Post on 23-Dec-2015
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.
-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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Image from Google Books.
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).
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Today’s protagonist: CO2
-A molecule of two atoms of Oxygen and one atom of Carbon
I kind of look like Princess Lea
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
Frankly, my dear, they just don’t make them like they used to.
Image from Wikipedia.
1783: A fellow named Benjamin Franklin casually noticed that volcanic eruptions cools climate.
Hmmmmmm
He was also known to do other scientific things that were not so smart.
Image from Wikimedia Commons.
Image from Wikimedia Commons.
1783
CO2 in the atmosphere: ~280 ppm
ppm = parts per million
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 about soon 11
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
Jean de Charpentier (1786-1855)
Image from Wikipedia.
Image from Wikimedia Commons, courtesy of Haeferl.
Image from NASA Earth Observatory, courtesy of National Snow and Ice Data Center Glacier Photo Collection.
Karl Schimper
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.
Jean Louis Rodolphe Agassiz (1807-1873)
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.
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.
Ya-hoo, I’ve got part ofNorth Dakota named after me.
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.
Image from “Georgiabeforepeople” wordpress blog.
Image from Wikimedia Commons.
Alexander von Humboldt
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.
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.
James Croll (1879-1958)
But, people wondered, why did ice ages happen?
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.
Hmmm..
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Image from Wikimedia Commons.
Image removed for copyright: “The janitor of Oz” cartoon
1870
CO2 in the atmosphere: ~287 ppm
No one is thinking about how much of it is in the air.
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Svante Arrhenius
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.
1896 - A big year for climate change science
Image from Wikimedia Commons.
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
Doesn’t sound likesuch a bad idea, even if it is true.
I think the measurements to prove this haven’t been done
1896
CO2 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.
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T.C. ChamberlinUW’s own…..
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 variable). I had streets and
buildings named after me in Madison.
Go Badgers. Image from the Wisconsin Electronic Reader.
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.
Милутин Миланковић (1879-1958)
(that’s Milutin Milanković to you and me)
It is not a good war to be Serbian, in the Austro-Hungarian 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.
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Image from Wikimedia Commons.
I’m crazy about my slide rule
Voila, le slide rule
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.
30SI?
Image from Wikimedia Commons.
Image from Wikimedia Commons.
Axial tilt - variation of rotation axis of Earth from 22.1° to 24.5° (presently at 23.4°)
Eccentricity - variation of Earth’s orbit from a circle
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100,000 yr (eccentricity) cycle
41,000 yr (axial tilt or obliquity) cycle
Image from Encyclopedia of Earth, originally from UCAR.
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.
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23,000 yr (precession) cycle
Image from Wikipedia, courtesy of Maksim.
Cycles of: 23,000 (precession), 41,000 (axial tilt or obliquity), and 100,000 (eccentricity) yrs
I say that the20,000 year cycle is most important.(and missing WW I was fabulous)
Here’s the prediction
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23,000 yrs
41,000 yrs
100,000 yrs
Images from Wikipedia. Graph from Wikipedia, courtesy of NASA.
Image from Wikimedia Commons.
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
Such a small variation in solar input could never cause a change in climate.
I think the measurements to prove this haven’t been done
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1930
CO2 in the atmosphere: ~297 ppm
Scientists still don’t accept Arrhenius’ idea.
There is no reliable measurement of CO2 in Earth’s atmosphere.
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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)
Svante ArrheniusCallendar 38
The University of Chicago PressImage from Wikimedia Commons.
1938
CO2 in the atmosphere: ~305 ppm
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.
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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=HxTZ446tbzE
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.
48Image from Wikimedia Commons.
Varved Clays, Whitefish Bay. Image by Ron Schott.
1945
CO2 in the atmosphere:
~310 ppm
People care about the World War II endingYear
1940 1945 1950 1955 1960 1965 1970 1975 1980
CO
2 C
once
ntra
tion
(ppm
)
308
310
312
314
316
318
320
322
324
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1955
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.
She sells sea shells by the sea shore.
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(Photo: Archives of the Rosenstiel School of Marine and Atmospheric Science, University of Miami) From Wikipedia.
Vostok Ice Core, Antarctica
Top of core Bottom of coreTIME
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Here’s the amazing thing: You can get past atmospheric air composition from ice cores (trapped air bubbles).
Photo from NOAA
From the Vostok and EPICA (Antarctica) and NGRIP (Greenland) ice cores: d18O, last 140kyr. Image from Wikipedia, courtesy of William Connolley.
1955Looking 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.
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.
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Image from Wikimedia Commons.
(Photo: Archives of the Rosenstiel School of Marine and Atmospheric Science, University of Miami) From Wikipedia.
1955It 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.
Drat.
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(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.