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Chapter 13:
Climate Change
& Ozone Loss
I. Climate Change
A. The Greenhouse Effect is natural.
1) First described by Swedish
physicist/chemist,
Svante Arrhenius in 1896
B. Global Warming
1) Enhanced greenhouse effect due to human activity
 Fossil fuel combustion, deforestation, etc.
C. A little history…
1) Ice Core Samples:
Gas trapped in ancient
glaciers tested for air
compositions
*Increasing CO2 levels correlate with:
• Rise in air temperature
• Increased fossil fuel use
• Deforestation
2) Since 1861…
• Avg. global temperature has risen 1°F
• Sea level has increased 4-10 inches
• 1990’s and 2000- 2009= warmest decades (2012
= warmest year)
3) Other signs…
•
•
•
•
Unusual weather patterns (ex. El Niño)
Shrinking glaciers
CO2 levels higher than in last 420,000 years
20th century was warmest in last 1,000 years
D. Main Greenhouse Gases:
Warming Potential (GWP)
InGlobal
other words…
describes
gas’ warming
CO2aequivalent
(CO“strength”
2e)
Abundance
1) CO2
GWP of CO2 = 1.0 (the standard)
2) CH4
GWP of CH4 = 21.0
3) N2O
4) CFCs (synthetic chlorofluorocarbon)
GWP
5) PFCs (synthetic perfluorocarbon)
6) SF5CF3 (synthetic trifluoromethyl sulfur pentafluoride)
Current Greenhouse Gas Emissions
United States
Global
Source: IPCC (2007)
Intergovernmental Panel on Climate Change
Greenhouse Gas Emissions by Source
United States
Global
Land Use, Land-Use Change, and Forestry in the
United States is a net sink and offsets approximately
15% of these greenhouse gas emissions.
Source: IPCC (2007)
Greenhouse
Gas
Sources of Atmospheric Increase
c & plants)
Carbon Dioxide (CO2) • Combustion (fossil fuels
• Deforestation
c
Methane (CH4)
•
•
•
•
Nitrous Oxide (N2)
• Combustion of fossil fuels
c
• Fertilizers (& production
c of)
Fluorinated Gases
• Refrigerants (AC’s, refrigerators,
etc.)
c
• Industrial processes c
Agriculture (rice paddies,
c cows, etc.)
Natural gas leaks
c
Anaerobic decomposition
(*landfills)
c
Melting permafrost (positive
feedback loop)
c
2008 Global CO2 Emissions from Fossil Fuel Combustion and some
Industrial Processes (million metric tons of CO2)
Source: National CO2 Emissions from Fossil-Fuel Burning, Cement Manufacture, and Gas Flaring: 1751-2008.
Global Carbon Dioxide (CO2) emissions from fossil-fuels 1990-2008
Source of data: Boden, T.A., G. Marland, and R.J. Andres (2010). Global, Regional, and National Fossil-Fuel CO2 Emissions. Carbon Dioxide
Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. doi
10.3334/CDIAC/00001_V2010.
Total U.S. Greenhouse Gas Emissions, 1990-2010
All emission estimates from the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 19902010 .
E. Looking Towards the Future
1) Scientific Consensus: It’s time to change! (see p. 306)
•
Established in 1988 by World
Meteorological Organization & the
United Nations Environment Program
•
Over 2,000 scientists from 195
countries
•
•
Signed 1997; first commitment 2008
Amendment 2012
Cooperating countries commit to reduce GHG emissions
2008-2012: 5% below 1990 levels
2013-2020: 18% below 1990 levels
Mechanisms:
International Emissions Trading
Clean Development Mechanism
Joint Implementation
Kyoto Protocol participation map (commitment period: 2013-2020)
Parties; Annex I & II countries with binding targets
Parties; Developing countries without binding targets
States not Party to the Protocol
Signatory country with no intention to ratify the treaty, with no binding targets
Countries that have denounced the Protocol, with no binding targets
Parties with no binding targets in the second period, which previously had targets
E. Looking Towards the Future
2) Reducing Greenhouse Warming (see p. 313-316)
• Higher energy efficiency
• Change/tighten government regulations on
fossil fuels & emissions
• Alternate/renewable energy sources
• Harvest trees sustainably (sustainable yield)
• Carbon Dioxide Capture & Sequestration
Preparing for the effects of global warming…
Also…
Use & engineer
drought-resistant plants
II. Ozone Depletion (see p 321)
A. Summary of CFC/Ozone Reactions:
CCl3F + UV
Cl + O3
ClO + O
Cl + CCl2F
ClO + O2
Cl + O2
UV
CFCl32
Cl
Cl C
F Cl
O
O
O O
O
O O
O
O O
ClO
O
O O
O
O O
O
O
O O
O O
O
O O
O O
O
O
O O
O
O O
B. Ozone Depleting Chemicals (ODCs) Include…
*Released by human activities since the 1950s
1) Chlorofluorocarbons (CFCs)
a) Released from A/Cs, refrigerators, etc.
b) Propellants (spray cans); the US banned use
for this purpose in 1986
c) Produced while making/burning plastics
d) Very persistent  65-385 years
2) Other ODCs:
a) Halon: fire extinguishers
2) Other ODCs:
b) Methyl Bromide: pest fumigant
2) Other ODCs:
c) Carbon Tetrachloride (CCL4): used to be in fire
extinguishers and solvent
2) Other ODCs:
d) Methyl Chloroform/TCE (trichloroethene): dry
cleaning solvent
2) Other ODCs:
e) HCl: released by space shuttles
Good thing we
cancelled the
program!
C. Seasonal Ozone Thinning
1) Thinning is most severe over the poles
*Greatest over Antarctica
2) Why seasonal?
Polar Winter:
• No direct solar radiation
• Chlorine (from CFCs) trapped in the polar vortex
Polar Spring:
• Direct solar radiation
• Cl released & reacts with ozone
• 40%-50% ozone loss
Polar Summer:
• Vortex weakens
• CFCs & Cl disperse
• Ozone rebuilds
Which month?
D. Effects on Human Health
1) More sun burns
…I was in the Bahamaaas!
2) Eye Cataracts
3) Immune System Suppression
4) Skin Cancer (p. 321)
a) Squamous Cell Carcinoma
• Upper epidermis
• Least dangerous but can metastasize
b) Basal Cell Carcinoma
• Most common
• Curable if treated early
c) Melanoma
• Cancerous melanocytes (pigment cells)
• Metastasizes quickly
• Most deadly (kills ¼ of victims)
*Mostly caused by
UV-A
E. Environmental Effects
1) Reduced crop yield (up to $2.5 billion loss/year!)
2) Reduced forest productivity
3) Reduced phytoplankton productivity
Increased UV exposure
F. Solutions
1) Substitutions for CFCs
a) HCFCs: less reactive/persistent
b) HFCs: non-reactive with ozone
*DuPont took 14 years to change production!
2) Montreal Protocol (1987 – present)
a) Goal: Reduce ODC emissions/find alternatives
b) All UN recognized nations have ratified the treaty