Global Climate Change:Global Climate Changehome.olemiss.edu/~cmchengs/Global Warming/Session...

Global Climate Change:Global Climate Change:Global Climate Change:Global Climate Change:Scales and ComplexitiesScales and Complexitiespp

“Left” side of screen“Left” side of screen “Right” side of screen“Right” side of screen

Climate Change/VariabilityClimate Change/VariabilityE th’ hi t (4 6 billi ) i fill dEarth’s history (4.6 billion years) is filled with climate changes at all scales:– warmer intervals, colder intervals– changes in atmospheric compositionchanges in atmospheric composition– intervals of different land, ocean, mountain

distributiondistributionClimatic variability refers to fluctuations in the characteristic (expected!) elements--mainly TA and P y A

MS Climate Controls:MS Climate Controls:Location

T i t l idl tit d– Tropics to lower midlatitude– Bermuda High

W t li /t d– Westerlies/trades– Continent/Gulf of Mexico

cP vs mT air masses– cP vs mT air masses– Frontal passages, hurricanes, thunderstorms,

tornadoestornadoesResult – humid subtropical climate (less than 8% of land surface))

GCM forecast for July 2029 temp (mean GCM forecast for July 2029 temp (mean change = +1.5change = +1.5ooC) [notice geographic nonC) [notice geographic non--gg ) [ g g p) [ g g p

uniformity]uniformity]

Source = Goddard Institute for Space Studies

Comparison: Comparison: One state vs aOne state vs aOne state vs a One state vs a hemispherehemisphere——geographic nongeographic nongeographic nongeographic non--uniformity!!uniformity!!

Proof of Global Warming!!Proof of Global Warming!!

What Is The Evidence for Past What Is The Evidence for Past GlobalGlobal Changes in Climate?Changes in Climate?GlobalGlobal Changes in Climate?Changes in Climate?

Instrument measurements--150 years at bestHistorical data--1000 yearsP d tProxy data:– Continental glaciation (landforms, etc.)– ice sheets: cores, isotope analysis, SL changes– sediments: lake/sea floorsediments: lake/sea floor– fossils, pollen, tree ringsTh d liThese are used to reconstruct past climates

What Are Possible Causes of What Are Possible Causes of Climate Changes on These Scales?Climate Changes on These Scales?Climate Changes on These Scales?Climate Changes on These Scales?

Natural causes (in order of scale)Anthropogenic causes--CO O ??Anthropogenic causes--CO2, O3 ??

Fox huntingFox hunting

Continental DriftContinental Drift

Milankovitch Cycles: Orbital Eccentricities = Variations in Milankovitch Cycles: Orbital Eccentricities = Variations in Insolation??Insolation??

“Stretch”“Stretch”----100,000 year 100,000 year cyclecycle

“Wobble”“Wobble”----26,000 year cycle26,000 year cycle“Roll”“Roll”----41,000 year cycle41,000 year cycle

Sunspot Sunspot activityactivityactivityactivity

MaunderMaunder

Sunspot outbreakSunspot outbreak normalnormal

Maunder Maunder Minimum: 1645Minimum: 1645--17151715——less than less than one normal year’sone normal year’sone normal year’s one normal year’s worth in a 70worth in a 70--yr yr period=coldest period=coldest part of Little Ice part of Little Ice AgeAge

Mount St. Helens EruptionMount St. Helens Eruption----May 18, 1980May 18, 1980(Volcanic Ash Blown into the Atmosphere)(Volcanic Ash Blown into the Atmosphere)

Approximate volume of volcanic debris Approximate volume of volcanic debris emitted during some wellemitted during some well--known eruptionsknown eruptions

Tambora ejected Tambora ejected over 100 times moreover 100 times moreover 100 times more over 100 times more ash than did Mount ash than did Mount St. HelensSt. Helens——1816=“year without 1816=“year without a summer”a summer”

Carbon dioxide concentrations over the last 1000 yearsCarbon dioxide concentrations over the last 1000 years

Rapid increase Rapid increase since 1850 is tied since 1850 is tied t f il f lt f il f lto fossil fuel to fossil fuel emissionsemissions

Calculate amount of CO2 released by Calculate amount of CO2 released by burning of fossil fuels since 1958 (260 b tons)burning of fossil fuels since 1958 (260 b tons)

Emissions more than enough toEmissions more than enough to cause the observed increasesBut, measured rate of increase is 44% less than the total emissionsPuzzle—where is the “missing” 44%?Answer—”mopped up” (absorbed) by oceans and terrestrial biosphere

The The Balance Balance Balance Balance

of of NatureNatureNatureNature

Long-term Carbon Dioxide Atmospheric Concentration, Vostok Ice Sheet, Antarctica

400 000 years

290

310400,000 years

250

270

n (p

pm)

230

250

ncen

tratio

n

190

210

CO

2 Con

150

170

2 4 7 7 6 8 6 1 2 7 1 0 0 0 9 6 4 0 0 4 5

2342

3388

4

8572

7

1125

77

1257

46

1328

18

1382

26

1643

41

1915

92

2081

77

2172

71

2267

10

2392

50

2538

80

2686

79

2878

46

3033

34

3189

80

3352

90

3730

14

4140

85

Age of Entrapped Air, Yr BP

Reconstruction of Past Reconstruction of Past ClimatesClimates

Let’s look at what is mostly acceptedLet s look at what is mostly accepted as the history of climate on earth– throughout geologic time– in historic times– in the most recent yearsTh l k t f fl t tiThen look at causes of fluctuations we are experiencing today (measured!)

QuaternaryQuaternary

GeologicGeologicGeologic Geologic perspective on perspective on climateclimateclimate climate changechange——4.5 4.5 billibillibillion yearsbillion years

Last 600,000 yearsLast 600,000 years

100 000100 000--year glaciationsyear glaciations100,000100,000--year glaciationsyear glaciations

10,00010,000--year interglacialsyear interglacials

Last 11,000 yearsLast 11,000 years

LastLastMedieval maximumLast Last

glaciationglaciation

Historic records (1000 years)Historic records (1000 years)

Thermal Thermal max of max of early early 1900s1900s

Valley Valley ForgeForge

Variation of Annual Mean Land Surface Variation of Annual Mean Land Surface Temperature of the World, 1866Temperature of the World, 1866--2005 2005 p ,p ,

(departures from 1951(departures from 1951--80 mean)80 mean)

Thermal max of early y1900s

“Hockey “Hockey S i k”S i k”Stick” Stick” graphgraphg pg p

When did the instrumental When did the instrumental record begin?!record begin?!

The analysis missed a couple of major, The analysis missed a couple of major, historic climate fluctuationshistoric climate fluctuations ——is it credible?is it credible?historic climate fluctuations historic climate fluctuations is it credible?is it credible?

Within a trend of overall cooling, global temps can vary widely, creating warming trends like we are now experiencing

Remember, the “now” is the end of a Remember, the “now” is the end of a very long story of ups and downs….very long story of ups and downs….

Illustration of “perspective”Illustration of “perspective”You may have seen this structure before, but it can still get your attention.

p pp p

Did you know the world's tallest building is in Canada?

It's called the Canadian National Tower in Toronto and is used forIt s called the Canadian National Tower in Toronto and is used for telecommunications.

It's height is 553.3 meters or 1,815 feet so you know it's been g yphotographed a lot.

I'm a big fan of architecture and have gone back and looked at thisphoto several times.

It's truly amazing. See for yourself....

Distribution of temperature stations (a) now (b) preDistribution of temperature stations (a) now (b) pre--19001900

(a)(a)

(b)(b)

Temperature measurements prior and Temperature measurements prior and subsequent to changing from old max/min liquid subsequent to changing from old max/min liquid q g g / qq g g / q

in glass thermometers to new electronic in glass thermometers to new electronic thermometersthermometers

(Karl et al., 1995)

Hadley NASA

Since 1998 only

Hadley Center for Climate PredictionHadley Center for Climate Prediction——largest largest precipitous change ever measured, up or downprecipitous change ever measured, up or downp p g , pp p g , p

SatelliteSatellite--measured monthly globally averaged measured monthly globally averaged lower atmospheric temperature variationslower atmospheric temperature variationsp pp p

30

Hurricane Frequency

25

30

Are hurricanes increasing?

Is there a natural cause?

20

d St

orm

s

s e e u c use?

15

ber

of N

amed

5

10Num

0

5

197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005

Year

Lots of FEMA trailors!Lots of FEMA trailors!

The history of theThe history of the Atlantic Multidecadal OscillationAtlantic Multidecadal Oscillation (AMO)(AMO)Index shows that positive and negative phases typically last Index shows that positive and negative phases typically last forfor 20 to 40 years20 to 40 years.. Since 1994, the AMO index has been Since 1994, the AMO index has been positive, indicating that the United States might be headed positive, indicating that the United States might be headed into a prolonged period of increased hurricane activityinto a prolonged period of increased hurricane activityinto a prolonged period of increased hurricane activity.into a prolonged period of increased hurricane activity.

Regional variationRegional variation----Redneck hot tub!Redneck hot tub!

Greensburg, KS EFGreensburg, KS EF--5 5 May 2007May 2007

Tornadoes Reported Per Year

2000 350

1600

1800

2000

300

350

1200

1400

1600

nado

es

200

250

illio

ns)

Population Population growthgrowth

800

1000

ber o

f Tor

n

150

200

Popu

latio

n (m

400

600Num

0

100 U.S.

P

Reported Reported t dt d

0

200

0

50tornadoestornadoes

1950

1953

1956

1959

1962

1965

1968

1971

1974

1977

1980

1983

1986

1989

1992

1995

1998

2001

2004

Year

Atmospheric CirculationAtmospheric Circulation----Normal ConditionsNormal Conditions

Atmospheric CirculationAtmospheric Circulation----El Nino ConditionsEl Nino Conditions

Light at the end of the tunnelLight at the end of the tunnel

Climate ChangeClimate Change——Increased Increased impacts on a more populous Earthimpacts on a more populous Earthimpacts on a more populous Earthimpacts on a more populous Earth

•• Atlanta water supply 2007Atlanta water supply 2007——distributiondistribution•• Atlanta water supply 2007Atlanta water supply 2007——distribution distribution problem?problem?–– 9 million in GA9 million in GA9 million in GA9 million in GA–– 7 million in north GA7 million in north GA–– 5 million in Atlanta!! 5 million in Atlanta!!

•• MS Delta aquiferMS Delta aquifer——water volume declinewater volume decline–– Much more irrigation nowMuch more irrigation now–– Drought increases demand, multiplies impact Drought increases demand, multiplies impact

ControversyControversy CautionCautionControversyControversy----CautionCaution

•• Scientific polarizationScientific polarization•• Political/policy confusionPolitical/policy confusionPolitical/policy confusionPolitical/policy confusion•• Firing 3 State ClimatologistsFiring 3 State Climatologists•• Alarmism “snake oil salesmen”Alarmism “snake oil salesmen”•• Alarmism, “snake oil salesmen”Alarmism, “snake oil salesmen”