THE GREENHOUSE EFFECT

Stephen E. Schwartz

Atmospheric Sciences Division

CSSP Lecture

July 27, 2005

http://www.ecd.bnl.gov/steve/schwartz.html

steve

THE GREENHOUSE EFFECT

GLOBAL ENERGY BALANCEGlobal and annual average energy fluxes in watts per square meter

343

237

237≈ 254K

390≈288K

106 68

169

327 9016

Rayleigh

Aerosol

α = 31%

69% = 1 -α

1/4 S0 1/4 S0 =(1-α ) σT4

Shortwave Longwave

H2O, CO2, CH4...

Atmosphere

LS

Schwartz, 1996, modified from Ramanathan, 1987

ATMOSPHERICRADIATION

Energy per area pertime

Power per area

Unit:Watt per square meterW m-2

Everybody talks about the weather — Everybody talks about the weather —

But nobody does anything about it.But nobody does anything about it.

– Mark Twain– Mark Twain

Now with the greenhouse effect, we ARE doing something about it. What are we doing?

RADIATIVE FORCING

A change in a component of the Earth’s radiationbudget.

370360350340330320310

20001990198019701960

C. D. Keeling

Year

CO

2 co

ncen

trat

ion

(ppm

)

180

200

220

240

260

280

300

320

340

360

380

800 1000 1200 1400 1600 1800 2000

Law Dome Adelie LandSipleSouth Pole

Mauna Loa Hawaii

ATMOSPHERIC CARBON DIOXIDE IS INCREASING

Global carbon dioxide concentration over the last thousand years

Polar ice cores

370360350340330320310

20001990198019701960

C. D. Keeling

Year

CO

2 co

ncen

trat

ion

(ppm

)

180

200

220

240

260

280

300

320

340

360

380

800 1000 1200 1400 1600 1800 2000

Law Dome Adelie LandSipleSouth Pole

Mauna Loa Hawaii

ATMOSPHERIC CARBON DIOXIDE IS INCREASING

Global carbon dioxide concentration and infrared radiative forcing over the last thousand years

Polar ice cores

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Forcing, W

m-2

Mann et al., Geophysical Research Letters, 1999

Northern Hemisphere temperature trend (1000-1998), fromtree-ring, coral, and ice-core proxy records As calibrated byinstrumental measurements.

1000 1200 1400 1600 1800 2000YEAR

-1.0

-0.5

0.0

0.5

1.0T

EM

PE

RA

TU

RE

AN

OM

ALY

(o C

)

Reconstruction (AD 1000-1980)Instrumental data (AD 1902-1998)Calibration period (AD 1902-1980) meanReconstruction (40 year smoothed)Linear trend (AD 1000-1850)

1998

THE TEMPERATURE'S RISING

GLOBAL AVERAGE TEMPERATURE TREND1856-2002

Temperature Anomaly Relative to Base Period 1961-1990

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Tem

pera

ture

Ano

mal

y, K

2000

2000

1990

1990

1980

1980

1970

1970

1960

1960

1950

1950

1940

1940

1930

1930

1920

1920

1910

1910

1900

1900

1890

1890

1880

1880

1870

1870

1860

1860

Climate Research Unit, East Anglia UK

INDICATIONS OF SYSTEMATIC WARMINGIN RECENT YEARS

The 1990s were the warmest decade in the instrumentalrecord.

The warmest two years of the entire instrumental record havebeen 1998 and 2002.

The nine warmest years globally have now occurred in the1990s and 2000s.

Global warming overthe past millennium

Very rapidly we have entereduncharted territory -– what some callthe anthropocene climate regime.Over the 20th century, humanpopulation quadrupled and energyconsumption increased sixteenfold.Near the end of the last century, wecrossed a critical threshold, andglobal warming from the fossil fuelgreenhouse became a major, andincreasingly dominant, factor inclimate change. Global mean surfacetemperature is higher today than it’sbeen for at least a millennium.

Martin Hoffert, NYU

GREENHOUSE GAS MIXING RATIOS OVER THE INDUSTRIAL PERIOD

280

300

320

340

360

ppm

CO2

ice core

in situ↓ ← →

800

1200

1600

ppb

CH4

ice core insitu

Antarctica

Greenland↓ ↑

↑

↓

280

300

320

ppb

N2O

ice core in situ↓

↑

1850 1875 1900 1925 1950 1975 2000 0

200

400

600

CFC-11CFC-12other trace gas forcingpp

t

CFCs

converted to CFC-11 amount

Hansen et al., PNAS. 1998

GREENHOUSE GAS FORCINGS OVER THE INDUSTRIAL PERIOD2.5

2.0

1.5

1.0

0.5

0.0

For

cing

rel

ativ

e to

185

0, W

m-2

2000197519501925190018751850

Year

Total

CO2

CH4

N2OCFC-12CFC-11

Other

Data: GISS

WHERE IS ALLTHIS CO

COMING FROM?2

WHO IS RESPONSIBLE?

ATMOSPHERIC CARBON DIOXIDETime series 1700 - 2003

500

450

400

350

300

Car

bon

diox

ide

mix

ing

ratio

, ppm

2000195019001850180017501700

Law Dome (Antarctica) Siple (Antarctica)Mauna Loa (Hawaii)

Law - Etheridge et al.Siple - Friedli et al.

Mauna Loa - Keeling

ATMOSPHERIC CO2 EMISSIONSTime series 1700 - 2003

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Car

bon

diox

ide

emis

sion

s, p

pm/y

r

2000195019001850180017501700

6

5

4

3

2

1

0

Carbon dioxide em

issions, Pg C

/yr

Fossil Fuel Emissions

Fossil Fuel - Marland

ATMOSPHERIC CARBON DIOXIDETime series 1700 - 2003

500

450

400

350

300

Car

bon

diox

ide

mix

ing

ratio

, ppm

2000195019001850180017501700

Fossil Fuel Cumulative Emissions

Law Dome (Antarctica) Siple (Antarctica)Mauna Loa (Hawaii)

Law - Etheridge et al.Siple - Friedli et al.

Mauna Loa - KeelingFossil Fuel - Marland

LAND USE CARBON EMISSIONS BY SOURCE REGION

1000 Tg = 1 Pg = 1015 g,Equivalent to 0.47 ppm

Carbon flux estimated as land area times carbon emissions associated withland clearing or afforestation (uptake).

United States dominates emissions before 1900 and uptake after 1940.

ATMOSPHERIC CO2 EMISSIONSTime series 1700 - 2003

3.0

2.5

2.0

1.5

1.0

0.5

0.0

Car

bon

diox

ide

emis

sion

s, p

pm/y

r

2000195019001850180017501700

6

5

4

3

2

1

0

Carbon dioxide em

issions, Pg C

/yr

Land Use Emissions Fossil Fuel Emissions

Fossil Fuel - MarlandLand Use - Houghton

Prior to 1910 CO2 emissions from land use changes were dominant.

Subsequently fossil fuel CO2 has been dominant and rapidly increasing!

ATTRIBUTION OF INCREASE INATMOSPHERIC CO2

Comparison of cumulative CO2 emissions from fossil fuel combustion andland use changes with measured increases in atmospheric CO2.

500

450

400

350

300

Car

bon

diox

ide

mix

ing

ratio

, ppm

2000195019001850180017501700

400

300

200

100

0

Cum

ulative carbon dioxide emissions, P

g C

Fossil Fuel Cumulative Emissions

Fossil + Land UseCumulative Emissions

Land Use ChangeCumulative Emissions

Law Dome (Antarctica) - Etheridge et al Siple (Antarctica) - Law et alMauna Loa (Hawaii) - Keeling

Prior to 1970 the increase in atmospheric CO2 was dominated byemissions from land use changes, not fossil fuel combustion.

HOW MUCH CARBONIS IN A GALLON

OF GASOLINE?

? ??

? ?

1 lb? 2 lbs?3 lbs!? 5 lbs!?!

?

All of this carbon goes into the atmosphere as carbon dioxide whenyou burn the gasoline in your car.

? ?

YOUR FAMILY’S CONTRIBUTION TO THEGREENHOUSE EFFECT

0.8

0.6

0.4

0.2

0.0CO

2 em

issi

ons,

Pou

nds

(C)

per

KW

H

Coal Oil Natural gas Nuclear

CARBON DIOXIDE EMISSIONS FROMELECTRIC ENERGY PRODUCTION

(1990's Technology)

Suffolk County 2001Legislation

How much does your household contribute?

A typical household using 1000 kilowatt hours of electricityper month is responsible for emission of 3 tons of carbona year in the form of carbon dioxide.

YOUR CONTRIBUTION TO THE GREENHOUSE EFFECT

0.49 lbs Carbon per KWH

At half a pound of carbon per KWH, the average household is responsible for emission of 500 pounds of carbon a month.

Breath of Fresh AirGaffney signs bill to limit greenhouse gas emissions

July 25, 2001By Emi Endo

Suffolk County ExecutiveRobert Gaffney yesterdaysigned into law a bill aimed atlimiting greenhouse gasemissions locally, althoughcritics questioned how much itwould actually reduce theemissions.

Beginning in March, for every100 megawatts of newgeneration added in thecounty, the emissions ratemust be reduced by 1 percent,

until a 20-percent reduction isachieved. Power plants thatexceed the standard would facefines.

During negotiations, Fisherraised the emissions limit fromless than 1,500 pounds to1,800 pounds of carbondioxide per megawatt hour andcut the penalties from $5 foreach ton of carbon dioxideemissions exceeding the limitto $2.

Suffolk County Limits CO Emissions2

0.49 lbs Carbon per KWH

WHERE DOES YOUR ELECTRIC ENERGYCOME FROM?

50

40

30

20

10

0

Per

cent

of T

otal

Coal Natural Gas Oil Hydro Geothermal Solar Wind Biomass Nuclear

SOURCES OF ELECTRIC ENERGYIN THE UNITED STATES

- - - FOSSIL FUEL - - -

- - - Less than 1 % each - - -

- - - - - Renewable - - - - -

Annual Total 3.71 Trillion KWH

On Long Island most electric energy derives from combustion of oil.

WHAT COUNTRY USES THE MOSTELECTRIC POWER?

WHAT COUNTRY USES THE MOSTELECTRIC POWER?

30

20

10

0

Per

cent

of T

otal

US China Russia Japan Germany

ANNUAL ENERGY CONSUMPTIONTotal Global Consumption 382 Quadrillion BTU

Selected Countries

No surprise. It's the United States.

WHAT COUNTRY USES THE MOSTELECTRIC POWER PER CAPITA?

WHAT COUNTRY USES THE MOSTELECTRIC POWER PER CAPITA?

No surprise. It's the United States again.

400

300

200

100

0Mill

ion

BT

U p

er p

erso

n pe

r ye

ar

US China Russia Japan Germany

PER CAPITA ENERGY CONSUMPTIONSelected Countries

Looking to theFuture . . .

Prediction is difficult, especially about the future.

– Niels Bohr

THE “BIBLE” OF CLIMATE CHANGE RESEARCH

WMO

Cambridge University Press, 2001

THE BIBLE OF CLIMATE CHANGEIt's big and thick.Every household should have one.No one reads it from cover to cover.You can open it up on any page

and find something interesting.It was written by a committee.It is full of internal contradictions.It deals with cataclysmic events such as

floods and droughts.It has its true believers and its rabid skeptics.

FUTURE CLIMATE IS HIGHLY UNCERTAIN

(IPCC, 2001)

Contributors to uncertainty include emissions, concentrations, and Earth'sclimate sensitivity.

RESEARCH AT BROOKHAVENNATIONAL LABORATORY IS HELPING

TO ANSWER THESE QUESTIONS.