Transcript Climate Change - Day 1

Climate Change
Learning Goals for the Module:
1) Uncertainty
2) Historical development of the idea
(hypotheses->theory->public acceptance)
3) Numerical modeling (Theoretical way of
knowing)
4) Holistic science & systems thinking
5) Science interaction with Society
Uncertainty
-Uncertainty is always with us and can never
be eliminated from our lives. Our
understanding of the past and our
anticipation of the future will always be
obscured by uncertainty.
-All decisions about the future, big and small,
must be made in the absence of certainty.
Waiting until uncertainty is eliminated before
making decisions is always an implicit
endorsement of the status quo, and often an
excuse for maintaining it.
Image from Google Books.
-As the future unfolds, “mid-course
corrections” can be made that take into
account new information and new
technology.
-Uncertainty, far from being a barrier to
progress, is actually a strong stimulus for and important ingredient of - creativity.
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IPCC: Critical aspects
Validation - assessment of the accuracy of
the model
Attribution - the ability to assign causes to
effects (distinguish causation from
correlation)
Prediction - specification, in advance, of
events or changes in a system
Relevance
*******************************************
* SCIENCE ALERT
* An E-mail Service of the NewsHour with Jim Lehrer
* and the Online NewsHour
*******************************************
November 19, 2007
* U.N. CLIMATE CHANGE REPORT
The United Nations Intergovernmental Panel on Climate Change
(IPCC) released its fourth and final report this week. The world
will have to stop greenhouse gas emissions growth by 2015, and
reduce emissions by up to 85 percent over the next 40 years, in
order to avoid the worst effects of global warming, the panel found.
The report will provide the basis for U.N. climate talks in Bali in
December.
For more NewsHour climate change coverage, visit
www.pbs.org/newshour/indepth_coverage/science/globalwarming.
Scientific Ways of Knowing
Induction -> Approach is observing (Empiricists)
1. Natural Observation – observation of natural system
without manipulation
2. Experimentation – observation of natural system with
manipulation
Deduction -> Approach is modeling (Theoreticians)
1. Numerical modeling –quantitative models designed to
make predictions of geometry or behavior of natural
systems
Historical Approach to Climate Change
Historical approaches illustrate that multiple
ways of knowing are used to investigate and
determine scientific phenomena, and
emphasize the Nature of Science.
Chronology based on Weart (2008).
Today’s protagonist: CO2
-A molecule of two atoms of
Oxygen and one atom of Carbon
I kind of look like
Princess Lea
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Image from Wikipedia.
Nature of Science: The social contexts within which science is conducted, or the “values and
beliefs inherent to the development of scientific knowledge”.
This definition explicitly includes the following: 1) Science is tentative and subject to change; 2)
Science is influenced by social and cultural norms; and 3) Science is the product of human
imagination and creativity.
Process of Scientific Inquiry: The diverse ways in which scientists study the natural
world and propose explanations based on the evidence derived from their work (i.e., what
scientists do).
This definition encompasses the multiple “ways of knowing”: Observation,
experimentation, analysis and simulation/modeling are legitimate ways in which
researchers gather evidence to pursue scientific questions. There is no single “scientific
method”. Scientific inquiry includes evaluation of these lines of evidence, analyzing and
interpreting different forms of data (both qualitative and quantitative).
Climate Change
Historical Approach
Early research on climate was concerned
about the cause of ice ages, not whether the
climate change was occuring.
Today’s protagonist: CO2
-A molecule of two
atoms of Oxygen
and one atom of
Carbon dioxide
I kind of look like
Princess Lea
Image from Wikipedia.
Frankly, my
dear, they just
don’t make
them like they
used to.
1783: A fellow named Benjamin Franklin casually noticed that volcanic
eruptions cools climate.
Hmmmmmm
Image from Wikimedia Commons.
He was also known to
do other scientific things
that were not so smart.
Image from Wikimedia Commons.
CO2 in the atmosphere: ~280 ppm
ppm = parts per million
CO2 Concentration (ppm)
1783
310
305
300
295
290
285
280
275
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960
Year
The Scottish physician Joseph Black had just shown the
gas to exist 30 years earlier.
No one had any idea how much of it was in the air.
Note that this data is from
ice cores, which we’ll talk
11
about soon
1837
Louis Aggasiz (zoologist,
technically an ichthyologist)
proposes that huge areas of
Europe were once covered by ice,
and that the Earth experienced Ice
Ages
Image from NASA Earth Observatory,
courtesy of National Snow and Ice Data
Center Glacier Photo Collection.
Image from Wikipedia.
Jean de Charpentier (1786-1855)
Image from Wikimedia Commons, courtesy of Haeferl.
Schimper proposed that ice lay over not
just the Swiss Alps, but over much of
Europe, Asia, and North America. Called
this Eiszeit (or Ice Age).
Swiss Alps. Photo from Wikimedia Commons.
Image from Wikipedia.
Karl Schimper
I completely gave up studying fossil
fish when I realized I could utilize (i.e.,
swipe) the idea of continental
glaciation.
Image derived from Wikimedia Commons.
Jean Louis Rodolphe Agassiz (1807-1873)
Northern hemisphere glaciation during the last ice ages.
Image from Wikipedia, courtesy of Hannes Grobe/AWI.
Image removed due to
copyright: Reconstruction of the
maximum extent of Wisconsin
ice sheets in North America-20,000 to 14,000 years ago.
Image available from
Geospectra.net.
Agassiz was a celebrity in the US, had a chair at
Harvard, and had one of the largest glacial
features - Freshwater Lake Agassiz - named after
him.
Ya-hoo, I’ve got part of
North Dakota named
after me.
Image from “Georgiabeforepeople” wordpress blog.
Image from Wikimedia Commons.
Three stages of
scientific discovery:
1) People deny it is
true;
2) They then deny it
is important; and
3) They finally credit
the wrong person.
Crazed, hunchback stature
Image from Wikimedia Commons.
Alexander von Humboldt
Image from Wikimedia Commons.
1837
Carbon dioxide in the atmosphere: ~285 ppm
Charles Thilorier described solid carbon dioxide
three years earlier (1834). He opened a
pressurized container of liquid carbon dioxide to
find "snow" of solid CO2.
No one had any idea how much of it was in the air.
But, people wondered, why did ice ages happen?
Hmmm..
In 1870, Croll (an ex-janitor) proposed that
slight variations in the Earth’s orbits might
explain the ice ages.
This was a superb insight, but it needed
some qualitative analysis. This is going to
have to wait for a while.
Image removed
for copyright:
“The janitor of
Oz” cartoon
Image from Wikimedia Commons.
James Croll (1879-1958)
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1870
CO2 in the atmosphere: ~287 ppm
CO2 Concentration (ppm)
310
305
300
295
290
285
280
275
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960
Year
No one is thinking about how much of it is in the air.
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1896 - A big year for climate change science
In 1896, Svante
Arrhenius (a chemist)
realizes that humans
are producing CO2 at a
geological rate. He
published first
prediction of how
human production of
CO2 would affect the
global climate.
He was, within error, of
the value in the 2007
IPCC report.
Not bad for a guy who
likes Swedish meatballs.
Image from Wikimedia Commons.
Svante Arrhenius
1896? The problem was
recognized in 1896?
Well, yes and no. The scientific community
did not really accept this idea, which was
way, way ahead of its time.
I’m skeptical
I think the measurements to prove
this haven’t been done
Doesn’t sound like
such a bad idea, even if
it is true.
1896
CO2 in the atmosphere: ~290 ppm
CO2 Concentration (ppm)
310
305
300
295
290
285
280
275
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960
Year
One guy in Sweden is thinking that maybe people are adding
some of this to the atmosphere.
There is no reliable measurement of it and attempts to
measure it (in Europe) have large amounts of variability.
25
In 1897, T.C.
Chamberlin
(geologist) produced
a model for global
carbon exchange
including feedbacks.
He is beginning to
think in a different
way (feedbacks, not
just control of one
I had streets and
variable).
buildings named after
me in Madison.
Go Badgers.
Image from the Wisconsin Electronic Reader.
UW’s own…..
T.C. Chamberlin
1896-7
Carbon dioxide in the atmosphere: ~290 ppm
One guy in Sweden is thinking that maybe people
are adding some of this to the atmosphere.
There is no reliable measurement of it and attempts
to measure it (in Europe) have large amounts of
variability.
1914-1918: World War I
Photo from Wikipedia.
It is not a good war to be Serbian, in the AustroHungarian empire. Milankovic, a Serbian engineer, is
effectively put under house arrest rather than in prison,
because Austrian scientists argue on his behalf. But,
making the best of things, Milankovic decides to pick up
Croll’s idea of orbital variations causing ice ages.
This is a very good thing
for the science of climate
change.
Image from Wikimedia Commons.
Милутин Миланковић (1879-1958)
(that’s Milutin Milanković to you and me)
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Milankovic formulates an idea about orbital variations
and then spends 20 years working out the mathematics
(with his trusty slide rule) of three possible variations in
the Earth’s orbit.
I’m crazy
about my
slide rule
Image from Wikimedia Commons.
Image from Wikimedia Commons.
SI?
Voila, le slide rule
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Image from Encyclopedia of Earth, originally from UCAR.
Eccentricity - variation of Earth’s orbit from
a circle
100,000 yr (eccentricity) cycle
Axial tilt - variation of rotation axis of
Earth from 22.1° to 24.5°
(presently at 23.4°)
41,000 yr (axial tilt or obliquity) cycle
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Image from Wikipedia, courtesy of Maksim.
Precession of the equinoxes - the change in the direction of the Earth's axis of rotation
relative to the Sun at the time of being closest and farthest from the sun in its orbit.
23,000 yr (precession) cycle
32
Here’s the
prediction
I say that the
20,000 year cycle is most
important.
(and missing WW I was
fabulous)
Image from Wikimedia Commons.
23,000 yrs
41,000 yrs
100,000 yrs
Cycles of: 23,000 (precession), 41,000 (axial tilt or obliquity),
and 100,000 (eccentricity) yrs
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Images from Wikipedia.
Graph from Wikipedia, courtesy of NASA.
In 1930, he publishes the
results.
Do people accept it? There is general
acceptance that it happens, but there is
not acceptance that it does anything to
affect the climate.
I’m skeptical
I think the measurements to prove
this haven’t been done
Such a small variation in
solar input could never
cause a change in
climate.
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1930
CO2 in the atmosphere: ~297 ppm
CO2 Concentration (ppm)
310
305
300
295
290
285
280
275
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960
Year
Scientists still don’t accept Arrhenius’ idea.
There is no reliable measurement of CO2 in Earth’s
atmosphere.
35
1938: A hypothesis is born
Callender proposes that
anthropogenic (human-induced)
global warming is underway.
How did he know -> Natural
Observation (Empirical).
Callendar, an engineer
who did meteorology
as a hobby, documents
rise in temperature and
a 10% rise in CO2.
Callendar argues that
CO2 greenhouse
global warming is
underway, reviving
interest in the question.
The University of Chicago Press
Human-induced greenhouse
warming
Hypothesis
(1896)
Hypothesis
(1938)
Image from Wikimedia Commons.
The University of Chicago Press
Svante Arrhenius
Callendar
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1938
CO2 in the atmosphere: ~305 ppm
CO2 Concentration (ppm)
310
305
300
295
290
285
280
275
1760 1780 1800 1820 1840 1860 1880 1900 1920 1940 1960
Year
There is no reliable measurement of CO2 in Earth’s
atmosphere.
There are still no climate scientists. This is a hobby or
sidelight for those in other fields.
39
A small aside - What’s the
deal with CO2 and why is it a
“greenhouse” gas?
With the added bonus of understanding
how your microwave works
Image from Wikimedia Commons, originally from NASA.
Image from Wikimedia Commons, originally from NASA.
Image removed due to copyright:
Electromagnetic radiation is self-propagating.
See original image from University of Oregon.
Image by Robert A. Rohde from Wikimedia Commons.
Image removed due to copyright: Carbon Dioxide
infrared absorption. Image available from
Elmhurst.edu.
Resonant frequency
http://www.youtube.com/watch?v=HxTZ446t
bzE
Yea, I sort of figured resonance out too.
Image from Wikimedia Commons
1939
At international meeting,
community of scientists agree that
the problem of ice ages is too
difficult to solve with the tools at
hand.
The idea of ice ages, not global
warming, is still the principal
scientific focus.
1939-1945: World War II
Image from Wikimedia Commons.
1945
Geologists discover
varves (yearly changes
in deposition) that
indicate changes in
climate occur every
~20,000 years.
That sounds
very
familiar.
Varved Clays, Whitefish Bay. Image by Ron Schott.
48
Image from Wikimedia Commons.
1945
CO2 in the atmosphere:
~310 ppm
CO2 Concentration (ppm)
324
322
320
318
316
314
312
310
308
1940 1945 1950 1955 1960 1965 1970 1975 1980
Year
People care about the World War II ending
49
1955
She sells sea shells
by the sea shore.
Cesare Emiliani (1922-1995),
Geochemist
He used the newly established technique of
investigating different isotopes of oxygen
(Oxygen-18 vs. Oxygen-16). By measuring
how much of these two different isotopes
there is, one can determine the temperature
at which sea shells (like a clam) grew.
(Photo: Archives of the Rosenstiel School of Marine and
Atmospheric Science, University of Miami) From Wikipedia.
50
Vostok Ice Core, Antarctica
Here’s the amazing thing:
You can get past
atmospheric air composition
from ice cores (trapped air
bubbles).
Photo from NOAA
Top of core
TIME
Bottom of core
51
From the Vostok and EPICA (Antarctica) and NGRIP (Greenland) ice cores: d18O, last 140kyr.
Image from Wikipedia, courtesy of William Connolley.
Looking at fossil shells in a core,
he looked back over 1,000,000
years of geologic time and
realized that there are lots of ice
ages, that they happened every
100,000 years.
1955
This meant that Milankovic was
right about variations in Earth’s
orbits causing major climate
changes, but wrong about which
orbital variation was the most
important.
Drat.
(Photo: Archives of the Rosenstiel School of Marine and
Atmospheric Science, University of Miami) From Wikipedia.
52
Image from Wikimedia Commons.
1955
Drat.
It turns out that Emiliani was also wrong in
detail. He was completely sure that the
Oxygen isotope record provided
temperatures. It turns out that it does not – it
provides an estimate of the evaporation from
the ocean, because the heavier Oxygen-18
sticks around in the ocean when there are
large ice sheets.
Another great example of how scientists can
be wrong in detail, but very useful.
(Photo: Archives of the Rosenstiel School of Marine and
Atmospheric Science, University of Miami) From Wikipedia.
From the Vostok and EPICA (Antarctica) and NGRIP (Greenland) ice cores: d18O, last 140kyr.
Image from Wikipedia, courtesy of William Connolley.
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