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Email Scott.Denning@ColoState.edu for a copy of this presentation

Scott Denning

Director of Education, CMMAP

Atmospheric Science, CSU

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Climate is complicated have to ask experts Concern about global warming is based on recent

temperature trends 9 of the 10 hottest years on record If somebody could find some other cause for recent

warming, we could quit worrying

Global warming is a theory based on complicatedcomputer models

If we stop burning coal, well freeze in the dark!

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If you dont like the weather: Wait five minutes!

If you don

t like the climate: Move!

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Depends on where you live: Latitude! Altitude (mountains vs valley) Whats upwind (ocean vs land)

Changes very slowly Very predictable We can predict that Miami is warmer than

Minneapolis for precisely the same reasonsthat we can predict a warmer future!

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Dayis warmer than night Summer is warmer than winter Miami is warmer than Minneapolis

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Nearly all of the air ismade of oxygen (O2)and nitrogen (N2) inwhich two atoms of

the same elementshare electrons

Infrared (heat)energy radiated upfrom the surface canbe absorbed by thesemolecules, but not

very well

N N

O O

Diatomic molecules can

vibrate back and forth likeballs on a spring, but the

ends are identical

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Carbon dioxide (CO2)and water vapor (H2O)are different!

They have many moreways to vibrate androtate, so they arevery good at absorbing

and emitting infrared(heat) radiation

Molecules that have manyways to wiggle are called

Greenhouse molecules

O OC

H H

O

Absorption spectrum of CO2 was measured by John Tyndall in 1863

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Doubling CO2 wouldadd 4 watts toevery square meterof the surface of

the Earth, 24/7 Doing that would

make the surfacewarmer

This was knownbefore light bulbswere invented!

4 Watts

John Tyndall, January 1863

1 m

1 m

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People are worried about climate changebecause its been getting warmer lately

WRONG! Were concerned because we know thatwhen we add energy to things, they warm up

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Land vs ocean! North vs South Global mean

warming of 2 to 5 C

North American warming of 3 to 6 C

= 5 to 11 F

Arctic warming of 8 to 14 F

LowEmissions

HighEmissions

ModerateEmissions

Rainfall? Agriculture?

Water supply? Ski industry?

Mass immigration?

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DenverAmarillo

Grand JunctionTucson

Illinois"Mississippi

Water? Crops?

Real Estate? Health?

on average?

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2 2 = 4 billion tons go out

Ocean

Fossil FuelBurning

+

8

800billion tons carbon

4billiontons go in

ATMOSPHERE

billion tons added

every year

Extra heat comes from the water, not the faucet!

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If China and Indiaindustrialize withcoal, CO2 will riseto 5x preindustrial

Extra CO2 will lastfor millennia aftercoal is gone

The heck with Polar Bears what would that do to farmers?

CO2

(ppm)

GtC/

yr

Warming

(Celsius)

CO2

warming

year

you are

here

When we reduce or stop burning fossil fuel, CO2will go away and things will go back to normal

emissions

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Much of the region

already receives only

marginal precipitation

Just enough snow to

support forests and

reservoirs

Just enough irrigation

water to support

farming

Just enough water to

support 5.1 million

people

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CO2molecules absorb & re-emit thermalradiation (John Tyndall, 1863)

Each doubling of the number of CO2molecules would add 4 W m-2to the Earth24/7 (Svante Arrhenius, 1896)

If China and India industrialize with coal,CO2 will approach 400% preindustrial by

2100 (so 8 Watts, not 4, on each sq m) Additional CO2 will continue adding heat

to Earthfor thousands of years

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When and precisely howthe climatewill change, especially locally The economic, political, and socialconsequences of these changes

What to do about all of this

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The sky is falling! Be skeptical be very skeptical !

Without the subsidy of cheap fossilenergy, civilization will crumble

People will freeze in the dark!

Well starve!

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Billions of Tons

Carbon Emitted

per Year

Historicalemissions

0

8

16

1950 2000 2050 2100

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1.6

Interim Goal

Billions of Tons

Carbon Emitted

per Year

Historicalemissions Flat path

StabilizationTriangle

0

8

16

1950 2000 2050 2100

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1.6

Billions of Tons

Carbon Emitted

per Year

Historicalemissions Flat path

0

8

16

1950 2000 2050 2100

16 GtC/y

Eight wedges

Goal: In 50 years, sameglobal emissions as today

http://www.princeton.edu/wedges/

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Awedge

is a strategy to reduce carbon emissions that

grows in 50 years from zero to 1.0 GtC/yr. The strategyhas already been commercialized at scale somewhere.

1 GtC/yr

50 years

Total = 25 Gigatons carbon

Cumulatively, a wedge redirects the flow of 25 GtC in its first 50years. This is 2.5 trillion dollars at $100/tC.

A solution to the CO2 problem should provide at least one wedge.

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Energy Efficiency &Conservation (4)

CO2 Capture

& Storage (3)

StabilizationTriangle

Renewable Fuels& Electricity (4)

Forest and Soil

Storage (2)

Fuel Switching(1)

Nuclear Fission (1)

2007 20578 GtC/y

16 GtC/y

TriangleStabilization

http://www.princeton.edu/wedges/

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Double the fuel efficiency of the

world s cars or halve miles traveled

Produce today s electric capacity

with double today s efficiency

Use best efficiency practices in

all residential and commercial

buildings

Replacing all theworld s incandescent

bulbs with CFL swould provide 1/4 of

one wedge

Efficiency

There are about 600million cars today,

with 2 billionprojected for 2061

Average coal plant efficiency is 32% today

Photos courtesy of Ford Motor Co., DOE, EPA

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Substitute 1400 natural gas electric plantsfor an equal number of coal-fired facilities

A wedge requires an amount of natural gas equal

to that used for all purposes today

Fuel

Switching

Photo by J.C. Willett (U.S. Geological Survey).

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Implement CCS at

800 GW coal electric plants or 1600 GW natural gas electric

plants or

180 coal synfuels plants or 10 times today s capacity of

hydrogen plants

Graphic courtesy of Alberta Geological Survey

Carbon

Capture &Storage

There are currently three storage projects that each inject

1 million tons of CO2 per year by 2061 we d need 3500.

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Wind

ElectricityInstall 1 million 2 MW

windmills to replace

coal-based electricity,

OR

Use 2 million windmills

to produce hydrogen

fuel

Photo courtesy of DOE

A wedge worth of wind electricity

will require increasing current

capacity by a factor of 30

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Solar

Electricity

Photos courtesy of DOE Photovoltaics Program

Install 20,000 square kilometers for

dedicated use by 2054

A wedge of solar electricity would mean

increasing current capacity 700 times

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To provide a decent standard of living forbillions of people on Earth

We must be able to generate huge amountsof energy without releasing CO2

This is definitely do-able(as an engineering task)

but expensive and politically difficult Cant do it by tinkering around the edges Requires profound change to energy and

economics

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Somebody presents you with a grand idea fortransforming the world economy: Dig 8 billion tons of carbon out of the ground

every year

Build a system of pipelines, supertankers,railroads, highways, and trucks to deliver it toevery street corner on the planet

Build millions of cars every year, and millions ofmiles of roads to drive them on

Generate and pipe enough electricity to everyhouse to power lights & stereos & plasma TVs

and heres the itemized bill

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Some people think:Our modern lifestyle is only possible

because of the subsidy of cheap fossilfuel. When we stop burning coal well

freeze in the dark!

I prefer:Our well-being depends on creativity

and hard work. Before we run out ofoil, well invent energy technologies forthe 21st Century.

Our future is bright.