Sustainability and Globalization

1. Sustainabilityand Globalization Global Warming

2. Global Warming • A global issue with regards to sustainability • A world-wide warming of the Earth’s lower atmosphere.

3. Definitions • Climate: The long term average weather for an area: Months, years, centuries.

4. Definitions • Climate: The long term average weather for an area: Months, years, centuries. • Weather: the state of atmospheric conditions over a short period of time: Hours or days.

5. Climate Control • Orbital factors - Milankovitch • Reflectivity of Earth’s surface (Albedo) • Solar radiation • Volcanic activity • Ocean currents • Atmospheric composition

6. Climate Control • Orbital factors - Milankovitch cycles

7. Milankovitch cycles • Amount of heat reaching earth from the sun varies due to: • Eccentricity - 100,000 yrs

8. Eccentricity Fig. 18.39 a-c Tilt W. W. Norton Precession

9. Milankovitch cycles • Amount of heat reaching earth from the sun varies due to: • Eccentricity - 100,000 yrs • Earth’s tilt - 41,000 yrs

10. Eccentricity Fig. 18.39 a-c Tilt W. W. Norton Precession

11. Milankovitch cycles • Amount of heat reaching earth from the sun varies due to: • Eccentricity - 100,000 yrs • Earth’s tilt - 41,000 yrs • Precession - 23,000 yrs

12. Eccentricity Fig. 18.39 a-c Tilt W. W. Norton Precession

13. Milankovitch cycles • Amount of heat reaching earth from the sun varies due to: • Eccentricity - 100,000 yrs • Earth’s tilt - 41,000 yrs • Precession - 23,000 yrs • Overall temperature effect +/-4˚C

14. Fig. 18.39 d W. W. Norton

15. Climate Control • Orbital factors - Milankovitch • Reflectivity of Earth’s surface (Albedo)

16. Reflectivity of Earth’s Surface (Abedo)

17. Reflectivity • Sun’s heat may be reflected back out -thus not absorbed by Earth.

18. Reflectivity • Sun’s heat may be reflected back out -thus not absorbed by Earth. • Albedo = the degree of reflectivity

19. Reflectivity • Sun’s heat may be reflected back out -thus not absorbed by Earth. • Albedo = the degree of reflectivity • Albedo increases with: • Increased cloud cover • Increased snow cover • Increased aerosols in atmosphere

20. Climate Control • Orbital factors - Milankovitch • Reflectivity of Earth’s surface (Albedo) • Solar radiation

21. Solar radiation • Fluctuates with sunspot activity • Increases in sunspots = increased energy production of sun. • Sunspot cycle is ~9 to 11.5 years

22. Fig. 19.13 a Courtesy of SOHO/MDI consortium. SOHO is a project of international cooperation between ESA and NASA

24. Climate Control • Orbital factors - Milankovitch • Reflectivity of Earth’s surface (Albedo) • Solar radiation • Volcanic Activity

25. Volcanic Activity • Sulfur dioxide gas is ejected into the stratosphere, • Combines with water to form an aerosol (mist) of sulfuric acid • Blocks in coming solar radiation • Cools Earth

26. Climate Control • Orbital factors - Milankovitch • Reflectivity of Earth’s surface (Albedo) • Solar radiation • Volcanic Activity • Ocean currents

27. Ocean currents • Important system that moves cold and warm water. • Can redistribute heat on earth’s surface

29. Climate Control • Milankovitz cycles • Reflectivity of Earth’s surface (Albedo) • Solar radiation • Volcanic activity • Ocean currents • Atmospheric composition

30. Atmospheric composition • Greenhouse gases • Carbon dioxide, methane, CFCs, water vapor

31. Atmospheric composition • Greenhouse gases • Carbon dioxide, methane, CFCs, water vapor • Earth has a natural Greenhouse Effect • Warmer than moon

32. Atmospheric composition • Greenhouse gases • Carbon dioxide, methane, CFCs, water vapor • Earth has a Greenhouse Effect • Warmer than moon • Past record shows correlation between composition and temperatures.

33. Why does CO2 Matter? • Greenhouse Effect: • Naturally occurs • CO2 holds Earth’s heat in

34. The greenhouse effect • The Sun radiates UV energy towards Earth. • One third of that Ultraviolet energy is simply reflected away from the Earth. • But the rest is absorbed by the Earth. • In response, the Earth radiates IR energy. • This Infrared energy is also known as heat.

36. The greenhouse effect • Gas molecules in the Earth’s atmosphere absorb the heat (IR energy) that the Earth radiates. • These gases are known as “greenhouse gases”. • The gases then re-emit the IR energy back down towards the Earth, warming the atmosphere.

38. Why does CO2 Matter? • Greenhouse Effect: • Naturally occurs • CO2 holds Earth’s heat in • Amount of CO2 in atmosphere has increased over past 150 years

40. Where does CO2 come from? • Short term carbon cycling occurs between plants, animals and the atmosphere through respiration. • Long term cycling occurs when the plant or animal remains are buried with sediments in the crust and cannot decay.

41. Where does CO2 come from? • Long term cycling occurs when the plant or animal remains are buried with sediments in the crust and cannot decay. • Some of these remains become fossil fuels: • Coal, oil, gas

42. Where does CO2 come from? • Burning carbon-based fuel (fossil fuels) produces Carbon Dioxide (CO2) fossil fuel + O2 = Heat energy + H2O + CO2

43. Carbon-based fuels (fossil fuels) • Provide > 40% world’s energy needs • Provides 90% of world’s transportation needs. • Also used to make: plastic, paint, nylon, synthetic rubber, fertilizer.

44. How do we know the CO2 comes from humans burning fossils fuels? • Climate models • Scientists use what we know about the controls on climate to reproduce the record of past temperatures. • Then look at which controls influence it the most.

45. Record of past temperatures

47. Results of Climate Models for last 1000 yrs • Solar and volcanic forcing have been responsible for some of the variations in Northern Hemisphere temperature over the past 1000 years.

48. Results of Climate Models for last 1000 yrs • Neither solar nor volcanic influence can explain the dramatic warming of the late 20th century. • Influences of solar or volcanic effects during the 20th century would actually have resulted in a small cooling since 1960.

49. Results of Climate Models for last 1000 yrs • Only by adding the human-caused increase in greenhouse gas concentrations are the models able to explain the unprecedented warmth of the late 20th century.

50. IPCC: Intergovern-mental Panel on Climate Change