1. 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

2. 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?

3. 12 Average temperature over past 900,000 years Thousands of years ago Average surface temperature (°C) 900800700600500400300200100Present 9 10 11 13 14 15 16 17 Past Global Temperatures

4. Temperature change over past 22,000 years Years ago Temperature change (°C) 20,00010,0002,0001,000200100Now -5 -4 -3 -2 0 1 2 End of last ice age Agriculture established Average temperature over past 10,000 years = 15°C (59°F) Past Global Temperatures

5. Temperature change over past 1,000 years Year Temperature change (°C) 100011001200130014001500160017001800190020002101 -0.5 0.0 0.5 1.0 Recent Trends in Global Temperature

6. Average temperature over past 130 years Year Average surface temperature (°C) 186018801900192019401960198020002020 13.6 13.8 14.0 14.2 14.4 14.6 14.8 15.0 Recent Trends in Global Temperature

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

8. 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?

9. The Natural Greenhouse Effect (tropospheric heating effect)Greenhouse Effect The Natural Greenhouse Effect (tropospheric heating effect)Greenhouse Effect

10. 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

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

12. Hydrologic (Water) Cycle 

13. The Carbon Cycle (Terrestrial)

14. The Carbon Cycle (Aquatic)

15. Greenhouse Gases from Human Activities Greenhouse Gas Average Time in the Troposphere Relative Warming Potential (CO 2 ) Carbon Dioxide 50-120 years 1 Methane 12-18 years 23 Nitrous Oxide 114-120 years 296 Chloroflorocarbons 11-20 years 900-8,300 Hydrochloro- flurocarbons 9-390 years 470-2,000 Hydroflurocarbons 15-390 years 130-12,700 Halons 65 years 5,500 Carbon Tetrachloride 42 years 1,400

16. 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

17. 14.7 14.6 14.5 14.4 14.3 14.2 14.1 14.0 13.9 13.8 Temperature (Cº) Year 19701980199020002005 380 375 365 355 345 335 325 CO 2 concentration (ppm) 8.4 8.0 7.6 7.2 6.8 6.4 6.0 4.8 5.6 5.2 Fossil fuels burn (billions of metric tons of oil equivalent) CO 2 Temperature Fossil fuels Connections

18. Projecting Future Changes in Earth’s Climate  Climate models (see Spotlight p. 457)  Apparent influence of human activities  Could be natural changes Fig. 18-11 p. 455

19. 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

21. 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

22. Possible Effects Melting ice caps & glaciers –Evidence = retreating glaciers, shrinking ice sheets Sea Level Rise –FROM added volumes of freshwater BUT also from thermal expansion –Coastline threats (resulting in population displacement – LA, NYC, Miami) Permafrost Decline in tundra regions (microclimate changes) Δ in Precipitation Patterns –Frequent drought, rain, snow, flooding –Increased frequency and intensity of storms over warmed surface waters (Katrina) Δ in Biology –Migration patterns disrupted, Food web disturbances, Habitat fragmentation (reduced realized niche) Human Health –Heat related illness –Disease spread by organisms now with extended range (mosquitos & malaria) Agriculture –Sea level rise will impact farmland by flooding coastal regions –Severe Drought

23. Some Possible Effects of a Warmer World Fig. 18-16 p. 461 Fig. 18-16 p. 461

24. Solutions? Options  Do nothing  Do more research  Act now to reduce risks  Act now no-regrets strategy Fig. 18-20 p. 466

25. Removing CO 2 From the Atmosphere Fig. 18-21 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

26. 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

27. Reducing Greenhouse Gas Emissions INTERNATIONAL EFFORT 1992 Earth Summit GOAL  stabilize greenhouse gases at low levels to prevent dangerous human influence on climate BUT NO DETAILS!

28. Reducing Greenhouse Gas Emissions Kyoto Protocol (1997)Kyoto Protocol (1997) –161 nations –Required 38 developed countries to cut greenhouse emissions 5.2% below 1990 levels by 2012.. –Did not require developing countries to make cuts. –Allowed emission trading among participating countries. –Was not ratified until 2005 –Approximately 180 participating countries.

29. United States did not ratify Kyoto Protocol 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

30. 1997 Kyoto ProtocolKyoto Protocol 1997 Kyoto ProtocolKyoto Protocol GOAL  set specific guidelines on reducing greenhouse emissions US initially ratified in 1998 BUSH withdrew in 2001 due to unacceptable economic burden BUSH alternative: voluntary instead of mandatory emission reductions OBAMA not focused on ratifying Kyoto as it expires Kyoto may be baby step in dealing with global climate change!

31. 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 2010. 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.

32. MITIGATION = to change current efforts to postpone global warming –Alternative Fuel Development –Increase Energy Efficiency Energy pricing taxes Eliminate energy subsidies –Plant trees to absorb CO 2 to act as carbon sinks –Carbon Management capture and preventative release of CO 2 from combustion store captured CO 2 in underground geologic formations, oceans unproven technology –Fertilize Ocean with Iron to: –increase numbers of phytoplankton –phytoplankton would remove CO 2 from water –CO 2 from atm would replace CO 2 in water –Zoo/phytoplankton then die and sink to bottom! Ecological Effects? U.S. CO 2 Reductions

33. US CO 2 Reduction Strategies ADAPTATION = adapt to changing conditions –Build dikes/levees for sea level rise (New Orleans, Army COE) –Switch to more tropical crops for farming (Do you like bananas?) –Upgrade city systems to deal with possible flooding (Upgrade Infrastructure $$)

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

35. Ozone Depletion in the Stratosphere (the other story)

36. Altitude (kilometers) Ozone concentration (ppm) Altitude (miles) Stratospheric ozone Stratosphere Troposphere 40 35 30 25 20 15 10 5 0 05 1520 0 5 10 15 20 25 Photochemical ozone Benefical Ozone Harmful Ozone

37. Ozone Depletion in the Stratosphere Importance of Ozone Importance of Ozone Essential for terrestrial lifeEssential for terrestrial life Reduces sunburnReduces sunburn Prevents tropospheric ozonePrevents tropospheric ozone Stratospheric Ozone absorbs: all UV-C radiation (most energetic, most lethal) most UV-B radiation but NO UV-A radiation

38. Causes of Ozone DepletionOzone Depletion Causes of Ozone DepletionOzone Depletion O 3 destroyed by CFCs (chloroflourocarbons) –CFCs used in aerosol propellants, coolants, solvents, insulation/styrofoam, fire retardants CFCs & others released into lower atm (troposphere) CFCs move/drift upward into stratosphere UV radiation breaks apart CFCs releasing Cl Sunlight causes chemical reaction allowing Cl to attack O 3  O 2 THUS reducing O 3 levels

39. Ozone Depletion in the Stratosphere Fig. 18-26 p. 473

40. 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. 20-18, p. 486 Stepped Art

41. Ozone Depleting Chemicals Chlorofluorocarbons (CFCs) Methyl bromide (fumigant) Halons (fire extinguishers) Carbon tetrachloride (solvent) Methyl chloroform (cleaning solvent and propellant) N-propyl bromide (solvent)

42. Effects of Ozone Depletion EFFECTS of O 3 DEPLETION 1.  UV radiation reaches surface of Earth 2. Health Problems including skin cancer, cataracts, weak immune systems 3. Disrupts ecosystems: phytoplankton production, DNA mutations

43. 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.

44. Seasonal Thinning at the Poles  Ozone thinning (hole)  Polar vortex Fig. 18-30 p. 475

45. 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

46. Fig. 20-22, 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

47. Reducing Ozone Depletion 1987 Montreal Protocol Goals 1. 50% reduction in CFC production by 1998 2. Phase out use of CFCs in developed countries by 1996 3. Phase out use of CFCs in developing countries by 2005

48. Solutions: Protecting the Ozone Layer  Use CFC substitutes  Montreal Protocol (1987)  only CFCs  Montreal Protocol (1987)  only CFCs

49. 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

50. 2007 FRQ #3