemaincauseoftherecenttemperatureincrease?

6. BywhichprocessesareanthropogenicCO2andCH4produced?

7. Whatothergreenhousegasescontributetoglobalwarming?

8. WhatistheKeelingcurve?

9. HowdoseasonalvariationsinatmosphericCO2comparetotheoverallchangesince1958?

10. WhywouldatmosphericCO2changethroughouttheyear?

11. HowhasatmosphericCO2changedrecentlyincomparisontoearlierinthe20thcentury?

12. Discusstheworld’stopCO2emitters.

13. Whatnaturalprocessescouldchangeglobalaveragetemperatureandcantheyexplainthecurrentwarming?

14. Describehowsealevelhaschangedinthelast100years.Whyisthischangeoccurring?

15. Whatarethepredictionsfortemperatureandsealevelchangeforthiscentury?

16. WhatistheKyotoProtocol?Discuss.

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Chapter 10 Study Guide

17. DiscussthesuccessortotheKyotoProtocol.

18. WhatistheOzonehole?Whatcausesit?

19. WhatistheMontrealProtocol?Discuss.

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Chapter 18 Study Guide

Case Studies

Case Study 1: Projected Consequences of Global Warming for San Diego

On Nov. 19, 2008 the San Diego Union Tribune released a report written by the San Diego Foundation (SDF) to the California Climate Action team to describe the consequences of climate change for the San Diego Region by 2050. The Tribune summarized the main projections:

o sea level will be 12-18 inches higher o the region will require 37% more water while resources (such as the

Colorado River) will be less by at least 20% o the fire season will start earlier; the number of days with ideal conditions

for large wildfires will increase by up to 20% o peak electricity demand will be 70% higher

The summary of the San Diego Foundation actually goes further and says it more bluntly: In 2050, if current trends continue ...

o sea level will be 12-18 inches higher o San Diego's climate will be hotter and drier o Wildfires will be more frequent and intense o We will face severe water shortage o Public health will be at risk, especially among the elderly and children o Native plant and animal species will be lost forever o We will not be able to meet our energy needs

The full report is available in pdf format at the SDF website.