Environmental Science: Toward a Sustainable Future Richard T. Wright The Atmosphere: Climate, Climate Change, and Ozone Depletion PPT by Clark E. Adams Chapter 20

El Niño: What Happened? Jet streams shifted from normal course Cause unknown AprilMay June

The El Niño Effects: Fig Landslides on the California coast Mildest hurricane season in many years Rain five times normal in an East Africa drought region Record crop harvests in India, Australia, and Argentina

La Niña: What Happened? Easterly trade winds reestablished with greater intensity Upwelling of colder water from ocean depths Jet streams are weakened Global patterns in moisture and evaporation return to “normal”

Atmospheric Structure

Weather: Solar Energy Balance Most solar energy absorbed by atmosphere, oceans, and land

Weather: Convection Cell

Tornadoes Cold low-pressure air mass collides with a warm high- pressure air mass

Fujita Scale Measures the Intensity of Tornadoes F-0: 40–72 mph, chimney damage, tree branches broken F-1: 73–112 mph, mobile homes pushed off foundations or overturned F-2: 113–157 mph, considerable damage, mobile homes demolished, trees uprooted

Fujita Scale Measures the Intensity of Tornadoes F-3: 158–205 mph, roofs and walls torn down, trains overturned, cars thrown F-4: 207–260 mph, well-constructed walls leveled F-5: 261–318 mph, homes lifted off foundation and carried considerable distances, autos thrown as far as 100 meters

Climates in the Past

Ocean and Atmosphere Covers 75% of the Earth’s surface Major source of water to hydrologic cycle Major source of heat to atmosphere Stores and conveys heat

The Ocean Conveyor System

The Earth as a Greenhouse

Factors Affecting Global Temperatures Cloud cover: cooling Changes in Sun’s intensity: cooling or warming Volcanic activity: cooling Sulfate aerosols: cooling

Atmospheric CO 2 Concentrations

Global Surface Temperatures

Global Carbon Cycle

Impacts of Global Warming Melting of polar ice caps Flooding of coastal areas Massive migrations of people inland

Evidences of Climatic Change 17 of the hottest years on record have occurred since 1980 (Fig. 20-5) Wide-scale recession of glaciers Sea level rising Predicted mean global temperature change by 2100 is between 1.5 and 4.5 o C

Responses to Climate Change Response 1: mitigation = reduce CO 2 emissions Response 2: adaptation = accepting and learning to live with the consequences of climate change

Framework Convention on Climate Change (FCC) Relied on voluntary approach to reduce CO 2 emissions Developing countries continue toward developed nation status using fossil fuels

Framework Convention on Climate Change (FCC) To achieve a 7% reduction by 2010 requires a 25% reduction of present use By 2010 CO 2 emissions will have increased by 30%

Framework Convention on Climate Change (FCC) Bottom line: need 60% reduction (144 ppm) in CO 2 emission worldwide NOW to stabilize greenhouse gas concentrations at today’s levels

Depletion of Ozone Layer Radiation and importance of the shield Formation and breakdown of the shield Coming to grips with ozone depletion

Good Ozone! Bad Ozone!

Electromagnetic Spectrum

Formation of the Ozone Shield Reaction #1: UV light + O 2 O + O Reaction #2: Free O + O 2 O3O3 Reaction #3: Free O + O 3 O 2 + O 2 Reaction #4: UV light + O 3 O + O 2

Breakdown of Ozone Shield Reaction #5: CFCl 3 + UV Cl + CFCl 2 Reaction #6: Cl + O 3 ClO + O 2 Reaction #7: ClO + ClO 2 Cl + O 2 Which reaction releases Cl from CFCs? Which reaction generates more Cl? Chlorine is a catalyst that destroys the production of ________?

Montreal Protocol 1987 – scale back CFC production by 50% by 2000

Coming to Grips with Ozone Depletion: Montreal Protocol 1990 – amendment to completely phase out ozone-destroying chemicals by – amendment to completely phase out ozone-destroying chemicals by 1996 Why the rush?

Ozone Hole: 11 million sq.mi.

The Clean Air Act of 1990: Title IV Restricts production, use, emissions, and disposal of ozone-depleting chemicals Regulates the servicing of refrigeration and air-conditioning units “Protecting Stratospheric Ozone”

Greenhouse GasesOzone Where Type of Light Chemicals What’s the big deal? Major Law How do we fix it?

End of Chapter 20