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CHAPTER 13 Climate Change and Ozone

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GREENHOUSE GASES & THEIR EFFECT ON THE GLOBAL CLIMATE The Greenhouse Effect

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For a stable temperature Incoming solar energy warms atmosphere Must be balanced by outgoing energy Different layers of atmosphere = different average temperature Troposphere Greenhouse effect Greenhouse gases Greenhouse gases H 2 O, CO 2, CH 4, N 2 O, CFCs

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Greenhouse Effect Greenhouse gases in the atmosphere trap heat in the troposphere (and therefore warm it) Allow light, infrared radiation, UV radiation to pass through the troposphere Earths surface absorbs this solar energy, releases as longer- wavelength solar radiation (heat) Some heat released, but much re-absorbed by greenhouse gases and re-emitted into the troposphere BrainPop BrainPop

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Greenhouse Effect Concentrations of greenhouse gasses play a key role in determining earths average temperature/climate Small changes in concentration can lead to large changes in climate Primary greenhouse gas = H 2 O Concentration already relatively high (1-5%) Human input has little effect GHG w. 2 nd largest concentration in atm = CO 2 only constitutes 0.037% of the troposphere human effect?

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Greenhouse Gas Sources CO 2 Fossil fuel burning, deforestation, plant burning CH 4 CH 4 Rice paddies, cattle, landfills, coal production, natural gas leaks Rice paddies

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Greenhouse Gas Sources CFCs Air conditioners, refrigerators, plastic foams N 2 O Fossil fuel burning, fertili- zers, livestock wastes

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Global Warming Potential (GWP) See page 305, Table 13-1

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HOW IS THE GLOBE WARMING & WHAT ARE THE IMPACTS OF HUMAN ACTIVITIES? Global Warming

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Since the Industrial Revolution, humans have contributed to global warming by: burning fossil fuels, deforestation/burning of grasslands, agricultural practices, and use of CFCs. Developed countries account for about 60% of CO2 emissions and developing countries for 40% U.S. contributed 26% global CO2 emissions 1999 (plants) Other large contributors: European Union, China Increased input of greenhouse gases from human activities Enhance the earths natural greenhouse effect Raise the average global temperature- Global Warming

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Temperature vs. CO 2

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Trends in CO 2 and other Greenhouse Gases

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Average Temperature: 1950-2000

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Effects of Global Warming IPCC projects temperature +1.4-5.8 o C (1990 to 2100) IPCC Northern hemisphere warm more and faster than southern hemisphere Melting of ice caps and other floating ice at poles Shrinking of glaciers Sea-level rise (10-15 cm) Earlier springs, later falls More unusual weather, storms Alter structure/location of biomes, rain patterns, water resources, when/where crops can be grown Affects of all these things on wildlife?wildlife

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An earlier spring in Montana's Glacier National Park means full waterfalls at first but much drier summers. Photo/caption: NPR

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Joe Giersch, an ecologist with the U.S. Geological Survey, studies stoneflies that live only in the melt from glaciers and snowpack in the northern Rockies. Photo/caption: NPR

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Lednia tumana is fish food that's long thrived in the glacier-fed streams of Glacier National Park. But as the glaciers are disappearing, so is the fly. Photo/caption: NPR

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National Academy of Sciences, 2001 Greenhouse gases are accumulating in the Earths atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise The changes observed over the last several decades are likely mostly due to human activities Global warming could have serious adverse societal and ecological impacts by the end of this century.

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Factors affecting climate change Solar output Albedo Earths ability to reflect light (land, water, ice) Oceans Help moderate temperature High specific heat Absorb CO 2 = carbon sink Future? Might amplify global warming by releasing more CO 2 or might dampen it by absorbing more heat. Currents disrupted? (Figure 13-9, p. 309)

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Factors affecting climate change Water Vapor/Clouds Could warm or cool both? Aerosols condensation nuclei (like cloud seeding) Contain CFCs CO 2 & Photosynthesis Increase rate, decrease CO 2 ? Methane Bogs, wetlands, melting of the tundras permafrost

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Rate of Climate Change Slow (several hundred years) Organisms able to adapt Rapid (several decades) People: Unable to have enough time to Switch where food is grown Relocate people (flooded regions) Build dikes/levees/dams Other organisms: Unable to have enough time to naturally adapt to new environment Results? Starvation, chaos, loss of biodiversity

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Effects of a Warmer World Section 13-4 Figure 13-11, page 311 6 Degrees Could Change the World

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Climate Change Solutions

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Our Options Do nothing Do more research first Act now (key preventative strategies) Act now to reduce risks

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Slowing Global Warming Replace oil & coal with cleaner energy Natural gas, wind/solar energy Clean emissions prior to release into atmosphere Waste less energy (higher efficiency) Employ sustainable agriculture practices Reforestation Slow population growth Government action Regulations, subsidies, etc.

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Reducing CO 2

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Reducing CH 4

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Reducing N 2 O

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Reducing CFCs

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Focus on CO 2

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Relevant Laws & Treaties Clean Air Act 1970 addresses criteria pollutants, smog, acid rain, stratospheric ozone, general authorities (covers GHG) Rio Earth Summit 1992 106 developed nations agreed to reduce GHG emissions Not required, so most did not meet goals Convention on Climate Change - Kyoto Protocol 1997 161 nations negotiated new treaty 38 developed countries required to cut GHG Developing countries no obligation until next meeting 2001 President Bush not interested 2009 Copenhagen, attempted to update, failed 2014 President Obama spoke in New York (pep rally Paris, 2015)President Obama spoke in New York

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Preparation for Global Warming Waste less water Develop crops that use less water Stockpile 1-5 years of food Connect wildlife reserves with corridors, move toward poles Move hazardous wastes away from coastal areas Prohibit new construction on low-lying coastal areas

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DEPLETION OF O3 IN THE STRATOSPHERE & HOW TO PROTECT THE OZONE LAYER Stratospheric Ozone

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The Ozone Layer In the stratosphere Protects living things from the suns harmful radiationsuns harmful radiation

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Ozone Depletion Thinning of the ozone layer in lower stratosphere Serious threat to people, animals, plants Worse at polespoles

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Ozone Depletion: Causes CFCs chlorofluorocarbons Coolants air conditioners, refrigerators Propellants in aerosols Cleaners/Sterilizers/ Fumigants

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How CFCs Damage O 3

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Environmental/Human Effects

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Effects of Ozone Depletion As more UV radiation reaches the earth: Serious health effects occur Ocular cataracts, skin cancer, immunosuppression Damage to plants Fewer crops, TL 1 greatly reduced More smog Possible climate changes

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Ozone & Cancer 90% of melanoma comes from exposure to UV-A rays 10% from UV-B rays Tips: Avoid sun between 10am and 3pm Use sunscreen with UV-A and UV-B protection

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Ozone Depletion: Other Causes ODCs ozone-depleting compounds Halons: fire extinguishers Methyl bromide: widely used fumigant, ag pesticides Carbon tetrachoride: solvent Methyl chloroform: cleaning solvent Same effects as CFCs

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Protecting the Ozone Stop producing ozone-depleting chemicals Substitutes are available for almost all CFCs Use hydrocarbons Ex: HC refrigerator technologyHC refrigerator technology Montreal Protocol- 1987 36 nations Cut emissions of CFCs See Relevant Laws & Treaties Doc Did not address other chemicals Met again with more countries involved in London & Copenhagen in early 1990s New protocol to phase out ODCs

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Will These Treaties Work? Growing concern regarding whether or not requirements are being met Hard to monitor because the gases involved are colorless, odorless Must use expensive technology/instruments and highly trained scientists to measure/track levels/emissions Effectiveness of treaties is under consideration Regardless, treaties are an important precedent for global cooperation

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For your test Due in your box tomorrow before test: Chapter 12 Review Questions: 2-11, 16-20 Chapter 13 Review Questions: 5-7, 9, 11, 14, 16, 18, 20, 23 Make sure you have read all of Chapters 12 & 13 Practice FRQs E-mail and hard copy