1. Climate Change: The Move to Action (AOSS 480 // NRE 480) Richard B. Rood Cell: 301-526-8572 2525 Space Research Building (North Campus) rbrood@umich.edu http://aoss.engin.umich.edu/people/rbrood Winter 2012 January 24, 2012

2. Class News Ctools site: AOSS_SNRE_480_001_W12AOSS_SNRE_480_001_W12 2008 and 2010 Class On Line:2008 and 2010 Class –http://climateknowledge.org/classes/index.php /Climate_Change:_The_Move_to_Actionhttp://climateknowledge.org/classes/index.php /Climate_Change:_The_Move_to_Action

3. Reading Response: Due Jan 31, 2012 The World Four Degrees Warmer –New et al. 2011New et al. 2011 Reading responses of roughly one page (single- spaced). The responses do not need to be elaborate, but they should also not summarize the reading. They should be used by you as think pieces to refine your questions and insight from the readings. They must be submitted via CTools at least two hours before the start of lecture for the relevant readings.

4. Supporting Reading Next Reading: Radiative Balance –Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties (2005) Board on Atmospheric Sciences and Climate (BASC) Chapter 1BASC http://www.nap.edu/books/0309095069/html From class website –Executive SummaryExecutive Summary –Chapter 1: Radiative ForcingChapter 1: Radiative Forcing

5. The Current Climate (Released Monthly) Climate Monitoring at National Climatic Data Center.Climate MonitoringNational Climatic Data Center –http://www.ncdc.noaa.gov/oa/ncdc.htmlhttp://www.ncdc.noaa.gov/oa/ncdc.html State of the Climate: Global

6. Some Project Ideas Education –Strategies when policy requires teaching “denial” –Incorporation into engineering curriculum –Earth science in K-12; admission to college Cities (esp Great Lakes) Adaptation Climate in the Keystone Pipeline Great Lakes Seasonal forecast information / Long-term projections / Use of information / Effectiveness of communication efforts

7. Today Scientific investigation of the Earth’s climate: Foundational information –Radiative Balance –Earth System –Aerosols

8. Scientific investigation of Earth’s climate SUNEARTH EARTH: EMITS ENERGY TO SPACE  BALANCE PLACE AN INSULATING BLANKET AROUND EARTH FOCUS ON WHAT IS HAPPENING AT THE SURFACE

9. Focus attention on the surface of the Earth

10. Simple earth 1 GO TO

11. Radiation Balance Figure

12. Radiative Balance (Trenberth et al. 2009)Trenberth et al. 2009

13. Let’s build up this picture Follow the energy through the Earth’s climate. As we go into the climate we will see that energy is transferred around. –From out in space we could reduce it to just some effective temperature, but on Earth we have to worry about transfer of energy between thermal energy and motion of wind and water.

14. But the Earth’s surface temperature is observed to be, on average, about 15 C (~59 F). The sun-earth system (What is the balance at the surface of Earth?) SUN Earth Based on conservation of energy: If the Earth did NOT have an atmosphere, then, the temperature at the surface of the Earth would be about -18 C ( ~ 0 F). Welcome Back Radiative Balance. This is conservation of energy, which is present in electromagnetic radiation.

15. Building the Radiative Balance What happens to the energy coming from the Sun? Energy is coming from the sun. Two things can happen at the surface. In can be: Reflected Top of Atmosphere / Edge of Space Or Absorbed

16. Building the Radiative Balance What happens to the energy coming from the Sun? We also have the atmosphere. Like the surface, the atmosphere can: Top of Atmosphere / Edge of Space Reflect or Absorb

17. Building the Radiative Balance What happens to the energy coming from the Sun? In the atmosphere, there are clouds which : Top of Atmosphere / Edge of Space Reflect a lot Absorb some

18. Building the Radiative Balance What happens to the energy coming from the Sun? For convenience “hide” the sunbeam and reflected solar over in “RS” Top of Atmosphere / Edge of Space RS

19. Building the Radiative Balance What happens to the energy coming from the Sun? Consider only the energy that has been absorbed. What happens to it? Top of Atmosphere / Edge of Space RS

20. Building the Radiative Balance Conversion to terrestrial thermal energy. 1) It is converted from solar radiative energy to terrestrial thermal energy – the motion of molecules. (Like a transfer between accounts) Top of Atmosphere / Edge of Space RS

21. Building the Radiative Balance Redistribution by atmosphere, ocean, etc. 2) It is redistributed by the atmosphere, ocean, land, ice, life. (Another transfer between accounts) Top of Atmosphere / Edge of Space RS

22. Building the Radiative Balance Terrestrial energy is converted/partitioned into three sorts SURFACE 3) Terrestrial energy ends up in three reservoirs (Yet another transfer ) Top of Atmosphere / Edge of Space ATMOSPHERE CLOUD RS WARM AIR (THERMALS) PHASE TRANSITION OF WATER (LATENT HEAT) RADIATIVE ENERGY (infrared) It takes heat to Turn ice to water And water to “steam;” that is, vapor

23. Building the Radiative Balance Which is transmitted from surface to atmosphere SURFACE 3) Terrestrial energy ends up in three reservoirs Top of Atmosphere / Edge of Space ATMOSPHERE CLOUD RS (THERMALS)(LATENT HEAT) (infrared) CLOUD

24. Building the Radiative Balance And then the infrared radiation gets complicated SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE CLOUD RS (THERMALS)(LATENT HEAT) (infrared) CLOUD 1) Some goes straight to space 2) Some is absorbed by atmosphere and re-emitted downwards 3) Some is absorbed by clouds and re-emitted downwards 4) Some is absorbed by clouds and atmosphere and re-emitted upwards

25. Put it all together and this what you have got. The radiative balance

26. Thinking about the greenhouse A thought experiment of a simple system. SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) 1)Let’s think JUST about the infrared radiation Forget about clouds for a while 2) More energy is held down here because of the atmosphere It is “warmer” 3) Less energy is up here because it is being held near the surface. It is “cooler”

27. Thinking about the greenhouse A thought experiment of a simple system. SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) T effective 1)Remember we had this old idea of a temperature the Earth would have with no atmosphere. This was ~0 F. Call it the effective temperature. Let’s imagine this at some atmospheric height. 2) Down here it is warmer than T effective T > T effective 3) Up here it is cooler than T effective T < T effective

28. Thinking about the greenhouse Why does it get cooler up high? SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) 1) If we add more atmosphere, make it thicker, then 2) The part coming down gets a little larger. It gets warmer still. 3) The part going to space gets a little smaller It gets cooler still. The real problem is complicated by clouds, ozone, ….

29. So what matters? Things that change reflection Things that change absorption Changes in the sun If something can transport energy DOWN from the surface. THIS IS WHAT WE ARE DOING

30. Today Scientific investigation of the Earth’s climate: Foundational information –Radiative Balance –Earth System –Aerosols

31. CLOUD-WORLD The Earth System ATMOSPHERE LAND OCEAN ICE (cryosphere) SUN

32. CLOUD-WORLD The Earth System ATMOSPHERE LAND OCEAN ICE (cryosphere) SUN Where absorption is important

33. CLOUD-WORLD The Earth System ATMOSPHERE LAND OCEAN ICE (cryosphere) SUN Where reflection is important

34. CLOUD-WORLD The Earth System ATMOSPHERE LAND OCEAN ICE (cryosphere) SUN Solar Variability

35. CLOUD-WORLD The Earth System ATMOSPHERE LAND OCEAN ICE (cryosphere) SUN Possibility of transport of energy down from the surface

37. CLOUD-WORLD Earth System: Sun ATMOSPHERE LANDOCEAN ICE (cryosphere) SUN Lean, J., Physics Today, 2005 SUN: Source of energy Generally viewed as stable Variability does have discernable signal on Earth Impact slow and small relative to other changes Lean: Living with a Variable Sun

38. CLOUD-WORLD Earth System: Atmosphere ATMOSPHERE Change CO2 Here LANDOCEAN ICE (cryosphere) SUN The Atmosphere: Where CO 2 is increasing from our emissions Absorption and reflection of radiative energy Transport of heat between equator and pole Weather: Determines temperature and rain What are the most important greenhouse gasses? Water (H 2 O) Carbon Dioxide (CO 2 ) Methane (CH 4 )

39. Cloudy Earth

40. CLOUD-WORLD Earth System: Cloud World ATMOSPHERE LANDOCEAN ICE (cryosphere) SUN Cloud World: Very important to reflection of solar radiation Very important to absorption of infrared radiation Acts like a greenhouse gas Precipitation, latent heat Related to motion in the atmosphere Most uncertain part of the climate system. Reflecting Solar Cools Largest reflector Absorbing infrared Heats

41. CLOUD-WORLD Earth System: Land ATMOSPHERE LAND Change Land Use Here OCEAN ICE (cryosphere) SUN Land: Absorption of solar radiation Reflection of solar radiation Absorption and emission of infrared radiation Plant and animal life Impacts H 2 O, CO 2 and CH 4 Storage of moisture in soil CO 2 and CH 4 in permafrost Land where consequences are, first and foremost, realized for people. What happens to atmospheric composition if permafrost thaws? Can we store CO 2 in plants? Adaptability and sustainability?

42. CLOUD-WORLD Earth System: Ocean ATMOSPHERE LAND OCEAN ICE (cryosphere) SUN Ocean: Absorption of solar radiation Takes CO 2 out of the atmosphere Plant and animal life Impacts CO 2 and CH 4 Takes heat out away from surface Transport of heat between equator and pole Weather regimes: Temperature and rain What will the ocean really do? Will it absorb all of our extra CO 2 ? Will it move heat into the sub-surface ocean? Changes in circulation? Does it buy us time? Does this ruin the ocean? Acidification Doney: Ocean Acidification

43. Today Scientific investigation of the Earth’s climate: Foundational information –Radiative Balance –Earth System –Aerosols

44. Following Energy through the Atmosphere We have been concerned about, almost exclusively, greenhouse gases. –Need to introduce aerosols Continuing to think about –Things that absorb –Things that reflect

45. Aerosols Aerosols are particulate matter in the atmosphere. –They impact the radiative budget. –They impact cloud formation and growth.

46. Aerosols: Particles in the Atmosphere Aerosols: Particles in the atmosphere. Water droplets – (CLOUDS) “Pure” water Sulfuric acid Nitric acid Smog … Ice Dust Soot Salt Organic hazes AEROSOLS CAN: REFLECT RADIATION ABSORB RADIATION CHANGE CLOUD DROPLETS

47. Earth’s aerosols

48. Dust and fires in Mediterranean

49. Forest Fires in US

50. The Earth System Aerosols (and clouds) SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) Clouds are difficult to predict or to figure out the sign of their impact Warmer  more water  more clouds More clouds mean more reflection of solar  cooler More clouds mean more infrared to surface  warmer More or less clouds? Does this stabilize? Water in all three phases essential to “stable” climate CLOUD

51. The Earth System: Aerosols SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) Aerosols directly impact radiative balance Aerosols can mean more reflection of solar  cooler Aerosols can absorb more solar radiation in the atmosphere  heat the atmosphere In very polluted air they almost act like a “second” surface. They warm the atmosphere, cool the earth’s surface. AEROSOLS ? Composition of aerosols matters. This figure is simplified. Infrared effects are not well quantified

52. South Asia “Brown Cloud” But don’t forget –Europe and the US in the 1950s and 1960s Change from coal to oil economy

53. Coal emits sulfur and smoke particulates “Great London smog” of 1952 led to thousands of casualties. –Caused by cold inversion layer  pollutants didn’t disperse + Londoners burned large amounts of coal for heating Demonstrated impact of pollutants and played role in passage of “Clean Air Acts” in the US and Western Europe Asian Brown Cloud (But don’t forget history.)

54. Current Anthropogenic Aerosol Extreme South Asian Brown Cloud

55. Aerosol: South & East Asia http:// earthobservatory.nasa.gov/Newsroom/NasaNews/2001/200108135050.html

56. Reflection of Radiation due to Aerosol http:// earthobservatory.nasa.gov/Newsroom/NasaNews/2001/200108135050.html

57. Atmospheric Warming: South & East Asia http:// earthobservatory.nasa.gov/Newsroom/NasaNews/2001/200108135050.html WARMING IN ATMOSPHERE, DUE TO SOOT (BLACK CARBON)

58. Surface Cooling Under the Aerosol http:// earthobservatory.nasa.gov/Newsroom/NasaNews/2001/200108135050.html

60. Natural Aerosol

61. Earth’s aerosols

62. Volcanoes and Climate Alan Robock: Volcanoes and Climate Change (36 MB!)Alan Robock: Volcanoes and Climate Change (36 MB!) Alan Robock Department of Environmental Sciences

63. Explosive NET COOLING Stratospheric aerosols (Lifetime  1-3 years) Ash Effects on cirrus clouds absorption (IR) IR Heating emission IR Cooling More Downward IR Flux Less Upward IR Flux forward scatter Enhanced Diffuse Flux Reduced Direct Flux Less Total Solar Flux Heterogeneous  Less O 3 depletion Solar Heating H 2 S SO 2 NET HEATING Tropospheric aerosols (Lifetime  1-3 weeks) Quiescent SO 2  H 2 SO 4  H 2 SO 4 CO 2 H 2 O backscatter absorption (near IR) Solar Heating More Reflected Solar Flux Indirect Effects on Clouds Alan Robock Department of Environmental Sciences

64. Robock and Mao (1995) Superposed epoch analysis of six largest eruptions of past 120 years Year of eruption Significant cooling follows sun for two years Alan Robock Department of Environmental Sciences

65. The Earth System Aerosols (and clouds) SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) Aerosols impact clouds and hence indirectly impact radiative budget through clouds Change their height Change their reflectivity Change their ability to rain Change the size of the droplets CLOUD

66. Aerosols and Clouds and Rain

67. Some important things to know about aerosols They can directly impact radiative budget through both reflection and absorption. They can indirectly impact radiative budget through their effects on clouds  both reflection and absorption. They have many different compositions, and the composition matters to what they do. They have many different, often episodic sources. They generally fall out or rainout of the atmosphere; they don’t stay there very long compared with greenhouse gases. They often have large regional effects. They are an indicator of dirty air, which brings its own set of problems. They are often at the core of discussions of geo-engineering

68. Scientific investigation of Earth’s climate