lecture1 aug28-bb
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Logistics
Textbook: The Earth System (3rd ed.) by L. R. Kump, J. F. Kasting, and R. G. Crane.
Available at the Campus Bookstore at Queens College Student Union.
You are welcome to look online for a cheaper version of this text.
Office Hours: Friday: 2:00-3:00 PM(Also available by appointment!)
Email: cyi@qc.cuny.edu Telephone: 718-997-3366Office: E-222 Science Bldg
More LogisticsGrading: Homework 15%, 2 exams (20% each), Final Exam 30%, Class Participation 15% Homeworks: Homework sets (~three sets) distributed and collected at the start of the lecture.
Exams: 2 in-class + cumulative, closed-book final
The secret to success in this course: is to attend every lecture, focus on my lecture notes and homework, ask questions, and answer my questions.
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Exam policy Midterms – multiple choice plus essay
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Makeup exam will be all essay that will be harder than the regular exams.
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5
Tree’s Lecture 1Gaia’s HypothesisGlobal warming
GAIA HYPOTHESIS
• the idea of the Earth as a single living superorganism
• James Lovelock• Gaia - a new look
at life on Earth, Oxford University Press, 1979.
The whole idea is:
The Earth as a single living superorganism that biosphere, the atmosphere, the lithosphere and the hydrosphere are in some kind of balance -- that they maintain a homeostatic condition.
This homeostasis is much like the internal maintenance of our own bodies; processes within our body insure a constant temperature, blood pH, electrochemical balance, etc.
The Gaia Hypothesis:
1) Earth is a self-regulating system
2) The system includes both life and the physical world
3) The system is capable of maintaining a surface environment that is suitable for life
We will use a model to understand and practice this theory in next a few lectures.
• Let’s first think about more immediate and practical questions, especially the topic of human-induced global warming
• To get us thinking about this, let’s consider what has happened the past two summer…
Global Warming
US summer heat wave smashes records– July 12, 2011
http://thewatchers.adorraeli.com/2011/07/31/wild-us-summer-heat-wave-smashes-records/
• Graph shows high daily temperature on July 12, 2011• 1,479 daily U.S. temperature records were broken in the month of July
http://www.businessinsider.com/texas-drought-2011-08
• In addition, the state of Texas was hit with its worst drought ever• Although there is no assurance that this drought has been self-induced, --indeed, it is blamed mostly on La Niña--this is precisely the kind of thing that is predicted to happen as the global climate warms
1945 1955 1965 1975 1985 1995 2005 20156.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
Year
Land
ave
rage
tem
pera
ture
(oC
)
PDSI
(Yi et al., 2013)
Land
Land warming
Land warming
Land dryingLand drying
PDSI = Palmer Drought Severity Index
What cause global warming?
CO2 typically hits a seasonal peak in the Northern Hemisphere
Atmospheric CO2 levels have never been as high as they are now during at least the past 800,000 years.
Atmospheric CO2 levels have never been as high as they are now during at least the past 800,000 years.
Atmospheric CO2 has seasonally approached 400 PPM on May 2, 2013!
Atmospheric CO2 has seasonally approached 400 PPM on May 2, 2013!
9.7±0.5PgC
Source: Peters et al. 2012a; Le Quéré et al. 2012; CDIAC Data; Global Carbon Project 2012
Fossil and Cement Emissions
Fossil fuel emissions
Land use
Fossil fuel emissions
Land use
How to divide this carbon cake by the
air, ocean and land?
How to divide this carbon cake by the
air, ocean and land?
Fossil fuel emissions
Land use
Fossil fuel emissions
Land use
Fossil fuel emissions
Land use
Fossil fuel emissions
Land use
Which part is more uncertain?
Which part is more uncertain?
Global Carbon Budget
The dashed land-use change line does not include management-climate interactions
The land sink was a source in 1987 and 1998 (1997 visible as an emission)Source: Le Quéré et al. 2012; Global Carbon Project 2012
Greatest variation in land carbon sink
Source: Le Quéré et al. 2012; Global Carbon Project 2012
Steadily increasingSteadily increasing
Huge fluctuation in land carbon sink!
Huge fluctuation in land carbon sink!
Hence atmospheric CO2Hence atmospheric CO2
What controls land carbon sink?
What controls land carbon sink?
Do these climate changes affect the net ecosystem exchanges of CO2 (NEE)?
We need find evidence from observations!!!
CarbonCO2
ClimateT
positive coupling
Positi ve or negati ve?
The temperature at northern-high latitudes will be increased much more than others near the end of 21th
century, as predicted by many climate models (IPCC, 2007)
Warming in the 21st Century
High latitudes
Projected decreases in precipitation are likely in most subtropical land regions near the end of 21th century, as
predicted by many climate models (IPCC, 2007)
Drying in the 21st CenturyLow latitudes
Eddy Flux Tower
CO2 H2O
CH4 T
CO2 H2O
CH4 TCO2 H2O
CH4 T
Eddy-Flux Tower
Does Climate Control NEE?
30
What are drivers of the vegetation distribution?
http://www.ncdsnet.net/~kinney/library/biome2.gif
Why so little carbon is here?
Too dry!!!
Why so much carbon is here?
Abundant rain and energy!
6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
Photosynthesis
Using light converts carbon and water into sugars
Autotrophic respiration (plants respiration)
Heterotrophic respiration (soil respiration)
RespirationOrganic matter is converted back into CO2
Atmosphere
Biosphere
Photosynthesis
Photosynthesis > Respiration
Respiration
The ecosystem acts as A Carbon Sink
Atmosphere
Biosphere
Photosynthesis
Photosynthesis < Respiration
Respiration
The ecosystem acts as A Carbon Source
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