1. Climate Change: The Move to Action (AOSS 480 // NRE 480)
Richard B. Rood
Cell:
2525 Space Research Building (North Campus)
Winter 2010
February 9, 2010

2. Class News Ctools site: AOSS 480 001 W10 On Line: 2008 Class
Reference list from course
Rood Blog Data Base
Reading

3. Make Up Class / Opportunity
Make up Class on March 8, Dana 1040, 5:00 – 7:30 PM, Joint with SNRE 580
V. Ramanathan, Scripps, UC San Diego
Please consider this a regular class and make it a priority to attend.
Pencil onto calendar on April 6, Jim Hansen, time TBD.

4. Class Projects Think about Projects for a while
The role of the consumer
Energy efficiency / Financing Policy
Science influence on policy, Measurements of carbon, influence
Role of automobile, transportation, life style
Water, fresh water, impact on carbon,
Geo-engineering, public education, emergency management, warning,
Water, insurance, Midwest development, Michigan, regional
Dawkins, socio-biology
What leads to a decision
What does it really mean in the village
Geo-engineering, urban sustainability
US Policy, society interest, K-12, education

5. Projects; Short Conversation
Finance/Energy Efficiency/Development of Technology/Reduction of Emissions
“Geo-engineering” --- managing heating in the near-term/Role of Attribution/Managing the climate, what climate information is needed

6. Groups that have organized a short presentation, discussion
Next week
Groups that have organized a short presentation, discussion
Title
Your vision
What disciplines are present in your group

7. Today
Foundation of science of climate change (continued)

8. Summary Points Theory / Empirical Evidence
CO2 and Water Vapor Hold Heat Near Surface
Correlated Observations
CO2 and Temperature Observed to be strongly related on long time scales (> 100 years)
CO2 and Temperature not Observed to be strongly related on short time scales (< 10 years)
Observations
CO2 is Increasing due to Burning Fossil Fuels
Theory / Conservation Principle
Mass and Energy Budgets
 Concept of “Forcing”

9. Let’s look at just the last 1000 years
Surface temperature and CO2 data from the past 1000 years. Temperature is a northern hemisphere average. Temperature from several types of measurements are consistent in temporal behavior. {
Note that on this scale, with more time resolution, that the fluctuations in temperature and the fluctuations in CO2 do not match as obviously as in the long, 350,000 year, record.
What is the cause of the temperature variability? Can we identify mechanisms, cause and effect? How?
This is an important point in the ultimate argument, on short time scales co2 and T are not so well correlated. T responds to other factors. These factors will be evaluated based on modeling experiments, which follow from (imperfect) observations of cause and effect as determined by observable events, e.g. volcanos.

10. Important Concept
We are working with, calculating budgets, for existing, “stable” systems. They are in balance.
We are interested in changes in the balance.
What we are changing:
CO2 in atmosphere (ocean-land-fossil fuel burning)
How does this change?
Phase of water in current climate (vapor, liquid, ice)
Energy and exchange of energy within the Earth’s system
?????

11. Radiative Balance of The Earth
Over some suitable time period, say a year, maybe ten years, if the Earth’s temperature is stable then the amount of energy that comes into the Earth must equal the amount of energy that leaves the Earth.
Energy comes into the Earth from solar radiation.
Energy leaves the Earth by terrestrial (mostly infrared) radiation to space.
(Think about your car or house in the summer.)

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

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

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

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

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

17. Energy doesn’t just come and go
The atmosphere and ocean are fluids. The horizontal distribution of energy, leads to making these fluids move. That is “weather” and ocean currents and the “general circulation.”

18. Transport of heat poleward by atmosphere and oceans
Weather ... The weather is how we feel the climate day to day.
It is likely to change because we are changing the distribution of average heating.
It is likely to change because warm air can hold more water, which also changes the distribution of energy.

19. To complete the basic picture we need
Aerosols
Internal Variability
Feedbacks: Response to a change in forcing
Important details that we have to remember
Land surface / land use changes
Other green house gases
Air quality
Abrupt climate change

20. Following Energy through the Atmosphere
We have kept in our mind, mostly, greenhouse gases.
Need to introduce aerosols
We have been thinking about
Things that absorb
Things that reflect
Responses to energy  Feedbacks

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

22. Earth System: Cloud World
SUN
Earth System: Cloud World
Cloud World:
Very important to reflection of solar radiation
Very important to absorption of infrared radiation
Acts like a greenhouse gas
Precipitation, latent heat
Most uncertain part of the climate system.
Reflecting Solar Cools
Largest reflector
Absorbing infrared Heats
CLOUD-WORLD
ATMOSPHERE
In the absence of clouds the albedo would be closer to 0.1 rather than 0.3.
OCEAN
LAND
ICE
(cryosphere)

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

24. 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

25. Earth’s aerosols

26. Dust and fires in Mediterranean

27. Forest Fires in US

28. The Earth System Aerosols (and clouds)
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
Top of Atmosphere / Edge of Space
CLOUD
ATMOSPHERE
(infrared)
SURFACE

29. The Earth System: Aerosols
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.
Top of Atmosphere / Edge of Space
ATMOSPHERE
AEROSOLS ?
(infrared)
SURFACE
Composition of aerosols matters.
This figure is simplified.
Infrared effects are not well quantified

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

31. Asian Brown Cloud (But don’t forget history.)
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

32. Earth’s aerosols

33. Current Anthropogenic Aerosol Extreme

34. Aerosol: South & East Asia

35. Reflection of Radiation due to Aerosol

36. Atmospheric Warming: South & East Asia
WARMING IN ATMOSPHERE, DUE TO SOOT (BLACK CARBON)

37. Surface Cooling Under the Aerosol

38. Earth’s aerosols

39. Natural Aerosol Extreme

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

41. Department of Environmental Sciences
Explosive
backscatter
absorption (near IR)
Solar Heating
More Reflected
Solar Flux
absorption (IR) IR
Heating
emission
IR Cooling
More
Downward
IR Flux
Less
Upward
Stratospheric aerosols
(Lifetime » 1-3 years)
H2S
SO2
® H2SO4
NET HEATING
Heterogeneous ® Less
O3 depletion Solar Heating
CO2
H2O
forward scatter
Enhanced
Diffuse
Flux
Reduced
Direct
Less Total
Solar Flux
Ash
Effects
on cirrus
clouds
Tropospheric aerosols
(Lifetime » 1-3 weeks)
This diagram shows the main components of non-explosive and explosive volcanic eruptions, and their effects on shortwave and longwave radiation.
Quiescent
Indirect Effects on Clouds
SO2 ® H2SO4
NET COOLING
Alan Robock
Department of Environmental Sciences

42. Superposed epoch analysis of six largest eruptions of past 120 years
Year of eruption
Superposed epoch analysis of six largest eruptions of past 120 years
Significant cooling follows sun for two years
Robock and Mao (1995)
Robock and Mao (1995) removed the ENSO signal, and averaged the temperature change for the six largest recent eruptions, showing the anomaly from the preceding 5-year period. The cooling follows the sun for two years after the eruptions, but is displaced north of the Equator because there is more land in the Northern Hemisphere, so the cooling is larger there. The volcanic aerosol clouds were fairly evenly distributed in latitude.
Robock, A. and J. Mao, The volcanic signal in surface temperature observations, J. Climate, 8, , 1995.
Alan Robock
Department of Environmental Sciences

43. The Earth System Aerosols (and clouds)
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
Top of Atmosphere / Edge of Space
CLOUD
ATMOSPHERE
(infrared)
SURFACE

44. Aerosols and Clouds and Rain

45. 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

46. Let’s take a breath
We have now seen the basics of the climate change problem
reduced it to an energy balance that alters absorption and reflection
greenhouse gases
changes at the Earth’s surface
aerosols
seen that there is significant natural variability in the climate
identified the role of the major components of the physical climate system
exposed the role of water in the physical climate

47. Radiative Forcing IPCC 2007

48. Let’s look at just the last 1000 years
Surface temperature and CO2 data from the past 1000 years. Temperature is a northern hemisphere average. Temperature from several types of measurements are consistent in temporal behavior. {
Note that on this scale, with more time resolution, that the fluctuations in temperature and the fluctuations in CO2 do not match as obviously as in the long, 350,000 year, record.
What is the cause of the temperature variability? Can we identify mechanisms, cause and effect? How?
This is an important point in the ultimate argument, on short time scales co2 and T are not so well correlated. T responds to other factors. These factors will be evaluated based on modeling experiments, which follow from (imperfect) observations of cause and effect as determined by observable events, e.g. volcanos.

49. Sources of internal variability
This is, in principle, natural variability.
That does not mean that these modes of variability remain constant as the climate changes.

50. Internal Variability?
There are modes of internal variability in the climate system which cause global changes.
El Nino – La Nina
What is El Nino
North Atlantic Oscillation
Climate Prediction Center: North Atlantic Oscillation
Annular Mode
Inter-decadal Tropical Atlantic
Things we have not observed?

51. Changes during El Nino

52. Times series of El Nino (NOAA CPC)
LA NINA
OCEAN TEMPERATURE
EASTERN PACIFIC
ATMOSPHERIC
PRESSURE
DIFFERENCE

53. Some good El Nino Information
NOAA Climate Prediction: Current El Nino / La Nina
NOAA CPC: Excellent slides on El Nino
This is a hard to get to educational tour. This gets you in the middle and note navigation buttons on the bottom.

54. An interesting time to study?
GISS Temperature 2002
El Nino
An interesting time to study?

55. Definitely Important: Must be accounted for in determining trends
Internal Variability
Definitely Important: Must be accounted for in determining trends
El Nino – La Nina
What is El Nino
North Atlantic Oscillation
Climate Prediction Center: North Atlantic Oscillation

56. ENOUGH!

57. Taking a breath We have not
Looked at what the atmosphere and ocean look like
Talked about how we measure climate change
Talked about how we predict climate change
Talked about how we make attributions of climate change to greenhouse gases
Addressed the role of “abrupt” climate change

58. The predictions and observations so far are either in the sense of:
Abrupt climate change
The predictions and observations so far are either in the sense of:
Relatively small changes in the dynamic balance of the climate system
Incremental changes to the stable climate.
What about “abrupt” climate change?

59. Note to professor: Force students to think and speak
What might cause something to change abruptly in the climate system?
Lamont-Doherty: Abrupt Climate Change
NAS: Abrupt Climate Change
Wunderground.com: Abrupt Climate Change

60. What is a stable climate?
LIQUID - ICE
NOAA Paleoclimate
Schlumberger

61. Younger Dryas POSSIBLE EVIDENCE OF CHANGE IN OCEAN CIRCULATION
WHAT DOES THIS MEAN?

62. Next time: Fundamental Science of Climate
Figure SPM.5. Solid lines are multi-model global averages of surface warming (relative to 1980–1999) for the scenarios A2, A1B and B1, shown as continuations of the 20th century simulations. Shading denotes the ±1 standard deviation range of individual model annual averages. The orange line is for the experiment where concentrations were held constant at year 2000 values. The grey bars at right indicate the best estimate (solid line within each bar) and the likely range assessed for the six SRES marker scenarios. The assessment of the best estimate and likely ranges in the grey bars includes the AOGCMs in the left part of the figure, as well as results from a hierarchy of independent models and observational constraints. {Figures 10.4 and 10.29}

63. The Earth System
SUN
Increase greenhouse gases reduces cooling rate  Warming
Changes in land use impact absorption and reflection
Solar
variability
Cloud feedback?
Aerosols cool?
Cloud feedback?
ATMOSPHERE
LAND
OCEAN
ICE
Water vapor feedback accelerates warming
Ice-albedo feedback accelerates warming