Atmospheric and Climate Atmospheric and Climate ChangeChange

Chapter 13Chapter 13

13-1 Climate and Climate Change13-1 Climate and Climate Change

ObjectivesObjectives

1.1.Explain the difference between weather and Explain the difference between weather and climate.climate.

2.2.Identify four factors that determine climate.Identify four factors that determine climate.

3.3.Explain why different parts of the earth have Explain why different parts of the earth have different climates.different climates.

4.4.Explain what causes the seasons.Explain what causes the seasons.

What Factors determine climate?What Factors determine climate?

ClimateClimate-long term prevailing -long term prevailing weatherweather (state of the atmosphere)(state of the atmosphere)

Determined by:Determined by:

Latitude, atmospheric conditions, Latitude, atmospheric conditions, circulation patterns, oceanic patterns, circulation patterns, oceanic patterns, local geography, solar activity, and local geography, solar activity, and volcanic activity.volcanic activity.

LatitudeLatitude

–Amount of solar energy Amount of solar energy that reaches the surfacethat reaches the surface

Atmospheric circulationAtmospheric circulation–Warm air rises, cold air Warm air rises, cold air

sinkssinks–Warm air holds more Warm air holds more

moisturemoisture–Heat differences cause Heat differences cause

windswinds

Global Circulation PatternsGlobal Circulation Patterns– Patterns are disrupted at the equatorPatterns are disrupted at the equator

Cool air rises at the equator and is forced to the Cool air rises at the equator and is forced to the polespoles

Air condenses and 30 degrees N and S Air condenses and 30 degrees N and S Air sinks, causes water to evaporate from landAir sinks, causes water to evaporate from land Flows back to the poles or equatorFlows back to the poles or equator

Prevailing winds (westerlies)Prevailing winds (westerlies)– Blow from one direction most of the yearBlow from one direction most of the year– Trade winds at 30 degrees N and STrade winds at 30 degrees N and S

Ocean Circulation patternsOcean Circulation patterns– Hold vast amounts of heatHold vast amounts of heat– Currents redistribute heatCurrents redistribute heat– Cold and warm currentsCold and warm currents

–El NinoEl Nino – Southern – Southern OscillationOscillationShort-term periodic change in the Short-term periodic change in the

location of warm and cold currents location of warm and cold currents in the Pacific oceanin the Pacific ocean

Winds in west Pacific become Winds in west Pacific become stronger and push warm water stronger and push warm water eastwardeastward

Causes drought in Indonesia and Causes drought in Indonesia and AustraliaAustralia

–La Nina -La Nina -Water in the Pacific is Water in the Pacific is colder than usualcolder than usual

–Pacific Decadal oscillationPacific Decadal oscillationLong term change in Long term change in currentscurrents

Local geographyLocal geography

–Mountain rangesMountain ranges

Seasonal changesSeasonal changes

Solar activitySolar activity

–Increase UV and energy Increase UV and energy from the sunfrom the sun

Volcanic activityVolcanic activity

–Releases gases (SOReleases gases (SO22)and )and

dust into the atmosphere dust into the atmosphere which affects weatherwhich affects weather

13-2 Ozone Shield13-2 Ozone ShieldObjectivesObjectives1.1.Explain how the ozone layer shields the Earth from Explain how the ozone layer shields the Earth from

much of the sun’s harmful radiation.much of the sun’s harmful radiation.2.2.Explain how chlorofluorocarbons damage the Explain how chlorofluorocarbons damage the

ozone layer.ozone layer.3.3.Explain the process by which the ozone hole forms.Explain the process by which the ozone hole forms.4.4.Describe the damaging effects of ultraviolet Describe the damaging effects of ultraviolet

radiation.radiation.5.5.Explain why the threat to the ozone layer is still Explain why the threat to the ozone layer is still

continuing today.continuing today.

Ozone ShieldOzone Shield

Ozone layerOzone layer – ozone is – ozone is concentratedconcentrated–OO33

–Absorbs UV – protects DNA Absorbs UV – protects DNA of all living thingsof all living things

Chemicals that cause Ozone Chemicals that cause Ozone depletiondepletion

–CFC’s CFC’s (chlorofluorocarbons)(chlorofluorocarbons) damages ozonedamages ozoneStable at surface but reacts Stable at surface but reacts in atmospherein atmosphere

destroys ozone moleculesdestroys ozone molecules

Ozone holeOzone hole Thinning of atmospheric ozone Thinning of atmospheric ozone

that occurs at the polesthat occurs at the poles

–First report in 1985, but noticed First report in 1985, but noticed in 1970’sin 1970’s

– Chlorine reacts with ozone and destroys itChlorine reacts with ozone and destroys it Form in Form in polar stratospheric cloudspolar stratospheric clouds

– Can’t be replaced by ground level ozoneCan’t be replaced by ground level ozone

AffectsAffects

–Increased UV radiationIncreased UV radiationDamages DNADamages DNACancerCancerWeaker immune systemWeaker immune system

Kills phytoplanktonKills phytoplanktonHarms amphibians, marine Harms amphibians, marine life, and plantslife, and plants

Protection of OzoneProtection of Ozone

–International agreements International agreements (Montreal Protocol) to (Montreal Protocol) to eliminate CFC useeliminate CFC useUS pledged to ban all US pledged to ban all substances by 200substances by 200–Did we do it??Did we do it??

Level is going downLevel is going down

It will be years before It will be years before affects of programs can be affects of programs can be measured because CFCs measured because CFCs stay active for 60-120 stay active for 60-120 yearsyears

13-3 Global Warming13-3 Global Warming

ObjectivesObjectives

1.1. Explain why Earth’s atmosphere is like the glass in Explain why Earth’s atmosphere is like the glass in a greenhouse.a greenhouse.

2.2. Explain why carbon dioxide in the atmosphere Explain why carbon dioxide in the atmosphere appears to be increasing.appears to be increasing.

3.3. Explain why many scientists think that the Earth’s Explain why many scientists think that the Earth’s climate may be becoming increasingly warmer.climate may be becoming increasingly warmer.

4.4. Describe what a warmer Earth might be like.Describe what a warmer Earth might be like.

Greenhouse affectGreenhouse affect

Traps sun energyTraps sun energyMajor Major greenhouse gases greenhouse gases (absorb and radiate heat):(absorb and radiate heat):

Water vapor, COWater vapor, CO22, CFCs, , CFCs,

methane, and nitrous methane, and nitrous oxidesoxides

KeelingKeeling

– Started measuring COStarted measuring CO22 levels levels

1958 – 314 ppm1958 – 314 ppm 2000 – 368 ppm2000 – 368 ppm

– Increased use of fossil fuelsIncreased use of fossil fuels

– Levels have normal seasonal fluctuationsLevels have normal seasonal fluctuations

–Increase of COIncrease of CO22 could cause could cause

a global rise in temperature a global rise in temperature ((global warmingglobal warming))Glaciers and poles meltGlaciers and poles melt

–Sea level riseSea level rise

AffectsAffects

–Increase of global temperatureIncrease of global temperature

–Rise of sea levelRise of sea levelLoss of coastlineLoss of coastline

–AgricultureAgricultureDroughts or too much rainDroughts or too much rain

Some scientists believe that the Some scientists believe that the warming is part of natural climatic warming is part of natural climatic variabilityvariability–What is the evidenceWhat is the evidence??

Consequences of a Warmer EarthConsequences of a Warmer Earth

These things could happen rather caused These things could happen rather caused by nature or man….by nature or man….

Melting of ice and sea level riseMelting of ice and sea level rise Global weather patterns changeGlobal weather patterns change Human health problemsHuman health problems AgricultureAgriculture Plants and animalsPlants and animals

How do we reduce the risk?How do we reduce the risk?

ReforestationReforestation Reduce dependence of on Reduce dependence of on

fossil fuelsfossil fuels Reduce use of harmful Reduce use of harmful

chemicalschemicals International agreements - International agreements -

–Kyoto ProtocolKyoto Protocol