Climate Change: An Inter-disciplinary Approach to Problem Solving (AOSS 480 // NRE 480) Richard B. Rood Cell: Space Research Building (North Campus) Winter 2015 January 27, 2015

Class Information and News Ctools site: AOSS_SNRE_480_001_W15AOSS_SNRE_480_001_W15 –Record of course Rood’s Class MediaWiki SiteClass MediaWiki Site – A tumbler site to help me remember –

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

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

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 Salt Organic hazes AEROSOLS CAN: REFLECT RADIATION ABSORB RADIATION CHANGE CLOUD DROPLETS

Earth’s aerosols

Earth’s Aerosols

Dust and fires in Mediterranean

Forest Fires in US

The Earth System: Clouds SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) 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 CLOUD

The Earth System: Aerosols SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) 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 ? 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 1950s and 1960s Change from coal to oil economy

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

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

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

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

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

Aerosol relation to clouds

The Earth System Aerosols and Clouds Interactions SURFACE Top of Atmosphere / Edge of Space ATMOSPHERE (infrared) 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 CLOUD

Aerosols and Clouds and Rain Less

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

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

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

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.  Medieval warm period  “Little ice age”

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 ) )

Little Ice Age Miller et al. Onset of Little Ice AgeOnset 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

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

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

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

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

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

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

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 RealClimate

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