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GEOL0860 EnvironmentalGeology Dr.R.C.Capo

(12) ClimateandGlobalChangeI Fall2013

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Reading:Chapters13,19-21

Whatcontrolsglobalclimatepatterns?

1.Latitudinalcontrol

2.Oceans:

3.Altitude

4.RainshadowEffect:

WhytheGobiisa

desertandnotlike

Pennsylvania

5.Urbanvs.rural:urbanheatisland

6.Albedo=Surfacereflectivity

7.WindsCoriolusforce

JetStream:migrates

ocean currents moderate temperature

GD vs PAsame latitudeGD behind the

mountain rang

Airport temp colder than that in oakland- concrete tends to create

warm area (microclimate zone)

reflectivity of the surface- high albedo (snow)light hits it and tends to reflect

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Globalclimatechange:therehavebeennumerouswarmperiodsandatleastsixmajorIceAges

SnowballEarthevidenceforearly,verylong,deepiceagesWhatdrivesglobalclimatechange?

Tectonics(movesplatestowardpolesorequator)Example:350millionyearsago:

Ocean/atmospherecirculation Volcanicactivitycancause:

Example:

Anthropogenic(thatsus,folks)welltalkaboutthatlater. Solar/orbitalvariations(Earthsorbitaroundthesunisvariable)

Solar/orbitalvariations:

PleistoceneIceAge:

glacial-interglacials=iceadvancesandretreats

Lastglacialmaximum:LGM=18,000yearsago

Why?Earthsorbitalvariations

Tilt,precessionandeccentricity

Temperaturerangebetweenglacialandinterglacials:

Only3to6C!

Glacier:massive,landboundmassofcompacted,movingsnowandice

ALPINEglaciers

Formwhere?

Latitudes: Elevation:

InmountainsExamples:

Changes in Position of continents: tectonicscs

cooling

Southern Gondwanaland

more volcanic eruptions- putsparticles up into the airlight reflects- coolsMt Pinatubo, Phillippines

Global cooling of .5C in 1992

~

precession- wobbling of the earth, tilt chaas it goes around

last 2 million years

- shape of the orbit in cycles

features about the orbit of the earth that vary and can cause climate c

ALL

High

AlpsRockiesCascades

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CONTINENTALglaciers

Where?

Latitudes:HIGH Elevation:ALLIcesheetsExamples:

Glaciallandscapes:

a.Erosionalfeatures

Chattermarksandglacialstriations

formfrom:glaciermovementover

rocks

Glacialvalleyshapes:

1. U-shapedvalleys

2.Hangingvalleys

Fjord:

Horn:fromcirqueserodedonthreesides

Lakes-scouredoutbyglaciers

Alpine:tarns Continental:largelakes Twoexamples:

b,Depositionalfeatures

Till:

Loess:fine-grainedwind-blowndepositsof:

Asaglaciermeltsandretreatsinterglacialfeatures

(even sea level)

(Polar- most at poles)

Antarctica--> has largest icebergs

Greenland--> tallest bergs(icebergs)Crevasses- cracks that

form in brittle upper 40m of a glacier

deep, narrow inlet

Cirque- circular basins (ski areas)

ex: finger lakes, NY

Great lakes

carved out by glaciers!!!!

example that's gone now: Glacial lake MissoulaChanneled scablands formed where dam was breachedunsorted sediments

Dust (silt)

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Moraines Drumlins

Example:Adirondackshavebotherosionalanddepositionalfeatures

Alpineandcontinentalglaciersaremeltingveryrapidlywhy?

Globalclimatechange:thehumanfactor.Recentunprecedentedchanges--likelyresultofhumanactivities

RecentrapidtemperatureriseiscorrelatedwitharapidriseinatmosphericCO 2(andotheranthropogenicgreenhousegases)sincetheIndustrialAge

Humanactivities,especiallytheuseoffossilfuelsisincreasingemissionofCO2andothergases

GlobalmeansurfaceairtemperaturewilllikelyincreaseThisislargerandmorerapidthananyinhumanhistory

(Terminal)

(valley) (till)

arctic sea ice decline,