Global Warming: Global Warming: Manmade Mess or Nature’s Norm? or Nature s Norm? Dr. Roy W. Spencer Principal Research Scientist The University of Alabama in Huntsville
CO 2 Is Necessary for Life on Earth 1) Only 29 of every 100,000 molecules of air are CO2 ) O y 9 o e e y 00,000 o ecu es o a a e CO 2) Mankind’s CO 2 emissions are only ~ 5% of Natural Flows of CO2 3) NATURE CONSUMES ~50% OF OUR YEARLY CO2 EMISSIONS
The Greenhouse Effect of CO2 is SMALL The Greenhouse Effect of CO2 is SMALL 1 Water Vapor 1.Water Vapor 90-95% 2. Clouds 3. Carbon dioxide 4. Methane… The Greenhouse Effect is a “radiative blanket”: The Greenhouse Effect is a radiative blanket : it traps heat in the lower atmosphere Examples: Humid night warmer than dry, p g y, Cloudy night warmer than clear.
The DIRECT Warming effect of More CO2 from burning Fossil Fuels is small g INDIRECT effects are called “FEEDBACKS” Projected Warming (deg. F) 6 o – 10 o 6 o 10 o 4 o 6 o 4 – 6 2 o <1 o 2000 2020 2040 2060 2080 2100 YEAR
⇒ 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 Positive Feedback in Climate Models? iti F db k i Cli t M d l ?
Observed Behavior of the Ancient Climate System …but there’s just one problem…. Mr. Gore ASSUMES that the CO2 changes Al Gore’s Stage Prop: The Vostok Ice Core Data caused the temperature changes p g Ice Core Data “Suggests” Positive Feedback….but….
…temperature LEADS CO 2 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 models climate 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, or 2) DECREASE i f 2) DECREASE infrared radiation being lost to space. d di ti b i l t t
1 st SATELLITE TEST OF THE CLIMATE MODELS (how they gain and lose INFRARED energy) 1400 1200 Positive Feedback Periods (clouds AMPLIFY warming) 1000 Negative GOOD of 5-Year Feedback 800 18 IPCC (clouds REDUCE AGREEMENT warming) Models for EMITTED 600 Number o INFRARED 400 200 200 S t llit Satellite 0 -4 4 -3 3 -2 2 -1 1 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 Feedback Parameter Estimate (W m-2 K-1)
2 nd SATELLITE TEST OF THE CLIMATE MODELS (how they gain and lose SOLAR energy) Positive Feedback Negative Feedback 1400 (clouds AMPLIFY (clouds REDUCE warming) warming) warming) warming) 1200 Periods 1000 TERRIBLE of 5-Year 800 AGREEMENT for REFLECTED Satellite 600 Number o SUNLIGHT 18 IPCC 400 Models 200 200 0 -4 4 -3 3 -2 2 -1 1 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 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 1200 Positive Feedback Periods (clouds AMPLIFY TERRIBLE warming) 1000 Negative AGREEMENT AGREEMENT of 5-Year Feedback for REFLECTED 800 18 IPCC (clouds REDUCE SUNLIGHT+ warming) Models 600 Number o EMITTED EMITTED Satellite INFRARED 400 200 200 0 -4 4 -3 3 -2 2 -1 1 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 Feedback Parameter Estimate (W m-2 K-1)
Why Would Models Cause Clouds to AMPLIFY Warming? (positive feedback => high sensitivity) (positive feedback => high sensitivity) Again (as in CO 2 � temperature relationship): Cause versus Effect Cause 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 built upon faulty assumptions. f lt ti
IPCC Claim: Climate “Skeptics” Do Not Publish 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 9 Oscillations, 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: – Spencer & Braswell, 2008: Potential Biases in Feedback Diagnosis ll 2008 P t ti l Bi i F db k Di i S & B 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 CO 2 hasn’t Caused Global Warming over the last 100 years..then what has ? HOW ABOUT MOTHER NATURE? HOW ABOUT MOTHER NATURE? 2 c. Pacific Decadal Oscillation, 1902-2006 1.6 Natural 1.2 Cloud Cloud 0.8 PDO Index Pacific 0.4 Variations 0 Decadal -0.4 Oscillation -0.8 -1.2 1 2 -1.6 ? -2 1902 1912 1922 1932 1942 1952 1962 1972 1982 1992 2002 YEAR YEAR 0 6 0.6 a. Global Mean Temperature, 1902-2006 0.4 LAND + (deg. C) OCEAN 0.2 Global T Anomaly Surface 0 Natural Temperature Temperature OCEAN -0.2 ONLY Variations -0.4 -0.6 1902 1912 1922 1932 1942 1952 1962 1972 1982 1992 2002
A Simple Model Forced by Cloud Changes Assumed Associated with the Pacific Decadal Oscillation: Pacific Decadal Oscillation: PDO Can explain 2/3 of 20 th Century Warming 0.6 Simple Model of PDO Cloud Changes Thermometer Causing Global Warming data 0.4 0.2 (deg. C) PDO+CO2 0 T Anomaly PDO-only -0.2 -0 4 -0.4 -0.6 -0.8 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 YEAR
…and Recent Satellite Data Suggests that there Indeed IS a Connection between the PDO and Cloud Variations PDO INDEX PDO INDEX (monthly) 2000 2001 2002 2003 2004 2005 2.5 2.0 1.5 1.0 PDO Index PDO Index 0.5 2000-2005 0.0 -0.5 -1.0 -1.5 -2.0 CERES LW+SW Flux Anomalies YEAR YEAR 60N-60S Oceans -1.0 m-2 K-1) Aqua Satellite -0.5 A Flux Anom. (W m Observed Cloud 0.0 Changes 0.5 2000 2005 2000-2005 TO 1.0 1.5 2000 2001 2002 2003 2004 2005
..so…Maybe Mother Nature Caused Climate Variability over the Last 2,000 Years 2000 Years of Global Temperatures 1 (30-year averages, last data year 2007) 0 8 0.8 Medieval Warm Period 0.6 UK Met Office & U. of E. Anglia 0 4 0.4 (thermometers, (thermometers data years 1850-2007) 0.2 rees C 0 Deg -0.2 Vikings arrive in Greenland -0.4 End of Viking g Dr. Craig Loehle (2007) Dr. Craig Loehle (2007) Colonization of (average of 18 Greenland -0.6 non-tree ring proxies, End of Viking Little Ice Age data years AD 1 - 1995) colonization of -0.8 Greenland CO2 from Law Dome Ice Core -1 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 YEAR (A.D.) R. W. Spencer, 2007
Science Conclusions 1. Satellite data + simple model suggest the climate system is driven more by natural cloud changes than by CO2. 2. IPCC “Scientific Consensus” of CO2 driving climate is g due to a mix-up between CAUSE and EFFECT when observing natural cloud fluctuations. 3. If clouds drive climate change more than CO2, then CO2 increases are not very important.
…but if there is any risk… shouldn’t humanity avoid producing CO 2 ? 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
UAH Globally Averaged Satellite-Based Temperature 1.1 of the Lower Atmosphere* 1 deg. C.) 0.9 (Jan. 1979 - September 2008) 0.8 0.8 Avg. Temp. (d 0.7 El Nino 0.6 Warming 0.5 0 4 0.4 1979-1998 A 0.3 0.2 0.1 0 0 parture from -0.1 -0.2 September -0.3 2008 -0.4 0 4 Dep Mt. Pinatubo -0.5 Cooling * Surface to 8 miles altitude -0.6 1979 81 83 85 87 89 91 93 95 97 99 2001 03 05 07 09 YEAR YEAR
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