6/9/2010
NASA image of the atmosphere
1
Public Perception
and
Science
of
Climate Change
Senior Statesmen of Virginia
Robert McGrath
6/9/2010
2
Points to this talk
• State of the politics and public attitude.
• Facts about what humans are doing to the
atmosphere.
• Primer on Climate Science
• Silliness and Hyperbole
• Conclusion
– Brief summary on science and overview of
costs of policy actions
– Thoughts on what needs to happen…
6/9/2010
3
Politics and Public Attitude
•G20 leaders on record as accepting IPCC climate
projections and the need to reduce GHG levels to hold
ΔT to 2 oC (compared to pre- industrial era)
•U.S. political situation: President and House have
declared GHG reduction goals of 20% by 2020 and 83%
by 2050 (compared to 2005).
•House passed resolution (HR2454) last summer; very
heavy slogging ahead in Senate. [Vote on “resolution of
disapproval of EPA findings” tomorrow!]
•Copenhagen (December 2009): confirmed proposals
give ∆T ≈ 4 oC
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Politics/Public Attitude
4
What does the U.S. public think?
Is there solid evidence the earth is warming? (percent
who said YES)
71% (4/08)
57% (10/09)
because of human activity?
Entire sample:
47%
36%
Republicans:
27%
18%
Democrats:
58%
50%
Independents:
50%
33%
Pew Research Center (10/09)
Policy options for addressing climate change? (percent
strongly supporting)
Increased Fossil Fuel Taxes
18%
Increased Gasoline Taxes
10%
Miller Center Survey (9/08)
How does the public know what it thinks?
•Media…loves sound bites, controversy, catastrophe, potential
catastrophes
•Internet…Google “climate change” get 22 million hits! Many of
them for partisan cheerleading and mudslinging… the climate wars!
Alarmists
Skeptics
Fundamentalists
Deniers
Hysterics
Traitors
•Movies… e.g. Al Gore’s An Inconvenient Truth
•Reports… e.g. from IPCC, and U.S. Climate Change Research
Program
•U.S. political leadership… ?
Bottom line…lots of talk such as: “what’s the big deal…it’s been
hotter or colder before, it’s nature”, or “so what does Al Gore
have to say about all this snow?”
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Politics/Public Attitude
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Politics and views on climate science tend to be
correlated
Some striking quotes from politicians:
• The theory of global warming… is a very dangerous theory (Vaclav
Klaus, Czech Rep. 2007)
• They are about to impose a communist world government on the
world. You have a president who has very strong sympathies with that
point of view. (Lord Christopher Monckton 2009)
•
I called the threat of catastrophic global warming the "greatest hoax
ever perpetrated on the American people," a statement that, to put it
mildly, was not viewed kindly by environmental extremists and their
elitist organizations. (James Inhofe Senate floor speech 2005)
• The evidence that humans are causing global warming is
overwhelming and undeniable (Al Gore, An Inconvenient Truth, 2006)
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Politics/Public Attitude
7
Climate scientists:
As advocates/activists…
• The extent of unfounded skepticism… is dangerous…those
who still think this is all a mistake or a hoax need to think
again. (John Holdren 2008)
• There’s enough carbon in the ground to really cook us. (Steven
Chu)
• If there’s no action before 2012, that’s too late…this is the
defining moment. (Rajendra Pachauri 2007)
• Chairmen of fossil-fuel companies should be “tried for high
crimes against humanity and nature.” Freight trains carrying
coal are “death trains.” (James Hansen)
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Politics/Public Attitude
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As (somewhat) inept advocates…
“The IPCC reports have underestimated the pace of
climate change while overestimating societies'
abilities to curb greenhouse gas emissions.”
( from Science Magazine editorial and accompanying photo (5/7/2010))
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Politics/Public Attitude
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“Instantly” substituted illustration
(no Photoshop, from National Geographic)
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Politics/Public Attitude
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CO2: How much do we emit?
Millions of Metric Tons of CO2
from U.S. EPA
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Humans and Atmosphere
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CO2: what happens to it?
Baseline
for most of
Industrial
Age is 280
ppmv)
(from Keeling, Scripps Inst. Of Oceanography)
Humans and Atmosphere
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CO2: how much of what we emit stays in the
atmosphere?
Earth diameter = 8,000 miles, and Atmosphere pressure = 14.7 lbs/sqin
So… atmosphere weighs about 5.9 million billion tons
The weight of the “Human” CO2 adds up to about 2.0 thousand billion
tons
If all this CO2 stayed in the atmosphere, CO2 concentrations would
increase by 220 parts per million (volume)
Conclusion: oceans plus biosphere have absorbed only
about ½ of “human” CO2 up until now.
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Humans and Atmosphere
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Climate science: historical temperature records
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Climate Science Primer
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Climate science: weather, climate and modeling
• Earth’s temperature determined by balance between
incoming solar radiation and outgoing heat radiation.
• GHG’s e.g., CO2, (or H2O) act as “leaky” blanket. Earth’s
average temperature + 16 o C. (-18 oC without GHG’s.)
• Movements of energy and masses of air make weather
and climate:
– equatorial regions get more sun than polar regions,
– land, ice, and water reflect the sun’s energy differently,
– oceans take longer to heat (or cool) than land.
• AOGC Models try to treat the entire coupled system:
atmosphere+ oceans+ land.
– Complicated
– Many approximations!
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Climate Science Primer
15
Model predictions for the next 100 years: how
accurate are they likely to be?
A2 scenario: temps go
up somewhere
IPCC 2007 report (central result)
between 2.0 and 5.4 oC
6/9/2010
Even more fun!
Figure SPM.5
Equilibrium temperature increases somewhere between
oC with the full “dose” of CO .
4.2 and 9.4 Climate
2
Science Primer
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Model predictions for the next 100 years: how
accurate are they likely to be?
• IPCC averages model results to get the so-called
most likely answers.
• These models are darned complicated.
• When CO2 goes up, water vapor (powerful GHG!)
goes up.
• BUT what does the water vapor do?
• The models disagree considerably over the fate of
the extra water vapor.
• Also considerable uncertainty about influence of
human-caused aerosols in the atmosphere.
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Climate Science Primer
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Model predictions for the next 100 years: how
accurate are they likely to be?
Clouds vs. more water vapor… biggest feedback uncertainty
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Climate Science Primer
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Is the recent past temperature record understood?
Slope = 0.7 0C/century
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Climate Science Primer
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Is the recent past temperature record understood?
from Lean and Rind, Geophysical Res. Letters (2009)
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Climate Science Primer
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Silliness and hyperbole
Perpetrators:
Gore movie, media in general, some scientists
 Downplay uncertainties
 Assume warming means human-caused warming.
 Extreme events (e.g. hurricanes) “show” models are right.
Skeptics
 “models aren’t evidence”
 CO2 is “good” for us
 CO2 lag as temperature increases during interglacials (Gore
movie) shows CO2 doesn’t have anything to do with
temperature increase “something else has caused it… the
computer models don’t know what it is.”
 Lack of warming in recent years means global warming is much
ado about nothing or even a hoax.
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Silliness and Hyperbole
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from An Inconvenient Truth (2006)
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Silliness and Hyperbole
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shown in An Inconvenient Truth
(data from NOAA/NCDC)
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Silliness and Hyberpole
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Al Gore showed a version of this:
Hurricane damages (in dollars) by year
from Piekle, Landsea et al. (2007)
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Silliness and Hyperbole
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Adjusted Hurricane damages by year
from Piekle, Landsea et al.
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Silliness and Hyperbole
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Hurricanes striking U.S. mainland
25
20
15
10
5
0
1900-1909 1910-1919 1920-1929 1930-1939 1940-1949 1950-1959 1960-1969 1970-1979 1980-1989 1990-1999
All Categories
6/9/2010
Category 4 & 5
Silliness and hyperbole
from Landsea (NOAA)
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Summary about the science…
We’re in a warming period, but so far not very dramatic.
Observations are consistent with warming being due to
increasing GHG’s.
NAS’s America’s Climate Choices: "Climate change is
occurring, is caused largely by human activities, and
poses significant risks for — and in many cases is already
affecting — a broad range of human and natural systems“
(May 2010)
Model predictions have large uncertainties.
Uncertainties make public decision making and actions
even harder.
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Conclusion
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Policy questions/choices…
Do nothing.
Ask what’s the society cost of transitioning from
fossil fuels to other energy sources compared to the
cost of doing nothing? Escalate the modeling!
Combine models about economics with models
about climate.
Get answers accompanied by more uncertainties.
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Conclusion
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Example results from these combined economics-climate
models
Analysis
Outcome
∆T≤
(oC)
C cost in
2020 per ton
(2005 $)
C cost in
2050 per ton
(2005 $)
Stern (LSE-UK)
1.5
372
594
Nordhaus (Yale)
2.5
48
48
90
Nordhaus
2.0
87
267
2.0
(HR 2454)
15 ↔ 30
Energy
Modeling Forum
(Stanford led)
65 ↔ 135
Gas up 13 ¢ per gallon; electricity up 1.4 ¢ per kw-hr (coal produced)
Nation’s tax bill up 75 B$ [compare 188 B$ imported oil bill (2009)]
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Conclusion
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Thoughts of what needs to happen…
Majority climate science community needs to be candid and
innovative in helping the public understand the situation recognizing:
Evidence of human caused warming up until now is obscure.
There remain huge uncertainties in the modeling (e.g., fate of
water vapor, contribution of human caused aerosols) Warming
over last 100 years is only about 40% of what it would have been
with standard climate “sensitivity” and NO aerosols.
Modeling is essential, improvements in modeling and in data
gathering are making predictions more reliable.
Skeptics have burden to show why the AOGCM’s can safely be
dismissed.
“Outlaw” hyperbole, distortions, silliness, ad hominem arguments
Intelligent public discussion has to be the basis for intelligent
public policy!
Is it possible?
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Conclusion
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Circa early 1950’s:
6/9/2010
2004:
Conclusion
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