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

Climate Change:Simple, Serious,

Solvable

Scott DenningDirector of Education, CMMAP

Atmospheric Science, CSU

Common Myths about Climate

Be skeptical … be very skeptical !• 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

complicated computer models• If we stop burning coal, we’ll freeze in the

dark!

Weather vs Climate

what’s the difference?• If you don’t like the weather:– Wait five minutes!

• If you don’t like the climate:– Move!

Location! Location! Location!• Depends on where you live:

– Latitude!– Altitude (mountains vs valley)– What’s upwind (ocean vs land)

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

than Minneapolis for precisely the same reasons that we can predict a warmer future!

Climate is Place

Ever Wonder Why?

• Day is warmer than night• Summer is warmer than winter• Miami is warmer than Minneapolis

Heat Budgets

Dancing Molecules and Heat Rays!

• Nearly all of the air is made of oxygen (O2) and nitrogen (N2) in which two atoms of the same element share electrons

• Infrared (heat) energy radiated up from the surface can be absorbed by these molecules, but not very well

N N

O O

Diatomic molecules can vibrate back and forth like balls on a spring, but the ends are identical

Dancing Molecules and Heat Rays!

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

• They have many more ways to vibrate and rotate, so they are very good at absorbing and emitting infrared (heat) radiation

Molecules that have many ways to wiggle are called “Greenhouse” molecules

O OC

H H

O

Absorption spectrum of CO2 was measured by John Tyndall in 1863

Common Sense• Doubling CO2

would add 4 watts to every square meter of the surface of the Earth, 24/7

• Doing that would make the surface warmer

• This was known before light bulbs were invented!

4 Watts

John Tyndall, January 1863

1 m

1 m

Common Myth #1“People are worried about climate change

because it’s been getting warmer lately”

WRONG! We’re concerned because we know that when we add energy to things, they warm up

• Land vs ocean!• North vs South

• Global mean warming of 2º to 5º C

• North American warming of 3º to 6º C= 5º to 11º F

• Arctic warming of 8º to 14º F

LowEmissions

HighEmissions

ModerateEmissions

Rainfall? Agriculture? Water supply? Ski industry?Mass immigration?

How much warmer?

Where is it 10°F Warmer

Denver Amarillo

Grand Junction Tucson

Illinois MississippiWater? Crops?

Real Estate? Health?

“on average?”

2 2 = 4 billion tons go out

Ocean Land Plants and soils (net)

Fossil FuelBurning

+

8

800billion tons carbon

4billion tons go in

ATMOSPHERE

billion tons added every year

CO2 “Budget” of the World

Extra heat comes from the water, not the faucet!

Shanghai, China 1990

Shanghai, China 2012

• If China and India industrialize with coal, CO2 will rise to 5x preindustrial

• Extra CO2 will last for millennia after coal is gone

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

CO

2 (pp

m)

GtC

/yr

War

min

g (C

elsi

us)

CO2

warming

year

you arehere

Common Myth #2“When we reduce or stop burning fossil fuel,

CO2 will go away and things will go back to normal”

emissions

A Region On the EdgeMuch 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

Insect Pests

Western US

Wildfires

Irrigated Agriculture

Real Estate Development

We Know for Sure• CO2 molecules absorb & re-emit

thermal radiation (John Tyndall, 1863)• Each doubling of the number of CO2

molecules would add 4 W m-2 to the Earth 24/7 (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 Earth for thousands of years

What We’re Not So Sure

About• When and precisely how the

climate will change, especially locally

• The economic, political, and social consequences of these changes

• What to do about all of this

The Worst Myth of All

“The sky is falling!”Be skeptical … be very skeptical !

• Without the subsidy of cheap fossil energy, civilization will crumble

• People will freeze in the dark!• We’ll starve!

Billions of Tons Carbon Emitted per Year

Historical emissions

0

8

16

1950 2000 2050 2100

Historical Emissions

1.6

Interim Goal

Billions of Tons Carbon Emitted per Year

Current p

ath = “r

amp”

Historical emissions Flat path

Stabilization Triangle

0

8

16

1950 2000 2050 2100

The “Stabilization Triangle”

1.6

Billions of Tons Carbon Emitted per Year

Current p

ath = “r

amp”

Historical emissions Flat path

0

8

16

1950 2000 2050 2100

16 GtC/y

Eight “wedges”

Goal: In 50 years, sameglobal emissions as today

“Stabilization Wedges”

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

What is a “Wedge”?A “wedge” is a strategy to reduce carbon emissions that grows in 50 years from zero to 1.0 GtC/yr. The strategy has 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 50 years. This is 2.5 trillion dollars at $100/tC.

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

Energy Efficiency & Conservation (4)

CO2 Capture & Storage (3)

Stabilization Triangle

Renewable Fuels& Electricity (4)

Forest and Soil Storage (2)

Fuel Switching(1)

Nuclear Fission (1)

2007 20578 GtC/y

16 GtC/y

TriangleStabilization

Fifteen Wedges in 4 Categories

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

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 the world’s incandescent bulbs with CFL’s would provide 1/4 of one wedge

Efficiency

There are about 600 million cars today, with 2 billion projected for 2061

Average coal plant efficiency is 32% today

Photos courtesy of Ford Motor Co., DOE, EPA

Substitute 1400 natural gas electric plants for 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).

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.

Wind Electricity

Install 1 million 2 MW windmills to replace coal-based electricity, ORUse 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

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

Solutions• To provide a decent standard of living

for billions of people on Earth• We must be able to generate huge

amounts of energy without releasing CO2

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

• but expensive and politically difficult• Can’t do it by “tinkering around the

edges”• Requires profound change to energy

and economics

Imagine it’s 1800, and you’re in charge …

Somebody presents you with a grand idea for transforming 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 to every street corner on the planet

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

Generate and pipe enough electricity to every house to power lights & stereos & plasma TVs… “and here’s the itemized bill …”

Choose Your Future• Some people think:

– “Our modern lifestyle is only possible because of the subsidy of cheap fossil fuel. When we stop burning coal we’ll freeze in the dark!”

• I prefer:– “Our well-being depends on

creativity and hard work. Before we run out of oil, we’ll invent energy technologies for the 21st Century.

–Our future is bright.”