Transcript global warming Defend Science Lecture

Where to Tan and Buy Beach Property:
An Overview on Global Warming
Dennis Baldocchi
Professor of Biometeorology
Department of Environmental Science, Policy and Management
&
Berkeley Atmospheric Science Center
Defend Science, April, 2006
Knowledge is Power
• Background
– ‘Greenhouse-Effect’ Principles
• Historic and Current Observations
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Methods
Trace Gases
Temperature
Sea Level and Sea Ice
• Model Predictions
• Scientists Defending Global Warming
Physics of the Atmosphere
Climate Concepts
• Atmosphere is a Dynamic and Complex System
– Multiple Positive and Negative Feedbacks that
operate across a Spectrum of Time and Space Scales
– Non-Linear Processes
– Sensitivity to Initial Conditions
– Thresholds and Tipping Points
Schellnhuber, Tipping Point
Radiative Balance of Earth without an Atmosphere
Radiation intercepted by Earth equals that
radiated back into space.
Trad~251 K = -22 C
4
(1-a)S*/4=sT
-2
Solar constant, S*=1366 W m
albedo, a = 0.33
Absorption Cross-Section (cm -1/(molecule cm-2)
Many Atmospheric Trace Gases Absorb & Re-emit Infrared Radiation
1e-17
H2O
CO2
1e-18
1e-19
1e-20
1e-21
1
10
Wavelength (microns)
HI-Tran Database
100
Radiation Streams in a Greenhouse Atmosphere
Temperature of Earth with Atmosphere:
Tsfc~288 K
Trends in Trace Gases:
Ancient and Recent
Paleo- CO2 and Temperature Record
320
Barnola et al
Vostok Ice Core
300
CO2 (ppm)
280
260
240
220
200
180
160
0
100000
200000
300000
400000
Years before Present
4
Temperature Variation
2
0
-2
-4
-6
-8
Vostok Ice Core
Petit et al. 1999 Nature
-10
-12
0
100000
200000
300000
Years Before Present
400000
Changing CO2 Re-enforces T anomalies
Vostok Ice Core
Data of Petit et al
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Temperature Anomalies
2
Coefficients:
b[0]: -25.77
b[1]: 0.092
r ²: 0.776
0
-2
-4
-6
-8
-10
160
180
200
220
240
CO2 (ppm)
260
280
300
Bender, GBC, 2003
Contemporary CO2 Record
Mauna Loa
Keeling data
380
370
360
CO2 (ppm)
350
340
330
320
310
300
1950
1960
1970
1980
year
1990
2000
2010
13C
Isotope record:
Evidence of Fossil Fuel Combustion
Antarctic Ice Core
(Francey et al. 1999)
-6.0
-6.2
-6.4
13
 C
-6.6
-6.8
-7.0
-7.2
-7.4
-7.6
1300
1400
1500
1600
1700
1800
1900
2000
2100
Year
•Plant based Carbon has a 13C signature ~ -25 per mil
•Combustion of Fossil Fuels Dilutes the Atmospheric Background
Atmospheric CO2 Burden
Rate of Change in Atmospheric C
Mauna Loa, data of Keeling
Fossil Fuel Emissions
data of Marland et al.
15
Change in CO2 (Gt (10 g) per year)
8
Indonesia Fires
7
6
average  = 3.08 Gt C yr-1
std dev = 1.21 Gt C yr-1
5
4
3
2
1
Mt Pinatubo Eruption
0
1950
1960
1970
1980
Year
1990
2000
2010
Evidence of Global Warming :
Direct and Indirect Confirmation by Multiple Methods
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Observations
– Climate Networks (~1850 to present)
• Air, Sea and Soil Temperature Networks
– Phenology Networks
• Date of flowering (lilac, cherries, fruit trees)
• Timing of grape harvest
– Sea Level
– Tree Rings (~1000 to present)
– Stable Isotopes
• Ice Cores (600 kyr BCE to present)
• Oxygen isotope ratio (18O/16O) in calcium carbonate of
seashells (forams)
– Satellite Observations
• Length of Growing Season (1970s to present)
• Extent of Sea Ice
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Modeling
– Global Circulation-Climate Models
• Diagostic
• Prognostic
Temperature Anomaly Trends:
Instrument Record
Waple et al 2002 BAMS
Proxy Temperature Record:
Tree Rings, Coral, sediments, ice cores
Courtesy of ME Mann, Penn State
Climate Statistics:
Mean vs Probablity Distribution
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Tropical Cyclones, Hurricanes
El Nino/La Nina
Extra-Tropical, Severe Winter Storms
Precipitation, Drought
Temperature, Extreme Heat and Cold
Floods, Winter Storms, Thunderstorms
Thunderstorms: Hail, Lightening, Fire,
Tornados
Hansen et al. 2005, JGR
Climate Proxy:
Beginning of growing season and temperature in Germany
Chmielewski, AgForMet
Change in Arctic Ice and Greenland
NOAA/CIRES
Arctic Ice Extent
What’s Happening Locally?:
Sea Level at Ft Point
http://pubs.usgs.gov/fs/1999/fs175-99/
Trends in Winter Chill Hour Accumulation (degree hours per year)
Nov-Mar, 32 to 45 F
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-500 to -400
-400 to -300
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-300 to -200
-200 to -100
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-100 to -50
-50 to 0
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-119
Baldocchi and Wong, 2006, Cal EPA Report
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Future Conditions
Climate Model Refinements
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Sulfate aerosols
Transient Changes in Trace Gases
Suite of Radiative trace gases, CO2, H2O, CFC, N2O
Coupled ocean and atmosphere
Cloud/water vapor feedbacks
Finer Resolution, 19 layers, 250 km grid
Improved Land Surface schemes
– BATS, SIB-I, SIB-II, LSX
GFDL/NOAA
http://www.gfdl.gov/~rjs/stouffer_MBO.html
Sealevel Rise, GFDL,/NOAA
http://www.gfdl.gov/~tk/climate_dynamics/fig4.gif
Further Refinements
• Coupling Climate, Biogeochemistry and Ecosystem
Dynamic models
– Climate Change is needed to predict Vegetation
Changes
– Changes in Vegetation affects land/surface
interactions and Climate
– Mass and energy fluxes are constrained by links to
Biogeochemistry
– Assess changes in landcover due to mankind
Defenders of Climate Science
• Michael Mann, Penn State
• James Hansen, NASA/GISS
Michael Mann, Penn State
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Was subject to criticism of ‘Hockey stick’ Climate data, which was featured
in IPCC report
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In 2005, Texas Representative Joe Barton, chair of the United States House
of Representatives’ Energy and Commerce Committee and a global
warming skeptic, demanded information on the location of data archives,
computer codes, grant awards, and other research details from Mann and
his hockey stick colleagues.
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Details are available at http://branch.ltrr.arizona.edu
National Academy Science has been commission to report on paleoclimate
reconstruction
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www.realclimate.org
McIntyre and McKitrick (2003, GRL), an Mining Executive and an Economistis
falsely claim that the ‘hockey stick’ is an artifact of the use of series with infilled data
and the convention by which certain networks of proxy data were represented
Other Critics (von Storch, Science; Burger and Cubasch, GRL) detrended proxy data
before calibration
Mann expects that this report will reaffirm ours and other studies leading to the same
common conclusion, that late 20th century warmth is anomalous in this context
James Hansen, NASA/GISS
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Subject of 60 Minutes Interview and New York Times
article on Restrictions by NASA for Scientists to
communicate with Journalists and on having had research
results and reports edited by Bush Administration staff.
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The new NASA guidelines prohibit the editing of reports to
alter scientific data, as well as any public affairs
management of NASA projects by non-agency institutions.
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NASA scientists may draw conclusions from their research
and communicate them to the media, but "must make clear
that they are presenting their individual views — not the
views of the agency — and ask that they be sourced as
such.“ (April 2, 2006)
the new policy is a substantial improvement
– "things have changed dramatically since this became
a public issue ... hopefully similar things will happen
at other agencies that have had problems." (James
Hansen)
Conclusions
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Climate system is inherently noisy, but Trends are Emerging
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Climate Forecasts are based on fundamental principles of Physics, Biology and Chemistry
Climate Change is Associated with many complex feedbacks
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Change can be slow at first, but accelerate later as ice-caps melt, albedo decreases and moisture in the
atmosphere increases
Science is Not Democratic
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We view climate system with multiple tools at multiple time and space scales
Consistent and Repeatable Patterns are Arising
Hypotheses are Rejected and Accepted based on observation and theoretical principles
Policy and Science
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Society is holding Climate Change Scientists to a much Higher Burden of proof than for other economic and
political decisions (eg Weapons of Mass Destruction, War in Iraq, Purchase of stocks and bonds).
It is prudent and pre-cautionary to rely on the ability of scientifically-based models to predict trends through
and out of inherently noisy environmental signals in order to make effective policy
Penny wise versus Dollar Foolish
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The Long-Term costs of responding to unmitigated climate change could far exceed the current savings associated with
doing nothing now(health, governmental stability);
We need to Change How Business is Accounted by Internalizing Externalities.
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The current cost of oil does not reflect the effects of climate change on societies and ecosystems
Climate Skeptics
• Senator James Inhofe, OK
– ‘Global Warming is a Hoax’
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Michael Crichton, Author
– State of Fear
• Patrick Michaels, State Climatologist, Virginia
– "The American people have just been bludgeoned with climate
disaster stories for God knows how long," …"and they're just,
they've got disaster fatigue.“ (ABC News)
– Robert Novak claims that Hansen in 1988 over-predicted global
warming by 400% (a story originated by Pat Michaels and
subsequently propagated by Michael Crichton)
• Fred Singer
Radiative Forcing
Hansen et al 2005 JGR
2x CO2 and ground Temperature
http://www.giss.nasa.gov/cgi-bin/co2hansen.cgi