html5-img
1 / 54

The earth's changing climate

Chapter 13. The earth's changing climate. Reconstructing Past Climates. Techniques Glacial landscapes CLIMAP Ice cores Otoliths Dendrochronology Climate Throughout the Ages Earth 8-15ºC warmer than it is today Ice Age/ Interglacials Younger- Dryas , mid-Holocene maximum.

abla
Télécharger la présentation

The earth's changing climate

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 13 The earth's changing climate

  2. Reconstructing Past Climates • Techniques • Glacial landscapes • CLIMAP • Ice cores • Otoliths • Dendrochronology • Climate Throughout the Ages • Earth 8-15ºC warmer than it is today • Ice Age/Interglacials • Younger-Dryas, mid-Holocene maximum

  3. Fig. 13-1, p. 375

  4. Fig. 13-1a, p. 375

  5. Fig. 13-1b, p. 375

  6. Fig. 13-2, p. 375

  7. Fig. 13-3, p. 376

  8. Fig. 13-3a, p. 376

  9. Fig. 13-3b, p. 376

  10. Fig. 13-4, p. 377

  11. Reconstructing Past Climate • Topic: Ocean Conveyor and Climate Change • Cold, salty water sinks near Greenland driving warm water north. • If the conveyor stops much colder over Europe • Climate During the past 100 years • Little Ice Age • Modern warming

  12. Fig. 13-5, p. 379

  13. Reconstructing Past Climate • Temperature Trend During the Past 100+ Years • Largest increase in temperature of any century during the past 1000 years • 0.6ºC is significant when compared to the last 1000 years • Scientists point to carbon dioxide and greenhouse gases as the cause

  14. Fig. 13-6, p. 380

  15. Climate Change by Natural Events • External Causes • Change in incoming radiation • Change in composition of the atmosphere • Change in Earth’s surface • Feedback Mechanisms • Water vapor-greenhouse gas feedback (+) • Snow-albedo feedback (+) • Infrared radiation (-)

  16. Fig. 13-7, p. 381

  17. Fig. 13-7a, p. 381

  18. Fig. 13-7b, p. 381

  19. Fig. 13-7c, p. 381

  20. Climate Change by Natural Events • Plate Tectonics and Mountain Building • Theory of plate tectonics • Ridge and subduction • Mountain interaction with airflow and ocean currents • Variation on the Earth’s Orbit • Milankovich Theory • Eccentricity • Precession • Obliquity

  21. Fig. 13-8, p. 382

  22. Fig. 13-8a, p. 382

  23. Fig. 13-8b, p. 382

  24. Fig. 13-9, p. 383

  25. Fig. 13-10, p. 384

  26. Fig. 13-10a, p. 384

  27. Fig. 13-10b, p. 384

  28. Fig. 13-10c, p. 384

  29. Fig. 13-11, p. 384

  30. Stepped Art Fig. 13-11, p. 384

  31. Climate Change By Natural Events • Variations in Solar Output • Sunspots cause more radiation to be generated by the sun • Mauncher minimum • Topic: Climate Models • General circulation models (GCMs) are not perfect but extremely sophisticated and serves as the most reliable current predictive tool.

  32. Fig. 13-13, p. 386

  33. Climate Change by Humans • Atmospheric Particles • Aerosols = natural + anthropogenic • Aerosols in the troposphere (sulfate) may cause cooling due to reflection of radiation • Topic: Nuclear winter • Explosions cause debris to rise and circulate absorbing sunlight creating darkness and cold. • Volcanic Explosions: ash and dust in the stratosphere reflect light and cool

  34. Fig. 13-14, p. 387

  35. Fig. 13-15, p. 387

  36. Climate Change by Humans • Recent Global Warming: Perspective • Since the beginning of the 20th century average global surface temperature has increase 0.8ºC • Radiative Forcing Agents • Carbon dioxide and other greenhouse gases disrupt radiative equilibrium, forming an increase in temperature

  37. Fig. 13-16, p. 393

  38. Fig. 13-16a, p. 393

  39. Fig. 13-16b, p. 393

  40. Topic: The Sahel • Recent studies suggest that the dry periods were due to a cooler North Atlantic Ocean, and aerosols from North America may exacerbate desertification.

  41. Climate Change by Humans • Advanced Topics: • Radiative Forcing • Any change in average net radiation that occurs at the top of the atmosphere which is due to some change in the climate system is called radiative forcing. • Climate Models and Recent Temperature • It is difficult to unequivocally prove greenhouse forcing due to the noise in the system. • Model well sulfate aerosols, greenhouse gases, change in solar radiation

  42. Climate Change by Humans • Future Global Warming: Projections • Double carbon dioxide levels will cause a surface warming of 2-4.5ºC • Uncertainties: • The effect of water and land on rising levels of carbon dioxide • Amount or greenhouse gases • Question of Clouds • Clouds reflect radiation and emit infrared radiation, positive and negative feedbacks

  43. Fig. 13-17, p. 394

  44. Fig. 13-18, p. 395

  45. Fig. 13-19, p. 396

  46. Fig. 13-20, p. 397

  47. Fig. 13-20a, p. 397

  48. Fig. 13-20b, p. 397

  49. Climate Change by Humans • Consequences of Global Warming • Land areas warm faster • Rise in sea level • Fertilize plants • Land Use Change • Desertification • Plagues and climate

  50. Fig. 13-21, p. 398

More Related