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
MO
SP
HR
E
LA
B
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
OT
FO
R
SC
IEN
TIS
TS
!
Th
e w
ay
I se
e i
t….
My
pers
on
al
op
inio
n
WH
AT
CA
N Y
OU
YO
U D
O
TO
HE
LP
SL
OW
D
OW
N G
LO
BA
L
CL
IMA
TE
CH
AN
GE
?
Neil
deG
rass
e T
yson
, A
stro
nom
er
makes
a v
ery
good
poin
t...
Temperature (Northern Hemisphere) CO2 Concentrations
1000 Years of CO2 & Global Warming
Deg
ree
Cels
ius
Incre
ase
Part
s P
er
Mil
lion
Year Year
1
00
0
120
0
140
0
160
0
180
0
200
0
100
0
120
0
140
0
160
0
180
0
200
0
2007
Goal: Reductions in CO2 Per Year
Bil
lion
s of
Metr
ic T
on
s C
arb
on
2007Reductions in CO2
Per Year
Gig
ato
n
Carb
on
Produce electricity efficientlyUse electricity efficientlyVehicle efficiencySolar and Wind PowerBiofuelsCarbon capture and storage
Bil
lion
s of
Metr
ic T
on
s C
arb
on
Our Goal
How ozone is destroyed by CFCs