Climate Change and Ozone LossClimate Change and Ozone Loss

G. Tyler Miller’sLiving in the Environment

13th Edition

Chapter 18

G. Tyler Miller’sLiving in the Environment

13th Edition

Chapter 18

Temperature change over past 22,000 yearsTemperature change over past 22,000 years

Years agoYears ago

Tem

per

atu

re c

han

ge

(°C

)T

emp

erat

ure

ch

ang

e (°

C)

20,00020,000 10,00010,000 2,0002,000 1,0001,000 200200 100100 NowNow

-5-5

-4-4

-3-3

-2-2

-1-1

00

11

22

End oflast iceage

Agriculture establishedAgriculture established

Average temperature over pastAverage temperature over past10,000 years = 15°C (59°F)10,000 years = 15°C (59°F)

Past Global TemperaturesPast Global TemperaturesPast Global TemperaturesPast Global Temperatures

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

Recent Trends in Global Temperature

Recent Trends in Global Temperature

Average temperature over past 130 yearsAverage temperature over past 130 years

YearYear

Ave

rag

e su

rfac

e te

mp

erat

ure

(°C

)A

vera

ge

surf

ace

tem

per

atu

re (

°C)

18601860 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

Recent Trends in Global Temperature

Recent Trends in Global Temperature

Climate ChangeClimate Change

Past globaltemperatures

Past globaltemperatures

Recent trends in global temperatures

Recent trends in global temperatures

• Radioisotopes in rocks and Radioisotopes in rocks and fossilsfossils

• Plankton and radioisotopes in Plankton and radioisotopes in ocean sedimentsocean sediments

• Pollen from lake bottomsPollen from lake bottoms• Ice cores from ancient glaciersIce cores from ancient glaciers• Tree ringsTree rings• Radioisotopes in coralsRadioisotopes in corals• Historical recordsHistorical records• Temperature measurementsTemperature measurements

How do we know what past temperature changes were?

How do we know what past temperature changes were?

The Natural Greenhouse Effect

(tropospheric heating effect)

The Natural Greenhouse Effect

(tropospheric heating effect)

Greenhouse Gases in the Largest Concentration

Greenhouse Gases in the Largest Concentration

•Water VaporWater Vapor•Carbon DioxideCarbon Dioxide

Hydrologic (Water) CycleHydrologic (Water) Cycle

The Carbon Cycle (Terrestrial)The Carbon Cycle (Terrestrial)

The Carbon Cycle (Aquatic)The Carbon Cycle (Aquatic)

Climate Change and Human ActivitiesClimate Change and Human Activities

1)1) Increased use of fossil fuels (COIncreased use of fossil fuels (CO2 2 ,, CHCH44))

2)2) Deforestation (CODeforestation (CO2 2 ,, NN22O)O)

3)3) Cultivation of Rice Patties (NCultivation of Rice Patties (N22O)O)

Global warmingGlobal warming = = Enhanced greenhouse Enhanced greenhouse effecteffect

1)1) Melting icecaps and glaciersMelting icecaps and glaciers

2)2) Coral reef bleachingCoral reef bleaching

3)3) OtherOther

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

Some Possible Effects of a Warmer World

Some Possible Effects of a Warmer World

• Water Distribution• Plant and Animal Biodiversity Loss• Ocean Currents and Sea Levels• Extreme Weather• Human Population and Health• Agriculture and Forests

Some Possible Effects of a Warmer World

Some Possible Effects of a Warmer World

Fig. 18-16p. 461

Fig. 18-16p. 461

Removing CO2 From the AtmosphereRemoving CO2 From the Atmosphere

Fig. 18-21p. 467

Treeplantation

Coalpower plant

Tanker deliversCO2 from plantto rig

Oil rig

Crop field Switchgrassfield

Spent oil reservoir isused for CO2 deposit

CO2 is pumpeddown to reservoir through abandoned oil field

Abandonedoil field

CO2 is pumped downfrom rig for Deep ocean disposal

= CO2 deposit

= CO2 pumping

Reducing Greenhouse Gas EmissionsReducing Greenhouse Gas Emissions

• Rio Earth Summit (1992)Rio Earth Summit (1992)– 106 nations106 nations– Scientific uncertainty must not be Scientific uncertainty must not be

used as justification to do nothing.used as justification to do nothing.– Industrialized nations must take Industrialized nations must take

lead in slowing down lead in slowing down raterate and and degreedegree of global warming. of global warming.

– Developed countries Developed countries voluntarily voluntarily committed to reducing COcommitted to reducing CO22 to to 1990 levels by the year 20001990 levels by the year 2000

Reducing Greenhouse Gas EmissionsReducing Greenhouse Gas Emissions

• Kyoto TreatyKyoto Treaty (1997) (1997)– 161 nations161 nations– Required 38 developed countries to Required 38 developed countries to

cut greenhouse emissions 5.2% below cut greenhouse emissions 5.2% below 1990 levels by 2012..1990 levels by 2012..

– Did Did notnot require developing countries require developing countries to make cuts.to make cuts.

– Allowed emission trading among Allowed emission trading among participating countries.participating countries.

– Was not ratified until 2005Was not ratified until 2005– Approximately 180 participating Approximately 180 participating

countries.countries.

United States did not ratify United States did not ratify Kyoto Treaty -Kyoto Treaty -United States did not ratify United States did not ratify Kyoto Treaty -Kyoto Treaty -

1)1) Treaty fails to require emission Treaty fails to require emission reductions from developing reductions from developing countries (81% of world’s countries (81% of world’s population)population)

2)2) Economists predicted it would have Economists predicted it would have devastating impact on U.S. devastating impact on U.S. economy and workerseconomy and workers

Some U.S. CO2 ReductionsSome U.S. CO2 Reductions

• Concern among leaders of some U.S. companies.

• Several major companies have established targets to reduce greenhouse gas emissions by 10-65% from 1990 levels by 2010.

• Automobile companies investing in hybrid gas-electric and fuel cell engines.

• Local governments established programs to reduce greenhouse gas emissions.

• California first state to require a reduction in CO2

emissions from motor vehicles beginning in 2009.

A growing number of A growing number of analysts suggest we analysts suggest we should begin to prepare should begin to prepare for the possible effects of for the possible effects of long-term atmospheric long-term atmospheric warming and climate warming and climate change!change!

Ozone Depletion in the Ozone Depletion in the StratosphereStratosphere

(the other story)(the other story)

Ozone Depletion in the Ozone Depletion in the StratosphereStratosphere

(the other story)(the other story)

Alt

itu

de

(k

ilom

ete

rs)

Ozone concentration (ppm)

Alt

itu

de

(m

iles)Stratospheric ozone

Stratosphere

Troposphere

40

35

30

25

20

15

10

5

00 5 10 15 20

0

5

10

15

20

25

Photochemical ozone

Benefical Ozone

Harmful Ozone

Ozone Depletion in the StratosphereOzone Depletion in the Stratosphere

Importance of OzoneImportance of Ozone• Essential for terrestrial lifeEssential for terrestrial life• Reduces sunburnReduces sunburn• Prevents tropospheric ozonePrevents tropospheric ozone

Ozone Depletion in the StratosphereOzone Depletion in the Stratosphere

Fig. 18-26 p. 473Fig. 18-26 p. 473

SunOnce free, the chlorine atom is off to attack another ozone moleculeand begin the cycle again.

A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O2.

The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO).

UV radiation

Cl Cl

ClC

F

The chlorine atom attacks an ozone (O3) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O2).

Cl

Cl

OO

O

Cl

ClO

ClO

OO

OO

Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl3, breaking off a chlorine atom and leaving CFCl2.

O

Fig. 20-18, p. 486

Stepped Art

Ozone Depleting ChemicalsOzone Depleting Chemicals

Chlorofluorocarbons (CFCs)Methyl bromide (fumigant)Halons (fire extinguishers)Carbon tetrachloride (solvent)Methyl chloroform (cleaning

solvent and propellant)N-propyl bromide (solvent)

OZONE DEPLETION IN THE STRATOSPHEREOZONE DEPLETION IN THE STRATOSPHERE

• During four months of each year up to half of the ozone in the stratosphere over Antarctica and a smaller amount over the Artic is depleted.

Reasons for ConcernReasons for Concern

Increased incidence and severity of sunburn Increased incidence and severity of sunburn

Increase in eye cataracts Increase in eye cataracts

Increased incidence of skin cancer Increased incidence of skin cancer

Immune system suppression Immune system suppression

Increase in acid deposition Increase in acid deposition

Lower crop yields and decline in productivity Lower crop yields and decline in productivity

Fig. 20-22, p. 489

This long-wavelength(low-energy) form of UV radiation causes aging of the skin, tanning, and sometimes sunburn. It penetrates deeply and may contribute to skin cancer.

This shorter-wavelength (high-energy) formof UV radiation causes sunburn, prematureaging, and wrinkling. It is largely responsiblefor basal and squamous cell carcinomasand plays a role in malignant melanoma.

Epidermis

Squamous Cell Carcinoma

Basal Cell Carcinoma

Melanoma

Sweatgland

Dermis

Squamous cells

Thin layer ofdead cells

Basal layer

Melanocyte cells

Bloodvessels

UltravioletB

UltravioletA

Hair

Basalcell

Solutions: Protecting the Ozone LayerSolutions: Protecting the Ozone Layer

Use CFC substitutes Use CFC substitutes

Montreal Protocol (1987)only CFCs

Montreal Protocol (1987)only CFCs

Copenhagen Copenhagen Protocol Protocol (1992)(1992)

all ODCsall ODCs

Characteristics of Global Warming and Ozone Depletion

Characteristics of Global Warming and Ozone Depletion

Global Warming

COCO22, CH, CH44, NO, NOxx (greenhouse gases)(greenhouse gases)

Absorbs infrared (IR) Absorbs infrared (IR) radiationradiation

Raising the earth’s Raising the earth’s surface surface temperaturetemperature

Decrease burning of Decrease burning of fossil fuelsfossil fuels

Ozone Depletion

OO33, O, O22, and CFCs, and CFCs

Absorbs ultraviolet Absorbs ultraviolet (UV) radiation(UV) radiation

Decreasing ODecreasing O33 concentration in the concentration in the stratospherestratosphere

Eliminate CFCsEliminate CFCs