APES Mrs. Sealy

1. APES Mrs. Sealy

2. I. Past Climate Change • A. Over the past 900,000 years earth’s climate has undergone long periods of cooling and global Warming • B. During global cooling, thick glacial ice covers most of the world. This is an ice age and lasts about 100,000 years. • C. During global warming we have warm interglacial periods that last about 10,000 years. We are currently nearing the end of a warm period. • D. How we know: tree rings, plankton in ocean sediments, gases trapped in glaciers, pollen from lake bottoms, historical records, direct measurement since 1860.

3. Average temperature over past 900,000 years 17 16 15 14 13 Average surface temperature (°C) 12 11 10 9 900 800 700 600 500 400 300 200 100 Present Thousands of years ago Fig. 18.2a, p. 447

4. Agriculture established Average temperature over past 10,000 years = 15°C (59°F) Temperature change over past 22,000 years 2 1 0 -1 End of last ice age Temperature change (°C) -2 -3 -4 -5 20,000 10,000 2,000 1,000 200 100 Now Years ago Fig. 18.2b, p. 447

5. Temperature change over past 1,000 years 1.0 0.5 0.0 Temperature change (°C) -0.5 -1.0 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2101 Year Fig. 18.2c, p. 447

6. Average temperature over past 130 years 15.0 14.8 14.6 14.4 Average surface temperature (°C) 14.2 14.0 13.8 13.6 1860 1880 1900 1920 1940 1960 1980 2000 2020 Year Fig. 18.2d, p. 447

7. 380 360 340 320 300 Concentration of carbon dioxide in the atmosphere (ppm) 280 Carbon dioxide 260 240 +2.5 220 0 200 Variation of temperature (˚C) from current level –2.5 180 –5.0 –7.5 Temperature change –10.0 End of last ice age 160 120 80 40 0 Fig. 18.3, p. 449 Thousands of years before present

8. II. The greenhouse effect (Tropospheric Heating Effect) • A. To remain at a constant temperature the Earth must balance incoming energy with outgoing energy. The average temperature of the atmosphere remains constant. • B. Certain gases absorb incoming radiation and transform it to longer wavelength radiation (heat) • C. The two predominant gases are carbon dioxide and water vapor • D. Other gases that play a role are ozone, CFC’s, nitrous oxide, and methane • E. Not really like a greenhouse or a car with rolled up windows, the gases actually trap the heat. • F. The earth also naturally cools itself by evaporation of surface waters and rising water vapor that condenses high in the atmosphere to form clouds • G. Analysis of gases trapped in ancient glaciers in Antarctica reveal that carbon dioxide levels normally fluctuate between 190 to 200 ppm

9. III. Global Warming • A. Scientifically there is no debate: greenhouse gases have risen in recent years. This is directly related to human activities such as burning fossil fuels, using CFCs, deforestation and the use of inorganic fertilizers. • B. There has been a significant increase in Carbon Dioxide levels since 1750 and a huge increase since 1950 • C. There is more CO2 in the atmosphere than there has been in the last 420,000 years and is rising at a rate of .5% per year • D. The 20th century was the hottest century on record in the past 1,000 years. • E. Since 1860 the average global temperature near Earth’s surface has risen by .6-.7 C with most of the increase occurring since 1946. • F. The 15 warmest years on record since 1860 have occurred in the last two decades. The five hottest years on record before 2000 were 1998, 1997, 1995, 1990, and 1999.

10. 410 360 Parts per million 310 260 1800 1900 2000 2100 Year Fig. 18.4a, p. 450 Carbon dioxide (CO2)

11. 2.4 1.8 Parts per million 1.2 0.6 1800 1900 2000 2100 Year Fig. 18.4b, p. 450 Methane (CH4)

12. 320 310 Parts per million 300 290 260 1800 1900 2000 2100 Year Fig. 18.4c, p. 450 Nitrous Oxide

13. Carbon dioxide Methane Nitrous oxide 250 200 Index (1900 = 100) 150 100 1990 2000 2025 2050 2075 2100 Fig. 18.5, p. 451 Year

14. 1.2 Observed 1.0 Model of greenhouse gases + aerosols + solar output 0.8 0.6 Temperature change (°C) from 1980–99 mean 0.4 0.2 0.0 -0.2 1860 1880 1900 1920 1940 1960 1980 2000 2010 Year Fig. 18.7, p. 453

15. G. Other observed signs of global warming: • 1. increased temperatures and melting of the ice cap • 2. retreat of Himalayan glaciers • 3. northward migration of some warm climate fish • 4. bleaching of coral reefs • 5.  Sea levels rise-48 centimeters (19 inches)-due to global warming and deforestation.      • 6. Warming or cooling by more than 1oC has caused serious disruptions of the current structure and functioning of Earth's ecosystems

16. 6.0 5.5 5.0 4.5 4.0 3.5 3.0 Change in temperature (ºC) 2.5 2.0 1.5 1.0 0.5 0 Fig. 18.8, p. 453 1850 1875 1900 1925 1950 1975 2000 2025 2050 2075 2100 Year

17. H. Other possible reasons for global warming • 1. normal temperature fluctuations • 2. normal climatic changes enhanced by human activities • I. It is clear that during the past 200 years we have significantly changed the Earth’s atmosphere, what is not clear is the implication of this.

18. IV. Scientific Consensus About Future Global Warming and • * The Intergovernmental Panel on Climate Change (IPCC) is a network of 2,500 of the world’s leading climate experts from 70 nations established by the UN to study climate change. •   IPCC projects that the Earth's temp will rise to 1-5.8oC between 2000 and 2010 if the carbon dioxide doubles it will continue for hundreds of years. • The evidence is stronger than ever that humans have contributed substantially to the observed climate change over the last 50 years • The biggest concern is not how much it rises, but how fast it rises. A warming of just 1 C per century is faster than any other temperature change occurring in the last 10,000years-. •  Northern Hemisphere-warm faster because of heat-absorbing ocean and that water cools more slowly •  More warming at the poles •  5 of 9 ice shelves have broken up since 1950 • Climate models project as the earth's atmosphere warms the rate of water evaporation will rise • Global average precipitation will rise at mid-high latitude.

19. VI. How do Changes in Solar Output Affect Earth's Temperature? • Solar output varies according to 11 and 22 year sunspots • Sunspots - when strong solar magnetic fields periodically protrude through the sun's surface and slightly increase the sun's energy output, temporarily warming or cooling the Earth. • Sunspots account for only 10-30% of the warming during the past century. • If the sun continues to warm and our human activities don’t change there will be even more greenhouse gases in the troposphere.

20. VII. How do the Oceans affect Climate? • The world's oceans amplify global warming by releasing carbon dioxide into atmosphere or the world’s oceans can dampen global warming by absorbing more heat. • 29% of excess carbon dioxide is removed by oceans, which decreases global warming. • It takes hundreds of years for deep vertical mixing to take place • Deep ocean currents may be disrupted • Currents act as a giant conveyor belt, which transfers heat and stores carbon dioxide in the deep-sea heat, from tropical waters to Europe • Global warming will reduce density and salinity of water. • If heat transfer loops stop it could cause an atmosphere change more than 5`C.

21. Greenland Greenland Cold water melting from Antarctica's ice cap and icebergs falls to the ocean floor and surges northward, affecting worldwide circulation. Cold water melting from Antarctica's ice cap and icebergs falls to the ocean floor and surges northward, affecting worldwide circulation. Antarctica Fig. 18.10, p. 456

22. VIII. Water Vapor Content and Clouds Affect Climate • Warmer temps will increase evaporation and create more clouds. • Increase in water vapor may cause warming • Increase in production of clouds • By trapping heat it could have a warming effect or a cooling effect caused by reflecting sunlight back into space. • Scientists don't know what factors of clouds will be predominate • 1. day: clouds are reflective and have a cooling effect • 2. night: insulate and lead to warmer temps • 3. thin and high: warming effect • 4. low and thick: cooling effect

23. IX. Changes in Polar Ice Affect Climate • albedo: ability of the earth's surface to reflect light • Greenland and Antarctic-high albedo - light colored ice sheets reflect sunlight back into space-if they melt more sunlight would be absorbed and warming would be accelerated. • Global warming increase earth's water stored as ice • Warmer air carries more water vapor that drops snow on polar glaciers, which will affect more ice- perhaps leading to a new ice age.

24. Clouds 50–55% Snow 80–90% City 10–15% Forest 5% Grass 15–25% Bare sand 30–60% Oceans 5% Fig. 18.9, p. 454

25. X. Air Pollution Affects Climate • Affected by air pollution- offset by aerosols • Sulfur dioxide and tiny particles attract enough water molecules to increase cloud formation- has a high albedo- reflecting more sunlight. • Clouds at night will cause heat to be stored in earth's surface. • Northern Hemisphere - 90% of sulfur dioxide emissions, which may offset global warming. • Southern hemisphere - form particles in smoke emitted by burning rain forests, grass, woods, etc. • It is known that aerosols will have little effect on global warming. • Aerosols only stay in atmosphere for a few weeks • Component of acid rain that weakens trees, which creates more carbon dioxide in the atmosphere. • Increasing amount of aerosols in the world will kill people and crops.

26. XI. Increased Levels of Carbon Dioxide: Does It Affect Photosynthesis and Methane Emissions • Photosynthesis removes carbon dioxide from atmosphere and help slow global warming. • Increased carbon dioxide may increase photosynthesis • It will depend on different types of plants in different climate zones. • High plant growth can be offset by plant eating insects- • Carbon Dioxide increase will worsen global warming because the stomata will remain closed for longer periods of time- water can't get out and the plant and its surroundings get warmer. • Forest turnover: how fast trees grow and die in a forest • Reduces the biodiversity because of the reducing removal of carbon dioxide. • Global warming accelerated by increased release of methane. • Increase in carbon dioxide=an increase in methane • If arctic tundras melt, huge amounts of methane are released

27.  XII. Rapid Climate Shift • If global temps change over the next decades we will not be able to switch food-growing regions and relocate the world's population near the coast. • Lead to death, chaos and reduction in biodiversity. • Temperatures have shifted as much as 10`F in past decades that lasted 1000+ years • The shifts are disastrous for humans 

28. XIII. Human Responses Accelerate Global Warming • As temperatures increase people will use moreair conditioning, which requires more burning of fossil fuels which releases more carbon dioxide causing additional warming and more of a need for air conditioning. • Aerosols may offset warming but pollution will have serious health effects • Global warming and rises in average sea levels could either be half of current projections or double

29. XIV. Affected Food Production • Climate belts will shift northward -rise in global temperature cause a rise in food production • Depends on: • 1. fertility of the soil in northern forests • 2. amount of available money • Asia productivity will increase while US and Canada will decrease. • Will cause increase in hunger and starvation • Increase in temps will allow insects and pests to live through the winter destroying crops

30. XIV. Affected Food Production • Seafood supplies decrease due to flooding of coastal wetlands. • Reduce biodiversity because of the average temp and depth of tropical ocean waters • corals– become bleached & animals will die

31. XV. Global Warming's Effects on Forests and Biodiversity • The makeup and location of world's forests will change • Due to seed movement by animals forests will move further North • Mountaintops that are far North will become extinct- no where to go-causing release of carbon • Wildfires will happen in up to 90% of forests • Huge amounts of carbon dioxide will then accelerate global warming • Reductions in biodiversity due to mass extinction of animals that can't migrate • Fish would die because the temp would rise

32. Present range Future range Overlap Fig. 18.13, p. 459

33. XVI. What could Happen to Sea Levels? • They will rise because ocean expands when heated • Will rise because of melting glaciers and ice sliding into the sea • Sea levels will rise by as much as 48 cm. • Will effect cities near sea level (about 1/3 of world's people) would be flooded • Some islands would completely disappears • Beaches on East Coast might disappear within 25 to 50 years • Move barrier islands further inland, accelerate erosion, contaminate coastal aquifers with salt water

34. Today’s sea level 0 0 Height below present sea level (feet) Height above or below present sea level (meters) –130 –426 250,000 200,000 150,000 100,000 50,000 0 Years before present Present Fig. 18.11, p. 456

35. XVII. How Might Weather Extremes Change Our Life • More air will move across the surface because more heat is retained in climate system • There may be higher precipitation, clashing fronts and more violent weather • Increased intensity of hurricanes, typhoons and tornadoes • Financial challenges for insurance companies who have to pay billions of dollars to flood victims • Some companies are dropping their coverage or raising prices to be prepared and working with the government to decrease possible global warming

36. XVIII. How Might Human Health Be Affected • Global warming will bring more heat waves(double number of deaths) increase asthma and bronchitis • Disrupt supplies of food and water • Alter disease patterns • Insect diseases from tropical areas • Higher humidity levels • Rise in fungal skin diseases • Speed up bacterial growth • Climate change would lead to a large number of environmental refugees • Illegal migration would increase • Serious problems for foreign military and economic security policies of nations could occur

37. Agriculture Water Resources Forests • Shifts in food-growing areas • Changes in crop yields • Increased irrigation demands • Increased pests, crop diseases, and weeds in warmer areas • Changes in forest composition and locations • Disappearance of some forests • Increased fires from drying • Loss of wildlife habitat and species • Changes in water supply • Decreased water quality • Increased drought • Increased flooding Biodiversity Sea Level and Coastal Areas • Rising sea levels • Flooding of low-lying islands and coastal cities • Flooding of coastal estuaries, wetlands, and coral reefs • Beach erosion • Disruption of coastal fisheries • Contamination of coastal aquifiers with salt water • Extinction of some plant and animal species • Loss of habitats • Disruption of aquatic life Weather Extremes Human Health Human Population • Increased deaths from heat and disease • Disruption of food and water supplies • Spread of tropical diseases to temperate areas • Increased respiratory disease • Increased water pollution from coastal flooding • Prolonged heat waves and droughts • Increased flooding • More intense hurricanes, typhoons, tornadoes, and violent storms • Increased deaths • More environmental refugees • Increased migration Fig. 18.12, p. 458

38. XIX. Solutions: Dealing with the threat of Global Warming: Do More Research or Act Now? • 3 schools of thought: • 1 No Problem is a minority view- global warming is not a threat but a hoax. • 2.    Wait and See- Wait until more info is available about the global climate system. Why spend hundreds of billions of dollars phasing out fossil fuels and replacing deforestation with reforestation to help ward off something that might not happen. • 3 Precautionary principle- take action instead of doing research • 4. As a result of uncertainties in climate models scientists estimate that the projections from current climate models for the next 50-100 years could be half wrong or twice the current projections

39. XX. How can we slow Possible Global Warming? • We must reduce current global CO2 emissions by 66-83% •  Solutions: • a. quickest and cheapest way is to use energy more efficiently • b. increased use of nuclear energy • c. using natural gas- help to make the 40-50 year transition to an age of energy efficiency and renewable energy • d. phase out gov’t subsidies for fossil fuels over a decade/gradually phase in carbon taxes on fossil fuels • e. shift to renewable energy sources • f. reduce deforestation • g. slow population growth • h. reduce emissions of methane from leaking pipes and landfills • i. Increase government subsidies for renewable resources

40. XX. How can we slow Possible Global Warming? • 1997- ECONOMISTS & Nobel laureates signed statement: • a. sound economic analysis shows that greenhouse emissions can be out without harming American living standards • b. calling for carbon taxes as part of an international system of tradable permits for greenhouse gas emissions • Carbon tax based on • polluter- pays principle- requires industries & consumers to pay directly for the full environmental costs of the fuels they use • agree to global & national limits on greenhouse gas emissions

41. XXI. Can Technofixes save us? • Technofixes- technological solutions for dealing with possible global warming • Adding iron to oceans-would remove more CO2 through photosynthesis • Unfurling gigantic foil-surfaced sun mirrors in space to reduce solar input. • Injecting sunlight - reflecting sulfate particulates into the stratosphere - mimics cooling effects of giant volcanic eruptions • Massive reforestation, we need to plant trees in an area the size of Australia • Injecting CO2 into the ground or deep ocean  

42. Prevention Cleanup Cut fossil fuel use (especially coal) Remove CO2 from smokestack and vehicle emissions Shift from coal to natural gas Transfer energy efficiency and renewable energy technologies to developing countries Store (sequester CO2 by planting trees) Sequester CO2 underground Improve energy efficiency Sequester CO2 in soil Shift to renewable energy resources Sequester CO2 in deep ocean Reduce deforestation Use sustainable agriculture Slow population growth Fig. 18.14, p. 461

43. XXII. What has been done to reduce Greenhouse Gas emissions? • 2,200 delegates-161 nations met in Kyoto, Japan negotiated treaty to help slow global warming • The goal: • a. between 2008 & 2012: 12-38 developed countries should have cut greenhouse emissions to an average of 5.2% below 1990 levels • b. developing countries won’t be required to cut • c. there would be penalties for countries that violate treaty laws • d. forested countries get a break in their quotas • e. since the treaty was made, US cut greenhouse emissions by 7%, Japan by 6% and European countries by 8%

44. XXIII. How can we prepare for possible global warming? • waste less _energy__ • develop ____crops_ that need less water • move hazardous materials (storage tanks) away from the __coast • prohibit new construction or remolding on low-lying coastal areas • stockpile 1-5 years supply of key food • expand existing wild life reserves with corridors

45. N S Develop crops that need less water Waste less water Move hazardous material storage tanks away from coast Prohibit new construction on low-lying coastal areas Stockpile 1 to 5 year supply of key foods Expand existing wildlife reserves toward poles Connect wildlife reserves with corridors Fig. 18.15, p. 465

46. Part II: Ozone Depletion

47. Formation of the Ozone • Photosynthetic, oxygen-producing bacteria created ozone in the stratosphere about 3.8 million years ago. • 11-16 miles above the Earth’s surface oxygen is continually converted to ozone by ultraviolet radiation. The reaction is O2  O3 in the presence of sunlight. • Normally average levels of ozone don’t change. Amount produced is equal to ozone destruction. • Ozone absorbs 95% of harmful incoming _______________. • 3 types of UV Radiation: A, B, and C. All high level C is absorbed. ½ UVB and some UVA. • Ozone concentrations have been measured since ________ • During the 1980s normal ozone levels dropped 40-50 % in winter above temperate and tropical zones above both hemispheres. Expected to drop 7-13 % during 1990s.

48. Summary of Reactions CCl3F + UV Cl + CCl2F Cl + O3 ClO + O2 Cl + O Cl + O2 Repeated many times Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl3, breaking off a chlorine atom and leaving CFCl2. Sun Cl Cl C Once free, the chlorine atom is off to attack another ozone molecule and begin the cycle again. Cl F UV radiation Cl Cl O O A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O2. The chlorine atom attacks an ozone (O3) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O2). Cl Cl O O O O O Cl The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO). O O Fig. 18.16, p. 466 O

49. 400 October monthly means 350 300 Total ozone (Dobson units) 250 200 150 100 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Fig. 18.17, p. 467

50. 35 August 7, 1997 30 October 10, 1997 25 20 Altitude (kilometers) 15 10 5 0 5 10 15 Fig. 18.18, p. 467 Ozone partial pressure (milipascals)