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 11, 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

Project Teams Michigan Coal / Energy: Maggie Allan, Meghan Reynard, Evan Oswald, Yoichi Shiga Efficiency as effective mitigation: Rebecca Taylor, Erin Kashawlic, Rajesh Nerlikar, Amanda Herrick

Projects; Short Conversation “Geo-engineering” --- managing heating in the near-term / Role of Attribution / Managing the climate, what climate information is needed / Air quality Transportation / Automobiles / Energy / Market / Weather / Extreme Events / Agriculture / Carbon Sinks / Local Adaptation

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: 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

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.

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

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

Radiative Forcing IPCC 2007

Today: 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

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 natural variability. Solar variability Volcanic activity Internal “dynamics” Atmosphere - Weather Ocean Atmosphere-ocean interactions That does not mean that these modes of variability remain constant as the climate changes.

Changes during El Nino

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 Pacific Decadal Oscillation

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?

Pacific Decadal Oscillation Does the Pacific Decadal Oscillation operate regularly lasting 20-30 years, and does southern California experience droughts during that period? How is information gathered to support that? The Pacific Decadal Oscillation is one of several “oscillations” that are important to weather and climate. Some attributes of the Pacific Decadal Oscillation Information is gathered in the same way as climate and weather observations. Routine Focused

Pacific Decadal Oscillation: Basics Colors: Sea Surface Temperature difference from long term average. Arrows: Stress on the ocean surface caused by winds Cool here Warm here Better version of figure from JISAO

Some information on Pacific Decadal Oscillation Joint Institute for Study of Atmosphere and Ocean (JISAO): Pacific Decadal Oscillation Climate Prediction Center (CPC): 90 Day Outlook Summary Weather and Climate Linkage National Climatic Data Center (NCDC): Decadal Oscillations Review Paper from Rood Class References Mantua and Hare (2002) J of Oceanography

Today: 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

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.

More consideration of radiative energy in the atmosphere FEEDBACKS .... The idea that one thing causes a second thing to happen. That second thing then does something to the first thing It damps it, negative feedback It amplifies it, positive feedback Technical Reference: Soden and Held

The Earth System: Feedbacks 1 Infrared Proportional to Temperature SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) Assume that greenhouse gases remain the same Infrared emission is proportional to temperature Temperature increases  emission increases This is key to stabilizing the Earth’s climate!

The Earth System: Feedbacks 2 Water Vapor When it gets warmer more water, a greenhouse gas, will be in the atmosphere Higher temperature increases evaporation from land and ocean Higher temperature allows air to hold more water Increase of water increases thickness of blanket – increases temperature more This could runaway! Natural limit because of condensation  clouds, rain? Compensating circulation changes? Think deserts … SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared)

The Earth System: Feedbacks 3 Ice - Albedo When it gets warmer less ice Less ice means less reflection  warmer Warmer means less ice This could runaway! Cooler works the other way  ice-covered Top of Atmosphere / Edge of Space ICE

The Earth System: Feedbacks 4 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: Feedbacks 5 Something with the Ocean? Is there something with the ocean and ice? Land ice melting decreases ocean salinity (density) Sea-ice impacts heat exchange between ocean and atmosphere Sea-ice impacts solar absorption of ocean North Atlantic sea-ice and ocean interaction very important to the climate Think Gulf Stream Think climate and people and economy Is there a natural feedback that stabilizes climate? Even if there is, it would be very disruptive, perhaps not stable from a societal point of view.

Cloud-Ice-Atmosphere Feedback Some carry away messages This is where much of the discussion about scientific uncertainty resides. The Earth is at a complex balance point That balance relies on water to exist in all three phases. Too warm could run away to “greenhouse” vapor Too cold run away to “snowball” ice How clouds change is not well understood and much argued. The Iris Effect? Is there something in all of this that changes the sign; namely, that CO2 warming will be compensated by more cooling?

Earth System: Ice SUN ICE: Very important to reflection of solar radiation Holds a lot of water (sea-level rise) Insulates ocean from atmosphere (sea-ice) Ice impacts both radiative balance and water – oceans and water resources on land. . Large “local” effects at pole. Large global effects through ocean circulation and permafrost melting. Might change very quickly. CLOUD-WORLD ATMOSPHERE OCEAN LAND ICE (cryosphere)

The Earth System: ICE (Think a little more about ice) non-polar glaciers and snow polar (Greenland) (Antarctica) sea-ice Impacts regional water supply, agriculture, etc. Solar reflection, Ocean-atmosphere heat exchange Solar reflection, Ocean density, Sea-level rise (Tour of the cryosphere, Goddard Scientific Visualization Studio)

The Cryosphere TOUR OF CRYOSPHERE: MAIN NASA SITE

Let’s think about the Arctic for a while WWF: Arctic Feedbacks Assessment

Projected Global Temperature Trends: 2100 2071-2100 temperatures relative to 1961-1990. Special Report on Emissions Scenarios Storyline B2 (middle of the road warming). IPCC 2001

The Thermohaline Circulation (THC) (Global, organized circulation in the ocean) (The “conveyer belt”, “rivers” within the ocean) Blue shading, low salt Green shading, high salt Where there is localized exchange of water between the surface and the deep ocean (convection) Warm, surface currents. Cold, bottom currents. From Jianjun Yin, GFDL, see J. Geophysical Research, 2006

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

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}