Climate Change and Ozone Loss G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 18 G. Tyler Miller’s Living in the Environment 13 th Edition Chapter 18

Key Concepts How does the Earth’s climate fluctuate?How does the Earth’s climate fluctuate? What factors affect climate?What factors affect climate? What are the possible affects of global warming?What are the possible affects of global warming? How are human activities affecting the ozone layer?How are human activities affecting the ozone layer?

12 Average temperature over past 900,000 years Thousands of years ago Average surface temperature (°C) Present Past Global Temperatures

Temperature change over past 22,000 years Years ago Temperature change (°C) 20,00010,0002,0001, Now End of last ice age Agriculture established Average temperature over past 10,000 years = 15°C (59°F) Past Global Temperatures

Temperature change over past 1,000 years Year Temperature change (°C) Recent Trends in Global Temperature

Average temperature over past 130 years Year Average surface temperature (°C) Recent Trends in Global Temperature

Climate Change  Past global temperatures  Recent trends in global temperatures

Radioisotopes in rocks and fossilsRadioisotopes in rocks and fossils Plankton and radioisotopes in ocean sedimentsPlankton and radioisotopes in ocean 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?

The Natural Greenhouse Effect (tropospheric heating effect)

Moist surface warmed by sun Flows toward low pressure, picks up moisture and heat Warm, dry air Hot, wet air Falls, is compressed, warms Rises, expands, cools Heat released radiates to space LOW PRESSURE HIGH PRESSURE Cool, dry air Condensation and precipitation HIGH PRESSURE HIGH PRESSURE LOW PRESSURE LOW PRESSURE Natural Cooling Process

Greenhouse Gases in the Largest Concentration Water VaporWater Vapor Carbon DioxideCarbon Dioxide

Hydrologic (Water) Cycle 

The Carbon Cycle (Terrestrial)

The Carbon Cycle (Aquatic)

Greenhouse Gases from Human Activities Greenhouse Gas Average Time in the Troposphere Relative Warming Potential (CO 2 ) Carbon Dioxide years 1 Methane years 23 Nitrous Oxide years 296 Chloroflorocarbons years 900-8,300 Hydrochloro- flurocarbons years 470-2,000 Hydroflurocarbons years ,700 Halons 65 years 5,500 Carbon Tetrachloride 42 years 1,400

Climate Change and Human Activities 1)Increased use of fossil fuels (CO 2, CH 4 ) 2)Deforestation (CO 2, N 2 O) 3)Cultivation of Rice Patties (N 2 O) Global warming = Enhanced greenhouse effect –Melting icecaps and glaciers –Coral reef bleaching –Other

Temperature (Cº) Year CO 2 concentration (ppm) Fossil fuels burn (billions of metric tons of oil equivalent) CO 2 Temperature Fossil fuels Connections

Projecting Future Changes in Earth’s Climate  Climate models (see Spotlight p. 457)  Apparent influence of human activities  Could be natural changes Fig p. 455

Factors Affecting Changes in Earth’s Average Temperature  Changes in solar output  Changes in Earth’s albedo  Moderating effect of oceans  Clouds and water vapor  Air pollution

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 Fig p. 461 Fig p. 461

Solutions: Dealing with the Threat of Climate Change Options  Do nothing  Do more research  Act now to reduce risks  Act now no-regrets strategy Fig p. 466

Removing CO 2 From the Atmosphere Fig p. 467 Tree plantation Coal power plant Tanker delivers CO 2 from plant to rig Oil rig Crop fieldSwitchgrass field Spent oil reservoir is used for CO 2 deposit CO 2 is pumped down to reservoir through abandoned oil field Abandoned oil field CO 2 is pumped down from rig for Deep ocean disposal = CO 2 deposit = CO 2 pumping

Reducing Greenhouse Gas Emissions Rio Earth Summit (1992)Rio Earth Summit (1992) –106 nations –Scientific uncertainty must not be used as justification to do nothing. –Industrialized nations must take lead in slowing down rate and degree of global warming. –Developed countries voluntarily committed to reducing CO 2 to 1990 levels by the year 2000

Reducing Greenhouse Gas Emissions Kyoto Treaty (1997)Kyoto Treaty (1997) –161 nations –Required 38 developed countries to cut greenhouse emissions 5.2% below 1990 levels by –Did not require developing countries to make cuts. –Allowed emission trading among participating countries. –Was not ratified until 2005 –Approximately 180 participating countries.

United States did not ratify Kyoto Treaty - 1)Treaty fails to require emission reductions from developing countries (81% of world’s population) 2)Economists predicted it would have devastating impact on U.S. economy and workers

Some U.S. CO 2 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 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 CO 2 emissions from motor vehicles beginning in 2009.

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

Ozone Depletion in the Stratosphere (the other story)

Altitude (kilometers) Ozone concentration (ppm) Altitude (miles) Stratospheric ozone Stratosphere Troposphere Photochemical ozone Benefical Ozone Harmful Ozone

Ozone Depletion in the Stratosphere Importance of Ozone Essential for terrestrial lifeEssential for terrestrial life Reduces sunburnReduces sunburn Prevents tropospheric ozonePrevents tropospheric ozone

Ozone Depletion in the Stratosphere Fig p. 473

Sun Once free, the chlorine atom is off to attack another ozone molecule and 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 C F The chlorine atom attacks an ozone (O 3 ) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O 2 ). Cl O O O O O O O O O Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl 3, breaking off a chlorine atom and leaving CFCl 2. O Fig , p. 486 Stepped Art

Ozone 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 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.

Seasonal Thinning at the Poles  Ozone thinning (hole)  Polar vortex Fig p. 475

Reasons for Concern  Increased incidence and severity of sunburn  Increase in eye cataracts  Increased incidence of skin cancer  Immune system suppression  Increase in acid deposition  Lower crop yields and decline in productivity

Fig , 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) form of UV radiation causes sunburn, premature aging, and wrinkling. It is largely responsible for basal and squamous cell carcinomas and plays a role in malignant melanoma. Epidermis Squamous Cell Carcinoma Basal Cell Carcinoma Melanoma Sweat gland Dermis Squamous cells Thin layer of dead cells Basal layer Melanocyte cells Blood vessels Ultraviolet B Ultraviolet A Hair Basalcell

Solutions: Protecting the Ozone Layer  Use CFC substitutes  Montreal Protocol (1987)  only CFCs  Montreal Protocol (1987)  only CFCs Copenhagen Protocol (1992)  Copenhagen Protocol (1992)  all ODCs

Characteristics of Global Warming and Ozone Depletion Global Warming CO 2, CH 4, NO x (greenhouse gases) Absorbs infrared (IR) radiation Raising the earth’s surface temperature Decrease burning of fossil fuels Ozone Depletion O 3, O 2, and CFCs Absorbs ultraviolet (UV) radiation Decreasing O 3 concentration in the stratosphere Eliminate CFCs Ozone Depletion O 3, O 2, and CFCs Absorbs ultraviolet (UV) radiation Decreasing O 3 concentration in the stratosphere Eliminate CFCs

2007 FRQ #3