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 2010 February 9, 2010

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

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.

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

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

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

Today Foundation of science of climate change (continued)

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”

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.

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 ?????

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.)

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.

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

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

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

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

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.”

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.

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

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

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

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)

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

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

Earth’s aerosols

Dust and fires in Mediterranean

Forest Fires in US

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

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

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

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

Earth’s aerosols

Current Anthropogenic Aerosol Extreme

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

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

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

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

Earth’s aerosols

Natural Aerosol Extreme

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

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

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, 1086-1103, 1995. Alan Robock Department of Environmental Sciences

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

Aerosols and Clouds and Rain

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

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

Radiative Forcing IPCC 2007

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.

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.

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?

Changes during El Nino

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

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.

An interesting time to study? GISS Temperature 2002 1997-98 El Nino An interesting time to study?

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

ENOUGH!

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

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?

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

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

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

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}

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