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Earth System and Earth System and Climate: Introduction Climate: Introduction
(ESC-I)(ESC-I)
Coordinators: Coordinators:
Dr. Vinu Valsala and Dr. Supriyo ChakrabortyDr. Vinu Valsala and Dr. Supriyo Chakraborty
Short introduction of instructor.•Vinu K. Valsala (Vinu; E-mail:
•PhD in Ocean and Atmospheric Sciences
•Research interests– Climate, Variability and Global warming– Oceanography– Numerical Ocean Modeling– Ocean Biogeochemistry
Contents of ESC-Intro. course:• Earth System Science and Global Climate ChangeG
• Global Energy Balance P
• Global Carbon Cycle C
• Recycling of Elements; C, N, O2, O3 depletion C
• Global Biogeochemical Cycle- oceans C/B
• Short-term Climate variability, Global Warming P/C/BShould be covered in 7-hours
Text books:• Lee R. Kump, J. F. Kasting and R. G. Crane, 2010:
The earth systems, Prentice-Hall Inc, pages-420 (*** Exams will be based on this; copies please make
available in Library).
• A. E. Gill, 1980, Atmosphere and Ocean Dynamics, (Chapter-1 to 4), Int. Geo. Series, Vol.30.
• Sarmiento G. L., and N. Gruber, 2007, Ocean Biogeochemical Dynamics, Princeton. Univ. Press, pages-530.
• IPCC-AR4, 2007, Climate Change, The Physical Science Basis, Chapter-2, Technical Summary. PDF copy available at http://www.ipcc.ch/publications_and_data
Other materials:
• Please prepare class notes by yourself.
• We will provide you our ppt slides (in a common server)
• No DICTATION of class notes (you are grown enough for this introductory course !)
• Assignments/Quiz, – computer exercises of plotting the data,
interpretations.
Examinations and evaluation
Type Time Marks
Mid-term exam 2nd month of the class
30%
Final-term 4th month of the class
50%
Assignments/Quiz Two/Three times
20%
Total 100%
Let’s Start!
C
10-7100 102 103 105
ν107 1010
μ meter km galactic
νμ
minuteshours
days
years
k-years
galactic
Daily lifeSunny/Rain
Planets,Moon,stars
An year/1000 km
Climate
Earth system and climate:- A space-time perspective
Life
-zon
e
k-km
Weather: day-to-day states of the Atmosphere (environment)
Climate: A long term average of the states of the atmosphere.
Terminologies to remember: Geometry of earth
Latitude;90s~90n
Longitude;180w~180e or00 ~ 3600
Equator = 00
EastWest
North pole
South pole
Some useful quantities to rememberShape of the earth: Oblate spheroid
Image courtesy : Wikipedea
Radius of the earth: 6371 Km (6378.14 - 6356.8)Mass of the earth: 5.977x1024 KgAverage density = 5517 kg/m3Rotation speed = 0.729x10-4 rad/secAverage surface temperature = 288K, (150C)
Regional characterizations:
• Tropics• Sub-tropics• Mid-latitude• Polar
Tropical climateTemperate ClimatePolar Climate
Weather and Climate.
01-Augst to 08-August temperatures over a Particular location Weather
Weather representsday-to-day variationsin our atmosphere
Climate is a long termaverage of weather (100-years, 1000-years,50years, 30 years)
Major three themes that we address in this course is.
• The earth system itself, as a combination of Biota, Atmosphere, Hydrosphere and Solid
Earth.
• What causes current global climate change
• Climate is changing ever since the earth is formed 4.6 billion years ago. There are
episodic ice-ages and interglacial warmperiods. So, if the current climate is not warmed by humans, are we going back to ice-ages?
Schematics of earth system
Schematics showing interactions between various Components of Earth system.
Global Climate change.
Evidences of global change on short time scales.
Global average observed surface temperature trend
From IPCC Assessment Report 4 (AR-4), 2007
What causes in global temperature change in last 100 or 200 years?
• Are they part of any natural change?• Are they induced by humans (Anthropogenic?)
• Anthropogenic causes of climate change
• Fossil fuel burning• Deforestation • Ozone layer depletion
• What are the natural reasons for climate change?
The Green house effect.
Earth
Sun
Short w
ave
Long w
ave
(hea
t)
GH-effect helpsthe surface Temperature tobe warm at 150C
= CO2 and Other GH-gases
The status of present day green house gases and radiation budget.
Gas 1765
1992 Current rate of increase (% per year)
Pre-industrial
Anthropogenic
CO2 278 356 0.4 50 1.4
CH4 0.7 1.71 0.6 1.1 0.48
CFC-11 0.0 0.000268 0.0 0.0 0.07
N2O 0.275
0.31 0.25 1.25 0.15
Concentration (ppm)Radiative forcing (w/m2)
Sarmiento and Gruber, 2007, Ocean BGC Dyn.,
Radiative forcing per additional molecule relative to the radiative forcing due to one additional molecule of CO2.
Gas Relative Forcing
CO2 1
CH4 21
N2O 206
CFC-11 12,400
Addition of CH4 has more impact than addition of CO2.
Addition of N2O has more impact than addition of CH4
Present day CO2; Keeling curve.
© http://en.wikipedia.org/wiki/File:Mauna_Loa_Carbon_Dioxide-en.svg
Atmospheric CO2 from 1700 to 2010
But ~50% of man-made CO2 is absorbed by oceans and land.
50 % 20 %
30 %
Oceans sink ~30% ofanthropogenic CO2
Terrestrial ecosystemabsorbs ~ 20% of anthropogenic CO2.
Annual mean CO2 sinks and sources by terrestrial biospheres (~2 PgC/yr)
CarbonTracker data from ESRL, NOAA, USA.
Annual mean CO2 sinks and sources by the ocean (~2PgC/yr)
Shamil et al., 2012, Atm. Chm. Phy. Discussions
1990 2000 20101980
10
15 G
ram
Carb
on
/year
CO2 exchange between ocean & atmosphere, data developed at NIES, Japan.
Valsala et al.,2010, Tellus-B,- 1.5x1015 gC/yr
Global warming or Global Cooling ?
IPCC-AR4 report, 2007 Schematic
Human impacts on famines and mass deaths…(Ethiopian famine)
Normal
1984-85
Ethiopia
Long term climate change: by Natural causes (observed- for 1 million years)
0100-k300-k500-k700-k
Kilo-years
CO2
Petit et al,1999, Nature
T-Pro
xy
Higher CO2 leads to Higher temperaturesLower CO2 leads to lower temperatureBut what causes variations in CO2 ?Earth system as a self-regulatory system.
What are the natural causes of long term climate change? Milankovitch cycles (periodic)
Precision 19-23 k-yrs
Tilt 41-42 k-yrs
Eccentricity100-400 k-yrs
What are other natural causes of radiation budget change? (aperiodic)
0
50
100
150
200
250
300
350400
Mill
ion
s of
years
ag
o
Devonian
Carboniferous
Permian
Triassic
Jurassic
Cretaceous
Quaternary0
15
30
45
60
Quaternary
Miocene
Oligocene
Eocene
Paleocene
1
2
4
6
8
Pleistocene
Miocene
Pliocene
Pliocene
Continental drifts
Climate Humanevolution
= eradication of life;Are we driving nexteradication?
Tertiary