Global Warming:Global Warming:Manmade Mess

or Nature’s Norm?or Nature s Norm?Dr. Roy W. Spencer

Principal Research ScientistThe University of Alabama in Huntsville

1) Only 29 of every 100,000 molecules of air are CO2

CO2 Is Necessary for Life on Earth) O y 9 o e e y 00,000 o ecu es o a a e CO

2) Mankind’s CO2 emissions are only ~ 5% of Natural Flows of CO2

3) NATURE CONSUMES ~50% OF OUR YEARLY CO2 EMISSIONS

The Greenhouse Effect of CO2 is SMALLThe Greenhouse Effect of CO2 is SMALL

1 Water Vapor1.Water Vapor2. Clouds

3. Carbon dioxide

90-95%

4. Methane…

The Greenhouse Effect is a “radiative blanket”:The Greenhouse Effect is a radiative blanket :it traps heat in the lower atmosphereExamples: Humid night warmer than dry,p g y,

Cloudy night warmer than clear.

The DIRECT Warming effect ofMore CO2 from burning Fossil Fuels is smallg

ProjectedINDIRECT effects are called “FEEDBACKS”Warming(deg. F)

6o 10o

4o 6o

6o – 10o

2o

4 – 6

<1o

2000 2020 2040 2060 2080 2100YEAR

⇒All Climate Models Have Positive Feedbacks

Increasing CO2 causes weak warming at first,Warming is then AMPLIFIED by clouds, vapor

But What Evidence Supports P iti F db k i Cli t M d l ?Positive Feedback in Climate Models?

…but there’s just one problem….Mr. Gore ASSUMES that the CO2 changes

caused the temperature changes

Observed Behavior of the Ancient Climate SystemAl Gore’s Stage Prop: The Vostok Ice Core Data

p g

Ice Core Data “Suggests” Positive Feedback….but….

…temperature LEADS CO2 by ~ 800 years in Ice Cores…(so Ice Core data are largely irrelevant to global warming)( g y g g)

What if something else has caused warming?(science should always look for

alternative hypotheses)alternative hypotheses)

We Use SATELLITES to figure out how TODAY’s Climate System works, and compare it to

climate modelsclimate models.

Observed Behavior of Today’s Climate System:Satellite Comparisons of Clouds vs. Temperatures

NASA’s Aqua Satellite

There are TWO WAYS to Cause Global Warming

1) INCREASE solar radiation being absorbed, or2) DECREASE i f d di ti b i l t t2) DECREASE infrared radiation being lost to space.

1st SATELLITE TEST OF THE CLIMATE MODELS(how they gain and lose INFRARED energy)

1400

1000

1200

Peri

ods Positive Feedback

(clouds AMPLIFYwarming)

Negative

600

800of

5-Y

ear

18 IPCC Models

Feedback(clouds REDUCE

warming)

GOODAGREEMENTfor EMITTED

200

400

Num

ber

o

S t llit

INFRARED

0

200

-4 -3 -2 -1 0 1 2 3 4 5 6 7

Satellite

4 3 2 1 0 1 2 3 4 5 6 7

Feedback Parameter Estimate (W m-2 K-1)

2nd SATELLITE TEST OF THE CLIMATE MODELS(how they gain and lose SOLAR energy)

1400 Negative Feedback(clouds REDUCE

warming)

Positive Feedback(clouds AMPLIFY

warming)

1000

1200

Peri

ods

warming)warming)

TERRIBLEAGREEMENT

for REFLECTED 600

800of

5-Y

ear

SatelliteSUNLIGHT

200

400

Num

ber

o

18 IPCC Models

0

200

-4 -3 -2 -1 0 1 2 3 4 5 6 74 3 2 1 0 1 2 3 4 5 6 7

Feedback Parameter Estimate (W m-2 K-1)

TOTAL SATELLITE TEST OF THE CLIMATE MODELS(how they gain and lose SOLAR+INFRARED energy)

1400

TERRIBLEAGREEMENT

1000

1200

Peri

ods Positive Feedback

(clouds AMPLIFYwarming)

Negative AGREEMENTfor REFLECTED

SUNLIGHT+EMITTED

600

800of

5-Y

ear

18 IPCC Models

Feedback(clouds REDUCE

warming)

EMITTEDINFRARED

200

400

Num

ber

o

Satellite

0

200

-4 -3 -2 -1 0 1 2 3 4 5 6 74 3 2 1 0 1 2 3 4 5 6 7

Feedback Parameter Estimate (W m-2 K-1)

Why Would ModelsCause Clouds to AMPLIFY Warming?

(positive feedback => high sensitivity)(positive feedback => high sensitivity)

Again (as in CO2 temperature relationship):Cause versus EffectCause versus Effect

When researches examine satellite data,When researches examine satellite data,they assume temperature changes

cause cloud changes(but not vice versa)

…and so climate models are builtf lt tiupon faulty assumptions.

IPCC Claim: Climate “Skeptics” Do NotPublish Their Results

(we publish but don’t publish anything(we publish, but don t publish anything the mainstream media likes)

• New Finding: Satellite observed tropical climate variability exhibits low sensitivity:– Spencer, Braswell, Christy, & Hnilo, 2007: Cloud and Radiation

Budget Changes Associated with Tropical Intraseasonal Oscillations Geophysical Research Letters August 9Oscillations, Geophysical Research Letters, August 9.

• New Finding: A simple climate model used to demonstrate natural cloud variability biases climate sensitivity estimates to the high side:

S & B ll 2008 P t ti l Bi i F db k Di i– Spencer & Braswell, 2008: Potential Biases in Feedback Diagnosis from Observational Data: A Simple Model Demonstration, J. Climate(in press).

– Reviewed by 2 IPCC model experts– Reviewed by 2 IPCC model experts.

• New Finding: Satellite observed global oceans shows low sensitivity, outside the range of ALL 18 IPCC climate models:– Spencer & Braswell, 2008: Satellites Reveal a Climate System Less

Sensitive than in Models, Geophysical Research Letters, submitt..

IF Manmade CO2 hasn’t Caused Global Warmingover the last 100 years..then what has?

HOW ABOUT MOTHER NATURE?Pacific Decadal Oscillation, 1902-2006

0.81.21.6

2c.

HOW ABOUT MOTHER NATURE?

NaturalCloud

1 2-0.8-0.4

00.4

PDO

Inde

x Pacific Decadal Oscillation

CloudVariations

-2-1.6-1.2

1902 1912 1922 1932 1942 1952 1962 1972 1982 1992 2002

YEAR0 6

?YEAR

Global

Global Mean Temperature, 1902-2006

0.2

0.4

0.6

(deg

. C)

a.LAND +OCEAN

Surface Temperature

-0.4

-0.2

0

T A

nom

aly

OCEANONLY

NaturalTemperatureVariations

-0.61902 1912 1922 1932 1942 1952 1962 1972 1982 1992 2002

A Simple Model Forced by Cloud ChangesAssumed Associated with the

Pacific Decadal Oscillation:Pacific Decadal Oscillation:PDO Can explain 2/3 of 20th Century Warming

0.4

0.6 Simple Model of PDO Cloud ChangesCausing Global Warming Thermometer

data

0

0.2

(deg

. C) PDO+CO2

-0 4

-0.2

T A

nom

aly

PDO-only

-0.6

-0.4

-0.81900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

YEAR

PDO INDEX

…and Recent Satellite Data Suggests thatthere Indeed IS a Connection between

the PDO and Cloud Variations

1.5

2.0

2.52000 2001 2002 2003 2004 2005

PDO INDEX(monthly)

-0.5

0.0

0.5

1.0

PDO

Inde

xPDO Index2000-2005

YEARCERES LW+SW Flux Anomalies

-2.0

-1.5

-1.0

-1.0

-0.5

YEAR

m-2

K-1

)60N-60S Oceans

Aqua Satellite0.0

0.5

A F

lux

Ano

m. (

W mObserved Cloud

Changes2000 2005 1.0

1.52000 2001 2002 2003 2004 2005

TO2000-2005

..so…Maybe Mother Nature Caused Climate Variabilityover the Last 2,000 Years

0 8

1 2000 Years of Global Temperatures(30-year averages, last data year 2007)

0 4

0.6

0.8

UK Met Office & U. of E. Anglia(thermometers

Medieval Warm Period

0

0.2

0.4

rees

C

(thermometers, data years 1850-2007)

-0.4

-0.2Deg

Dr. Craig Loehle (2007)

Vikings arrivein Greenland

End of Viking

-0.8

-0.6

Dr. Craig Loehle (2007)(average of 18

non-tree ring proxies,data years AD 1 - 1995) Little Ice AgeEnd of Viking

colonization ofGreenland

gColonization ofGreenland

-10 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

YEAR (A.D.) R. W. Spencer, 2007

CO2 from Law Dome Ice Core

Science Conclusions

1. Satellite data + simple model suggest theclimate system is driven more by natural cloudchanges than by CO2.

2. IPCC “Scientific Consensus” of CO2 driving climate is gdue to a mix-up between CAUSE and EFFECT whenobserving natural cloud fluctuations.

3. If clouds drive climate change more than CO2, thenCO2 increases are not very important.

…but if there is any risk…shouldn’t humanity avoid producing CO2?

1. Maybe not....⇒No large-scale replacements for fossil fuels⇒More CO2 increases agricultural productivity⇒A little warming is, on whole, beneficial.

2. Why have most countries signed the Kyoto Protocol?⇒Political power (follow the $$$)⇒Transfer of wealth to poor countries⇒Transfer of wealth to poor countries

3. Eventually, we’ll need replacements for fossil fuels⇒This will require wealth for R&D⇒ Wealth generation requires free markets…not

gov’t regulation.g g

0.80.9

11.1

deg.

C.)

UAH Globally Averaged Satellite-Based Temperatureof the Lower Atmosphere*

(Jan. 1979 - September 2008)

0 40.50.60.70.8

Avg

. Tem

p. (d

El Nino Warming

00.10.20.30.4

1979

-199

8 A

0 4-0.3-0.2-0.1

0

part

ure

from

September2008

-0.6-0.5-0.4

1979 81 83 85 87 89 91 93 95 97 99 2001 03 05 07 09

YEAR

Dep Mt. Pinatubo

Cooling * Surface to 8 miles altitude

YEAR