Climate Change: The Move to Action (AOSS 480 // NRE 501) Richard B. Rood Space Research Building (North Campus) Winter 2008 January 31, 2008

Class News A ctools site for all –AOSS W08 This is the official repository for lectures Class Web Site and Wiki –Climate Change: The Move to ActionClimate Change: The Move to Action –Winter 2008 TermWinter 2008 Term Wunderground Climate Page –Posted Introduction of the New Rough Guide –My recent series on models

Readings on Local Servers Assigned –Stott: External Forcings of 20th Century ClimateStott: External Forcings of 20th Century Climate –Andronova: Anthropogenic Forcing of 20 th Century ClimateAndronova: Anthropogenic Forcing of 20 th Century Climate –Roe: Climate SensitivityRoe: Climate Sensitivity Of Interest –IPCC Figures in PPTIPCC Figures in PPT –Robock: Volcanoes and Climate (powerpoit, 36MB!)Robock: Volcanoes and Climate (powerpoit, 36MB!)

QuikClimate AOSS 605 First specific readings for Quikclimate (Physical Climate Course) –Hartmann: Chapter 5: Hydrological CycleHartmann: Chapter 5: Hydrological Cycle –Oort & Rasmusson: Chapter 12: Hydrological CycleOort & Rasmusson: Chapter 12: Hydrological Cycle

Lectures coming up MLK Day Keynote Speaker: Dr. Warren Washington // Climate Modeling // Tuesday, February 5, :00pm to 5:30pm //Location: Stamps Auditorium, North Campus, Charles R. Walgreen, Jr. Drama CenterMLK Day Keynote Speaker: Dr. Warren Washington Erb Speaker Series: Jim Nixon, Alcoa, "Challenges for an Energy Intensive Business in a Carbon Constrained World" Tuesday, February 5, :00pm to 6:30pm Ross School, Wyly 0750Erb Speaker Series: Jim Nixon, Alcoa, "Challenges for an Energy Intensive Business in a Carbon Constrained World"

Tuesday February 5 Warren Washington will be here for questions and discussion. –1) How has the discussion of climate change varied from President to President? –2) What are the next steps in research an management of the climate? –3) How do we change to get climate information generated and needed for societal needs?

Tuesday February 5 WE STILL START PROMPTLY AT 10:30 If schedule work we should walk into this room about 10:20.

Outline of Lecture Introduction to Models Conservation equation –Calculation of production and loss terms Volcanoes –Internal variability El Nino The last 100 years. Climate Sensitivity Radiative Forcing

What is a Model? Model –A work or construction used in testing or perfecting a final product. –A schematic description of a system, theory, or phenomenon that accounts for its known or inferred properties and may be used for further studies of its characteristics. Numerical Experimentation –Given what we know, can we predict what will happen, and verify that what we predicted would happen, happened?

What do we do? We develop models based on the conservation of energy and mass and momentum, the fundamental ideas of classical physics. (Budget equations)

Symbolic Energy Balance Equation E a t+  t = E a t +  t ( (P a – L a E a ) + (Tr a  oil + M a ) ) Atmosphere: Symbols E = “Energy” P = Production L = Loss rate Tr = Transfer M = Motion Superscripts a is for atmosphere o is for ocean i is for ice l is for land Variables t = time  t = time increment

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

Symbolic Energy Balance Equation (Earth System) E a t+  t = E a t +  t ( (P a – L a E a ) + (Tr a  oil + M a ) ) Atmosphere: E o t+  t = E o t +  t ( (P o – L o E o ) + (Tr o  ail + M o ) ) Ocean: E i t+  t = E i t +  t ( (P i – L i E i ) + (Tr i  oal + M i ) ) Ice: E l t+  t = E l t +  t ( (P l – L l E l ) + (Tr l  oia + M l ) ) Land:

A point With this model we are now existing inside of the climate system rather than sitting out in space looking at the global balance. –Inside – we are especially interested in what goes on at the surface of the Earth –Inside – we have to worry about the climate every day, we don’t have the benefit of the average –Inside – we have to deal with the complexity Conservation is still true, but you have to think about being embedded in the system, not a distant observer of the system

What do we do? We develop models based on the conservation of energy and mass and momentum, the fundamental ideas of classical physics. (Budget equations) We determine the characteristics of production and loss from theory and observations of, for instance, the eruption of a major volcano and the temperature response as measured by the global observing system.

Consider just the Production and Loss Rate (We call this forcing.) P a – L a E a We can divide this, conceptually, into two:  That in absence of the influence of the “industry” of humans  That which includes the influence of the “industry” of humans Variability of the sun What volcanoes put in the atmosphere Greenhouse gases prior to industrial revolution Aerosols from, for instance, sea salt and desert dust Changes in greenhouse gases due to burning of fuel Aerosols from “industrial” emissions Changes in gases due to changes in what is growing Change in absorption and reflection due to land use change More?

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

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

What do we do? We develop models based on the conservation of energy and mass and momentum, the fundamental ideas of classical physics. (Budget equations) We determine the characteristics of production and loss from theory and observations of, for instance, the eruption of a major volcano and the temperature response as measured by the global observing system. We attempt to predict the temperature (“Energy”) response. We evaluate (validate) how well we did, characterize the quality of the prediction relative to the observations, and determine, sometimes with liberal interpretation, whether or not we can establish cause and effect.

Schematic of a model experiment.   Start model prediction Model prediction without forcing Model prediction with forcing Model prediction with forcing and source of internal variability Observations or “truth” E a t+  t = E a t +  t ( (P a – L a E a ) + (Tr a  oil + M a ) )

CO 2 and Temperature for Last 1000 years Surface temperature and CO 2 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 CO 2 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? {

What do we know from model experiments and evaluation (validation) with observations With consideration of solar variability and volcanic activity, the variability in the temperature record prior to 1800 can be approximated. After 1800 need to consider the impact of man –Deforestation of North America –Fossil fuel emission –Change from coal to oil economy –Clean air act Only with consideration of CO 2, increase in the greenhouse effect, can the temperature increase of the last 100 years be modeled.

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

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

Changes during El Nino

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

Some good El Nino Information NOAA Climate Prediction: Current El Nino / La NinaNOAA 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.

Back to the Predictions So we have constructed these models. –Defining the production and loss. –Model the conservation laws that support internal variability. –We make predictions of the past and present and work to validate performance There are successes There are failures –Some of which are persistent. –We draw our conclusions

Here is a strong figure But it has some issues

NATURAL FORCING HUMAN-MADE FORCING

Third Assessment Report of the IPCC (2001): General circulation model results Fig Pinatubo

Attribution experiments with models Meehl et al., J. Climate (2004)

Figure TS.23

Think about this figure What are the strengths and the weakness that are represented in this figure?

Hansen et al: (1998) & (2001) (-2.7, -0.6) (-3.7, 0.0) Climate Forcing ICONIC FIGURE ALERT

Positive radiative forcing warms climate Negative radiative forcing cools climate ? ICONIC FIGURE ALERT from Joyce Penner

Introduce the Idea of Climate Sensitivity (Evaluating Uncertainty) Different Models have different sensitivity. Some show larger changes for a given change in CO 2 than others. Let’s imagine having two groups, those with high sensitivity and those with low sensitivity.

Let’s Split up the Model World High Climate Sensitivity –High Aerosol Forcing –Low Aerosol Forcing Low Climate Sensitivity –High Aerosol Forcing –Low Aerosol Forcing

Low climate sensitivity, low aerosol forcing Observed temperature change Climate model with low climate sensitivity and small aerosol forcing from Joyce Penner

High climate sensitivity, high aerosol forcing Observed temperature change Climate model with high climate sensitivity and high aerosol forcing from Joyce Penner

Let’s Split up the Model World High Climate Sensitivity –High Aerosol Forcing (Can fit observations) –Low Aerosol Forcing (Cannot fit observations) Low Climate Sensitivity –High Aerosol Forcing(Cannot fit observations) –Low Aerosol Forcing (Can fit observations)

Is this too much detail? There is a point –We have this forcing of the energy in the climate system; primary, change of the speed at which the Earth cools. This will warm. –The Earth will respond to this Change the energy transport rate between equator and pole. Feedbacks to the radiative budget. –Some will enhance heating –Some will retard heating –Is there any reason to expect that the Earth will respond to maintain the same equilibrium temperature at the surface? Is there a feedback which essentially balances the heating?

Positive radiative forcing warms climate Negative radiative forcing cools climate ? HERE IS YOUR BEST CHANCE AT COOLING from Joyce Penner

High climate sensitivity and large aerosol forcing Low Climate sensitivity and small aerosol forcing And in another 100 years from Joyce Penner

Radiative Forcing IPCC 2007

Schematic Summary IF WE CHOOSE TO DO SOMETHING ABOUT THIS, THEN CHANGE ENERGY BALANCE CHANGE ABSORPTION OF RADIATIVE ENERGY CHANGE REFLECTION OF RADIATIVE ENERGY ~2 out of 340 W / m 2

Start to think about the 2100 predictions

As people sitting here on earth, what climate parameters/events do we care about? Temperature Water –Precipitation –Evaporation –Humidity Air Composition –Air quality –Aerosols –Carbon dioxide Winds Clouds / Sunlight Sea-level Rise Droughts Floods Extreme Weather

Have a good weekend Warren Washington on Tuesday