How to Cool the How to Cool the EarthEarth

Charlie ZenderDepartment of Earth System ScienceUC Irvine

Swiss American Chamber of Commerce, Beverly Hills, CA March 18, 2010

Thornton Bank Wind FarmThornton Bank Wind Farm

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Global Average Temperature

Global Average Sea Level

Northern Hemisphere Snow Cover

1850 19501900 2000

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IPCC, UCS

Year 2100: Hot, dry, and crowded...Year 2100: Hot, dry, and crowded...

Best Case

Worst CaseWorst CaseTemperature:4-7 °F WarmerSea Level:1-2 ft. higherPopulation:9-12 billion

Harness Wind to Cool Climate by...Harness Wind to Cool Climate by...

● Wind/wave/tidal power displaces fossil fuels otherwise used in power generation

● Wind-assisted or -driven ship propulsion

Passively Offsetting GHG Emissions:

… or by Actively Cooling Surface:● Wind powered fleet of autonomous vessels

brighten clouds to reduce absorbed sunlight

160 MW Offshore Wind Farm, Horns Rev, Denmark

Is This All it Takes to Save the World?Is This All it Takes to Save the World?

Wind Power FundamentalsWind Power Fundamentals● Power produced proportional to rotor area and to

cube of wind speed● Wind Speed increases with height● Offshore winds are faster than onshore● Typical wind turbine produces ~1-5 MW, enough to

power ~1000-5000 houses

Annual Average Surface Wind Speed, 2001Annual Average Surface Wind Speed, 2001

Capps and ZenderCapps and Zender

““The US is the Saudi Arabia of Wind ReservesThe US is the Saudi Arabia of Wind Reserves""

Capps and Zender

Installation of Large Wind TurbinesInstallation of Large Wind Turbines

Wind Power Displaces Fossil Fuels: Wind Power Displaces Fossil Fuels: How many Turbines to power BEVs?How many Turbines to power BEVs?

● Modern 126 m turbines provide ~ 5 MW● Wind conversion/transmission losses 5-10%● BEV plug-to-wheel efficiency ~75-86%● 73,000-144,000 5 MW turbines suffice● Compare: US produced 300,000 airplanes in WWII● Would reduce US CO2 emissions by 25%, and

vehicle-related air pollution deaths by 15,000 yr-1

*BEV = Battery-powered Electric Vehicle

Same location...six months laterSame location...six months later

SWAY: Conceptual Deep Water Wind Farm

Is Is ThisThis All It Takes to Save the World? All It Takes to Save the World?Of Course Not. But...Of Course Not. But...Wind Farms Could Reduce CO2e by ~25%Wind Farms Could Reduce CO2e by ~25%

USS Constitution (3968 mUSS Constitution (3968 m²² sail) sail)

USCSG Eagle (2070 mUSCSG Eagle (2070 m²² sail) sail)

Traditional Wind-Assisted ShippingTraditional Wind-Assisted Shipping

German Container Ship MS Beluga Skysails in 2008

Modern Wind-Assisted ShippingModern Wind-Assisted Shipping

Kite-Assisted Kite-Assisted Shipping:Shipping:

●Reduces fuel costs and emissions 20-30%

●Automatic controls ●No power cables●Faster winds aloft

MS Beluga with 160-320 m² SkySails Kite

German Rotor Ship Buckau (1926)

Flettner Rotors: Vertical Axis Wind TurbinesFlettner Rotors: Vertical Axis Wind Turbines

Geoengineering: Treat the Geoengineering: Treat the Symptom?Symptom?

Morton

An Inadvertent Truth: Ship Tracks Cool An Inadvertent Truth: Ship Tracks Cool Surface By Brightening CloudsSurface By Brightening Clouds

Salter and Latham

The “Twomey Effect”: Ships emit pollution particles which are Cloud Condensation Nuclei (CCN) that spread a cloud into more and smaller droplets, thus brightening it.

Wind-powered ships could inject sea-spray to Wind-powered ships could inject sea-spray to brighten clouds and to cool Earthbrighten clouds and to cool Earth

Salter and Latham

Cooling by Injecting Sea Spray in Cloudy AreasCooling by Injecting Sea Spray in Cloudy Areas

Latham et al.

Fewer Droplets

More Droplets

How Many Spray Vessels to Offset How Many Spray Vessels to Offset Global Warming? Global Warming?

● 1500 vessels could offset current warming● 50 new vessels per year offset future emissions● $50 million R&D + $2-4 million per vessel

Harvest Wind Power for Climate, Air Harvest Wind Power for Climate, Air Pollution, and Energy Security Pollution, and Energy Security

● Wind is abundant, clean, low-risk power source

● Wind-powered BEVs and wind-assisted shipping can eliminate ~25% of CO2e

● Geoengineered cooling by marine cloud brightening is plausible, reversible stop-gap strategy until CO2e reduced

Envirozine

AcknowledgementsAcknowledgements Dr. Scott Capps, UCLA

Dr. Harry Mangalam, UCI

Prof. Mark Jacobson, Stanford

National Science Foundation (NSF)

National Aeronautics and Space Administration (NASA)

ReferencesReferences● Balog, James (2008), National Geographic Magazine, June 2008.● Capps, S. B., and C. S. Zender (2009a), Global Ocean Wind Power Sensitivity to Surface

Layer Stability, Geophys. Res. Lett., 36, doi:10.1029/2008GL037063.● Capps, S. B., and C. S. Zender (2009b), The Estimated Global Ocean Wind Power

Potential from QuikSCAT Observations, Accounting for Turbine Characteristics and Siting, Submitted to J. Geophys. Res..

● IPCC (2007), Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.

● Jacobson, Mark (2009), Review of Solutions to Global Warming, Air Pollution, and Energy Security, Energy Environ. Sci., 2, 148-173, doi:10.1039/b809990c.

● Keith, David (2008), Engineering the Planet, Climate Change Science and Policy● Latham, John, et al. (2008), Global temperature stabilization via controlled albedo

enhancement of low-level maritime clouds, Phil. Trans. R. Soc. A, 366, 3969-3987, doi:10.1098/rsta.2008.0137.

● Morton, Oliver (2007), Climate change: Is this what it takes to save the world?, Nature, 447, 132-136, doi:10.1038/447132a.

● Salter, Stephen et al. (2008), Sea-going hardware for the cloud albedo method of reversing global warming, Phil. Trans. R. Soc. A, 366, doi:10.1098/rsta.2008.0136.

Greenhouse Gases (GHGs) are non-toxic and environmentally harmless...except they heatclimate and acidify the ocean.GHGs are by-products of core societal functions:

IPCC

Worldwide Electric Power Capacity* Worldwide Electric Power Capacity* CO2e

121 47 3—71.2 37 3—7

0.00075 0.5 42—620.26 0.18 34—55

0.354 1—8 9—118.7 < 3000 19—599 0.07—0.13 16—61

778 1.9 48—71

371 < 11 68—1800.0 < 0.5—13 310—570

1000 > 5 790—1020

Inter- Installed ExploitableRenewables: mittency Power (GW) Power (TW) (g CO2/kWh)Wind (onshore) HighWind (offshore) HighWaves MediumTides LowSolar CSP HighSolar PV HighGeothermal LowHydro LowNon-renewables:Nuclear LowClean Coal LowDirty Coal Low

*2005 world electric and total power production were 2 and 15 TW. (Jacobson)

Power FundamentalsPower FundamentalsPower measured in Watts (W), kiloWatts (kW), MegaWatts (MW) and GigaWatts (GW)● Average US house continually uses 1000 W● 1000 W for 1 hour ( = 1 kWh) costs $0.12 in LA

Two Contrasting Views of GeoengineeringTwo Contrasting Views of Geoengineering

Keith