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Global Warming. IB syllabus: 6.1.1-6.1.7 AP Syllabus Ch 18 Video - . http://wakeupfreakout.org/film/tipping.html. Syllabus Statements. 6.1.1: Describe the role of greenhouse gasses in maintaining mean global temperature. 6.1.2 : Describe how human activities add to greenhouse gasses.

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Global Warming


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    1. Global Warming IB syllabus: 6.1.1-6.1.7 AP Syllabus Ch 18 Video -

    2. http://wakeupfreakout.org/film/tipping.html

    3. Syllabus Statements • 6.1.1: Describe the role of greenhouse gasses in maintaining mean global temperature. • 6.1.2: Describe how human activities add to greenhouse gasses. • 6.1.3: Discuss qualitatively the potential effects of increased mean global temperature • 6.1.4: Discuss the feedback mechanisms that would be associated with an increase in mean global temperature • 6.1.5: describe and evaluate pollution management strategies to address the issue of global warming • 6.1.6: Outline the arguments surrounding global warming • 6.1.7: Evaluate contrasting human perceptions of the issue of global warming

    4. vocabulary Correlation Global warming Greenhouse gases Negative feedback Positive feedback

    5. Climate Change • Global climate change is a fact of earth’s history • Prolonged periods of global cooling & global warming over past 900,000 years • Glacial periods followed by warmer interglacial periods • Even in stable times regional changes in climate occur on regional scale • Evidence includes – historical records, tree rings, pollen, radioisotopes

    6. 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

    7. 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

    8. 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

    9. 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

    10. The Natural Greenhouse effect • Balance heat moving in & out of atmosphere • Keep constant moderate average temperature normal & necessary for life • Greenhouse gas molecules trap energy as IR radiation and heat lower atmosphere • Gasses = water, methane & carbon dioxide • Water relatively constant, CO2 fluctuates • Really a tropospheric heating effect • With natural cooling average global temp = 59 ˚F

    11. CO2 effects • Past CO2 levels determined from ice core data – analyzing content of gas bubbles trapped in different layers of glaciers • CO2 has varied historically but is peaking presently • Correlation between CO2 and temperature has been show dating back 460,000 years

    12. 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 Thousands of years before present

    13. Global Warming • Since 1750, Industrial Revolution • Sharp rise in fossil fuel use, landfills  CO2 & CH3 • Deforestation, Clear & burn grasslands  CO2 & N2O • Rice paddies, inorganic fertilizer use  N2O • Mostly cars (700 million) & coal power plants • Increased greenhouse gas from humans • Enhance natural Greenhouse effect • Raise average global temperature of atmosphere near earth’s surface  Global warming

    14. This one is all ours - CFCs

    15. Are we experiencing Global Warming? There is no longer a question • CO2 in troposphere highest in last 20 million years • 20th century hottest in last 1000 years • Since 1861 average global temp has risen 0.74 +/- 0.18 ˚C • Shrinking of glaciers, melting of ice caps • 10 – 20 cm rise in global sea level • Change of range of species, moving to poles • Timing of seasons has changed

    16. 14.7 8.4 380 8.0 14.6 375 7.6 14.5 Fossil fuels 7.2 14.4 365 Temperature 6.8 14.3 Fossil fuels burn (billions of metric tons of oil equivalent) CO2 concentration (ppm) Temperature (Cº) 355 6.4 14.2 6.0 345 14.1 5.6 14.0 CO2 335 5.2 13.9 13.8 4.8 325 1970 1980 1990 2000 2005 Year

    17. Evidence shows correlation not causation • Could be natural climate fluctuation • Could be global warming • Could be a combination of both • Remember that in all peer reviewed articles on the subject there is no question that this is a reality

    18. Effects of Rapid Climate Change • Affect water availability, altering precipitation & evaporation patterns • Shift areas where crops will grow • Change average sea levels • Alter the structure & location of the world’s biomes

    19. Where can we see change? • Antarctica: Surrounding ice cap holds 70% world fresh water, 90% reflective ice for cooling • Pieces the size of RI, CN are breaking off • Arctic: Ocean surface temp rising • Greenland: 85% ice sheet coverage + closest to the equator

    20. 8 4 6 3 4 2 2 1 0 0 ºC ºF Arctic Global average Temperature Projected 2025 2000 1950 1975 2050 1959 Year

    21. Seals Penguins Elephant Weddell Fur Emperor Adélie Krill Petrels concentrations Average minimum extent of summer icepack Average maximum event of winter icepack

    22. Today’s sea level 0 0 Height above or 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 If melting occurs…

    23. Can we project future changes? • Scientists create climate models • GCM – general circulation model – represents air circulation on earths surface • Also include: (1) ocean circulation, (2) air / ocean circulation, (3) solar input, (4) aerosols • IPCC – International Panel on Climate Change (p 455 for results) • Still debate on severity of the issue • Agree that more research necessary to improve models

    24. 15.0 Observed 14.8 Model of greenhouse gasses + aerosols + solar output 1.0 0.8 Temperature Change (°C) from 1860-1999 mean 0.6 0.2 0.0 -0.2 1860 1880 1900 1920 1940 1960 1980 2010 2000 Year

    25. 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 1850 1875 1900 1925 1950 1975 2000 2025 2050 2075 2100 Year Models Give A Range Of Possibility

    26. What will effect continued climate change? • Natural & Human influenced factors will effect the future of global climate • Factors may amplify current trends  positive feedback • Factors may dampen current trends  negative feedback • These factors could influence how fast and how much temperatures change • Also effect regional differences

    27. Feedback (Remember the time lag) Positive • Increase Temp • Melt Permafrost • Increased release of methane • Increase Temp more • Melt more Permafrost… Negative • Increased Temp • Increased evaporation in Tropics • Increased snowfall in poles • Increase icecap cover • Increased albedo • Decreased Temp

    28. Factors Effecting Temperature • Solar output varies overtime • May account for up to 50% of climate change • Increase in cosmic rays may decrease temperature, decrease in CR  increase temp. • Pollutant effects may outweigh or reverse this • Ice albedo (reflectivity) feedback system • Ice, snow, sand reflect most incoming sunlight • Sea ice reflects 80%, water absorbs 80% incoming solar radiation • Positive ice albedo feedback system – increase temp  melt ice  less albedo  increase temp …

    29. Clouds 50–55% Snow 80–90% City 10–15% Forest 5% Grass 15–25% Bare sand 30–60% Oceans 5%

    30. Factors Effecting Temperature II • Ocean effects • Remove 29% of excess CO2 emissions • Solubility decreases with increased temp. • Atmospheric heat transferred into deep ocean • Ocean currents moderate global climate  fresh water influx stops motion  temperature drop will result • Sea level changes effect amount of heat and CO2 & earth’s biome distribution • Thermal expansion of oceans possible too

    31. Greenland Greenland Antarctica Vertical & Horizontal Water movement in the ocean

    32. Factors Effecting Temperature III • Clouds & Water Vapor content • Warmer temp increases evaporation & cloud cover • Clouds have (1) warming effect by trapping heat (positive feedback) or (2) cooling effect by reflecting heat (negative feedback) • Depends on time of day, water content and cloud type • There is an effect but the degree is uncertain

    33. Human Factors I • Air Pollution • Aerosols are condensation nuclei for clouds • Input could either amplify or dampen GW • Aerosols fall out of atmosphere & inputs are being reduced • Increased CO2 levels • Could lead to plant growth removing more CO2 • Plants take in less as they mature, upon death they release it again • CO2 is a greenhouse gas trapping more heat • Soils may absorb some extra CO2

    34. Human Factors II • Greenhouse gas production • Power production, Land clearing practices, Transportation • Regional input global distribution • Lifestyle dependency on this process

    35. What will happen • Not a normal weather swing of a few degrees this is GLOBAL CLIMATE CHANGE • Water distribution will change • Plant and animal distribution will change • Ocean currents & sea level will change • Extreme weather may develop – drought, floods • Human health in older populations & urban areas

    36. • Less severe winters • More precipitation in some dry areas • Less precipitation in some wet areas • Increased food production in some areas • Expanded population and range for some plant and animal species adapted to higher temperatures Potential Benefits of Global Warming

    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 • Increased deaths from heat and disease • Disruption of food and water supplies • Spread of tropical diseases to temperate areas • Increased respiratory disease and pollen allergies • Increased water pollution from coastal flooding Human Population • Prolonged heat waves and droughts • Increased flooding from more frequent, intense, and heavy rainfall in some areas • Increased deaths • More environmental refugees • Increased migration

    38. Effects on Distribution of Biomes • Every 1 degree temp increase shifts climate belts up 150 meters in altitude & 100 km in latitude • Ranges of warm adapted plants and animals may increase • Dispersal method may effect ability of species to keep up with climate change • Extinction of plants and animals that could not migrate – specialized species decrease • Threaten existing wildlife reserves, parks, wetlands & coral reefs

    39. Wetter than now Drier than now

    40. Global agricultural regions will change characteristics • Decreased production in some areas

    41. Present range Future range Overlap

    42. Major urban region at risk Islands at risk

    43. What can you do in your own life to effect local green house emissions?

    44. Local Emissions Reductions • Waste less energy • Rely more on cleaner energy sources • Choose transportation wisely • Shifting to organic farming and sustainable agriculture • Gradually integrate solutions to decrease global warming, air pollution, deforestation & biodiversity loss