INTRODUCTION TO CLIMATE CHANGE

1. INTRODUCTION TOCLIMATE CHANGE Robert K. Kaufmann Museum of Science July 11, 2005 http://www.bu.edu/cees/people/faculty/kaufmann/index.html

2. Global Climate Change History of climate change The energy balance of planet Earth Human activity and radiatively active gases Climate models:where and how much will climate change Are humans responsible for climate change Climate change impacts on the environment and economy What if anything should be done about climate change?

3. Climate vs. Weather Weather: Conditions on any given day The temperature in Boston today is 86oF Climate: Average conditions on any given day over The average temperature in Boston on this day is 82oF

4. 15,000 Years of Temperature

5. 1000 Years of Temperature

6. Observational Record 0.6 0.4 0.2 Degrees Celsius 0 -0.2 -0.4 -0.6 1860 1880 1900 1920 1940 1960 1980 2000

7. Heat Balance of Planet Earth

8. 255oK Ground 5800oK lm = L/T CO2 H2O CH4 Ground

9. Radiatively Active Gases

10. Radiative Forcing 1.5 Carbon Dioxide Methane Solar Activity Trace Gases Anthropgenic Sulfates 1 0.5 0 -0.5 -1 -1.5

11. Changes in Out-Going Radiation 1970-1997

12. How Do Humans Affect Radiative Forcing?

13. Fossil Fuel Combustion -- CO2 7000 6000 5000 4000 3000 2000 1000 0

14. Carbon Emissions

15. Land-Use Change--CO2 Emissions 2000 1800 1600 1400 1200 1000 800 600 400 200 0

16. Land-Use Change & CH4 Emissions 400.0 350.0 300.0 250.0 200.0 150.0 100.0 50.0 0.0

17. Rice Cultivation

18. Livestock Organic matter + H2O CO2 + CH4 + Nutrients Methane emissions depend on: Type of animal Cows and sheep generate more methane than horses & pigs Diet dairy cows in developed nations generate 2.5 times more methane than similar cows in developing nations (technology effect)

19. Livestock 125 100 75 50 25 1840 1860 1880 1900 1920 1940 1960 1980 2000

20. Termites Biome 106 Termite/Acre Emission Rate Tropical forest 12.80 4.2 E-03 Temperature forest 2.43 1.8E-03 Savanna 17.81 8.0E-03 Temperature grassland 8.66 1.8E-03 Cultivated land 11.38 1.8E-03 Desert scrub 0.93 1.0E-03 Zimmerman et al., 1982 Science 218:563-565 Frasswer et al., 1986. Atmospheric Chemistry 4:295-310..

21. Sulfur Emissions

22. Anthropogenic Sulfur Emissions 80000 70000 60000 50000 40000 30000 20000 10000 0 1850 1858 1866 1874 1882 1890 1898 1906 1914 1922 1930 1938 1946 1954 1962 1970 1978 1986 1994

23. Radiative Forcing of Sulfur Emissions Direct Effect

24. The Heat Balance of Planet Earth SOx Ground

25. Indirect Effect Formation of Cloud Nuclei

26. Clouds The Heat Balance of Planet Earth SOx Ground

27. Climate Models: How, Where, and By How Much Will Climate Change?

28. Climate Models Track the flow of energy and water Differ according to their spatial and temporal resolution

29. upwelling upwelling One Dimensional Climate Models Infrared radiation Solar radiation Atmosphere Heat exchange Surface layer Sinking cold polar water Diffusive mixing Deep Ocean

30. Two Dimensional Climate Models

31. General Circulation Models

32. Causes For Temperature Change Doubling of radiative forcing……………1.2oC Increased water vapor……….. ……….1.6oC Increase in clouds………………………..0.8oC Changes in surface albedo……………….0.4oC Other changes……………………………0.2oC Total change in temperature…………….4.2oC

33. Forecasts for Climate Change More frequent extreme high temperatures and less frequent extreme low temperatures. Night-time low temperatures generally increase more than daytime highs, reducing diurnal temperature range. Decreased daily winter temperature variability and increased summer variability in mid-latitude N hemisphere Mid-continental summer drying due to precipitation not keeping up with temperature & evaporation Intensity of precipitation events increases.

34. Confidence in Model Predictions

35. Detection: Is temperature Increasing?

36. Uncertainty in the Observational Record Changes in measurement instruments Change from rural to urban Changes in location of measurements

37. Melting Ice Shelves There's no evidence of any period in the last 12,000 years where there was open water in the area that has now been exposed," Dr. Scambos said. New York Times March 20, 2002

38. Ice Shelf Break-Up Feb 17, 2002 Jan 31 2002 The speed of it is staggering," said Dr. David Vaughan, a glaciologist at the British Antarctic Survey. March 5 Feb 23, 2002 New York Times March 20, 2002

39. Attribution: Are Humans Responsible for Increased Global Temperatures?

40. General Circulation Models Do increases in greenhouse gases and anthropogenic sulfur emissions help GCM’s simulate the historical temperature record Control Scenario: Simulate model with constant radiative forcing, but natural variability Anthropogenic: Simulate model with greenhouse gases and sulfur emissions Full Simulation: Simulate model with both natural variability and anthropogenic activity

41. Experimental Results

42. Statistical Analysis of Historical Data

43. Emissions, Concentrations, & Temperature 0.40 0.30 0.20 0.10 0.00 Degrees C -0.10 -0.20 -0.30 -0.40 -0.50 -0.60 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990

44. How Much Doubt Exists: Fact or Fiction? “Ifrising carbon dioxide is the cause of rising temperatures, why didn’t it cause temperatures to rise from 1940 to 1970? “Trust me, the satellite data have been reanalyzed dozens of times,…they show much less warming than expected by theory

45. Remember Sulfur Aerosols! 2.5 2 1.5 Greenhouse Gases 1 Anthropogenic Forcing Watts per Square Meter 0.5 0 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 -0.5 Sulfur Aerosols -1 -1.5

46. Contamination Satellite Reconciliation Fu et al., 2004 Nature 429:55-58

47. Climate change impacts on the environment & economy Change in Sea Level Impact on agriculture Impact on Biomes

48. Changes in Sea Level Melting of Glaciers and Polar Ice Thermal Expansion of Water

49. Melting Glaciers Qori Kalis glacier in Peru's Quelccaya ice cap, Southern Andes

50. NH Sea Ice Extent, 1901-98