Climate Change and Ozone LossClimate Change and Ozone Loss

Climate ChangeReview session

Climate ChangeReview session

Brian Kaestner and Dr. Richard ClementsBrian Kaestner and Dr. Richard Clements

Key ConceptsKey Concepts

How does the Earth’s climate fluctuate How does the Earth’s climate fluctuate

What factors affect climate What factors affect climate

What are the possible effects of global warming What are the possible effects of global warming

What can humans do about potential climate change

What can humans do about potential climate change

Past Climate ChangePast Climate Change

Past globaltemperatures

Past globaltemperatures

Recent trends in global temperatures

Recent trends in global temperatures

Average temperature over past 900,000 yearsAverage temperature over past 900,000 years

Thousands of years agoThousands of years ago900900 800800 700700 600600 500500 400400 300300 200200 100100 PresentPresent

Av

era

ge

su

rfa

ce

te

mA

ve

rag

e s

urf

ac

e t

em

pe

ratu

re (

°C)

pe

ratu

re (

°C)

991010

1111

1212

1313

14141515

1616

1717

Av

era

ge

su

rfa

ce

te

mp

era

ture

(°C

)A

ve

rag

e s

urf

ac

e t

em

pe

ratu

re (

°C) Average temperature over past 130 yearsAverage temperature over past 130 years

YearYear18601860 18801880 19001900 19201920 19401940 19601960 19801980 20002000 20202020

13.613.6

13.813.8

14.014.0

14.214.2

14.414.4

14.614.6

14.814.8

15.015.0

Average temperature over past 900,000 years

Thousands of years ago

Ave

rag

e su

rfac

e te

mp

erat

ure

(°C

)

900 800 700 600 500 400 300 200 100 Present9

10

11

12

13

14

15

16

17

Temperature change over past 22,000 years

Years ago

Tem

per

atu

re c

han

ge

(°C

)

20,000 10,000 2,000 1,000 200 100 Now

-5

-4

-3

-2

-1

0

1

2

End oflast iceage

Agriculture established

Average temperature over past10,000 years = 15°C (59°F)

Temperature change over past 1,000 years

Year

Tem

per

atu

re c

han

ge

(°C

)

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2101

-1.0

-0.5

0.0

0.5

1.0

Average temperature over past 130 years

Year

Ave

rag

e su

rfac

e te

mp

erat

ure

(°C

)

1860 1880 1900 1920 1940 1960 1980 2000 2020

13.6

13.8

14.0

14.2

14.4

14.6

14.8

15.0

The Natural Greenhouse EffectThe Natural Greenhouse Effect

Greenhouse effectGreenhouse effect Greenhouse gasesGreenhouse gases

Rays of sunlight penetrate Rays of sunlight penetrate the lower atmosphere and the lower atmosphere and warm the earth's surface.warm the earth's surface.

The earth's surface absorbs much of The earth's surface absorbs much of the incoming solar radiation and the incoming solar radiation and degrades it to longer-wavelength degrades it to longer-wavelength infrared radiation (heat), which rises infrared radiation (heat), which rises into the lower atmosphere. Some of into the lower atmosphere. Some of this heat escapes into space and some this heat escapes into space and some is absorbed by molecules of is absorbed by molecules of greenhouse gases and emitted as greenhouse gases and emitted as infrared radiation, which warms the infrared radiation, which warms the lower atmosphere.lower atmosphere.

As concentrations of greenhouse As concentrations of greenhouse gases rise, their molecules gases rise, their molecules absorb and emit more infrared absorb and emit more infrared radiation, which adds more heat radiation, which adds more heat to the to the lower atmosphere.lower atmosphere.

(a)(a) (b)(b) (c)(c)

Carbon dioxide

Temperaturechange End of

last ice age

160 120 80 40 0Thousands of years before present

Co

nc

entr

ati

on

of

carb

on

dio

xid

ein

th

e a

tmo

sph

ere

(p

pm

)

180

200

220

240

260

280

300

320

340

360

380

–10.0

–7.5

–5.0

–2.5

0

+2.5

Va

riat

ion

of

tem

pe

ratu

re (

˚C)

fro

m c

urr

en

t le

vel

Carbon dioxide (CO2)

Year1800 1900 2000 2100

260

310

360

410P

arts

per

mil

lio

n

Methane (CH4)

Year1800 1900 2000 2100

0.6

1.2

1.8

2.4P

arts

per

mil

lio

n

Year1990 2000 2025 2050 2075 2100

100

150

200

250

Ind

ex

(19

00

= 1

00

)Carbon dioxide

MethaneNitrous oxide

Human Activities and Earth’s ClimateHuman Activities and Earth’s Climate

Action-Increased use of fossil fuelsAction-Increased use of fossil fuels-Deforestation -Deforestation

CausesGlobal warmingCausesGlobal warming

Leads to-Melting icecaps and glaciersLeads to-Melting icecaps and glaciers-Coral reef bleaching-Coral reef bleaching

Projecting Future Changes in Earth’s ClimateProjecting Future Changes in Earth’s Climate

Climate models Climate models

Apparent influence of human activities

Apparent influence of human activities

Could be natural changes

Could be natural changes

YearYear18601860 18801880 19001900 19201920 19401940 19601960 19801980 20002000 20102010

-0.2-0.2

0.00.0

0.20.2

0.40.4

0.60.6

0.80.8

1.01.0

1.21.2Observed

Model of greenhouse gases + aerosols + solar output

Tem

per

atu

re c

han

ge

(°C

) fr

om

198

0–9

9 m

ean

Tem

per

atu

re c

han

ge

(°C

) fr

om

198

0–9

9 m

ean

Factors Affecting Changes in Earth’s Average TemperatureFactors Affecting Changes in Earth’s Average Temperature

Changes in solar output Changes in solar output

Changes in Earth’s albedo Changes in Earth’s albedo

Moderating effect of oceans

Moderating effect of oceans

Clouds and water vapor Clouds and water vapor

Air pollution Air pollution

Oceans 5%

Bare sand 30–60%

Grass 15–25%

Clouds50–55%

Snow80–90%

City 10–15%

Forest 5%

Antarctica

Cold water melting fromAntarctica's ice cap and

icebergs falls to the ocean floor and surges northward, affecting

worldwide circulation.

Cold water melting fromAntarctica's ice cap and

icebergs falls to the ocean floor and surges northward, affecting

worldwide circulation.

GreenlandGreenland

Today’s sea level

Years before present Present

250,000 200,000 150,000 100,000 50,000 0

–130

0

–426

0

Hei

gh

t ab

ove

or

bel

ow

pre

sen

t se

a le

vel

(met

ers)

Hei

gh

t b

elo

w p

rese

nt

sea

leve

l (f

eet)

Presentrange

Futurerange

Overlap

Climate zonesMove 60-90 milesPer 1Degree C

Tree speciesCan migrateAbout 5 milesPer decade

Some Possible Effects of a Warmer WorldSome Possible Effects of a Warmer World

• Increased deaths from heat and disease

• Disruption of food and water supplies

• Spread of tropical diseases to temperate areas

• Increased respiratory disease

• Increased water pollution from coastal flooding

Human Health

• Rising sea levels• Flooding of low-lying

islands and coastal cities• Flooding of coastal

estuaries, wetlands, and coral reefs

• Beach erosion• Disruption of coastal

fisheries• Contamination of coastal

aquifiers with salt water

Sea Level and Coastal Areas

• Changes in forest composition and locations

• Disappearance of some forests

• Increased fires from drying

• Loss of wildlife habitat and species

Forests

• Changes in water supply

• Decreased water quality

• Increased drought

• Increased flooding

Water Resources

• Shifts in food-growing areas

• Changes in crop yields

• Increased irrigation demands

• Increased pests, crop diseases, and weeds in warmer areas

Agriculture

• Extinction of some plant and animal species

• Loss of habitats

• Disruption of aquatic life

Biodiversity

• Prolonged heat waves and droughts

• Increased flooding

• More intense hurricanes, typhoons, tornadoes, and violent storms

Weather Extremes

• Increased deaths

• More environmental refugees

• Increased migration

Human Population

N

S

Waste less waterDevelop crops that need less water

Move hazardous material storage tanks away from coast

Prohibit new construction on low-lying coastal areas

Stockpile 1 to 5 year supply of key foods

Expand existing wildlife reserves toward poles

Connect wildlife reserves with corridors

Solutions: Dealing with the Threat of Climate ChangeSolutions: Dealing with the Threat of Climate Change

OptionsOptions

Do nothing Do nothing

Do more research Do more research

Act now to reduce risks

Act now to reduce risks

Prevention Cleanup

Cut fossil fueluse (especiallycoal)

Shift from coalto natural gas

Transfer energyefficiency andrenewable energytechnologiesto developingcountries

Improve energyefficiency

Shift torenewableenergy resources

Reducedeforestation

Use sustainableagriculture

Slow populationgrowth

Remove CO2

from smokestackand vehicleemissions

Store (sequesterCO2 by plantingtrees)

Sequester CO2

underground

Sequester CO2 in soil

Sequester CO2 in deep ocean