Climate Change An Interdisciplinary Approach to Problem Solving

Climate Change: An Inter-disciplinary Approach to Problem Solving (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 2015 January 27, 2015

Class Information and News • Ctools site: AOSS_SNRE_480_001_W 15 – Record of course • Rood’s Class Media. Wiki Site – http: //climateknowledge. org/classes/index. php/Climate_Change: _The_Move_to_Action • A tumbler site to help me remember – http: //openclimate. tumblr. com/

Resources and Recommended Reading • NASA Resources – – – Aerosols: What and Why Important NASA/EO: Smoke and Clouds NASA/EO: Dust and Desertification NASA/EO: Volcanoes and Climate Change NASA/EO: Big Effects of Aerosols • Aerosols: Open Source Systems, Science, Solution – NASA – Realclimate • Aerosols Wikipedia • Miller et al. Onset of Little Ice Age

Outline: Class 7, Winter 2015 • • Basics of aerosols South and East Asian brown cloud Aerosol relation to clouds Volcanoes and climate – Models and Little Ice Age • Earth system summary • Changes in radiative balance

Changes in the sun Things that change reflection So what matters? THIS IS WHAT WE ARE DOING Things that change absorption Accumulation, transport and storage of energy in ocean, ice, land

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

Aerosols • Aerosols are fine, airborne particles consisting at least in part of solid material – They impact the radiative budget. • Absorb • Reflect – They impact cloud formation and growth.

Particles in the Atmosphere Clouds and Aerosols: Particles in the atmosphere. • Water (and other) droplets and ice particles – (CLOUDS) • “Pure” water • Sulfuric acid • Nitric acid • Smog • … • Dust • Soot / Black Carbon AEROSOLS CAN: • Salt REFLECT RADIATION • Organic hazes ABSORB RADIATION CHANGE CLOUD DROPLETS

Earth’s aerosols

Earth’s Aerosols http: //www-das. uwyo. edu/~geerts/cwx/notes/chap 02/aerosol&climate. html

Dust and fires in Mediterranean

Forest Fires in US

The Earth System: Clouds are difficult to predict or to figure out the sign of their impact Top of Atmosphere / Edge of Space • 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 ATMOSPHERE (infrared) SURFACE

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

South & East Asia “Brown Cloud” • But don’t forget – Europe and the US in the 1950 s and 1960 s • 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

Aerosol: South & East Asia http: //earthobservatory. nasa. gov/Newsroom/Nasa. News/200108135050. html

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

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

Surface Cooling Under the Aerosol http: //earthobservatory. nasa. gov/Newsroom/Nasa. News/200108135050. html

Aerosol relation to clouds

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

Aerosols and Clouds and Rain Less

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

More Reflected Solar Flux Stratospheric aerosols (Lifetime » 1 -3 years) Less Upward IR Flux backscatter absorption (near IR) H 2 S ® H SO 2 4 SO 2 CO 2 H 2 O ve osi l Exp Solar Heating Heterogeneous ® Less O 3 depletion Solar Heating NG Heating ATI IR HE NET Q absorption (IR) emission Reduced Direct Flux Enhanced Diffuse Flux Tropospheric aerosols (Lifetime » 1 -3 weeks) ent IR Cooling forward scatter Ash sc uie emission Less Total Solar Flux SO 2 ® H 2 SO 4 Indirect Effects on Clouds Alan Robock Department of Environmental Sciences Effects on cirrus clouds N ING L O O ET C More Downward IR Flux

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

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

Models and Little Ice Age

Temperature and CO 2: The 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. q Medieval warm period q “Little ice age”

Schematic of a model experiment. Observations or “truth” T T Start model prediction Model prediction without forcing Model prediction with forcing and source of internal variability Eat+Dt = Eat + Dt((Pa – La. Ea) + (Tra oil + Ma ))

Little Ice Age • Miller et al. Onset of Little Ice Age – Numerical Experiment based on observational evidence of decades long period of high volcanic activity • 50 years 4 major eruptions • Sea-ice/ocean feedbacks • No requirement of large changes solar energy

Earth-system Summary

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

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

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

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

The Earth System SUN CLOUD-WORLD ATMOSPHERE ICE (cryosphere) OCEAN LAND Storage and transport of energy. Influences surface air temperature

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

Changes in Radiative Forcing

Radiative forcing: Changes to absorption and reflection • Earth's most abundant greenhouse gases – – – water vapor (H 2 O) carbon dioxide (CO 2) methane (CH 4) nitrous oxide (N 2 O), commonly known as "laughing gas" ozone (O 3) chlorofluorocarbons (CFCs) • Long-lived, well mixed • Short-lived, regional variability • Aerosols, short-lived and regional

Radiative Forcing Changes Interesting History of This Plot at Real. Climate

Summary: Class 7, Winter 2015 • Aerosols – Absorb – Reflect – Human and natural – Regional – Short lived • Asian brown cloud demonstrate aerosol effects – Likely “masking” warming

Summary: Class 7, Winter 2015 • Aerosols change clouds – Precipitation – Characteristics of absorption and reflection • Volcanoes – Important natural drivers of climate variability – Provide one of our best “controlled” experiments • Considering all source of radiative forcing – Warming from greenhouse gases – Aerosols in net cooling black carbon management – Cloud-aerosol effects are cooling

Outline: Class 7, Winter 2015 • • Basics of aerosols South and East Asian brown cloud Aerosol relation to clouds Volcanoes – Models and Little Ice Age • Earth system summary • Changes in radiative balance