OZONE DEPLETION OZONE DEPLETION & CLIMATE CHANGE& CLIMATE CHANGE

(Ch 20)(Ch 20)

ELECTROMAGNETIC SPECTRUM

TYPES OF UV RADIATIONTYPES OF UV RADIATION

UV – A (AGING)UV – A (AGING): :

Low energy.

Thought to contribute to premature aging and wrinkling

of the skin and has recently been implicated as a cause of

skin cancer. 

  UV – B (BURNING)UV – B (BURNING): :

Medium energy.

UVB is more dangerous than UVA and has been implicated as a major cause of skin cancers,

sunburning and cataracts. 

  UV – C:UV – C:

High energy.

UVC is extremely dangerous but does not reach the earth’s

surface due to absorption in the atmosphere.  Most of the radiation below 290 nm is

absorbed by the ozone in the upper atmosphere.  Depletion of this layer increases the amount of UVC reaching ground level.

HEALTHHEALTH

OZONE LAYER DECREASES…. INCREASED UV RADIATION ENTERS

IMPACTS ON ENVIRONMENTAL SYSTEMS

Decreased Decreased primary primary

productivity productivity (land & ocean)(land & ocean)

Damage to Damage to fish/amphibianfish/amphibian

s/ mammalss/ mammals

Disrupt food Disrupt food chainchain

Effects on Effects on food crops food crops

(beans, wheat, (beans, wheat, rice, corn)rice, corn)

AT

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Cumulative Graph should look like…

OZONE DEPLETION

Ozone- molecule consisting of 3 oxygen atoms Benefit to humans because it

absorbs harmful UV radiation

Ozone layer is being depleted because of the addition of chemicals (esp. CFC’s) that break apart the ozone molecule

OZONE VIDEO (2:20)

CHEMICAL CLASSES OF OZONE DESTROYERS

CHLOROFLOUROCARBONS(CFC'S)

CHLOROFLOUROCARBONS(CFC'S)

No significant natural sources identified

Source: Air conditioning, Aerosol propellants, solvents, styrofoam

GREAT longevity takes 5-7 years for

CFC’s to go from ground to upper atm.

HALOCARBONS/HALONS (ODS)

HALOCARBONS/HALONS (ODS)

Highly reactive group 17 Cl, Br, F

Sources: Styrofoam, Solvents, Soil Fumigant, Fire Extinguishers

OZONE PHLEMISTRY WKST

O2 becomes O3

1)O2 + UV ●O + ●O

2) O2 + ●O O3 O3 becomes O2

1)O3 + UV O2 + ●O

2) O3 + ●O O2 + O2 CFCs degrades O3 into O2

1)CCl2F2 + UV ●CClF2 + ●Cl

2) ●Cl + O3 ClO● + O2

NO degrades O3 into O2

1) NO + O3 NO2 + O2 AIRPLANES!

OZONE CHEMISTRYfor the visual learners

STEP 1:NATURAL FORMATION OF OXYGEN

STEP 2: Natural Formation of Ozone in the STRATOSPHERE

Step 3: Natural Breakdown of Ozone in the STRATOSPHERE

PER CHLORINE ATOM BROKEN OFF BY UV RADIATION FROM CFC’S, 100-300,000 OZONE MOLECULES CAN BE BROKEN DOWN

(~900,000 O3 MOLEUCLES PER CFC!)

OZONE

CFCFree Radical

Chlorine

Free Radical Oxygen

OxygenCLO*

STEP 4: CFC’s BREAKING DOWN OZONE (anthropogenic causes)

Ozone over Antarctica

ANTARCTIC OZONE HOLE (16 MIN)

OZZY OZONE (10 MIN)

THOMAS MIDGLEY

CLIMATE CHANGE

Long-term change in the earth's climate, especially a change due to an increase in the average atmospheric

temperature.

CLIMATE CHANGE - GLOBAL WARMING

GLOBAL WARMING OR CLIMATE

CHANGE?

GLOBAL WARMING INDICATES THAT

THE GLOBAL TEMPERATURE IS

INCREASING AND IT IS GETTING HOTTER

EVERYWHERE.

CLIMATE CHANGE INDICATES THAT CLIMATES ARE SHIFTING AND

UNCHARACTERISTIC WEATHER PATTERNS

WILL ARISE WHEATHER THAT IS

HOTTER OR COOLER, WETTER OR DRYER.

There is absolutely ZERO debate that global temperatures have gone up and down for

centuries

Question is…

are HUMANS the

cause of the current

shift?

GREENHOUSE EFFECT

Causes of Causes of Climate ChangeClimate Change

Description of what it isDescription of what it isExplanation of how it impacts Explanation of how it impacts

climateclimate(What SCIENTISTS say)(What SCIENTISTS say)

Volcanic Volcanic eruptionseruptions

When volcanoes erupt, they release dissolved gases (like carbon dioxide,

water vapor and sulfur dioxide) into the atmosphere

Adds to the build-up of Greenhouse Gases

SunspotsSunspotsMore emitted radiation and increased

temperatures are found around sunspotsMore sunspots will increase the amount

of heat that stays within the atmosphere.

Earth’s orbitEarth’s orbitThere is variation in Earth’s tilt which affects the amount of solar radiation

received.

Depending on the season, more or less energy is received from the sun.

Carbon Carbon Dioxide Dioxide

fluctuationsfluctuations

As heat is reflected back out into space, carbon dioxide (CO2) absorbs some of the

heat.

Heat is retained in the atmosphere (not radiated back into space) causing the

global temperature to rise.

TRENDS IN ATMOSPHERIC CO2

Effects of Climate Change

1. HIGHER TEMPERATURES

Link: The Nature Conservancy

The five hottest years on record have all occurred since 1997.

2. CHANGING LANDSCAPES

Changing patterns of rain and snow are forcing trees and plants around the world to move toward polar regions and up mountain slopes

ALASKA - Portage Glacier

1914 2004

ARIZONA- Colorado River

June 2002

Dec 2003

Effects of Climate Change

3. WILDLIFE AT RISKRising temperatures are

changing weather and vegetative patterns across the globe, forcing animal

species to migrate to new, cooler areas in order to

survive.

Experts predict that 1/4 of

Earth’s species will be headed

for extinction by 2050

4. RISING SEAS

Sea level rise from climate change could displace tens of millions of people. Sea levels could continue to rise between 4 inches and 36 inches over the next 100 years.

Effects of Climate Change

5. INCREASED RISK OF DROUGHT, FIRE &

FLOODSMassive land erosion is one result of overgrazing &

drought in Kenya

6. STRONGER STORMS &

HURRICANESHurricanes and tropical storms to become more intense — lasting longer, unleashing stronger winds, and causing more damage to coastal ecosystems

Effects of Climate Change

7. MORE HEAT RELATED ILLNESS & DISEASE

As temperatures rise, so do the risks of heat-related illness and even death for the most vulnerable human populations. Increase the spread of infectious diseases.

8. ECONOMIC LOSSES Climate change could cost between

5 and 20 percent of the annual global gross domestic product. Declining crop yields could put

hundreds of thousands of people at risk for starvation.

Effects of Climate Change

9. OCEAN ACIDIFICATIO

N

As temperatures rise, so does the amount of carbon dioxide

in the ocean causing acidic water.

10. EL NINO & LA NINA

Weather patterns in the Pacific Ocean change causing an increased frequency of bad weather events to occur around the world.

Global Atmospheric Concentration of CO2

CLIMATE CHANGE CONTROVERSY?N

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Temperature (Northern Hemisphere) CO2 Concentrations

1000 Years of CO2 & Global Warming

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Goal: Reductions in CO2 Per Year

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Produce electricity efficientlyUse electricity efficientlyVehicle efficiencySolar and Wind PowerBiofuelsCarbon capture and storage

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Our Goal

How ozone is destroyed by CFCs