1. Climate Change Chapter 18

2. Global Change Population growth Distribution of water Distribution of food Climate change

3. Climate Change Earth’s average surface temperature Distribution of rainfall Patterns of temperature change and global conveyor belt

4. Factors Affecting Global Climate Change Relationship of Earth to Sun Anthropogenic causes

5. Anthropogenic Causes Atmospheric change due to carbon dioxide emissions, methane emissions, destruction of ozone by providing more surfaces-free radicals for reactions to occur in stratosphere (SOX, NOX, CO2, CH4), changes in vegetative cover, water pollution - eutrophication

6. Thousands of years ago Average surface temperature (°C) 900800700600500400300200100Present 9 10 11 12 13 14 15 16 17 Fig. 18.2a, p. 447 Average temperature over past 900,000 years

7. 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) Fig. 18.2b, p. 447 Temperature change over past 22,000 years

8. Year Temperature change (°C) 100011001200130014001500160017001800190020002101 -0.5 0.0 0.5 1.0 Fig. 18.2c, p. 447 Temperature change over past 1,000 years

9. Year Average surface temperature (°C) 186018801900192019401960198020002020 13.6 13.8 14.0 14.2 14.4 14.6 14.8 15.0 Fig. 18.2d, p. 447 Average temperature over past 130 years

10. How do we know? Recent history-have sufficient data from a variety of sources (hot air balloons, buoys, satellite data, pollen records, coral...) Ancient history- ice cores (Vostock), rocks, tree rings ) Geologic history-, deep ocean sampling(plankton & radioisotopes), rocks(fossils & radioisotopes)

11. Evidence of Global Change

12. How is this information processed? Modeling # factors, depth of data, period of time

13. Global cooling and warming cycles Global cooling, Ice Ages, last about 100,000 years Global warming, interglacial periods, last about 10,000 to 13,000 years Currently, we are living in an interglacial period

14. Climate and global warming Climate is statistics of meteorological conditions, temperature, precipitation, winds, over a long period of time-at least 30 years 0.5C of warming has occurred in last 130 years with the 1980s the warmest during that period Pattern parallels that of fossil fuel use and injection into the atmosphere of gases that can absorb radiation and lead to global warming

15. Greenhouse Effect Molecules of atmospheric gases vibrate and transform the absorbed energy into longer wavelength infrared radiation in the troposphere Convection currents distribute the heat

16.  of greenhouse gases Atmosphere is good absorber of infrared radiation (7.5  m) CO 2 and H 2 O vapor limit transmission to space at many 

17. Variation of Temperature, pressure, and altitude above Earth’s surface

18. Global Energy Balance for Atmosphere Numbers are %energy from incoming solar radiation

19. Greenhouse Effect Half of solar heat goes into latent heat, absorbed by water changing to water vapor Of 47% of initial solar energy absorbed at Earth’s surface, only 18% lost by radiation The remainder is captured by atmosphere-surface cycling which causes Earth to be 33C warmer than is would be without an atmosphere

20. Tropospheric heating effect Arrhenius !!!!! 1896 Not a guess, data supports Is THEORY in atmospheric science

21. Average Surface Temperature is about 15C (60F) Due to combination of greenhouse and global cooling processes Cooling processes: heat absorbed by evaporation of water, and water vapor stores heat in upper atmosphere (thermosphere)

22. Greenhouse Gas CO2 fossil fuel burning (75%), biomass burning CH4 rice, cows, landfills, coal production, coal seams, natural gas leaks, oil production N2O fossil fuel burning, fertilizers, livestock wastes, nylon prod CFCs air conditioners, refrigerators, foams HCFCs-” “ Halons- fire extinguishers CCl4 cleaning solvent

23. Carbon dioxide Temperature change End of last ice age 16012080400 Thousands of years before present Concentration of carbon dioxide in the atmosphere (ppm) 180 200 220 240 260 280 300 320 340 360 380 –10.0 –7.5 –5.0 –2.5 0 +2.5 Variation of temperature (˚C) from current level Fig. 18.3, p. 449 Correlation between CO2 and Temp Change

24. Surface Ozone: Top is Preindustrial and Lower frame is current (2002)

25. Changes in atmosphere, geosphere, & biosphere from glacial to interglacial periods

26. Ozone over Antarctica 1979 to 1990

27. Measurement of Air pollution from satellite

28. Drought from June to August in global climate model

29. Global Ocean Temp at depth of 160 m (vol transport stream )

30. Year 199020002025205020752100 100 150 200 250 Index (1900 = 100) Carbon dioxide Methane Nitrous oxide Fig. 18.5, p. 451 Projected emissions

31. Global warming is cyclical; the rate is not The rate of global warming is greater than past interglacial periods The CO2 in troposphere is higher than probably the last 20 million years 75% of CO2 since 1980 is due to fossil fuel burning; remainder is human changes in land use Average global temp has >0.6C mostly since 1946 Since 1861 9 of 10 warmest years have occurred since 1990 with the hottest in 1998 and 2001 Ice caps and glaciers shrinking Global sea level rise of 10-20 cm in 100 years Plants and animals are migrating north to meet optimum temperatures

32. Global Change Affect the availability of water resources by altering rates of evaporation and precipitation Shift areas where crops can be grown Change average sea levels Alter the structure and location of the world’s biomes

33. Positive feedback More product results in more production-eg. “nothing succeeds like success” Greater temp, more melting of snow, loss of albedo effect results in greater temp and still more melting of snow Thawing soil results in more microbial activity; more microbial activity results in more CO2 and more thawing soil Arctic circle, Greenland, and Antarctica all have thinning ice sheets, particularly Greenland The influx of freshwater from melting glaciers on Greenland could stop the global conveyor belt in the Atlantic

34. Antarctica 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. Greenland Fig. 18.10, p. 456 Global conveyor belt

35. Year 186018801900192019401960198020002010 -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Observed Model of greenhouse gases + aerosols + solar output Temperature change (°C) from 1980–99 mean Fig. 18.7, p. 453

36. Climate Models and IPCC IPCC: Intergovernmental Panel on Climate Change 2,000 climate scientists 90-95% chance that earth’s mean surface temp will >1.4-5.8C between 2000 and 2100; change btwn 2000 and 2030 will equal that of entire 20 th century Many greenhouse gases show increases due to anthropogenic activities Bush administration 2002 says climate changes anthropogenic and then reject Kyoto Treaty! Climate models are only models & have limitations

37. Building models Transect atmosphere mathematically Assign initial boundary condition for each variable to each cell in layer (solar radiation, precipitation, heat radiated by earth, cloudiness, interactions btwn atmosphere and oceans, greenhouse gases, & air pollutants) Develop equations that connect cells so vary together Run model to simulate changes that can be verified and then run to project future changes Reliability tied to accuracy of data inputs and magnification of errors over time, & chaos

38. Year 18501875190019251950197520002025205020752100 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Change in temperature (ºC) Fig. 18.8, p. 453 Measured vs predicted temperature changes

39. Change will not be evenly distributed Temp increases higher over land than over oceans Greater in high latitudes near earth’s poles than in lower latitude equatorial regions Much higher in inland regions in the northern latitudes

40. 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 Human Health 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 Sea Level and Coastal Areas Changes in forest composition and locations Disappearance of some forests Increased fires from drying Loss of wildlife habitat and species Forests Changes in water supply Decreased water quality Increased drought Increased flooding Water Resources Shifts in food-growing areas Changes in crop yields Increased irrigation demands Increased pests, crop diseases, and weeds in warmer areas Agriculture Extinction of some plant and animal species Loss of habitats Disruption of aquatic life Biodiversity Prolonged heat waves and droughts Increased flooding More intense hurricanes, typhoons, tornadoes, and violent storms Weather Extremes Increased deaths More environmental refugees Increased migration Human Population Fig. 18.12, p. 458

41. Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl 3, breaking off a chlorine atom and leaving CFCl 2. UV radiation 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 O 2. The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO). The chlorine atom attacks an ozone (O 3 ) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O 2 ). Cl C F O O O O O O O O O O Summary of Reactions CCl 3 F + UV Cl + CCl 2 F Cl + O 3 ClO + O 2 Cl + O Cl + O 2 Repeated many times Fig. 18.16, p. 466