Earth System and Climate: Introduction (ESC-I) Coordinators: Dr. Vinu Valsala and Dr. Supriyo Chakraborty.

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:

[email protected])

•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